1.
Saudi Arabia
–
Saudi Arabia is bordered by Jordan and Iraq to the north, Kuwait to the northeast, Qatar, Bahrain and the United Arab Emirates to the east, Oman to the southeast and Yemen to the south. It is separated from Israel and Egypt by the Gulf of Aqaba and it is the only nation with both a Red Sea coast and a Persian Gulf coast and most of its terrain consists of arid desert and mountains. The area of modern-day Saudi Arabia formerly consisted of four regions, Hejaz, Najd and parts of Eastern Arabia. The Kingdom of Saudi Arabia was founded in 1932 by Ibn Saud and he united the four regions into a single state through a series of conquests beginning in 1902 with the capture of Riyadh, the ancestral home of his family, the House of Saud. Saudi Arabia has since been a monarchy, effectively a hereditary dictatorship governed along Islamic lines. The ultraconservative Wahhabi religious movement within Sunni Islam has been called the predominant feature of Saudi culture, with its global spread largely financed by the oil and gas trade. Saudi Arabia is sometimes called the Land of the Two Holy Mosques in reference to Al-Masjid al-Haram and Al-Masjid an-Nabawi, the state has a total population of 28.7 million, of which 20 million are Saudi nationals and 8 million are foreigners. The states official language is Arabic, petroleum was discovered on 3 March 1938 and followed up by several other finds in the Eastern Province. Saudi Arabia has since become the worlds largest oil producer and exporter, controlling the second largest oil reserves. The kingdom is categorized as a World Bank high-income economy with a high Human Development Index and is the only Arab country to be part of the G-20 major economies. However, the economy of Saudi Arabia is the least diversified in the Gulf Cooperation Council, the state has attracted criticism for its treatment of women and use of capital punishment. Saudi Arabia is an autocracy, has the fourth highest military expenditure in the world. Saudi Arabia is considered a regional and middle power, in addition to the GCC, it is an active member of the Organisation of Islamic Cooperation and OPEC. Following the unification of the Hejaz and Nejd kingdoms, the new state was named al-Mamlakah al-ʻArabīyah as-Suʻūdīyah by royal decree on 23 September 1932 by its founder, Abdulaziz Al Saud. Although this is translated as the Kingdom of Saudi Arabia in English it literally means the Saudi Arab kingdom. Its inclusion expresses the view that the country is the possession of the royal family. Al Saud is an Arabic name formed by adding the word Al, meaning family of or House of, in the case of the Al Saud, this is the father of the dynastys 18th century founder, Muhammad bin Saud. There is evidence that human habitation in the Arabian Peninsula dates back to about 125,000 years ago
Saudi Arabia
–
Abdul Aziz
Ibn Saud, the first king of Saudi Arabia
Saudi Arabia
–
Flag
Saudi Arabia
–
Saudi Arabia political map
Saudi Arabia
–
Saudi Arabian administrative regions and roadways map.
2.
Product (chemistry)
–
Products are the species formed from chemical reactions. During a chemical reaction reactants are transformed into products after passing through an energy transition state. This process results in the consumption of the reactants, when represented in chemical equations products are by convention drawn on the right-hand side, even in the case of reversible reactions. The properties of such as their energies help determine several characteristics of a chemical reaction such as whether the reaction is exergonic or endergonic. Additionally the properties of a product can make it easier to extract and purify following a chemical reaction, reactants are molecular materials used to create chemical reactions. The atoms arent created or destroyed, the materials are reactive and reactants are rearranging during a chemical reaction. Here is an example of reactants, CH4 + O2, a non-example is CO2 + H2O or energy. Much of chemistry research is focused on the synthesis and characterization of beneficial products, as well as the detection, other fields include natural product chemists who isolate products created by living organisms and then characterize and study these products. The products of a chemical reaction influence several aspects of the reaction, if the products are lower in energy than the reactants, then the reaction will give off excess energy making it an exergonic reaction. Such reactions are thermodynamically favorable and tend to happen on their own, if the kinetics of the reaction are high enough, however, then the reaction may occur too slowly to be observed, or not even occur at all. If the products are higher in energy than the reactants then the reaction will require energy to be performed and is therefore an endergonic reaction. Additionally if the product is less stable than a reactant, then Lefflers assumption holds that the state will more closely resemble the product than the reactant. Ever since the mid nineteenth century chemists have been preoccupied with synthesizing chemical products. Much of synthetic chemistry is concerned with the synthesis of new chemicals as occurs in the design and creation of new drugs, in biochemistry, enzymes act as biological catalysts to convert substrate to product. For example, the products of the enzyme lactase are galactose and glucose, S + E → P + E Where S is substrate, P is product and E is enzyme. Some enzymes display a form of promiscuity where they convert a single substrate into multiple different products and it occurs when the reaction occurs via a high energy transition state that can be resolved into a variety of different chemical products. Some enzymes are inhibited by the product of their reaction binds to the enzyme and this can be important in the regulation of metabolism as a form of negative feedback controlling metabolic pathways. Product inhibition is also an important topic in biotechnology, as overcoming this effect can increase the yield of a product, Chemical reaction Substrate Reagent Precursor Catalyst Enzyme Product Derivative Chemical equilibrium Second law of thermodynamics
Product (chemistry)
–
Conversation of the
disaccharide sugar
lactose (substrate) to
monosaccharide sugars (products) by
lactase (enzyme)
3.
Petroleum
–
Petroleum is a naturally occurring, yellow-to-black liquid found in geological formations beneath the Earths surface, which is commonly refined into various types of fuels. Components of petroleum are separated using a technique called fractional distillation and it consists of hydrocarbons of various molecular weights and other organic compounds. The name petroleum covers both naturally occurring unprocessed crude oil and petroleum products that are made up of refined crude oil. A fossil fuel, petroleum is formed when large quantities of dead organisms, usually zooplankton and algae, are buried underneath sedimentary rock, Petroleum has mostly been recovered by oil drilling. Drilling is carried out studies of structural geology, sedimentary basin analysis. Petroleum is used in manufacturing a variety of materials. Concern over the depletion of the earths finite reserves of oil, the burning of fossil fuels plays the major role in the current episode of global warming. The word petroleum comes from Greek, πέτρα for rocks and Greek, the term was found in 10th-century Old English sources. It was used in the treatise De Natura Fossilium, published in 1546 by the German mineralogist Georg Bauer, Petroleum, in one form or another, has been used since ancient times, and is now important across society, including in economy, politics and technology. Great quantities of it were found on the banks of the river Issus, ancient Persian tablets indicate the medicinal and lighting uses of petroleum in the upper levels of their society. By 347 AD, oil was produced from bamboo-drilled wells in China, early British explorers to Myanmar documented a flourishing oil extraction industry based in Yenangyaung that, in 1795, had hundreds of hand-dug wells under production. The mythological origins of the oil fields at Yenangyaung, and its hereditary monopoly control by 24 families, Pechelbronn is said to be the first European site where petroleum has been explored and used. The still active Erdpechquelle, a spring where petroleum appears mixed with water has been used since 1498, Oil sands have been mined since the 18th century. In Wietze in lower Saxony, natural asphalt/bitumen has been explored since the 18th century, both in Pechelbronn as in Wietze, the coal industry dominated the petroleum technologies. In 1848 Young set up a small business refining the crude oil, Young eventually succeeded, by distilling cannel coal at a low heat, in creating a fluid resembling petroleum, which when treated in the same way as the seep oil gave similar products. The production of oils and solid paraffin wax from coal formed the subject of his patent dated 17 October 1850. In 1850 Young & Meldrum and Edward William Binney entered into partnership under the title of E. W. Binney & Co. at Bathgate in West Lothian, the worlds first oil refinery was built in 1856 by Ignacy Łukasiewicz. The demand for petroleum as a fuel for lighting in North America, edwin Drakes 1859 well near Titusville, Pennsylvania, is popularly considered the first modern well
Petroleum
–
Pumpjack pumping an oil well near
Lubbock, Texas
Petroleum
–
An oil refinery in Mina-Al-Ahmadi, Kuwait
Petroleum
–
Natural petroleum spring in
Korňa, Slovakia
Petroleum
–
Oil derrick in
Okemah, Oklahoma, 1922
4.
Chemical compound
–
A chemical compound is an entity consisting of two or more atoms, at least two from different elements, which associate via chemical bonds. Many chemical compounds have a numerical identifier assigned by the Chemical Abstracts Service. For example, water is composed of two atoms bonded to one oxygen atom, the chemical formula is H2O. A compound can be converted to a different chemical composition by interaction with a chemical compound via a chemical reaction. In this process, bonds between atoms are broken in both of the compounds, and then bonds are reformed so that new associations are made between atoms. Schematically, this reaction could be described as AB + CD → AC + BD, where A, B, C, and D are each unique atoms, and AB, CD, AC, and BD are each unique compounds. A chemical element bonded to a chemical element is not a chemical compound since only one element. Examples are the diatomic hydrogen and the polyatomic molecule sulfur. Chemical compounds have a unique and defined chemical structure held together in a spatial arrangement by chemical bonds. Pure chemical elements are not considered chemical compounds, failing the two or more atom requirement, though they often consist of molecules composed of multiple atoms. There is varying and sometimes inconsistent nomenclature differentiating substances, which include truly non-stoichiometric examples, from chemical compounds, other compounds regarded as chemically identical may have varying amounts of heavy or light isotopes of the constituent elements, which changes the ratio of elements by mass slightly. Characteristic properties of compounds include that elements in a compound are present in a definite proportion, for example, the molecule of the compound water is composed of hydrogen and oxygen in a ratio of 2,1. In addition, compounds have a set of properties. The physical and chemical properties of compounds differ from those of their constituent elements, however, mixtures can be created by mechanical means alone, but a compound can be created only by a chemical reaction. Some mixtures are so combined that they have some properties similar to compounds. Other examples of compound-like mixtures include intermetallic compounds and solutions of metals in a liquid form of ammonia. Compounds may be described using formulas in various formats, for compounds that exist as molecules, the formula for the molecular unit is shown. For polymeric materials, such as minerals and many metal oxides, the elements in a chemical formula are normally listed in a specific order, called the Hill system
Chemical compound
–
Pure
water (H 2 O) is an example of a compound: the
ball-and-stick model of the molecule (above) shows the spatial association of two parts
hydrogen (white) and one part
oxygen (red)
5.
Fossil fuel
–
Fossil fuels are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms, containing energy originating in ancient photosynthesis. The age of the organisms and their resulting fossil fuels is typically millions of years, Fossil fuels contain high percentages of carbon and include petroleum, coal, and natural gas. Other commonly used derivatives include kerosene and propane, Fossil fuels range from volatile materials with low carbon, hydrogen ratios like methane, to liquids like petroleum, to nonvolatile materials composed of almost pure carbon, like anthracite coal. Methane can be found in hydrocarbon fields either alone, associated with oil, non-fossil sources in 2006 included nuclear 8. 5%, hydroelectric 6. 3%, and others amounting to 0. 9%. World energy consumption was growing about 2. 3% per year, the use of fossil fuels raises serious environmental concerns. The burning of fossil fuels produces around 21.3 billion tonnes of carbon dioxide per year and it is estimated that natural processes can only absorb about half of that amount, so there is a net increase of 10.65 billion tonnes of atmospheric carbon dioxide per year. Carbon dioxide is a gas that increases radiative forcing and contributes to global warming. A global movement towards the generation of energy is underway to help reduce global greenhouse gas emissions. Over geological time, this matter, mixed with mud. Despite these heat driven transformations, the energy is still photosynthetic in origin. There is a range of organic, or hydrocarbon, compounds in any given fuel mixture. The specific mixture of hydrocarbons gives a fuel its characteristic properties, such as boiling point, melting point, density, viscosity, some fuels like natural gas, for instance, contain only very low boiling, gaseous components. Others such as gasoline or diesel contain much higher boiling components, terrestrial plants, on the other hand, tend to form coal and methane. Many of the coal fields date to the Carboniferous period of Earths history, terrestrial plants also form type III kerogen, a source of natural gas. Fossil fuels are of importance because they can be burned. The use of coal as a fuel predates recorded history, coal was used to run furnaces for the melting of metal ore. Semi-solid hydrocarbons from seeps were also burned in ancient times, commercial exploitation of petroleum, largely as a replacement for oils from animal sources, for use in oil lamps began in the 19th century. Natural gas, once flared-off as an byproduct of petroleum production, is now considered a very valuable resource
Fossil fuel
–
Coal, one of the fossil fuels.
Fossil fuel
–
A petrochemical refinery in
Grangemouth,
Scotland,
UK
Fossil fuel
–
An oil well in the
Gulf of Mexico
Fossil fuel
–
Air
6.
Coal
–
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams. The harder forms, such as coal, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure. Coal is composed primarily of carbon, along with quantities of other elements, chiefly hydrogen, sulfur, oxygen. A fossil fuel, coal forms when plant matter is converted into peat, which in turn is converted into lignite, then sub-bituminous coal, after that bituminous coal. This involves biological and geological processes that take place over time, throughout history, coal has been used as an energy resource, primarily burned for the production of electricity and heat, and is also used for industrial purposes, such as refining metals. Coal is the largest source of energy for the generation of electricity worldwide, the extraction of coal, its use in energy production and its byproducts are all associated with environmental and health effects including climate change. Coal is extracted from the ground by coal mining, since 1983, the worlds top coal producer has been China. In 2015 China produced 3,747 million tonnes of coal –47. 7% of 7,861 million tonnes world coal production, in 2015 other large producers were United States, India, European Union and Australia. The word originally took the col in Old English, from Proto-Germanic *kula. In Old Turkic languages, kül is ash, cinders, öčür is quench, the compound charcoal in Turkic is öčür kül, literally quenched ashes, cinders, coals with elided anlaut ö- and inflection affixes -ülmüş. At various times in the geologic past, the Earth had dense forests in low-lying wetland areas, due to natural processes such as flooding, these forests were buried underneath soil. As more and more soil deposited over them, they were compressed, the temperature also rose as they sank deeper and deeper. As the process continued the plant matter was protected from biodegradation and oxidation and this trapped the carbon in immense peat bogs that were eventually covered and deeply buried by sediments. Under high pressure and high temperature, dead vegetation was slowly converted to coal, as coal contains mainly carbon, the conversion of dead vegetation into coal is called carbonization. The wide, shallow seas of the Carboniferous Period provided ideal conditions for coal formation, the exception is the coal gap in the Permian–Triassic extinction event, where coal is rare. Coal is known from Precambrian strata, which predate land plants — this coal is presumed to have originated from residues of algae, in its dehydrated form, peat is a highly effective absorbent for fuel and oil spills on land and water. It is also used as a conditioner for soil to make it able to retain. Lignite, or brown coal, is the lowest rank of coal, jet, a compact form of lignite, is sometimes polished and has been used as an ornamental stone since the Upper Palaeolithic
Coal
–
Anthracite coal
Coal
–
Bituminous coal
Coal
–
Coastal exposure of the Point Aconi Seam (Nova Scotia)
Coal
–
Coal miner in Britain, 1942
7.
