1.
Jmol
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Jmol is computer software for molecular modelling chemical structures in 3-dimensions. Jmol returns a 3D representation of a molecule that may be used as a teaching tool and it is written in the programming language Java, so it can run on the operating systems Windows, macOS, Linux, and Unix, if Java is installed. It is free and open-source software released under a GNU Lesser General Public License version 2.0, a standalone application and a software development kit exist that can be integrated into other Java applications, such as Bioclipse and Taverna. A popular feature is an applet that can be integrated into web pages to display molecules in a variety of ways, for example, molecules can be displayed as ball-and-stick models, space-filling models, ribbon diagrams, etc. Jmol supports a range of chemical file formats, including Protein Data Bank, Crystallographic Information File, MDL Molfile. There is also a JavaScript-only version, JSmol, that can be used on computers with no Java, the Jmol applet, among other abilities, offers an alternative to the Chime plug-in, which is no longer under active development. While Jmol has many features that Chime lacks, it does not claim to reproduce all Chime functions, most notably, Chime requires plug-in installation and Internet Explorer 6.0 or Firefox 2.0 on Microsoft Windows, or Netscape Communicator 4.8 on Mac OS9. Jmol requires Java installation and operates on a variety of platforms. For example, Jmol is fully functional in Mozilla Firefox, Internet Explorer, Opera, Google Chrome, fast and Scriptable Molecular Graphics in Web Browsers without Java3D
2.
ChEMBL
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ChEMBL or ChEMBLdb is a manually curated chemical database of bioactive molecules with drug-like properties. It is maintained by the European Bioinformatics Institute, of the European Molecular Biology Laboratory, based at the Wellcome Trust Genome Campus, Hinxton, the database, originally known as StARlite, was developed by a biotechnology company called Inpharmatica Ltd. later acquired by Galapagos NV. The data was acquired for EMBL in 2008 with an award from The Wellcome Trust, resulting in the creation of the ChEMBL chemogenomics group at EMBL-EBI, the ChEMBL database contains compound bioactivity data against drug targets. Bioactivity is reported in Ki, Kd, IC50, and EC50, data can be filtered and analyzed to develop compound screening libraries for lead identification during drug discovery. ChEMBL version 2 was launched in January 2010, including 2.4 million bioassay measurements covering 622,824 compounds and this was obtained from curating over 34,000 publications across twelve medicinal chemistry journals. ChEMBLs coverage of available bioactivity data has grown to become the most comprehensive ever seen in a public database, in October 2010 ChEMBL version 8 was launched, with over 2.97 million bioassay measurements covering 636,269 compounds. ChEMBL_10 saw the addition of the PubChem confirmatory assays, in order to integrate data that is comparable to the type, ChEMBLdb can be accessed via a web interface or downloaded by File Transfer Protocol. It is formatted in a manner amenable to computerized data mining, ChEMBL is also integrated into other large-scale chemistry resources, including PubChem and the ChemSpider system of the Royal Society of Chemistry. In addition to the database, the ChEMBL group have developed tools and these include Kinase SARfari, an integrated chemogenomics workbench focussed on kinases. The system incorporates and links sequence, structure, compounds and screening data, the primary purpose of ChEMBL-NTD is to provide a freely accessible and permanent archive and distribution centre for deposited data. July 2012 saw the release of a new data service, sponsored by the Medicines for Malaria Venture. The data in this service includes compounds from the Malaria Box screening set, myChEMBL, the ChEMBL virtual machine, was released in October 2013 to allow users to access a complete and free, easy-to-install cheminformatics infrastructure. In December 2013, the operations of the SureChem patent informatics database were transferred to EMBL-EBI, in a portmanteau, SureChem was renamed SureChEMBL. 2014 saw the introduction of the new resource ADME SARfari - a tool for predicting and comparing cross-species ADME targets
3.
ChemSpider
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ChemSpider is a database of chemicals. ChemSpider is owned by the Royal Society of Chemistry, the database contains information on more than 50 million molecules from over 500 data sources including, Each chemical is given a unique identifier, which forms part of a corresponding URL. This is an approach to develop an online chemistry database. The search can be used to widen or restrict already found results, structure searching on mobile devices can be done using free apps for iOS and for the Android. The ChemSpider database has been used in combination with text mining as the basis of document markup. The result is a system between chemistry documents and information look-up via ChemSpider into over 150 data sources. ChemSpider was acquired by the Royal Society of Chemistry in May,2009, prior to the acquisition by RSC, ChemSpider was controlled by a private corporation, ChemZoo Inc. The system was first launched in March 2007 in a release form. ChemSpider has expanded the generic support of a database to include support of the Wikipedia chemical structure collection via their WiChempedia implementation. A number of services are available online. SyntheticPages is an interactive database of synthetic chemistry procedures operated by the Royal Society of Chemistry. Users submit synthetic procedures which they have conducted themselves for publication on the site and these procedures may be original works, but they are more often based on literature reactions. Citations to the published procedure are made where appropriate. They are checked by an editor before posting. The pages do not undergo formal peer-review like a journal article. The comments are moderated by scientific editors. The intention is to collect practical experience of how to conduct useful chemical synthesis in the lab, while experimental methods published in an ordinary academic journal are listed formally and concisely, the procedures in ChemSpider SyntheticPages are given with more practical detail. Comments by submitters are included as well, other publications with comparable amounts of detail include Organic Syntheses and Inorganic Syntheses
4.