Natural gas
–
It is formed when layers of decomposing plant and animal matter are exposed to intense heat and pressure under the surface of the Earth over millions of years. The energy that the plants originally obtained from the sun is stored in the form of bonds in the gas. Natural gas is a fuel used as a source of energy for heating, cooking. It is also used as fuel for vehicles and as a feedstock in the manufacture of plastics. Natural gas is found in underground rock formations or associated with other hydrocarbon reservoirs in coal beds. Petroleum is another resource and fossil fuel found in proximity to. Most natural gas was created over time by two mechanisms, biogenic and thermogenic, biogenic gas is created by methanogenic organisms in marshes, bogs, landfills, and shallow sediments. Deeper in the earth, at temperature and pressure, thermogenic gas is created from buried organic material. In petroleum production gas is burnt as flare gas. The World Bank estimates that over 150 cubic kilometers of gas are flared or vented annually. Before natural gas can be used as a fuel, most, Natural gas is often informally referred to simply as gas, especially when compared to other energy sources such as oil or coal. However, it is not to be confused with gasoline, especially in North America, Natural gas was used by the Chinese in about 500 BCE. They discovered a way to transport gas seeping from the ground in crude pipelines of bamboo to where it was used to salt water to extract the salt. The worlds first industrial extraction of gas started at Fredonia, New York. By 2009,66000 km³ had been used out of the total 850000 km³ of estimated remaining reserves of natural gas. An annual increase in usage of 2–3% could result in currently recoverable reserves lasting significantly less, unwanted natural gas was a disposal problem in the active oil fields. If there was not a market for natural gas near the wellhead it was expensive to pipe to the end user. In the 19th century and early 20th century, unwanted gas was burned off at oil fields
Natural gas
–
Natural gas coming out of the ground in Taiwan.
Natural gas
–
The global
Natural Gas Trade in 2013, numbers are in billion cubic meters per year.
Natural gas
–
Natural gas
drilling rig in Texas.
Natural gas
–
The location of
shale gas compared to other types of gas deposits.
8.
Corn
–
Maize, also known as corn, is a large grain plant first domesticated by indigenous peoples in Mexico about 10,000 years ago. The six major types of corn are dent corn, flint corn, pod corn, popcorn, flour corn, the leafy stalk of the plant produces separate pollen and ovuliferous inflorescences or ears, which are fruits, yielding kernels or seeds. Maize kernels are used in cooking as a starch. Most historians believe maize was domesticated in the Tehuacan Valley of Mexico, recent research modified this view somewhat, scholars now indicate the adjacent Balsas River Valley of south-central Mexico as the center of domestication. The Olmec and Mayans cultivated maize in numerous varieties throughout Mesoamerica, cooked and its believed that beginning about 2500 BC, the crop spread through much of the Americas. The region developed a network based on surplus and varieties of maize crops. Nevertheless, recent data indicates that the spread of maize took place even earlier, according to Piperno, A large corpus of data indicates that it was dispersed into lower Central America by 7600 BP and had moved into the inter-Andean valleys of Colombia between 7000 and 6000 BP. Since then, even earlier dates have been published, the study also demonstrated that the oldest surviving maize types are those of the Mexican highlands. Later, maize spread from this region over the Americas along two major paths and this is consistent with a model based on the archaeological record suggesting that maize diversified in the highlands of Mexico before spreading to the lowlands. Before they were domesticated, maize plants only grew small,25 millimetres long corn cobs, Maize is the most widely grown grain crop throughout the Americas, with 361 million metric tons grown in the United States in 2014. Approximately 40% of the crop—130 million tons—is used for corn ethanol, genetically modified maize made up 85% of the maize planted in the United States in 2009. After the arrival of Europeans in 1492, Spanish settlers consumed maize and explorers and traders carried it back to Europe, Spanish settlers far preferred wheat bread to maize, cassava, or potatoes. Maize flour could not be substituted for wheat for bread, since in Christian belief only wheat could undergo transubstantiation. At another level, Spaniards worried that by eating indigenous foods, which they did not consider nutritious, that not only would they weaken, despite these worries, Spaniards did consume maize and archeological evidence from Florida sites indicate they cultivated it as well. Maize spread to the rest of the world because of its ability to grow in diverse climates and it was cultivated in Spain just a few decades after Columbuss voyages and then spread to Italy, West Africa and elsewhere. The word maize derives from the Spanish form of the indigenous Taíno word for the plant and it is known by other names around the world. The word corn outside North America, Australia, and New Zealand refers to any cereal crop, in the United States, Canada, Australia, and New Zealand, corn primarily means maize, this usage started as a shortening of Indian corn. Indian corn primarily means maize, but can more specifically to multicolored flint corn used for decoration
Corn
–
Maize
Corn
–
A maize heap at the harvest site, India
Corn
–
Many small male flowers make up the male inflorescence, called the tassel.
Corn
–
Female inflorescence, with young
silk
9.
Sugar cane
–
It has stout, jointed, fibrous stalks that are rich in the sugar sucrose, which accumulates in the stalk internodes. The plant is two to six meters tall, all sugar cane species interbreed and the major commercial cultivars are complex hybrids. Sugarcane belongs to the grass family Poaceae, an important seed plant family that includes maize, wheat, rice, and sorghum. Sucrose, extracted and purified in specialized factories, is used as raw material in the food industry or is fermented to produce ethanol. Ethanol is produced on a large scale by the Brazilian sugarcane industry, sugarcane is the worlds largest crop by production quantity. In 2012, The Food and Agriculture Organization estimates it was cultivated on about 26×106 hectares, in more than 90 countries, Brazil was the largest producer of sugar cane in the world. The next five major producers, in decreasing amounts of production, were India, China, Thailand, Pakistan, the world demand for sugar is the primary driver of sugarcane agriculture. Cane accounts for 80% of sugar produced, most of the rest is made from sugar beets, sugarcane predominantly grows in the tropical and subtropical regions. Other than sugar, products derived from sugarcane include falernum, molasses, rum, cachaça, bagasse, in some regions, people use sugarcane reeds to make pens, mats, screens, and thatch. The young, unexpanded inflorescence of tebu telor is eaten raw, steamed, or toasted, the Persians, followed by the Greeks, discovered the famous reeds that produce honey without bees in India between the 6th and 4th centuries BC. They adopted and then spread sugarcane agriculture, merchants began to trade in sugar from India, which was considered a luxury and an expensive spice. Sugarcane is a tropical, perennial grass that forms lateral shoots at the base to produce multiple stems, the stems grow into cane stalk, which when mature constitutes around 75% of the entire plant. A mature stalk is composed of 11–16% fiber, 12–16% soluble sugars, 2–3% nonsugars. A sugarcane crop is sensitive to the climate, soil type, irrigation, fertilizers, insects, disease control, varieties, the average yield of cane stalk is 60–70 tonnes per hectare per year. However, this figure can vary between 30 and 180 tonnes per hectare depending on knowledge and crop management approach used in sugarcane cultivation, sugarcane is a cash crop, but it is also used as livestock fodder. Sugarcane is indigenous to tropical South and Southeast Asia, different species likely originated in different locations, with Saccharum barberi originating in India and S. edule and S. officinarum in New Guinea. It is theorized that sugarcane was first domesticated as a crop in New Guinea around 6000 BC, New Guinean farmers and other early cultivators of sugarcane chewed the plant for its sweet juice. The exact date of the first cane sugar production is unclear, the earliest evidence of sugar production comes from ancient Sanskrit and Pali texts
Sugar cane
–
Saccharum officinarum
Sugar cane
–
Cut sugarcane
Sugar cane
–
Sugarcane and bowl of refined sugar
Sugar cane
–
The westward diffusion of sugarcane in pre-Islamic times (shown in red), in the medieval
Arab world (green) and by Europeans in the 15th century (islands circled by violet lines)
10.
Alkene
–
In organic chemistry, an alkene is an unsaturated hydrocarbon that contains at least one carbon–carbon double bond. The words alkene, olefin, and olefine are used often interchangeably, acyclic alkenes, with only one double bond and no other functional groups, known as mono-enes, form a homologous series of hydrocarbons with the general formula CnH2n. Alkenes have two hydrogen atoms less than the corresponding alkane, the simplest alkene, ethylene, with the International Union of Pure and Applied Chemistry name ethene, is the organic compound produced on the largest scale industrially. Aromatic compounds are drawn as cyclic alkenes, but their structure and properties are different. This double bond is stronger than a single covalent bond and also shorter, each carbon of the double bond uses its three sp2 hybrid orbitals to form sigma bonds to three atoms. The unhybridized 2p atomic orbitals, which lie perpendicular to the created by the axes of the three sp² hybrid orbitals, combine to form the pi bond. This bond lies outside the main C–C axis, with half of the bond on one side of the molecule, rotation about the carbon–carbon double bond is restricted because it incurs an energetic cost to break the alignment of the p orbitals on the two carbon atoms. As a consequence, substituted alkenes may exist as one of two isomers, called cis or trans isomers, more complex alkenes may be named with the E–Z notation for molecules with three or four different substituents. For example, of the isomers of butene, the two groups of -but-2-ene appear on the same side of the double bond, and in -but-2-ene the methyl groups appear on opposite sides. These two isomers of butene are slightly different in their chemical and physical properties, a 90° twist of the C=C bond requires less energy than the strength of a pi bond, and the bond still holds. This contradicts a common assertion that the p orbitals would be unable sustain such a bond. In truth, the misalignment of the p orbitals is less than expected because pyramidalization takes place, trans-Cyclooctene is a stable strained alkene and the orbital misalignment is only 19° with a dihedral angle of 137° and a degree of pyramidalization of 18°. The trans isomer of cycloheptene is stable only at low temperatures, as predicted by the VSEPR model of electron pair repulsion, the molecular geometry of alkenes includes bond angles about each carbon in a double bond of about 120°. The angle may vary because of steric strain introduced by nonbonded interactions between groups attached to the carbons of the double bond. For example, the C–C–C bond angle in propylene is 123. 9°, for bridged alkenes, Bredts rule states that a double bond cannot occur at the bridgehead of a bridged ring system unless the rings are large enough. The physical properties of alkenes and alkanes are similar and they are colourless, nonpolar, combustable, and almost odorless. The physical state depends on mass, like the corresponding saturated hydrocarbons, the simplest alkenes, ethene, propene. Linear alkenes of approximately five to sixteen carbons are liquids, Alkenes are relatively stable compounds, but are more reactive than alkanes, either because of the reactivity of the carbon–carbon pi-bond or the presence of allylic CH centers
Alkene
–
A 3D model of
ethylene, the simplest alkene.
11.
Ethylene
–
Ethylene is a hydrocarbon which has the formula C 2H4 or H2C=CH2. It is a flammable gas with a faint sweet and musky odour when pure. Ethylene is widely used in the industry, and its worldwide production exceeds that of any other organic compound. Much of this production goes toward polyethylene, a used plastic containing polymer chains of ethylene units in various chain lengths. Ethylene is also an important natural plant hormone, used in agriculture to force the ripening of fruits and this hydrocarbon has four hydrogen atoms bound to a pair of carbon atoms that are connected by a double bond. All six atoms that comprise ethylene are coplanar, the H-C-H angle is 117. 4°, close to the 120° for ideal sp² hybridized carbon. The molecule is relatively rigid, rotation about the C-C bond is a high energy process that requires breaking the π-bond. The π-bond in the molecule is responsible for its useful reactivity. The double bond is a region of high density, thus it is susceptible to attack by electrophiles. Many reactions of ethylene are catalyzed by metals, which bind transiently to the ethylene using both the π and π* orbitals. Being a simple molecule, ethylene is spectroscopically simple and its UV-vis spectrum is still used as a test of theoretical methods. In the United States and Europe, approximately 90% of ethylene is used to produce ethylene oxide, ethylene dichloride, most of the reactions with ethylene are electrophilic addition. Polyethylene consumes more than half of the worlds ethylene supply, polyethylene, also called polyethene, is the worlds most widely used plastic. It is primarily used to make films in packaging, carrier bags, linear alpha-olefins, produced by oligomerization are used as precursors, detergents, plasticisers, synthetic lubricants, additives, and also as co-monomers in the production of polyethylenes. Ethylene is oxidized to ethylene oxide, a key raw material in the production of surfactants and detergents by ethoxylation. Ethylene oxide is hydrolyzed to produce ethylene glycol, widely used as an automotive antifreeze as well as higher molecular weight glycols, glycol ethers. Ethylene undergoes oxidation by palladium to give acetaldehyde and this conversion remains a major industrial process. The process proceeds via the initial complexation of ethylene to a Pd center, major intermediates from the halogenation and hydrohalogenation of ethylene include ethylene dichloride, ethyl chloride and ethylene dibromide
Ethylene
–
Ethylene
12.
Propylene
–
Propene, also known as propylene or methyl ethylene, is an unsaturated organic compound having the chemical formula C3H6. It has one double bond, and is the second simplest member of the class of hydrocarbons. At room temperature and atmospheric pressure, propene is a gas, propene has a higher density and boiling point than ethylene due to its greater mass. It has a lower boiling point than propane and is thus more volatile. It lacks strongly polar bonds, yet the molecule has a dipole moment due to its reduced symmetry. Propene has the empirical formula as cyclopropane but their atoms are connected in different ways. Propene is found in nature as a byproduct of vegetation and fermentation processes, propene is produced from fossil fuels—petroleum, natural gas, and, to a much lesser extent, coal. Propene is a byproduct of oil refining and natural gas processing, during oil refining, ethylene, propene, and other compounds are produced as a result of cracking larger hydrocarbon molecules to produce hydrocarbons more in demand. A major source of propene is naphtha cracking intended to produce ethylene, propene can be separated by fractional distillation from hydrocarbon mixtures obtained from cracking and other refining processes, refinery-grade propene is about 50 to 70%. A shift to lighter steam cracker feedstocks with relatively lower propene yields, on-purpose production methods are becoming increasingly significant. Propene yields of about 90 wt% are achieved and this option may also be used when there is no butene feedstock. In this case, part of the ethylene feeds an ethylene-dimerization unit that converts ethylene into butene, propane dehydrogenation converts propane into propene and by-product hydrogen. The propene from propane yield is about 85 m%, reaction by-products are usually used as fuel for the propane dehydrogenation reaction. As a result, propene tends to be the only product and this route is popular in regions, such as the Middle East, where there is an abundance of propane from oil/gas operations. In this region, the output is expected to be capable of supplying not only domestic needs, but also the demand from China. However, as natural gas offerings in the United States are significantly increasing due to the exploitation of shale gas. Chemical companies are planning to establish PDH plants in the USA to take advantage of the low price raw material. Numerous plants dedicated to propane dehydrogenation are currently under construction around the world, there are already five licensed technologies
Propylene
13.
Aromaticity
–
Aromatic molecules are very stable, and do not break apart easily to react with other substances. Organic compounds that are not aromatic are classified as aliphatic compounds—they might be cyclic, since the most common aromatic compounds are derivatives of benzene, the word “aromatic” occasionally refers informally to benzene derivatives, and so it was first defined. Nevertheless, many aromatic compounds exist. In living organisms, for example, the most common aromatic rings are the bases in RNA and DNA. An aromatic functional group or other substituent is called an aryl group, the earliest use of the term aromatic was in an article by August Wilhelm Hofmann in 1855. Hofmann used the term for a class of compounds, many of which have odors. In terms of the nature of the molecule, aromaticity describes a conjugated system often made of alternating single and double bonds in a ring. This configuration allows for the electrons in the pi system to be delocalized around the ring, increasing the molecules stability. The molecule cannot be represented by one structure, but rather a hybrid of different structures. These molecules cannot be found in one of these representations, with the longer single bonds in one location. Rather, the molecule exhibits bond lengths in between those of single and double bonds and this commonly seen model of aromatic rings, namely the idea that benzene was formed from a six-membered carbon ring with alternating single and double bonds, was developed by August Kekulé. The model for benzene consists of two forms, which corresponds to the double and single bonds superimposing to produce six one-and-a-half bonds. Benzene is a stable molecule than would be expected without accounting for charge delocalization. As is standard for resonance diagrams, the use of an arrow indicates that two structures are not distinct entities but merely hypothetical possibilities. Neither is a representation of the actual compound, which is best represented by a hybrid of these structures. A C=C bond is shorter than a C−C bond, but benzene is perfectly hexagonal—all six carbon–carbon bonds have the same length, intermediate between that of a single and that of a double bond. In a cyclic molecule with three alternating double bonds, cyclohexatriene, the length of the single bond would be 1.54 Å. However, in a molecule of benzene, the length of each of the bonds is 1.40 Å, a better representation is that of the circular π-bond, in which the electron density is evenly distributed through a π-bond above and below the ring
Aromaticity
–
Two different
resonance forms of benzene (top) combine to produce an average structure (bottom)
14.
Benzene
–
Benzene is an important organic chemical compound with the chemical formula C6H6. The benzene molecule is composed of 6 carbon atoms joined in a ring with 1 hydrogen atom attached to each, because it contains only carbon and hydrogen atoms, benzene is classed as a hydrocarbon. Benzene is a constituent of crude oil and is one of the elementary petrochemicals. Because of the cyclic continuous pi bond between the atoms, benzene is classed as an aromatic hydrocarbon, the second -annulene. Benzene is a colorless and highly flammable liquid with a sweet smell and it is used primarily as a precursor to the manufacture of chemicals with more complex structure, such as ethylbenzene and cumene, of which billions of kilograms are produced. Because benzene has a high number, it is an important component of gasoline. Because benzene is a carcinogen, most non-industrial applications have been limited. The word benzene derives historically from gum benzoin, a resin known to European pharmacists. An acidic material was derived from benzoin by sublimation, and named flowers of benzoin, the hydrocarbon derived from benzoic acid thus acquired the name benzin, benzol, or benzene. Michael Faraday first isolated and identified benzene in 1825 from the oily residue derived from the production of illuminating gas, in 1833, Eilhard Mitscherlich produced it by distilling benzoic acid and lime. He gave the compound the name benzin, in 1845, Charles Mansfield, working under August Wilhelm von Hofmann, isolated benzene from coal tar. Four years later, Mansfield began the first industrial-scale production of benzene, gradually, the sense developed among chemists that a number of substances were chemically related to benzene, comprising a diverse chemical family. In 1855, Hofmann used the word aromatic to designate this family relationship, in 1997, benzene was detected in deep space. The empirical formula for benzene was known, but its highly polyunsaturated structure. In 1865, the German chemist Friedrich August Kekulé published a paper in French suggesting that the structure contained a ring of six carbon atoms with alternating single and double bonds, the next year he published a much longer paper in German on the same subject. Kekulés symmetrical ring could explain these facts, as well as benzenes 1,1 carbon-hydrogen ratio. Here Kekulé spoke of the creation of the theory and he said that he had discovered the ring shape of the benzene molecule after having a reverie or day-dream of a snake seizing its own tail. This vision, he said, came to him years of studying the nature of carbon-carbon bonds
Benzene
–
A bottle of benzene. The warnings show benzene is a toxic and flammable liquid.
Benzene
–
Geometry of molecule
15.
Toluene
–
Toluene /ˈtɒljuːiːn/, also known as toluol /ˈtɒljuːɒl/, is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a benzene derivative, consisting of a CH3 group attached to a phenyl group. As such, its IUPAC systematic name is methylbenzene, Toluene is widely used as an industrial feedstock and a solvent. In 2013, worldwide sales of toluene amounted to about 24.5 billion US-dollars, as the solvent in some types of paint thinner, contact cement and model airplane glue, toluene is sometimes used as a recreational inhalant and has the potential of causing severe neurological harm. The compound was first isolated in 1837 through a distillation of oil by a Polish chemist named Filip Walter. In 1843, Jöns Jacob Berzelius recommended the name toluin, in 1850, French chemist Auguste Cahours isolated from a distillate of wood a hydrocarbon which he recognized as similar to Devilles benzoène and which Cahours named toluène. Toluene reacts as an aromatic hydrocarbon in electrophilic aromatic substitution. Because the methyl group has greater electron-releasing properties than an atom in the same position. It undergoes sulfonation to give p-toluenesulfonic acid, and chlorination by Cl2 in the presence of FeCl3 to give ortho, importantly, the methyl side chain in toluene is susceptible to oxidation. Toluene reacts with Potassium permanganate to yield benzoic acid, and with chromyl chloride to yield benzaldehyde, the methyl group undergoes halogenation under free radical conditions. For example, N-bromosuccinimide heated with toluene in the presence of AIBN leads to benzyl bromide, the same conversion can be effected with elemental bromine in the presence of UV light or even sunlight. Toluene may also be brominated by treating it with HBr and H2O2 in the presence of light. C6H5CH3 + Br2 → C6H5CH2Br + HBr C6H5CH2Br + Br2 → C6H5CHBr2 + HBr The methyl group in toluene undergoes deprotonation only with strong bases. Catalytic hydrogenation of toluene gives methylcyclohexane, the reaction requires a high pressure of hydrogen and a catalyst. Final separation and purification is done by any of the distillation or solvent extraction processes used for BTX aromatics, Toluene is so inexpensively produced industrially that it is not prepared in the laboratory. In principle it could be prepared by a variety of methods, Toluene is mainly used as a precursor to benzene via hydrodealkylation, C6H5CH3 + H2 → C6H6 + CH4 The second ranked application involves its disproportionation to a mixture of benzene and xylene. When oxidized it yields benzaldehyde and benzoic acid, two important intermediates in chemistry, in addition to the synthesis of benzene and xylene, toluene is a feedstock for toluene diisocyanate, trinitrotoluene, and a number of synthetic drugs. Toluene is a solvent, e. g. for paints, paint thinners, silicone sealants, many chemical reactants, rubber, printing ink, adhesives, lacquers, leather tanners
Toluene
16.
Xylene
–
Xylene, xylol or dimethylbenzene is any one of three isomers of dimethylbenzene, or a combination thereof. With the formula 2C6H4, each of the three compounds has a benzene ring with two methyl groups attached at substituents. They are all colorless, flammable liquids, some of which are of great industrial value, the mixture is referred to as both xylene and, more precisely, xylenes. Xylenes are an important petrochemical produced by reforming and also by coal carbonisation in the manufacture of coke fuel. They also occur in oil in concentrations of about 0. 5–1%. Small quantities occur in gasoline and aircraft fuels, xylenes are produced mainly as part of the BTX aromatics extracted from the product of catalytic reforming known as reformate. The xylene mixture is a greasy, colorless liquid commonly encountered as a solvent. Several million tons are produced annually, in 2011, a global consortium began construction of one of the world’s largest xylene plants in Singapore. Xylene was first isolated and named in 1850 by the French chemist Auguste Cahours, Xylene exists in three isomeric forms. The isomers can be distinguished by the designations ortho-, meta-, and para-, of the three isomers, the p-isomer is the most industrially sought after since it can be oxidized to terephthalic acid. Xylenes are produced by the methylation of toluene and benzene, commercial or laboratory grade xylene produced usually contains about 40-65% of m-xylene and up to 20% each of o-xylene, p-xylene and ethylbenzene. The ratio of isomers can be shifted to favor the highly valued p-xylene via the patented UOP-Isomar process or by transalkylation of xylene with itself or trimethylbenzene and these conversions are catalyzed by zeolites. The chemical and physical properties of xylene differ according to the respective isomers, the melting point ranges from −47.87 °C to 13.26 °C. The boiling point for each isomer is around 140 °C, the density of each isomer is around 0.87 g/mL and thus is less dense than water. Xylene in air can be smelled at concentrations as low as 0.08 to 3.7 ppm, xylenes form azeotropes with water and a variety of alcohols. With water the azeotrope consists of 60% xylenes and boils at 94.5 °C, as with many alkylbenzene compounds, xylenes form complexes with various halocarbons. The complexes of different isomers often have different properties from each other. P-Xylene is the precursor to terephthalic acid and dimethyl terephthalate
Xylene
–
The xylene isomers
17.
Isomers
–
An isomer is a molecule with the same molecular formula as another molecule, but with a different chemical structure. That is, isomers contain the number of atoms of each element. Isomers do not necessarily share similar properties, unless they also have the functional groups. There are two forms of isomerism, structural isomerism and stereoisomerism. In structural isomers, sometimes referred to as constitutional isomers, the atoms, Structural isomers have different IUPAC names and may or may not belong to the same functional group. For example, two position isomers would be 2-fluoropropane and 1-fluoropropane, illustrated on the side of the diagram above. In skeletal isomers the main chain is different between the two isomers. This type of isomerism is most identifiable in secondary and tertiary alcohol isomers, tautomers are structural isomers that spontaneously interconvert with each other, even when pure. They have different chemical properties and, as a consequence, distinct reactions characteristic to each form are observed, if the interconversion reaction is fast enough, tautomers cannot be isolated from each other. An example is when they differ by the position of a proton, such as in keto/enol tautomerism, there is, however, another isomer of C3H8O that has significantly different properties, methoxyethane. Unlike the isomers of propanol, methoxyethane has an oxygen connected to two carbons rather than to one carbon and one hydrogen. Methoxyethane is an ether, not an alcohol, because it lacks a hydroxyl group, propadiene and propyne are examples of isomers containing different bond types. Propadiene contains two double bonds, whereas propyne contains one triple bond, in stereoisomers the bond structure is the same, but the geometrical positioning of atoms and functional groups in space differs. This class includes enantiomers which are non-superposable mirror-images of each other, and diastereomers, enantiomers always contain chiral centers and diastereomers often do, but there are some diastereomers that neither are chiral nor contain chiral centers. Another type of isomer, conformational isomers, may be rotamers, diastereomers, for example, ortho- position-locked biphenyl systems have enantiomers. E/Z isomers, which have restricted rotation at a bond, are configurational isomers. They are classified as diastereomers, whether or not they contain any chiral centers, e/Z notation depicts absolute stereochemistry, which is an unambiguous descriptor based on CIP priorities. Cis–trans isomers are used to describe any molecules with restricted rotation in the molecule, for molecules with C=C double bonds, these descriptors describe relative stereochemistry only based on group bulkiness or principal carbon chain, and so can be ambiguous
Isomers
–
The different types of isomers, including position isomers 2-fluoropropane and 1-fluoropropane on the left
18.
Oil refinery
–
Oil refineries are typically large, sprawling industrial complexes with extensive piping running throughout, carrying streams of fluids between large chemical processing units. In many ways, oil refineries use much of the technology of, the crude oil feedstock has typically been processed by an oil production plant. There is usually an oil depot at or near an oil refinery for the storage of incoming crude oil feedstock as well as bulk liquid products, an oil refinery is considered an essential part of the downstream side of the petroleum industry. The lighter elements, however, form explosive vapors in the tanks and are therefore hazardous. Petroleum fossil fuels are burned in internal combustion engines to power for ships, automobiles, aircraft engines, lawn mowers, dirt bikes. Different boiling points allow the hydrocarbons to be separated by distillation, Oil can be used in a variety of ways because it contains hydrocarbons of varying molecular masses, forms and lengths such as paraffins, aromatics, naphthenes, alkenes, dienes, and alkynes. Once separated and purified of any contaminants and impurities, the fuel or lubricant can be sold without further processing, smaller molecules such as isobutane and propylene or butylenes can be recombined to meet specific octane requirements by processes such as alkylation, or more commonly, dimerization. The octane grade of gasoline can also be improved by catalytic reforming, the final step in gasoline production is the blending of fuels with different octane ratings, vapor pressures, and other properties to meet product specifications. Another method for reprocessing and upgrading these intermediate products uses a process to separate usable oil from the waste asphaltene material. Oil refineries are large plants, processing about a hundred thousand to several hundred thousand barrels of crude oil a day. Because of the capacity, many of the units operate continuously, as opposed to processing in batches. The high capacity also makes process optimization and advanced process control very desirable, petroleum products are usually grouped into four categories, light distillates, middle distillates, heavy distillates and residuum. This classification is based on the way crude oil is distilled and separated into fractions as in the above drawing and these are not usually transported but instead are blended or processed further on-site. Chemical plants are often adjacent to oil refineries or a number of further chemical processes are integrated into it. For example, light hydrocarbons are steam-cracked in a plant. Using the Claus process, hydrogen sulfide is afterwards transformed to elementary sulfur to be sold to the chemical industry, the rather large heat energy freed by this process is directly used in the other parts of the refinery. Often an electrical plant is combined into the whole refinery process to take up the excess heat. Desalter unit washes out salt from the oil before it enters the atmospheric distillation unit
Oil refinery
–
Anacortes Refinery (
Tesoro), on the north end of March Point southeast of
Anacortes, Washington
Oil refinery
–
The oil refinery in
Haifa, Israel is capable of processing about 9 million tons (66 million barrels) of
crude oil a year. Its two
cooling towers are landmarks of the city's skyline.
Oil refinery
–
Fire-extinguishing operations after the Texas City refinery explosion.
Oil refinery
–
Refinery of
Slovnaft in
Bratislava.
19.
Fluid catalytic cracking
–
Fluid catalytic cracking is one of the most important conversion processes used in petroleum refineries. It is widely used to convert the high-boiling, high-molecular weight hydrocarbon fractions of crude oils into more valuable gasoline, olefinic gases. It also produces gases that have more carbon-carbon double bonds. This portion of oil is often referred to as heavy gas oil or vacuum gas oil. In the FCC process, the feedstock is heated to a temperature and moderate pressure. The catalyst breaks the long-chain molecules of the high-boiling hydrocarbon liquids into much shorter molecules, during 2007, the FCC units in the United States processed a total of 5,300,000 barrels per day of feedstock and FCC units worldwide processed about twice that amount. FCC units are common in Europe and Asia because those regions have high demand for diesel and kerosene. In the US, fluid catalytic cracking is more common because the demand for gasoline is higher, the modern FCC units are all continuous processes which operate 24 hours a day for as long as 3 to 5 years between scheduled shutdowns for routine maintenance. There are several different proprietary designs that have developed for modern FCC units. Each design is available under a license that must be purchased from the developer by any petroleum refining company desiring to construct. A complete discussion of the advantages of each of the processes is beyond the scope of this article. The reactor and regenerator are considered to be the heart of the catalytic cracking unit. The schematic flow diagram of a typical modern FCC unit in Figure 1 below is based upon the side-by-side configuration, All of the cracking reactions take place in the catalyst riser within a period of 2–4 seconds. The flow of spent catalyst to the regenerator is regulated by a valve in the spent catalyst line. The regenerator operates at a temperature of about 715 °C and a pressure of about 2.41 barg, for that reason, FCC units are often referred to as being heat balanced. The hot catalyst leaving the regenerator flows into a catalyst withdrawal well where any entrained combustion flue gases are allowed to escape, the flow of regenerated catalyst to the feedstock injection point below the catalyst riser is regulated by a slide valve in the regenerated catalyst line. The hot flue gas exits the regenerator after passing through multiple sets of two-stage cyclones that remove entrained catalyst from the flue gas. The amount of catalyst circulating between the regenerator and the amounts to about 5 kg per kg of feedstock, which is equivalent to about 4.66 kg per litre of feedstock
Fluid catalytic cracking
–
Figure 1: A schematic flow diagram of a Fluid Catalytic Cracking unit as used in petroleum refineries
Fluid catalytic cracking
–
A typical fluid catalytic cracking unit in a petroleum refinery.
20.