European Chemicals Agency
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ECHA is the driving force among regulatory authorities in implementing the EUs chemicals legislation. ECHA helps companies to comply with the legislation, advances the safe use of chemicals, provides information on chemicals and it is located in Helsinki, Finland. The Agency, headed by Executive Director Geert Dancet, started working on 1 June 2007, the REACH Regulation requires companies to provide information on the hazards, risks and safe use of chemical substances that they manufacture or import. Companies register this information with ECHA and it is freely available on their website. So far, thousands of the most hazardous and the most commonly used substances have been registered, the information is technical but gives detail on the impact of each chemical on people and the environment. This also gives European consumers the right to ask whether the goods they buy contain dangerous substances. The Classification, Labelling and Packaging Regulation introduces a globally harmonised system for classifying and labelling chemicals into the EU. This worldwide system makes it easier for workers and consumers to know the effects of chemicals, companies need to notify ECHA of the classification and labelling of their chemicals. So far, ECHA has received over 5 million notifications for more than 100000 substances, the information is freely available on their website. Consumers can check chemicals in the products they use, Biocidal products include, for example, insect repellents and disinfectants used in hospitals. The Biocidal Products Regulation ensures that there is information about these products so that consumers can use them safely. ECHA is responsible for implementing the regulation, the law on Prior Informed Consent sets guidelines for the export and import of hazardous chemicals. Through this mechanism, countries due to hazardous chemicals are informed in advance and have the possibility of rejecting their import. Substances that may have effects on human health and the environment are identified as Substances of Very High Concern 1. These are mainly substances which cause cancer, mutation or are toxic to reproduction as well as substances which persist in the body or the environment, other substances considered as SVHCs include, for example, endocrine disrupting chemicals. Companies manufacturing or importing articles containing these substances in a concentration above 0 and they are required to inform users about the presence of the substance and therefore how to use it safely. Consumers have the right to ask the retailer whether these substances are present in the products they buy, once a substance has been officially identified in the EU as being of very high concern, it will be added to a list. This list is available on ECHA’s website and shows consumers and industry which chemicals are identified as SVHCs, Substances placed on the Candidate List can then move to another list
5.
PubChem
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PubChem is a database of chemical molecules and their activities against biological assays. The system is maintained by the National Center for Biotechnology Information, a component of the National Library of Medicine, PubChem can be accessed for free through a web user interface. Millions of compound structures and descriptive datasets can be downloaded via FTP. PubChem contains substance descriptions and small molecules with fewer than 1000 atoms and 1000 bonds, more than 80 database vendors contribute to the growing PubChem database. PubChem consists of three dynamically growing primary databases, as of 28 January 2016, Compounds,82.6 million entries, contains pure and characterized chemical compounds. Substances,198 million entries, contains also mixtures, extracts, complexes, bioAssay, bioactivity results from 1.1 million high-throughput screening programs with several million values. PubChem contains its own online molecule editor with SMILES/SMARTS and InChI support that allows the import and export of all common chemical file formats to search for structures and fragments. In the text search form the database fields can be searched by adding the name in square brackets to the search term. A numeric range is represented by two separated by a colon. The search terms and field names are case-insensitive, parentheses and the logical operators AND, OR, and NOT can be used. AND is assumed if no operator is used, example,0,5000,50,10 -5,5 PubChem was released in 2004. The American Chemical Society has raised concerns about the publicly supported PubChem database and they have a strong interest in the issue since the Chemical Abstracts Service generates a large percentage of the societys revenue. To advocate their position against the PubChem database, ACS has actively lobbied the US Congress, soon after PubChems creation, the American Chemical Society lobbied U. S. Congress to restrict the operation of PubChem, which they asserted competes with their Chemical Abstracts Service
6.