Chemical plant
–
A chemical plant is an industrial process plant that manufactures chemicals, usually on a large scale. The general objective of a plant is to create new material wealth via the chemical or biological transformation. Chemical plants use specialized equipment, units, and technology in the manufacturing process, some would consider an oil refinery or a pharmaceutical or polymer manufacturer to be effectively a chemical plant. Petrochemical plants are located adjacent to an oil refinery to minimize transportation costs for the feedstocks produced by the refinery. Speciality chemical and fine chemical plants are much smaller and not as sensitive to location. Tools have been developed for converting a base project cost from one location to another. Chemical plants use chemical processes, which are detailed industrial-scale methods, the same chemical process can be used at more than one chemical plant, with possibly differently scaled capacities at each plant. Also, a plant at a site may be constructed to utilize more than one chemical process. A chemical plant commonly has usually large vessels or sections called units or lines that are interconnected by piping or other material-moving equipment which can carry streams of material, such material streams can include fluids or sometimes solids or mixtures such as slurries. An overall chemical process is made up of steps called unit operations which occur in the individual units. A raw material going into a process or plant as input to be converted into a product is commonly called a feedstock. In addition to feedstocks for the plant as a whole, a stream of material to be processed in a particular unit can similarly be considered feed for that unit. Output streams from the plant as a whole are final products, however, final products from one plant may be intermediate chemicals used as feedstock in another plant for further processing. For example, some products from an oil refinery may used as feedstock in petrochemical plants, either the feedstock, the product, or both may be individual compounds or mixtures. It is often not worthwhile separating the components in these mixtures completely, specific levels of purity depend on product requirements, chemical processes may be run in continuous or batch operation. In batch operation, production occurs in time-sequential steps in discrete batches, a batch of feedstock is fed into a process or unit, then the chemical process takes place, then the product and any other outputs are removed. Such batch production may be repeated again and again with new batches of feedstock. Batch operation is used in smaller scale plants such as pharmaceutical or specialty chemicals production
Chemical plant
–
BASF Chemical Plant Portsmouth Site in the
West Norfolk area of
Portsmouth, Virginia,
United States. The plant is served by the
Commonwealth Railway.
Chemical plant
–
Distillation unit in
Italy
Chemical plant
–
History
21.
Steam cracking
–
The rate of cracking and the end products are strongly dependent on the temperature and presence of catalysts. Cracking is the breakdown of a large alkane into smaller, more useful alkanes and alkenes, simply put, hydrocarbon cracking is the process of breaking a long-chain of hydrocarbons into short ones. This process might require high temperatures and high pressure, fluid catalytic cracking produces a high yield of petrol and LPG, while hydrocracking is a major source of jet fuel, Diesel fuel, naphtha, and again yields LPG. Among several variants of thermal cracking methods Vladimir Shukhov, a Russian engineer, one installation was used to a limited extent in Russia, but development was not followed up. Among its advantages was the fact both the condenser and the boiler were continuously kept under pressure. In its earlier versions however, it was a process, rather than continuous. In 1924, a delegation from the American Sinclair Oil Corporation visited Shukhov, Sinclair Oil apparently wished to suggest that the patent of Burton and Humphreys, in use by Standard Oil, was derived from Shukhovs patent for oil cracking, as described in the Russian patent. If that could be established, it could strengthen the hand of rival American companies wishing to invalidate the Burton-Humphreys patent. At about that time however, fluid catalytic cracking was being explored and developed, thermal cracking remains important however, for example in producing naphtha, gas oil, and coke, and more sophisticated forms of thermal cracking have been developed for various purposes. These include visbreaking, steam cracking, and coking, a large number of chemical reactions take place during the cracking process, most of them based on free radicals. Computer simulations aimed at modeling what takes place during steam cracking have included hundreds or even thousands of reactions in their models, the main reactions that take place include, In these reactions a single molecule breaks apart into two free radicals. Only a small fraction of the feed molecules actually undergo initiation, in steam cracking, initiation usually involves breaking a chemical bond between two carbon atoms, rather than the bond between a carbon and a hydrogen atom. CH3CH3 →2 CH3• In these reactions a free radical removes a hydrogen atom from another molecule, CH3• + CH3CH3 → CH4 + CH3CH2• In these reactions a free radical breaks apart into two molecules, one an alkene, the other a free radical. This is the process results in alkene products. CH3CH2• → CH2=CH2 + H• In these reactions, the reverse of radical decomposition reactions and these processes are involved in forming the aromatic products that result when heavier feedstocks are used. CH3CH2• + CH2=CH2 → CH3CH2CH2CH2• In these reactions two free radicals react with other to produce products that are not free radicals. CH3• + CH3CH2• → CH3CH2CH3 CH3CH2• + CH3CH2• → CH2=CH2 + CH3CH3 There are three places where a molecule might be split. Each has a distinct likelihood, 48%, break at the CH3-CH2 bond, cH3* / *CH2-CH2-CH3 Ultimately this produces an alkane and an alkene, CH4 + CH2=CH-CH3 38%, break at a CH2-CH2 bond
Steam cracking
–
Refinery using the
Shukhov cracking process,
Baku,
Soviet Union, 1934.
22.
Natural gas liquids
–
Natural-gas processing begins at the well head. The composition of the raw natural gas extracted from producing wells depends on the type, depth, and location of the underground deposit, oil and natural gas are often found together in the same reservoir. The natural gas produced from oil wells is generally classified as associated-dissolved, Natural gas production absent any association with crude oil is classified as “non-associated. ”In 2009,89 percent of U. S. wellhead production of natural gas was non-associated. Natural-gas processing plants purify raw natural gas by removing common contaminants such as water, carbon dioxide, some of the substances which contaminate natural gas have economic value and are further processed or sold. A fully operational plant delivers pipeline-quality dry natural gas that can be used as fuel by residential, commercial and industrial consumers, raw natural gas comes primarily from any one of three types of wells, crude oil wells, gas wells, and condensate wells. Natural gas that comes from oil wells is typically called associated gas. This gas can have existed as a gas cap above the oil in the underground formation. Natural gas from gas wells and from wells, in which there is little or no crude oil, is called non-associated gas. Gas wells typically produce raw natural gas, while condensate wells produce raw natural gas along with other low molecular weight hydrocarbons. Those that are liquid at ambient conditions are called natural gas condensate, Natural gas is called sweet gas when relatively free of hydrogen sulfide, gas that does contain hydrogen sulfide is called sour gas. Such gas is referred to as coalbed gas or coalbed methane, coalbed gas has become an important source of energy in recent decades. Raw natural gas typically consists primarily of methane, the shortest and lightest hydrocarbon molecule and it also contains varying amounts of, Heavier gaseous hydrocarbons, ethane, propane, normal butane, isobutane, pentanes and even higher molecular weight hydrocarbons. When processed and purified into finished by-products, all of these are referred to as Natural Gas Liquids or NGL. Acid gases, carbon dioxide, hydrogen sulfide and mercaptans such as methanethiol and ethanethiol, water, water vapor and liquid water. Also dissolved salts and dissolved gases, liquid hydrocarbons, perhaps some natural-gas condensate and/or crude oil. Mercury, very small amounts of mercury primarily in elemental form, naturally occurring radioactive material, natural gas may contain radon, and the produced water may contain dissolved traces of radium, which can accumulate within piping and processing equipment. This can render piping and equipment radioactive over time, the raw natural gas must be purified to meet the quality standards specified by the major pipeline transmission and distribution companies. Those quality standards vary from pipeline to pipeline and are usually a function of a pipeline systems design, in general, the standards specify that the natural gas, Be within a specific range of heating value
Natural gas liquids
–
A natural-gas processing plant
23.
Propane
–
Propane is a three-carbon alkane with the molecular formula C3H8, a gas, at standard temperature and pressure, but compressible to a transportable liquid. A by-product of natural gas processing and petroleum refining, it is used as a fuel for engines, oxy-gas torches, portable stoves. Propane is one of a group of liquefied petroleum gases, the others include butane, propylene, butadiene, butylene, isobutylene, and mixtures thereof. Propane was first identified as a component in gasoline by Walter O. Snelling of the U. S. Bureau of Mines in 1910. The volatility of these lighter hydrocarbons caused them to be known as wild because of the vapor pressures of unrefined gasoline. On March 31, the New York Times reported on Snellings work with liquefied gas and that a steel bottle will carry enough gas to light an ordinary home for three weeks. It was during this time that Snelling, in cooperation with Frank P. Peterson, Chester Kerr, together, they established American Gasol Co. the first commercial marketer of propane. Snelling had produced relatively pure propane by 1911, and on March 25,1913, a separate method of producing LP gas through compression was created by Frank Peterson and its patent granted on July 2,1912. The 1920s saw increased production of LP gas, with the first year of recorded production totaling 223,000 US gallons in 1922. In 1927, annual marketed LP gas production reached 1 million US gallons, and by 1935, major industry developments in the 1930s included the introduction of railroad tank car transport, gas odorization, and the construction of local bottle-filling plants. The year 1945 marked the first year that annual LP gas sales reached a billion gallons, by 1947, 62% of all U. S. homes had been equipped with either natural gas or propane for cooking. In 1950,1,000 propane-fueled buses were ordered by the Chicago Transit Authority, in 2004 it was reported to be a growing $8-billion to $10-billion industry with over 15 billion US gallons of propane being used annually in the U. S. The prop- root found in propane and names of compounds with three-carbon chains was derived from propionic acid. Propane is produced as a by-product of two processes, natural gas processing and petroleum refining. The processing of natural gas involves removal of butane, propane, additionally, oil refineries produce some propane as a by-product of cracking petroleum into gasoline or heating oil. The supply of propane cannot easily be adjusted to meet increased demand, about 90% of U. S. propane is domestically produced. The United States imports about 10% of the propane consumed each year, with about 70% of that coming from Canada via pipeline, the remaining 30% of imported propane comes to the United States from other sources via ocean transport. After it is produced, North American propane is stored in salt caverns
Propane
–
A 20 lb (9.1 kg) steel propane cylinder. This cylinder is fitted with an overfill prevention device (OPD) valve, as evidenced by the trilobular handwheel.
Propane
Propane
–
Domestic spherical steel pressure vessel with
pressure regulator for propane storage in the United States. This example was installed on this property in 1974.
Propane
–
A local delivery truck, behind the pickup truck
24.
Catalytic reforming
–
The process converts low-octane linear hydrocarbons into branched alkanes and cyclic naphthenes, which are then partially dehydrogenated to produce high-octane aromatic hydrocarbons. The dehydrogenation also produces significant amounts of hydrogen gas, which is fed into other refinery processes such as hydrocracking. A side reaction is hydrogenolysis, which produces light hydrocarbons of lower value, such as methane, ethane, propane, however, the benzene content of reformate makes it carcinogenic, which has led to governmental regulations effectively requiring further processing to reduce its benzene content. Nor is this process to be confused with various other catalytic reforming processes that use methanol or biomass-derived feedstocks to produce hydrogen for fuel cells or other uses. In the 1940s, Vladimir Haensel, a research chemist working for Universal Oil Products, haensels process was subsequently commercialized by UOP in 1949 for producing a high octane gasoline from low octane naphthas and the UOP process become known as the Platforming process. The first Platforming unit was built in 1949 at the refinery of the Old Dutch Refining Company in Muskegon, in the years since then, many other versions of the process have been developed by some of the major oil companies and other organizations. Today, the majority of gasoline produced worldwide is derived from the catalytic reforming process. To name a few of the catalytic reforming versions that were developed, all of which utilized a platinum and/or a rhenium catalyst, Rheniforming. Powerforming, Developed by Esso Oil Company, currently known as ExxonMobil, magnaforming, Developed by Engelhard and Atlantic Richfield Oil Company. Ultraforming, Developed by Standard Oil of Indiana, now a part of the British Petroleum Company, houdriforming, Developed by the Houdry Process Corporation. CCR Platforming, A Platforming version, designed for continuous catalyst regeneration, Octanizing, A catalytic reforming version developed by Axens, a subsidiary of Institut francais du petrole, designed for continuous catalyst regeneration. Before describing the reaction chemistry of the reforming process as used in petroleum refineries. A petroleum refinery includes many unit operations and unit processes, the first unit operation in a refinery is the continuous distillation of the petroleum crude oil being refined. The naphtha is a mixture of many different hydrocarbon compounds. The heavy naphtha has a boiling point of about 140 to 150 °C. The naphthas derived from the distillation of crude oils are referred to as straight-run naphthas and it should be noted that there are a great many petroleum crude oil sources worldwide and each crude oil has its own unique composition or assay. Also, not all refineries process the same crude oils and each refinery produces its own straight-run naphthas with their own unique initial and final boiling points, in other words, naphtha is a generic term rather than a specific term. The table just below lists some fairly typical straight-run heavy naphtha feedstocks, available for catalytic reforming, some refineries may also desulfurize and catalytically reform those naphthas
Catalytic reforming
–
A catalytic reformer unit in a petroleum refinery. © BP p.l.c
25.
Detergent
–
A detergent is a surfactant or a mixture of surfactants with cleaning properties in dilute solutions. In most household contexts, the term detergent by itself refers specifically to laundry detergent or dish detergent, detergents are commonly available as powders or concentrated solutions. Detergents, like soaps, work because they are amphiphilic, partly hydrophilic and their dual nature facilitates the mixture of hydrophobic compounds with water. Because air is not hydrophilic, detergents are also foaming agents to varying degrees, detergents are classified into three broad groupings, depending on the electrical charge of the surfactants. The alkylbenzene portion of these anions is lipophilic and the sulfonate is hydrophilic, two different varieties have been popularized, those with branched alkyl groups and those with linear alkyl groups. The former were phased out in economically advanced societies because they are poorly biodegradable. An estimated 6 billion kilograms of detergents are produced annually for domestic markets. Bile acids, such as acid, are anionic detergents produced by the liver to aid in digestion and absorption of fats. The ammonium center is positively charged, non-ionic detergents are characterized by their uncharged, hydrophilic headgroups. Typical non-ionic detergents are based on polyoxyethylene or a glycoside, common examples of the former include Tween, Triton, and the Brij series. These materials are known as ethoxylates or PEGlyates and their metabolites. Glycosides have a sugar as their uncharged hydrophilic headgroup, examples include octyl thioglucoside and maltosides. HEGA and MEGA series detergents are similar, possessing an alcohol as headgroup. Zwitterionic detergents possess a net zero charge arising from the presence of numbers of +1. In World War I, there was a shortage of oils, synthetic detergents were first made in Germany. One of the largest applications of detergents is for household cleaning including dish washing and washing laundry, the formulations are complex, reflecting the diverse demands of the application and the highly competitive consumer market. Both carburetors and fuel injector components of Otto engines benefit from detergents in the fuels to prevent fouling, typical detergents are long-chain amines and amides such as polyisobuteneamine and polyisobuteneamide/succinimide. Reagent grade detergents are employed for the isolation and purification of integral membrane proteins found in biological cells, solubilization of cell membrane bilayers requires a detergent that can enter the inner membrane monolayer
Detergent
–
Detergents
Detergent
–
Borax -based washing detergent
26.
Adhesive
–
The use of adhesives offers many advantages over binding techniques such as sewing, mechanical fastening, thermal bonding, etc. Adhesives are typically organized by the method of adhesion and these are then organized into reactive and non-reactive adhesives, which refers to whether the adhesive chemically reacts in order to harden. Alternatively they can be organized by whether the raw stock is of natural or synthetic origin, Adhesives may be found naturally or produced synthetically. The earliest human use of substances was approximately 200,000 years ago. The first references to adhesives in literature first appeared in approximately 2000 BCE, the Greeks and Romans made great contributions to the development of adhesives. In Europe, glue was not widely used until the period 1500–1700 CE, from then until the 1900s increases in adhesive use and discovery were relatively gradual. Only since the last century has the development of synthetic adhesives accelerated rapidly, the earliest use of adhesives was discovered in central Italy when two stone flakes partially covered with birch-bark tar and a third uncovered stone from the Middle Pleistocene era were found. This is thought to be the oldest discovered human use of tar-hafted stones, the birch-bark-tar adhesive is a simple, one-component adhesive. Although sticky enough, plant-based adhesives are brittle and vulnerable to environmental conditions, the first use of compound adhesives was discovered in Sibudu, South Africa. The ability to produce stronger adhesives allowed middle stone age humans to attach stone segments to sticks in greater variations, more recent examples of adhesive use by prehistoric humans have been found at the burial sites of ancient tribes. Archaeologists studying the sites found that approximately 6,000 years ago the tribesmen had buried their dead together with food found in clay pots repaired with tree resins. The glue was analyzed as pitch, which requires the heating of tar during its production, the retrieval of this tar requires a transformation of birch bark by means of heat, in a process known as pyrolysis. The first references to adhesives in literature first appeared in approximately 2000 BCE, further historical records of adhesive use are found from the period spanning 1500–1000 BCE. Artifacts from this period include paintings depicting wood gluing operations and a made of wood. Other ancient Egyptian artifacts employ animal glue for bonding or lamination, such lamination of wood for bows and furniture is thought to have extended their life and was accomplished using casein -based glues. The ancient Egyptians also developed starch-based pastes for the bonding of papyrus to clothing, from 1 to 500 AD the Greeks and Romans made great contributions to the development of adhesives. Wood veneering and marquetry were developed, the production of animal and fish glues refined, egg-based pastes were used to bond gold leaves incorporated various natural ingredients such as blood, bone, hide, milk, cheese, vegetables, and grains. The Greeks began the use of slaked lime as mortar while the Romans furthered mortar development by mixing lime with volcanic ash and this material, known as pozzolanic cement, was used in the construction of the Roman Colosseum and Pantheon
Adhesive
–
Nitrocellulose adhesive outside a tube
Adhesive
–
A reconstruction of Ötzi's axe
Adhesive
–
Beeswax
Adhesive
–
Modern Slaked
Lime Factory in Ukraine
27.
Polymer
–
A polymer is a large molecule, or macromolecule, composed of many repeated subunits. Because of their range of properties, both synthetic and natural polymers play an essential and ubiquitous role in everyday life. Polymers range from familiar synthetic plastics such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure, Polymers, both natural and synthetic, are created via polymerization of many small molecules, known as monomers. The units composing polymers derive, actually or conceptually, from molecules of low molecular mass. The term was coined in 1833 by Jöns Jacob Berzelius, though with a distinct from the modern IUPAC definition. The modern concept of polymers as covalently bonded macromolecular structures was proposed in 1920 by Hermann Staudinger, Polymers are studied in the fields of biophysics and macromolecular science, and polymer science. Polyisoprene of latex rubber is an example of a polymer. In biological contexts, essentially all biological macromolecules—i. e, proteins, nucleic acids, and polysaccharides—are purely polymeric, or are composed in large part of polymeric components—e. g. Isoprenylated/lipid-modified glycoproteins, where small molecules and oligosaccharide modifications occur on the polyamide backbone of the protein. The simplest theoretical models for polymers are ideal chains, Polymers are of two types, Natural polymeric materials such as shellac, amber, wool, silk and natural rubber have been used for centuries. A variety of natural polymers exist, such as cellulose. Most commonly, the continuously linked backbone of a used for the preparation of plastics consists mainly of carbon atoms. A simple example is polyethylene, whose repeating unit is based on ethylene monomer, however, other structures do exist, for example, elements such as silicon form familiar materials such as silicones, examples being Silly Putty and waterproof plumbing sealant. Oxygen is also present in polymer backbones, such as those of polyethylene glycol, polysaccharides. Polymerization is the process of combining many small molecules known as monomers into a covalently bonded chain or network, during the polymerization process, some chemical groups may be lost from each monomer. This is the case, for example, in the polymerization of PET polyester, the distinct piece of each monomer that is incorporated into the polymer is known as a repeat unit or monomer residue. Laboratory synthetic methods are divided into two categories, step-growth polymerization and chain-growth polymerization. However, some methods such as plasma polymerization do not fit neatly into either category
Polymer
–
Appearance of real linear polymer chains as recorded using an
atomic force microscope on a surface, under liquid medium. Chain
contour length for this polymer is ~204 nm; thickness is ~0.4 nm.
Polymer
–
A polyethylene sample that has
necked under tension.
Polymer
–
A plastic item with thirty years of exposure to heat and cold, brake fluid, and sunlight. Notice the discoloration, swelling, and
crazing of the material
Polymer
–
Chlorine attack of acetal resin plumbing joint
28.
Plastic
–
Plastic is a material consisting of any of a wide range of synthetic or semi-synthetic organic compounds that are malleable and can be molded into solid objects. Plastics are typically organic polymers of high mass, but they often contain other substances. They are usually synthetic, most commonly derived from petrochemicals, due to their relatively low cost, ease of manufacture, versatility, and imperviousness to water, plastics are used in an enormous and expanding range of products, from paper clips to spaceships. They have already displaced many traditional materials, such as wood, stone, horn and bone, leather, paper, metal, glass, and ceramic, in most of their former uses. In developed countries, about a third of plastic is used in packaging, other uses include automobiles, furniture, and toys. In the developing world, the ratios may be different - for example, the worlds first fully synthetic plastic was bakelite, invented in New York in 1907 by Leo Baekeland who coined the term plastics. Toward the end of the century, one approach to this problem was met with wide efforts toward recycling, the word plastic is derived from the Greek πλαστικός meaning capable of being shaped or molded, from πλαστός meaning molded. The common word plastic should not be confused with the technical adjective plastic, used for insulating parts in electrical fixtures, paper laminated products, thermally insulation foams. Problems include the probability of moldings naturally being dark colors, One of the most expensive commercial polymers. It forms the basis of artistic and commercial acrylic paints when suspended in water with the use of other agents, polytetrafluoroethylene – Heat-resistant, low-friction coatings, used in things like non-stick surfaces for frying pans, plumbers tape and water slides. It is more known as Teflon. Urea-formaldehyde – One of the aminoplasts and used as an alternative to phenolics. Used as an adhesive and electrical switch housings. Early plastics were bio-derived materials such as egg and blood proteins, in 1600 BC, Mesoamericans used natural rubber for balls, bands, and figurines. Treated cattle horns were used as windows for lanterns in the Middle Ages, materials that mimicked the properties of horns were developed by treating milk-proteins with lye. In the 1800s, as industrial chemistry developed during the Industrial Revolution, the development of plastics also accelerated with Charles Goodyears discovery of vulcanization to thermoset materials derived from natural rubber. Parkesine is considered the first man-made plastic, the plastic material was patented by Alexander Parkes, In Birmingham, UK in 1856. It was unveiled at the 1862 Great International Exhibition in London, parkesine won a bronze medal at the 1862 Worlds fair in London
Plastic
–
Household items made of various types of plastic
Plastic
–
A chair made with a polypropylene seat
Plastic
–
Plastic (LDPE) bowl, by GEECO, Made in England, c1950.
Plastic
–
Molded plastic food replicas on display outside a restaurant in
Japan
29.
Resin
–
In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. They are often mixtures of compounds, principally terpenes. Many plants, particularly woody plants, produce resin in response to injury, the resin acts as a bandage protecting the plant from invading insects and pathogens. Plants secrete resins and rosins for their protective benefits, the resin produced by most plants is composed mainly of terpenes and derivatives. Some resins also contain a proportion of resin acids. The individual components of resin can be separated by fractional distillation, rosins on the other hand are less volatile and consist, inter alia, of diterpenes. Amber is fossil resin from coniferous and other tree species, copal, kauri gum, dammar and other resins may also be found as subfossil deposits. Subfossil copal can be distinguished from genuine fossil amber because it becomes tacky when a drop of a solvent such as acetone or chloroform is placed on it, african copal and the kauri gum of New Zealand are also procured in a semi-fossil condition. Solidified resin from which the volatile terpene components have been removed by distillation is known as rosin, typical rosin is a transparent or translucent mass, with a vitreous fracture and a faintly yellow or brown colour, non-odorous or having only a slight turpentine odor and taste. Rosin is insoluble in water, mostly soluble in alcohol, essential oils, ether and hot fatty oils, and softens and melts under the influence of heat, rosin consists of a complex mixture of different substances including organic acids named the resin acids. These are closely related to the terpenes, and derive from them through partial oxidation, Resin acids can be dissolved in alkalis to form resin soaps, from which the purified resin acids are regenerated by treatment with acids. Examples of resin acids are abietic acid, C20H30O2, plicatic acid contained in cedar, and pimaric acid, C20H30O2, a constituent of galipot resin. Abietic acid can also be extracted from rosin by means of hot alcohol, it crystallizes in leaflets, pimaric acid closely resembles abietic acid into which it passes when distilled in a vacuum, it has been supposed to consist of three isomers. Rosin is obtained from pines and some plants, mostly conifers. Propolis, consisting largely of resins collected from such as poplars and conifers, is used by honey bees to seal gaps in their hives. Shellac and lacquer are examples of insect-derived resins, asphaltite and Utah resin are petroleum bitumens, not a product secreted by plants, although it was ultimately derived from plants. These were highly prized substances, and required as incense in religious rites. The word resin has been applied in the world to nearly any component of a liquid that will set into a hard lacquer or enamel-like finish
Resin
–
Cedar of Lebanon cone showing flecks of resin as used in the
mummification of
Egyptian Pharaohs.
Resin
–
Insect trapped in resin
Resin
–
Extremely viscous resin extruding from the trunk of a mature
Araucaria columnaris.
Resin
–
Resin of a pine
30.
Fiber
–
Fiber or fibre is a natural or synthetic substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials, the strongest engineering materials often incorporate fibers, for example carbon fiber and ultra-high-molecular-weight polyethylene. Natural fibers develop or occur in the shape, and include those produced by plants, animals. Plant fibers are employed in the manufacture of paper and textile, wood fiber, distinguished from vegetable fiber, is from tree sources. Forms include groundwood, lacebark, thermomechanical pulp, and bleached or unbleached kraft or sulfite pulps, animal fibers consist largely of particular proteins. Instances are silkworm silk, spider silk, sinew, catgut, wool, sea silk and hair such as wool, mohair and angora, fur such as sheepskin, rabbit, mink, fox, beaver. Mineral fibers include the asbestos group, asbestos is the only naturally occurring long mineral fiber. Six minerals have been classified as asbestos including chrysotile of the serpentine class, short, fiber-like minerals include wollastonite and palygorskite. Instances are collagen family of proteins, tendon, muscle proteins like actin, cell proteins like microtubules and many others, spider silk, sinew, man-made or chemical fibers are fibers whose chemical composition, structure, and properties are significantly modified during the manufacturing process. Man-made fibers consist of regenerated fibers and synthetic fibers, the earliest semi-synthetic fiber is the cellulose regenerated fiber, rayon. Most semi-synthetic fibers are cellulose regenerated fibers, cellulose fibers are a subset of man-made fibers, regenerated from natural cellulose. The cellulose comes from sources, rayon from tree wood fiber, Modal from beech trees, bamboo fiber from bamboo, seacell from seaweed. In the production of fibers, the cellulose is reduced to a fairly pure form as a viscous mass. Therefore, the process leaves few characteristics distinctive of the natural source material in the finished products. Some examples are, rayon bamboo fiber Lyocell, a brand of rayon Modal, historically, cellulose diacetate and -triacetate were classified under the term rayon, but are now considered distinct materials. Synthetic come entirely from materials such as petrochemicals, unlike those man-made fibers derived from such natural substances as cellulose or protein. Metallic fibers can be drawn from ductile metals such as copper, gold or silver and extruded or deposited from more brittle ones, such as nickel, carbon fibers are often based on oxydized and via pyrolysis carbonized polymers like PAN, but the end product is almost pure carbon. Silicon carbide fibers, where the polymers are not hydrocarbons but polymers
Fiber
–
A bundle of
optical fibers
Fiber
–
Fundamentals
31.
Elastomer
–
An elastomer is a polymer with viscoelasticity and very weak inter-molecular forces, generally having low Youngs modulus and high failure strain compared with other materials. The term, which is derived from elastic polymer, is used interchangeably with the term rubber. Each of the monomers which link to form the polymer is made of carbon. Elastomers are amorphous polymers existing above their glass transition temperature, so that considerable segmental motion is possible, at ambient temperatures, rubbers are thus relatively soft and deformable. Their primary uses are for seals, adhesives and molded flexible parts, application areas for different types of rubber are manifold and cover segments as diverse as tires, shoe soles, and dampening and insulating elements. The importance of rubbers can be judged from the fact that global revenues are forecast to rise to US$56 billion in 2020, Rubber like solids with elastic properties are called elastomers. Polymer chains are held together in elastomers by weakest intermolecular forces and this weak binding forces permit the polymers to be stretched. Natural rubber, neoprene rubber, buna-s and buna-n are elastomers, elastomers are usually thermosets but may also be thermoplastic. The long polymer chains cross-link during curing, i. e. vulcanizing, the molecular structure of elastomers can be imagined as a spaghetti and meatball structure, with the meatballs signifying cross-links. The elasticity is derived from the ability of the chains to reconfigure themselves to distribute an applied stress. The covalent cross-linkages ensure that the elastomer will return to its original configuration when the stress is removed, as a result of this extreme flexibility, elastomers can reversibly extend from 5-700%, depending on the specific material. Without the cross-linkages or with short, uneasily reconfigured chains, the stress would result in a permanent deformation. Temperature effects are present in the demonstrated elasticity of a polymer. It is also possible for a polymer to exhibit elasticity that is not due to covalent cross-links, butyl rubber Halogenated butyl rubbers Styrene-butadiene Rubber Nitrile rubber, also called Buna N rubbers Hydrogenated Nitrile Rubbers Therban and Zetpol. One should go through all differentiation while editing between Plastics and articles thereof and Rubber and articles thereof
Elastomer
–
(A) is an unstressed polymer; (B) is the same polymer under stress. When the stress is removed, it will return to the A configuration. (The dots represent cross-links)
32.
Gels
–
A gel is a solid jelly-like material that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state, by weight, gels are mostly liquid, yet they behave like solids due to a three-dimensional cross-linked network within the liquid. It is the crosslinking within the fluid that gives a gel its structure, in this way gels are a dispersion of molecules of a liquid within a solid in which the solid is the continuous phase and the liquid is the discontinuous phase. The word gel was coined by 19th-century Scottish chemist Thomas Graham by clipping from gelatine, gels consist of a solid three-dimensional network that spans the volume of a liquid medium and ensnares it through surface tension effects. This internal network structure may result from physical bonds or chemical bonds, virtually any fluid can be used as an extender including water, oil, and air. Both by weight and volume, gels are mostly fluid in composition, edible jelly is a common example of a hydrogel and has approximately the density of water. Polyionic polymers are polymers with a functional group. The ionic charges prevent the formation of tightly coiled polymer chains and this allows them to contribute more to viscosity in their stretched state, because the stretched-out polymer takes up more space. A hydrogel is a network of polymer chains that are hydrophilic, hydrogels are highly absorbent natural or synthetic polymeric networks. Hydrogels also possess a degree of flexibility very similar to tissue, due to their significant water content. The first appearance of the term hydrogel in the literature was in 1894, common uses for hydrogels include, Scaffolds in tissue engineering. When used as scaffolds, hydrogels may contain human cells to repair tissue and they mimic 3D microenvironment of cells. Hydrogel-coated wells have been used for cell culture Environmentally sensitive hydrogels and these hydrogels have the ability to sense changes of pH, temperature, or the concentration of metabolite and release their load as result of such a change. Wound gels are excellent for helping to create or maintain a moist environment, reservoirs in topical drug delivery, particularly ionic drugs, delivered by iontophoresis. Natural hydrogel materials are being investigated for tissue engineering, these materials include agarose, methylcellulose, hyaluronan, an organogel is a non-crystalline, non-glassy thermoreversible solid material composed of a liquid organic phase entrapped in a three-dimensionally cross-linked network. The liquid can be, for example, a solvent, mineral oil. The solubility and particle dimensions of the structurant are important characteristics for the elastic properties, often, these systems are based on self-assembly of the structurant molecules. Organogels have potential for use in a number of applications, such as in pharmaceuticals, cosmetics, art conservation, a xerogel /ˈzɪəroʊˌdʒɛl/ is a solid formed from a gel by drying with unhindered shrinkage
Gels
–
An upturned vial of
hair gel
33.