International Chemical Identifier
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Initially developed by IUPAC and NIST from 2000 to 2005, the format and algorithms are non-proprietary. The continuing development of the standard has supported since 2010 by the not-for-profit InChI Trust. The current version is 1.04 and was released in September 2011, prior to 1.04, the software was freely available under the open source LGPL license, but it now uses a custom license called IUPAC-InChI Trust License. Not all layers have to be provided, for instance, the layer can be omitted if that type of information is not relevant to the particular application. InChIs can thus be seen as akin to a general and extremely formalized version of IUPAC names and they can express more information than the simpler SMILES notation and differ in that every structure has a unique InChI string, which is important in database applications. Information about the 3-dimensional coordinates of atoms is not represented in InChI, the InChI algorithm converts input structural information into a unique InChI identifier in a three-step process, normalization, canonicalization, and serialization. The InChIKey, sometimes referred to as a hashed InChI, is a fixed length condensed digital representation of the InChI that is not human-understandable. The InChIKey specification was released in September 2007 in order to facilitate web searches for chemical compounds and it should be noted that, unlike the InChI, the InChIKey is not unique, though collisions can be calculated to be very rare, they happen. In January 2009 the final 1.02 version of the InChI software was released and this provided a means to generate so called standard InChI, which does not allow for user selectable options in dealing with the stereochemistry and tautomeric layers of the InChI string. The standard InChIKey is then the hashed version of the standard InChI string, the standard InChI will simplify comparison of InChI strings and keys generated by different groups, and subsequently accessed via diverse sources such as databases and web resources. Every InChI starts with the string InChI= followed by the version number and this is followed by the letter S for standard InChIs. The remaining information is structured as a sequence of layers and sub-layers, the layers and sub-layers are separated by the delimiter / and start with a characteristic prefix letter. The six layers with important sublayers are, Main layer Chemical formula and this is the only sublayer that must occur in every InChI. The atoms in the formula are numbered in sequence, this sublayer describes which atoms are connected by bonds to which other ones. Describes how many hydrogen atoms are connected to each of the other atoms, the condensed,27 character standard InChIKey is a hashed version of the full standard InChI, designed to allow for easy web searches of chemical compounds. Most chemical structures on the Web up to 2007 have been represented as GIF files, the full InChI turned out to be too lengthy for easy searching, and therefore the InChIKey was developed. With all databases currently having below 50 million structures, such duplication appears unlikely at present, a recent study more extensively studies the collision rate finding that the experimental collision rate is in agreement with the theoretical expectations. Example, Morphine has the structure shown on the right, as the InChI cannot be reconstructed from the InChIKey, an InChIKey always needs to be linked to the original InChI to get back to the original structure
7.
Simplified molecular-input line-entry system
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The simplified molecular-input line-entry system is a specification in form of a line notation for describing the structure of chemical species using short ASCII strings. SMILES strings can be imported by most molecule editors for conversion back into two-dimensional drawings or three-dimensional models of the molecules, the original SMILES specification was initiated in the 1980s. It has since modified and extended. In 2007, a standard called OpenSMILES was developed in the open-source chemistry community. Other linear notations include the Wiswesser Line Notation, ROSDAL and SLN, the original SMILES specification was initiated by David Weininger at the USEPA Mid-Continent Ecology Division Laboratory in Duluth in the 1980s. The Environmental Protection Agency funded the project to develop SMILES. It has since modified and extended by others, most notably by Daylight Chemical Information Systems. In 2007, a standard called OpenSMILES was developed by the Blue Obelisk open-source chemistry community. Other linear notations include the Wiswesser Line Notation, ROSDAL and SLN, in July 2006, the IUPAC introduced the InChI as a standard for formula representation. SMILES is generally considered to have the advantage of being slightly more human-readable than InChI, the term SMILES refers to a line notation for encoding molecular structures and specific instances should strictly be called SMILES strings. However, the term SMILES is also used to refer to both a single SMILES string and a number of SMILES strings, the exact meaning is usually apparent from the context. The terms canonical and isomeric can lead to confusion when applied to SMILES. The terms describe different attributes of SMILES strings and are not mutually exclusive, typically, a number of equally valid SMILES strings can be written for a molecule. For example, CCO, OCC and CC all specify the structure of ethanol, algorithms have been developed to generate the same SMILES string for a given molecule, of the many possible strings, these algorithms choose only one of them. This SMILES is unique for each structure, although dependent on the algorithm used to generate it. These algorithms first convert the SMILES to a representation of the molecular structure. A common application of canonical SMILES is indexing and ensuring uniqueness of molecules in a database, there is currently no systematic comparison across commercial software to test if such flaws exist in those packages. SMILES notation allows the specification of configuration at tetrahedral centers, and these are structural features that cannot be specified by connectivity alone and SMILES which encode this information are termed isomeric SMILES
8.