United States
–
Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico. The state of Alaska is in the northwest corner of North America, bordered by Canada to the east, the state of Hawaii is an archipelago in the mid-Pacific Ocean. The U. S. territories are scattered about the Pacific Ocean, the geography, climate and wildlife of the country are extremely diverse. At 3.8 million square miles and with over 324 million people, the United States is the worlds third- or fourth-largest country by area, third-largest by land area. It is one of the worlds most ethnically diverse and multicultural nations, paleo-Indians migrated from Asia to the North American mainland at least 15,000 years ago. European colonization began in the 16th century, the United States emerged from 13 British colonies along the East Coast. Numerous disputes between Great Britain and the following the Seven Years War led to the American Revolution. On July 4,1776, during the course of the American Revolutionary War, the war ended in 1783 with recognition of the independence of the United States by Great Britain, representing the first successful war of independence against a European power. The current constitution was adopted in 1788, after the Articles of Confederation, the first ten amendments, collectively named the Bill of Rights, were ratified in 1791 and designed to guarantee many fundamental civil liberties. During the second half of the 19th century, the American Civil War led to the end of slavery in the country. By the end of century, the United States extended into the Pacific Ocean. The Spanish–American War and World War I confirmed the status as a global military power. The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the sole superpower. The U. S. is a member of the United Nations, World Bank, International Monetary Fund, Organization of American States. The United States is a developed country, with the worlds largest economy by nominal GDP. It ranks highly in several measures of performance, including average wage, human development, per capita GDP. While the U. S. economy is considered post-industrial, characterized by the dominance of services and knowledge economy, the United States is a prominent political and cultural force internationally, and a leader in scientific research and technological innovations. In 1507, the German cartographer Martin Waldseemüller produced a map on which he named the lands of the Western Hemisphere America after the Italian explorer and cartographer Amerigo Vespucci
United States
–
Native Americans meeting with Europeans, 1764
United States
–
Flag
United States
–
The signing of the
Mayflower Compact, 1620.
United States
–
The
Declaration of Independence: the
Committee of Five presenting their draft to the
Second Continental Congress in 1776
34.
Western Europe
–
Western Europe, or West Europe, is the region comprising the western part of Europe. Below, some different geographic and geopolitical definitions of the term are outlined, prior to the Roman conquest, a large part of Western Europe had adopted the newly developed La Tène culture. This cultural and linguistic division was reinforced by the later political east-west division of the Roman Empire. The division between these two was enhanced during Late Antiquity and the Middle Ages by a number of events, the Western Roman Empire collapsed, starting the Early Middle Ages. By contrast, the Eastern Roman Empire, mostly known as the Greek or Byzantine Empire, survived, in East Asia, Western Europe was historically known as taixi in China and taisei in Japan, which literally translates as the Far West. The term Far West became synonymous with Western Europe in China during the Ming dynasty, the Italian Jesuit priest Matteo Ricci was one of the first writers in China to use the Far West as an Asian counterpart to the European concept of the Far East. In his writings, Ricci referred to himself as Matteo of the Far West, the term was still in use in the late 19th and early 20th centuries. Post-war Europe would be divided into two spheres, the West, influenced by the United States, and the Eastern Bloc. With the onset of the Cold War, Europe was divided by the Iron Curtain, behind that line lie all the capitals of the ancient states of Central and Eastern Europe. Although some countries were neutral, they were classified according to the nature of their political. This division largely defined the popular perception and understanding of Western Europe, the world changed dramatically with the fall of the Iron Curtain in 1989. The Federal Republic of Germany peacefully absorbed the German Democratic Republic, COMECON and the Warsaw Pact were dissolved, and in 1991, the Soviet Union ceased to exist. Several countries which had part of the Soviet Union regained full independence. Although the term Western Europe was more prominent during the Cold War, it remains much in use, in 1948 the Treaty of Brussels was signed between Belgium, France, Luxembourg, the Netherlands and the United Kingdom. It was further revisited in 1954 at the Paris Conference, when the Western European Union was established and it was declared defunct in 2011, after the Treaty of Lisbon, and the Treaty of Brussels was terminated. When the Western European Union was dissolved, it had 10 member countries, six member countries, five observer countries. The CIA divides Western Europe into two smaller subregions, regional voting blocs were formed in 1961 to encourage voting to various UN bodies from different regional groups. The European Union is an economic and political union of 28 member states that are located primarily in Europe, some Western and Northern European countries of Iceland, Norway, Switzerland and Liechtenstein are members of EFTA, though cooperating to varying degree with the European Union
Western Europe
–
The Great Schism in
Christianity, the predominant religion in Western Europe at the time.
Western Europe
Western Europe
–
Geopolitical Occident of Europe
35.
Middle East
–
The Middle East is a transcontinental region centered on Western Asia and Egypt. The corresponding adjective is Middle-Eastern and the noun is Middle-Easterner. The term has come into usage as a replacement of the term Near East beginning in the early 20th century. Arabs, Turks, Persians, Kurds, and Azeris constitute the largest ethnic groups in the region by population. Indigenous minorities of the Middle East include Jews, Assyrians and other Arameans, Baloch, Berbers, Copts, Druze, Lurs, Mandaeans, Samaritans, Shabaks, Tats, in the Middle East, there is also a Romani community. European ethnic groups form a diaspora in the region include Albanians, Bosniaks, Circassians, Crimean Tatars, Franco-Levantines. Among other migrant populations are Bengalis as well as other Indians, Chinese, Filipinos, Indonesians, Pakistanis, the history of the Middle East dates back to ancient times, with the importance of the region being recognized for millennia. Most of the countries border the Persian Gulf have vast reserves of crude oil. The term Middle East may have originated in the 1850s in the British India Office, however, it became more widely known when American naval strategist Alfred Thayer Mahan used the term in 1902 to designate the area between Arabia and India. During this time the British and Russian Empires were vying for influence in Central Asia, Mahan realized not only the strategic importance of the region, but also of its center, the Persian Gulf. Mahan first used the term in his article The Persian Gulf and International Relations, published in September 1902 in the National Review, a British journal. The Middle East, if I may adopt a term which I have not seen, will some day need its Malta, as well as its Gibraltar, it does not follow that either will be in the Persian Gulf. The British Navy should have the facility to concentrate in force if occasion arise, about Aden, India, mahans article was reprinted in The Times and followed in October by a 20-article series entitled The Middle Eastern Question, written by Sir Ignatius Valentine Chirol. During this series, Sir Ignatius expanded the definition of Middle East to include regions of Asia which extend to the borders of India or command the approaches to India. After the series ended in 1903, The Times removed quotation marks from subsequent uses of the term, in the late 1930s, the British established the Middle East Command, which was based in Cairo, for its military forces in the region. After that time, the term Middle East gained broader usage in Europe, the description Middle has also led to some confusion over changing definitions. Before the First World War, Near East was used in English to refer to the Balkans and the Ottoman Empire, while Middle East referred to Iran, the Caucasus, Afghanistan, Central Asia, and Turkestan. The first official use of the term Middle East by the United States government was in the 1957 Eisenhower Doctrine, the Associated Press Stylebook says that Near East formerly referred to the farther west countries while Middle East referred to the eastern ones, but that now they are synonymous
Middle East
–
The
Temple Mount in
Jerusalem
Middle East
–
Map of the Middle East (green).
Middle East
–
The
Kaaba, located in
Mecca,
Saudi Arabia
Middle East
–
Islam is the largest religion in the Middle East. Here, Muslim men are
prostrating during prayer in a mosque.
36.
Asia
–
Asia covers an area of 44,579,000 square kilometres, about 30% of Earths total land area and 8. 7% of the Earths total surface area. The continent, which has long been home to the majority of the population, was the site of many of the first civilizations. Asia is notable for not only its large size and population. In general terms, Asia is bounded on the east by the Pacific Ocean, on the south by the Indian Ocean, the western boundary with Europe is a historical and cultural construct, as there is no clear physical and geographical separation between them. The most commonly accepted boundaries place Asia to the east of the Suez Canal, the Ural River, and the Ural Mountains, and south of the Caucasus Mountains, China and India alternated in being the largest economies in the world from 1 to 1800 A. D. The accidental discovery of America by Columbus in search for India demonstrates this deep fascination, the Silk Road became the main East-West trading route in the Asian hitherland while the Straits of Malacca stood as a major sea route. Asia has exhibited economic dynamism as well as robust population growth during the 20th century, given its size and diversity, the concept of Asia—a name dating back to classical antiquity—may actually have more to do with human geography than physical geography. Asia varies greatly across and within its regions with regard to ethnic groups, cultures, environments, economics, historical ties, the boundary between Asia and Africa is the Red Sea, the Gulf of Suez, and the Suez Canal. This makes Egypt a transcontinental country, with the Sinai peninsula in Asia, the border between Asia and Europe was historically defined by European academics. In Sweden, five years after Peters death, in 1730 Philip Johan von Strahlenberg published a new atlas proposing the Urals as the border of Asia, the Russians were enthusiastic about the concept, which allowed them to keep their European identity in geography. Tatishchev announced that he had proposed the idea to von Strahlenberg, the latter had suggested the Emba River as the lower boundary. Over the next century various proposals were made until the Ural River prevailed in the mid-19th century, the border had been moved perforce from the Black Sea to the Caspian Sea into which the Ural River projects. The border between the Black Sea and the Caspian is usually placed along the crest of the Caucasus Mountains, the border between Asia and the loosely defined region of Oceania is usually placed somewhere in the Malay Archipelago. The terms Southeast Asia and Oceania, devised in the 19th century, have had several different geographic meanings since their inception. The chief factor in determining which islands of the Malay Archipelago are Asian has been the location of the possessions of the various empires there. Lewis and Wigen assert, The narrowing of Southeast Asia to its present boundaries was thus a gradual process, Asia is larger and more culturally diverse than Europe. It does not exactly correspond to the borders of its various types of constituents. From the time of Herodotus a minority of geographers have rejected the three-continent system on the grounds there is no or is no substantial physical separation between them
Asia
–
Two-point equidistant projection of Asia and surrounding landmasses.
Asia
–
Asia
Asia
–
The racial diversity of Asia's peoples,
Nordisk familjebok (1904)
Asia
–
Ptolemy's Asia
37.
Butadiene
–
1, 3-Butadiene is a simple conjugated diene with the formula C4H6. It is an important industrial chemical used as a monomer in the production of synthetic rubber, the molecule can be viewed as two vinyl groups joined together. The word butadiene usually refers to 1, 3-butadiene, which has the structure H2C=CH−CH=CH2, although butadiene breaks down quickly in the atmosphere, it is nevertheless found in ambient air in urban and suburban areas as a consequence of its constant emission from motor vehicles. The name butadiene can also refer to the isomer,1, 2-butadiene, however, this allene is difficult to prepare and has no industrial significance. This diene is also not expected to act as a diene in a Diels–Alder reaction due to its structure, to effect a Diels–Alder reaction, only a conjugated diene will suffice. The rest of this article concerns only 1, 3-butadiene, in 1863, the French chemist E. Caventou isolated a previously unknown hydrocarbon from the pyrolysis of amyl alcohol. This hydrocarbon was identified as butadiene in 1886, after Henry Edward Armstrong isolated it from among the products of petroleum. In 1910, the Russian chemist Sergei Lebedev polymerized butadiene and obtained a material with rubber-like properties and this polymer was, however, found to be too soft to replace natural rubber in many applications, notably automobile tires. The butadiene industry originated in the leading up to World War II. In 1929, Eduard Tschunker and Walter Bock, working for IG Farben in Germany, worldwide production quickly ensued, with butadiene being produced from grain alcohol in the Soviet Union and the United States and from coal-derived acetylene in Germany. In the United States, western Europe, and Japan, butadiene is produced as a byproduct of the cracking process used to produce ethylene. When mixed with steam and briefly heated to high temperatures, aliphatic hydrocarbons give up hydrogen to produce a complex mixture of unsaturated hydrocarbons. The quantity of butadiene produced depends on the used as feed. Light feeds, such as ethane, give primarily ethylene when cracked, but heavier feeds favor the formation of heavier olefins, butadiene, butadiene can also be produced by the catalytic dehydrogenation of normal butane. The first such post-war commercial plant, producing 65,000 tons per year of butadiene, began operations in 1957 in Houston, today, butadiene from n-butane is commercially practiced using the Houdry catadiene process, which was developed during World War II. In other parts of the world, including South America, Eastern Europe, China, while not competitive with steam cracking for producing large volumes of butadiene, lower capital costs make production from ethanol a viable option for smaller-capacity plants. At the same time this type of manufacture was canceled in Brazil, nowadays there is no industrial production of butadiene from ethanol. Recently, Lanxess announced plans to produce butadiene from ethanol, the process remains in use today in China and India
Butadiene
38.
Industrial chemicals
–
The chemical industry comprises the companies that produce industrial chemicals. Central to the world economy, it converts raw materials into more than 70,000 different products. The plastics industry contains some overlap, as most chemical companies produce plastic as well as other chemicals, although chemicals were made and used throughout history, the birth of the heavy chemical industry coincided with the beginnings of the Industrial Revolution in general. One of the first chemicals to be produced in large amounts through industrial process was sulfuric acid, in 1736, the pharmacist Joshua Ward developed a process for its production that involved heating saltpeter, allowing the sulfur to oxidize and combine with water. It was the first practical production of acid on a large scale. John Roebuck and Samuel Garbett were the first to establish a factory in Prestonpans, Scotland, in 1749. In the early 18th century, cloth was bleached by treating it with urine or sour milk and exposing it to sunlight for long periods of time. His powder was made by reacting chlorine with dry slaked lime and proved to be a cheap and he opened a factory in St Rollox, north of Glasgow, and production went from just 52 tons in 1799 to almost 10,000 tons just five years later. Soda ash was used since ancient times in the production of glass, textile, soap, and paper, and the source of the potash had traditionally been wood ashes in Western Europe. By the 18th century, this source was becoming uneconomical due to deforestation, the Leblanc process was patented in 1791 by Nicolas Leblanc who then built a Leblanc plant at Saint-Denis. He was denied his prize money because of the French Revolution, however, it was in Britain that the Leblanc process really took off. William Losh built the first soda works in Britain at the Losh, Wilson and Bell works on the River Tyne in 1816, when these tariffs were repealed, the British soda industry was able to rapidly expand. James Muspratts chemical works in Liverpool and Charles Tennants complex near Glasgow became the largest chemical production centres anywhere, by the 1870s, the British soda output of 200,000 tons annually exceeded that of all other nations in the world combined. These huge factories began to produce a diversity of chemicals as the Industrial Revolution matured. Originally, large quantities of waste were vented into the environment from the production of soda. This provided for inspection of the factories and imposed heavy fines on those exceeding the limits on pollution. Methods were soon devised to make useful byproducts from the alkali, the Solvay process was developed by the Belgian industrial chemist Ernest Solvay in 1861. In 1864, Solvay and his brother Alfred constructed a plant in the Belgian town of Charleroi and in 1874, they expanded into a plant in Nancy
Industrial chemicals
–
Oil refinery in
Louisiana - an example of chemical industry
Industrial chemicals
–
Charles Tennant 's St. Rollox Chemical Works in 1831, then the biggest chemical enterprise in the world.
Industrial chemicals
–
Ernest Solvay, patented an improved industrial method for the manufacture of
soda ash.
Industrial chemicals
–
The factories of the German firm
BASF, in 1866.
39.
Plastics
–
Plastic is a material consisting of any of a wide range of synthetic or semi-synthetic organic compounds that are malleable and can be molded into solid objects. Plastics are typically organic polymers of high mass, but they often contain other substances. They are usually synthetic, most commonly derived from petrochemicals, due to their relatively low cost, ease of manufacture, versatility, and imperviousness to water, plastics are used in an enormous and expanding range of products, from paper clips to spaceships. They have already displaced many traditional materials, such as wood, stone, horn and bone, leather, paper, metal, glass, and ceramic, in most of their former uses. In developed countries, about a third of plastic is used in packaging, other uses include automobiles, furniture, and toys. In the developing world, the ratios may be different - for example, the worlds first fully synthetic plastic was bakelite, invented in New York in 1907 by Leo Baekeland who coined the term plastics. Toward the end of the century, one approach to this problem was met with wide efforts toward recycling, the word plastic is derived from the Greek πλαστικός meaning capable of being shaped or molded, from πλαστός meaning molded. The common word plastic should not be confused with the technical adjective plastic, used for insulating parts in electrical fixtures, paper laminated products, thermally insulation foams. Problems include the probability of moldings naturally being dark colors, One of the most expensive commercial polymers. It forms the basis of artistic and commercial acrylic paints when suspended in water with the use of other agents, polytetrafluoroethylene – Heat-resistant, low-friction coatings, used in things like non-stick surfaces for frying pans, plumbers tape and water slides. It is more known as Teflon. Urea-formaldehyde – One of the aminoplasts and used as an alternative to phenolics. Used as an adhesive and electrical switch housings. Early plastics were bio-derived materials such as egg and blood proteins, in 1600 BC, Mesoamericans used natural rubber for balls, bands, and figurines. Treated cattle horns were used as windows for lanterns in the Middle Ages, materials that mimicked the properties of horns were developed by treating milk-proteins with lye. In the 1800s, as industrial chemistry developed during the Industrial Revolution, the development of plastics also accelerated with Charles Goodyears discovery of vulcanization to thermoset materials derived from natural rubber. Parkesine is considered the first man-made plastic, the plastic material was patented by Alexander Parkes, In Birmingham, UK in 1856. It was unveiled at the 1862 Great International Exhibition in London, parkesine won a bronze medal at the 1862 Worlds fair in London
Plastics
–
Household items made of various types of plastic
Plastics
–
A chair made with a polypropylene seat
Plastics
–
Plastic (LDPE) bowl, by GEECO, Made in England, c1950.
Plastics
–
Molded plastic food replicas on display outside a restaurant in
Japan
40.
Synthetic rubber
–
A synthetic rubber is any artificial elastomer. These are mainly polymers synthesised from petroleum byproducts, about 15 billion kilograms of rubbers are produced annually, and of that amount two thirds are synthetic. Global revenues generated with synthetic rubbers are likely to rise to approximately US$56 billion in 2020, synthetic rubber, like natural rubber, has uses in the automotive industry for tires, door and window profiles, hoses, belts, matting, and flooring. The expanded use of vehicles, and particularly motor vehicle tires, starting in the 1890s. In 1909, a team headed by Fritz Hofmann, working at the Bayer laboratory in Elberfeld, Germany, succeeded in polymerizing Isoprene, the first rubber polymer synthesized from butadiene was created in 1910 by the Russian scientist Sergei Vasiljevich Lebedev. This form of synthetic rubber provided the basis for the first large-scale commercial production by the tsarist empire and this early form of synthetic rubber was again replaced with natural rubber after the war ended, but investigations of synthetic rubber continued. Russian American Ivan Ostromislensky who moved to New York in 1922 did significant early research on synthetic rubber, political problems that resulted from great fluctuations in the cost of natural rubber led to the enactment of the Stevenson Act in 1921. By 1925 the price of rubber had increased to the point that many companies were exploring methods of producing synthetic rubber to compete with natural rubber. K. Neoprene is highly resistant to heat and chemicals such as oil and gasoline, the company Thiokol applied their name to a competing type of rubber based on ethylene dichloride which was commercially available in 1930. The first rubber plant in Europe SK-1 was established by Sergei Lebedev in Yaroslavl under Joseph Stalins First Five-Year Plan on July 7,1932, in 1935, German chemists synthesized the first of a series of synthetic rubbers known as Buna rubbers. These were copolymers, meaning the polymers were made up from two monomers in alternating sequence, other brands included Koroseal, which Waldo Semon developed in 1935, and Sovprene, which Russian researchers created in 1940. B. F. Goodrich Company scientist Waldo Semon developed a new, Ameripol made synthetic rubber production much more cost effective, helping to meet the United States needs during World War II. The production of rubber in the United States expanded greatly during World War II. Military trucks needed rubber for tires, and rubber was used in almost every other war machine, the U. S. government launched a major effort to improve synthetic rubber production. A large team of chemists from many institutions were involved, including Calvin Souther Fuller of Bell Labs, the rubber designated GRS, a copolymer of butadiene and styrene, was the basis for U. S. synthetic rubber production during World War II. By 1944, a total of 50 factories were manufacturing it and it still represents about half of total world production. The Ferrara, Italy, synthetic rubber factory was bombed August 23,1944, three other synthetic rubber facilities were at Ludwigshafen/Oppau, Hanover/Limmer, and Leverkusen. A synthetic rubber plant at Oświęcim in Nazi-occupied Poland, was construction on March 5,1944
Synthetic rubber
–
Sheet of synthetic rubber coming off the rolling mill at the plant of
Goodrich (1941)
Synthetic rubber
–
World War II poster about synthetic rubber tires
41.
Dyes
–
A dye is a colored substance that has an affinity to the substrate to which it is being applied. The dye is applied in an aqueous solution, and may require a mordant to improve the fastness of the dye on the fiber. Both dyes and pigments are colored because they absorb some wavelengths of light more than others, in contrast to dyes, pigments are insoluble and have no affinity for the substrate. Some dyes can be precipitated with a salt to produce a lake pigment. The majority of natural dyes are from plant sources, roots, berries, bark, leaves, and wood, fungi, textile dyeing dates back to the Neolithic period. Throughout history, people have dyed their textiles using common, locally available materials, scarce dyestuffs that produced brilliant and permanent colors such as the natural invertebrate dyes Tyrian purple and crimson kermes were highly prized luxury items in the ancient and medieval world. Plant-based dyes such as woad, indigo, saffron, and madder were raised commercially and were important trade goods in the economies of Asia, across Asia and Africa, patterned fabrics were produced using resist dyeing techniques to control the absorption of color in piece-dyed cloth. Dyes from the New World such as cochineal and logwood were brought to Europe by the Spanish treasure fleets, dyed flax fibers have been found in the Republic of Georgia in a prehistoric cave dated to 36,000 BP. Archaeological evidence shows that, particularly in India and Phoenicia, dyeing has been carried out for over 5,000 years. The dyes were obtained from animal, vegetable or mineral origin, by far the greatest source of dyes has been from the plant kingdom, notably roots, berries, bark, leaves and wood, but only a few have ever been used on a commercial scale. The discovery of synthetic dyes late in the 19th century ended the large-scale market for natural dyes. These dyes are made from synthetic resources such as petroleum by-products, the first human-made organic aniline dye, mauveine, was discovered serendipitously by William Henry Perkin in 1856, the result of a failed attempt at the total synthesis of quinine. Other aniline dyes followed, such as fuchsine, safranine, many thousands of synthetic dyes have since been prepared. These may be natural or synthetic, other than pigmentation, they have a range of applications including organic dye lasers, optical media and camera sensors. This is the basic classification Dyes are classified according to their solubility, acid dyes are water-soluble anionic dyes that are applied to fibers such as silk, wool, nylon and modified acrylic fibers using neutral to acid dye baths. Attachment to the fiber is attributed, at least partly, to salt formation between anionic groups in the dyes and cationic groups in the fiber, acid dyes are not substantive to cellulosic fibers. Most synthetic food colors fall in this category, basic dyes are water-soluble cationic dyes that are mainly applied to acrylic fibers, but find some use for wool and silk. Usually acetic acid is added to the dye bath to help the uptake of the dye onto the fiber, basic dyes are also used in the coloration of paper
Dyes
–
Yarn drying after being dyed in the early American tradition, at
Conner Prairie living history museum.
Dyes
–
Dyeing wool cloth, 1482: from a French translation of
Bartolomaeus Anglicus
Dyes
–
Historical collection of over 10,000 dyes at Technical University Dresden,
Germany
Dyes
–
RIT brand dye from mid-20th century Mexico, part of the permanent collection of the
Museo del Objeto del Objeto
42.
Methylene diphenyl diisocyanate
–
Methylene diphenyl diisocyanate, most often abbreviated as MDI, is an aromatic diisocyanate. Three isomers are common, varying by the positions of the groups around the rings,2, 2-MDI,2, 4-MDI. The 4,4 isomer is most widely used, and is known as 4. This isomer is known as Pure MDI. MDI reacts with polyols in the manufacture of polyurethane and it is the most produced diisocyanate, accounting for 61. 3% of the global market in the year 2000. Total world production of MDI and polymeric MDI is over 5 million tonnes per year, the largest producer is Covestro followed closely by Yantai Wanhua. Other major producers are BASF, BorsodChem, Dow, Huntsman, Nippon Polyurethane Industry, all major producers of MDI are members of the International Isocyanate Institute, whose aim is the promotion of the safe handling of MDI and TDI in the workplace, community and environment. The isomer ratio is determined by the composition of the diamine. Distillation of the MDI mixture gives polymeric MDI and an MDI isomer mixture which has a low 2,4 isomer content, further purification entails fractionation of the MDI isomer mixture. The positions of the groups influences their reactivity. In 4, 4-MDI, the two groups are equivalent but in 2, 4-MDI the two groups display highly differing reactivities. The group at the 4-position is approximately four times more reactive than the group at the 2-position due to steric hindrance, the major application of 4, 4-MDI is the production of rigid polyurethane. Typically, one tonne of polyurethane foam needs 0.616 tonne of MDI and 0.386 tonne of polyol and these rigid polyurethane foams are good thermal insulators and used in nearly all freezers and refrigerators worldwide, as well as buildings. Typical polyols used are polyethylene adipate and poly glycol,4, 4-MDI is also used as an industrial strength adhesive, which is available to end consumers as various high-strength bottled glue preparations. MDI is the least hazardous of the commonly available isocyanates but is not benign and its very low vapour pressure reduces its hazards during handling compared to the other major isocyanates. However, it, like the other isocyanates, is an allergen, persons developing sensitivity to isocyanates may have dangerous systemic reactions to extremely small exposures, including respiratory failure. Handling MDI requires strict engineering controls and personal protective equipment, compared to other organic cyanates, MDI has a relatively low human toxicity. It is a potentially violently reactive material towards water and other nucleophiles
Methylene diphenyl diisocyanate
43.
Toluene diisocyanate
–
Toluene diisocyanate is an organic compound with the formula CH3C6H32. Two of the six isomers are commercially important,2, 4-TDI and 2. 2, 4-TDI is produced in the state, but TDI is often marketed as 80/20. It is produced on a scale, accounting for 34. 1% of the global isocyanate market in 2000. Approximately 1.4 billion kilograms were produced in 2000,2, 4-TDI is prepared in three steps from toluene via dinitrotoluene and 2, 4-diaminotoluene. Finally, the TDA is subjected to phosgenation, i. e. treatment with phosgene to form TDI and this final step produces HCl as a byproduct and is a major source of industrial hydrochloric acid. Distillation of the crude TDI mixture produces an 80,20 mixture of 2, 4-TDI and 2, 6-TDI, known as TDI. Differentiation or separation of the TDI can be used to produce pure 2, 4-TDI, the isocyanate functional groups in TDI react with hydroxyl groups to form carbamate links. The two isocyanate groups in TDI react at different rates, The 4-position is approximately four times more reactive than the 2-position,2, 6-TDI is a symmetrical molecule and thus has two isocyanate groups of similar reactivity, similar to the 2-position on 2, 4-TDI. However, since both groups are attached to the same aromatic ring, reaction of one isocyanate group will cause a change in the reactivity of the second isocyanate group. It is used in the production of polyurethane foams The LD50 for TDI is 5800 mg/kg for oral contact. Despite the indicated low toxicity, TDI is classified as “very toxic” by the European Community, in the United States, the Occupational Safety and Health Administration has set a permissible exposure limit with a ceiling at 0. This chemical was one of many that two massive explosions in a chemical warehouse stationed in Tianjin, China on August 13,2015. All major producers of TDI are members of the International Isocyanate Institute, whose aim is the promotion of the handling of TDI in the workplace, community
Toluene diisocyanate
–
Toluene-2,4-diisocyanate
44.
Polyurethanes
–
Polyurethane is a polymer composed of organic units joined by carbamate links. While most polyurethanes are thermosetting polymers that do not melt when heated, polyurethane polymers are traditionally and most commonly formed by reacting a di- or polyisocyanate with a polyol. Both the isocyanates and polyols used to make polyurethanes contain, on average, some noteworthy recent efforts have been dedicated to minimizing the use of isocyanates to synthesize polyurethanes, because the isocyanates raise severe toxicity issues. Non-isocyanate based polyurethanes have recently developed as a new class of polyurethane polymers to mitigate health. Polyurethane products often are simply called “urethanes”, but should not be confused with ethyl carbamate, polyurethanes neither contain nor are produced from ethyl carbamate. Otto Bayer and his coworkers at IG Farben in Leverkusen, Germany, the new polymers had some advantages over existing plastics that were made by polymerizing olefins or by polycondensation, and were not covered by patents obtained by Wallace Carothers on polyesters. Early work focused on the production of fibres and flexible foams, polyisocyanates became commercially available in 1952, and production of flexible polyurethane foam began in 1954 using toluene diisocyanate and polyester polyols. These materials were used to produce rigid foams, gum rubber. Linear fibers were produced from hexamethylene diisocyanate and 1, 4-butanediol, in 1956 DuPont introduced polyether polyols, specifically poly glycol, and BASF and Dow Chemical started selling polyalkylene glycols in 1957. Polyether polyols were cheaper, easier to handle and more water-resistant than polyester polyols, union Carbide and Mobay, a U. S. Monsanto/Bayer joint venture, also began making polyurethane chemicals. In 1960 more than 45,000 metric tons of flexible polyurethane foams were produced, in 1967, urethane-modified polyisocyanurate rigid foams were introduced, offering even better thermal stability and flammability resistance. During the 1960s, automotive interior safety components, such as instrument, in 1969, Bayer exhibited an all-plastic car in Düsseldorf, Germany. Further increases in stiffness were obtained by incorporating pre-placed glass mats into the RIM mold cavity, also known broadly as resin injection molding, polyurethane foams are now used in high-temperature oil filter applications. Polyurethane foam is made using small amounts of blowing agents to give less dense foam. In the early 1990s, because of their impact on ozone depletion, polyurethanes are in the class of compounds called reaction polymers, which include epoxies, unsaturated polyesters, and phenolics. The properties of a polyurethane are greatly influenced by the types of isocyanates, long, flexible segments, contributed by the polyol, give soft, elastic polymer. High amounts of crosslinking give tough or rigid polymers, the crosslinking present in polyurethanes means that the polymer consists of a three-dimensional network and molecular weight is very high. In some respects a piece of polyurethane can be regarded as one giant molecule, one consequence of this is that typical polyurethanes do not soften or melt when they are heated, they are thermosetting polymers
Polyurethanes
–
Polyurethane synthesis, wherein the urethane groups — NH-(C=O)-O- link the molecular units.
45.
Manufacturers
–
Manufacturing is the value added to production of merchandise for use or sale using labour and machines, tools, chemical and biological processing, or formulation. Manufacturing engineering or manufacturing process are the steps through which raw materials are transformed into a final product, the manufacturing process begins with the product design, and materials specification from which the product is made. These materials are modified through manufacturing processes to become the required part. Manufacturing takes turns under all types of economic systems, in a free market economy, manufacturing is usually directed toward the mass production of products for sale to consumers at a profit. In a collectivist economy, manufacturing is more directed by the state to supply a centrally planned economy. In mixed market economies, manufacturing occurs under some degree of government regulation, modern manufacturing includes all intermediate processes required the production and integration of a products components. Some industries, such as semiconductor and steel manufacturers use the term fabrication instead, the manufacturing sector is closely connected with engineering and industrial design. Examples of major manufacturers in North America include General Motors Corporation, General Electric, Procter & Gamble, General Dynamics, Boeing, Pfizer, examples in Europe include Volkswagen Group, Siemens, and Michelin. Examples in Asia include Sony, Huawei, Lenovo, Toyota, Samsung, in its earliest form, manufacturing was usually carried out by a single skilled artisan with assistants. In much of the world, the guild system protected the privileges. Before the Industrial Revolution, most manufacturing occurred in rural areas, entrepreneurs organized a number of manufacturing households into a single enterprise through the putting-out system. Toll manufacturing is an arrangement whereby a first firm with specialized equipment processes raw materials or semi-finished goods for a second firm, manufacturing provides important material support for national infrastructure and for national defense. On the other hand, most manufacturing may involve significant social and environmental costs, the clean-up costs of hazardous waste, for example, may outweigh the benefits of a product that creates it. Hazardous materials may expose workers to health risks and these costs are now well known and there is effort to address them by improving efficiency, reducing waste, using industrial symbiosis, and eliminating harmful chemicals. The negative costs of manufacturing can also be addressed legally, developed countries regulate manufacturing activity with labor laws and environmental laws. Across the globe, manufacturers can be subject to regulations and pollution taxes to offset the costs of manufacturing activities. Labor unions and craft guilds have played a role in the negotiation of worker rights. Environment laws and labor protections that are available in developed nations may not be available in the third world, tort law and product liability impose additional costs on manufacturing
Manufacturers
–
Textile factory (
Germany, circa 1975).
Manufacturers
Manufacturers
–
Assembly of Section 41 of a
Boeing 787 Dreamliner
Manufacturers
–
A female industrial
worker amidst heavy steel semi-products (KINEX BEARINGS,
Bytča,
Slovakia, c. 1995–2000)
46.
Synthesis gas
–
Syngas, or synthesis gas, is a fuel gas mixture consisting primarily of hydrogen, carbon monoxide, and very often some carbon dioxide. The name comes from its use as intermediates in creating synthetic natural gas, syngas is usually a product of gasification and the main application is electricity generation. Syngas is combustible and often used as a fuel of internal combustion engines and it has less than half the energy density of natural gas. Syngas can be produced from many sources, including gas, coal, biomass, or virtually any hydrocarbon feedstock, by reaction with steam. Syngas is a crucial resource for production of hydrogen, ammonia, methanol. Syngas is also used as an intermediate in producing synthetic petroleum for use as a fuel or lubricant via the Fischer–Tropsch process and previously the Mobil methanol to gasoline process. Production methods include steam reforming of natural gas or liquid hydrocarbons to produce hydrogen, the gasification of coal, biomass, the chemical composition of syngas varies based on the raw materials and the processes. Syngas produced by coal gasification generally is a mixture of 30 to 60% carbon monoxide,25 to 30% hydrogen,5 to 15% carbon dioxide and it also contains lesser amount of other gases. The main reaction that produces syngas, steam reforming, is a reaction with 206 kJ/mol methane needed for conversion. The first reaction, between incandescent coke and steam, is endothermic, producing carbon monoxide, and hydrogen H2. When the coke bed has cooled to a temperature at which the reaction can no longer proceed. The overall reaction is exothermic, forming producer gas, steam can then be re-injected, then air etc. to give an endless series of cycles until the coke is finally consumed. Producer gas has a lower energy value, relative to water gas. Pure oxygen can be substituted for air to avoid the dilution effect and this is primarily done by pressure swing adsorption, amine scrubbing, and membrane reactors. Conversion of biomass to syngas is typically low-yield, the University of Minnesota developed a metal catalyst that reduces the biomass reaction time by up to a factor of 100. The catalyst can be operated at atmospheric pressure and reduces char, the entire process is autothermic and therefore heating is not required. CO2 can be split into CO and then combined with hydrogen to form syngas and this technique was alleged to have been used during the Cold war in Russian nuclear submarines to allow them to get rid of CO2 gas without leaving a bubble trail. Publicly available journals published during the Cold War indicate that American submarines used conventional chemical scrubbers to remove CO2, documents released after the sinking of the Kursk, a Cold War era Oscar-class submarine, indicate that potassium superoxide scrubbers were used to remove carbon dioxide on that vessel
Synthesis gas
–
Types
47.
Hydrogen
–
Hydrogen is a chemical element with chemical symbol H and atomic number 1. With a standard weight of circa 1.008, hydrogen is the lightest element on the periodic table. Its monatomic form is the most abundant chemical substance in the Universe, non-remnant stars are mainly composed of hydrogen in the plasma state. The most common isotope of hydrogen, termed protium, has one proton, the universal emergence of atomic hydrogen first occurred during the recombination epoch. At standard temperature and pressure, hydrogen is a colorless, odorless, tasteless, non-toxic, nonmetallic, since hydrogen readily forms covalent compounds with most nonmetallic elements, most of the hydrogen on Earth exists in molecular forms such as water or organic compounds. Hydrogen plays an important role in acid–base reactions because most acid-base reactions involve the exchange of protons between soluble molecules. In ionic compounds, hydrogen can take the form of a charge when it is known as a hydride. The hydrogen cation is written as though composed of a bare proton, Hydrogen gas was first artificially produced in the early 16th century by the reaction of acids on metals. Industrial production is mainly from steam reforming natural gas, and less often from more energy-intensive methods such as the electrolysis of water. Most hydrogen is used near the site of its production, the two largest uses being fossil fuel processing and ammonia production, mostly for the fertilizer market, Hydrogen is a concern in metallurgy as it can embrittle many metals, complicating the design of pipelines and storage tanks. Hydrogen gas is flammable and will burn in air at a very wide range of concentrations between 4% and 75% by volume. The enthalpy of combustion is −286 kJ/mol,2 H2 + O2 →2 H2O +572 kJ Hydrogen gas forms explosive mixtures with air in concentrations from 4–74%, the explosive reactions may be triggered by spark, heat, or sunlight. The hydrogen autoignition temperature, the temperature of spontaneous ignition in air, is 500 °C, the detection of a burning hydrogen leak may require a flame detector, such leaks can be very dangerous. Hydrogen flames in other conditions are blue, resembling blue natural gas flames, the destruction of the Hindenburg airship was a notorious example of hydrogen combustion and the cause is still debated. The visible orange flames in that incident were the result of a mixture of hydrogen to oxygen combined with carbon compounds from the airship skin. H2 reacts with every oxidizing element, the ground state energy level of the electron in a hydrogen atom is −13.6 eV, which is equivalent to an ultraviolet photon of roughly 91 nm wavelength. The energy levels of hydrogen can be calculated fairly accurately using the Bohr model of the atom, however, the atomic electron and proton are held together by electromagnetic force, while planets and celestial objects are held by gravity. The most complicated treatments allow for the effects of special relativity
Hydrogen
–
Purple glow in its plasma state
Hydrogen
–
The
Space Shuttle Main Engine burnt hydrogen with oxygen, producing a nearly invisible flame at full thrust.
Hydrogen
–
Spectral lines of hydrogen
Hydrogen
–
First tracks observed in
liquid hydrogen bubble chamber at the
Bevatron
48.
Fertilizer
–
A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soils or to plant tissues to supply one or more plant nutrients essential to the growth of plants. Fertilizers enhance the growth of plants and this goal is met in two ways, the traditional one being additives that provide nutrients. The second mode by which some fertilizers act is to enhance the effectiveness of the soil by modifying its water retention and aeration and this article, like many on fertilizers, emphasises the nutritional aspect. The nutrients required for plant life are classified according to the elements. Instead compounds containing these elements are the basis of fertilizers, the macronutrients are consumed in larger quantities and are present in plant tissue in quantities from 0. 15% to 6. 0% on a dry matter basis. Plants are made up of four elements, hydrogen, oxygen, carbon. Carbon, hydrogen and oxygen are widely available as water and carbon dioxide, although nitrogen makes up most of the atmosphere, it is in a form that is unavailable to plants. Nitrogen is the most important fertilizer since nitrogen is present in proteins, DNA, to be nutritious to plants, nitrogen must be made available in a fixed form. Only some bacteria and their host plants can fix atmospheric nitrogen by converting it to ammonia, phosphate is required for the production of DNA and ATP, the main energy carrier in cells, as well as certain lipids. Micronutrients are consumed in quantities and are present in plant tissue on the order of parts-per-million, ranging from 0.15 to 400 ppm DM. These elements are present at the active sites of enzymes that carry out the plants metabolism. Because these elements enable catalysts their impact far exceeds their weight percentage, Fertilizers are classified in several ways. They are classified according to whether they provide a single nutrient, multinutrient fertilizers provide two or more nutrients, for example N and P. Fertilizers are also sometimes classified as inorganic versus organic. Inorganic fertilizers exclude carbon-containing materials except ureas, organic fertilizers are usually plant- or animal-derived matter. Inorganic are sometimes called synthetic fertilizers since various chemical treatments are required for their manufacture, the main nitrogen-based straight fertilizer is ammonia or its solutions. Ammonium nitrate is widely used. Urea is another source of nitrogen, having the advantage that it is solid and non-explosive, unlike ammonia and ammonium nitrate. A few percent of the fertilizer market has been met by calcium ammonium nitrate
Fertilizer
–
A large, modern fertilizer spreader
Fertilizer
–
A
Lite-Trac Agri-Spread
lime and fertilizer spreader at an agricultural show
Fertilizer
–
Compost bin for small-scale production of organic fertilizer
Fertilizer
–
A large commercial compost operation
49.
Urea
–
Urea, also known as carbamide, is an organic compound with the chemical formula CO2. This amide has two groups joined by a carbonyl functional group. Urea serves an important role in the metabolism of nitrogen-containing compounds by animals and is the main nitrogen-containing substance in the urine of mammals and it is a colorless, odorless solid, highly soluble in water, and practically non-toxic. Dissolved in water, it is neither acidic nor alkaline, the body uses it in many processes, most notably nitrogen excretion. The liver forms it by combining two molecules with a carbon dioxide molecule in the urea cycle. Urea is widely used in fertilizers as a source of nitrogen and is an important raw material for the chemical industry, Friedrich Wöhlers discovery in 1828 that urea can be produced from inorganic starting materials was an important conceptual milestone in chemistry. More than 90% of world production of urea is destined for use as a nitrogen-release fertilizer. Urea has the highest nitrogen content of all solid nitrogenous fertilizers in common use, therefore, it has the lowest transportation costs per unit of nitrogen nutrient. The standard crop-nutrient rating of urea is 46-0-0, many soil bacteria possess the enzyme urease, which catalyzes conversion of urea to ammonia or ammonium ion and bicarbonate ion. Thus urea fertilizers rapidly transform to the form in soils. Ammonium and nitrate are readily absorbed by plants, and are the dominant sources of nitrogen for plant growth, Urea is also used in many multi-component solid fertilizer formulations. Urea is highly soluble in water and is also very suitable for use in fertilizer solutions. For fertilizer use, granules are preferred over prills because of their particle size distribution. The most common impurity of synthetic urea is biuret, which impairs plant growth, Urea is usually spread at rates of between 40 and 300 kg/ha but rates vary. Smaller applications incur lower losses due to leaching, during summer, urea is often spread just before or during rain to minimize losses from volatilization. Because of the nitrogen concentration in urea, it is very important to achieve an even spread. The application equipment must be calibrated and properly used. Drilling must not occur on contact with or close to seed, Urea dissolves in water for application as a spray or through irrigation systems
Urea
Urea
–
Urea
Urea
–
Urea plant using ammonium carbamate briquettes, Fixed Nitrogen Research Laboratory, ca. 1930
50.
Chemical
–
A chemical substance is a form of matter that has constant chemical composition and characteristic properties. It cannot be separated into components by physical methods, i. e. without breaking chemical bonds. Chemical substances can be chemical elements, chemical compounds, ions or alloys, Chemical substances are often called pure to set them apart from mixtures. A common example of a substance is pure water, it has the same properties. Other chemical substances commonly encountered in pure form are diamond, gold, table salt, however, in practice, no substance is entirely pure, and chemical purity is specified according to the intended use of the chemical. Chemical substances exist as solids, liquids, gases, or plasma, Chemical substances may be combined or converted to others by means of chemical reactions. Forms of energy, such as light and heat, are not matter, a chemical substance may well be defined as any material with a definite chemical composition in an introductory general chemistry textbook. According to this definition a chemical substance can either be a chemical element or a pure chemical compound. But, there are exceptions to this definition, a substance can also be defined as a form of matter that has both definite composition and distinct properties. The chemical substance index published by CAS also includes several alloys of uncertain composition, in geology, substances of uniform composition are called minerals, while physical mixtures of several minerals are defined as rocks. Many minerals, however, mutually dissolve into solid solutions, such that a rock is a uniform substance despite being a mixture in stoichiometric terms. Feldspars are an example, anorthoclase is an alkali aluminium silicate. In law, chemical substances may include both pure substances and mixtures with a composition or manufacturing process. For example, the EU regulation REACH defines monoconstituent substances, multiconstituent substances and substances of unknown or variable composition, the latter two consist of multiple chemical substances, however, their identity can be established either by direct chemical analysis or reference to a single manufacturing process. For example, charcoal is a complex, partially polymeric mixture that can be defined by its manufacturing process. Therefore, although the chemical identity is unknown, identification can be made to a sufficient accuracy. The CAS index also includes mixtures, polymers almost always appear as mixtures of molecules of multiple molar masses, each of which could be considered a separate chemical substance. However, the polymer may be defined by a precursor or reaction
Chemical
–
Steam and liquid water are two different forms of the same chemical substance, water.
Chemical
–
Colors of a single chemical (
Nile red) in different solvents, under visible and UV light, showing how the chemical interacts dynamically with its solvent environment.
Chemical
–
Native sulfur crystals. Sulfur occurs naturally as elemental sulfur, in
sulfide and
sulfate minerals and in
hydrogen sulfide.
Chemical
–
Potassium ferricyanide is a compound of potassium, iron, carbon and nitrogen; although it contains cyanide anions, it does not release them and is nontoxic.
Media related to Petrochemicals at Wikimedia Commons