Chemical formula
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These are limited to a single typographic line of symbols, which may include subscripts and superscripts. A chemical formula is not a name, and it contains no words. Although a chemical formula may imply certain simple chemical structures, it is not the same as a full chemical structural formula. Chemical formulas can fully specify the structure of only the simplest of molecules and chemical substances, the simplest types of chemical formulas are called empirical formulas, which use letters and numbers indicating the numerical proportions of atoms of each type. Molecular formulas indicate the numbers of each type of atom in a molecule. For example, the formula for glucose is CH2O, while its molecular formula is C6H12O6. This is possible if the relevant bonding is easy to show in one dimension, an example is the condensed molecular/chemical formula for ethanol, which is CH3-CH2-OH or CH3CH2OH. For reasons of structural complexity, there is no condensed chemical formula that specifies glucose, chemical formulas may be used in chemical equations to describe chemical reactions and other chemical transformations, such as the dissolving of ionic compounds into solution. A chemical formula identifies each constituent element by its chemical symbol, in empirical formulas, these proportions begin with a key element and then assign numbers of atoms of the other elements in the compound, as ratios to the key element. For molecular compounds, these numbers can all be expressed as whole numbers. For example, the formula of ethanol may be written C2H6O because the molecules of ethanol all contain two carbon atoms, six hydrogen atoms, and one oxygen atom. Some types of compounds, however, cannot be written with entirely whole-number empirical formulas. An example is boron carbide, whose formula of CBn is a variable non-whole number ratio with n ranging from over 4 to more than 6.5. When the chemical compound of the consists of simple molecules. These types of formulas are known as molecular formulas and condensed formulas. A molecular formula enumerates the number of atoms to reflect those in the molecule, so that the formula for glucose is C6H12O6 rather than the glucose empirical formula. However, except for very simple substances, molecular chemical formulas lack needed structural information, for simple molecules, a condensed formula is a type of chemical formula that may fully imply a correct structural formula. For example, ethanol may be represented by the chemical formula CH3CH2OH
9.
Melting point
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The melting point of a solid is the temperature at which it changes state from solid to liquid at atmospheric pressure. At the melting point the solid and liquid phase exist in equilibrium, the melting point of a substance depends on pressure and is usually specified at standard pressure. When considered as the temperature of the change from liquid to solid. Because of the ability of some substances to supercool, the point is not considered as a characteristic property of a substance. For most substances, melting and freezing points are approximately equal, for example, the melting point and freezing point of mercury is 234.32 kelvins. However, certain substances possess differing solid-liquid transition temperatures, for example, agar melts at 85 °C and solidifies from 31 °C to 40 °C, such direction dependence is known as hysteresis. The melting point of ice at 1 atmosphere of pressure is close to 0 °C. In the presence of nucleating substances the freezing point of water is the same as the melting point, the chemical element with the highest melting point is tungsten, at 3687 K, this property makes tungsten excellent for use as filaments in light bulbs. Many laboratory techniques exist for the determination of melting points, a Kofler bench is a metal strip with a temperature gradient. Any substance can be placed on a section of the strip revealing its thermal behaviour at the temperature at that point, differential scanning calorimetry gives information on melting point together with its enthalpy of fusion. A basic melting point apparatus for the analysis of crystalline solids consists of an oil bath with a transparent window, the several grains of a solid are placed in a thin glass tube and partially immersed in the oil bath. The oil bath is heated and with the aid of the melting of the individual crystals at a certain temperature can be observed. In large/small devices, the sample is placed in a heating block, the measurement can also be made continuously with an operating process. For instance, oil refineries measure the point of diesel fuel online, meaning that the sample is taken from the process. This allows for more frequent measurements as the sample does not have to be manually collected, for refractory materials the extremely high melting point may be determined by heating the material in a black body furnace and measuring the black-body temperature with an optical pyrometer. For the highest melting materials, this may require extrapolation by several hundred degrees, the spectral radiance from an incandescent body is known to be a function of its temperature. An optical pyrometer matches the radiance of a body under study to the radiance of a source that has been previously calibrated as a function of temperature, in this way, the measurement of the absolute magnitude of the intensity of radiation is unnecessary. However, known temperatures must be used to determine the calibration of the pyrometer, for temperatures above the calibration range of the source, an extrapolation technique must be employed
10.
Anthraquinones
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For the parent molecule 9, 10-antraquinone, see anthraquinone Anthraquinones are a class of naturally occurring phenolic compounds based on the 9, 10-anthraquinone skeleton. A type II polyketide synthase is responsible for anthraquinone biosynthesis in the bacterium Photorhabdus luminescens, chorismate, formed by isochorismate synthase in the shikimate pathway, is an important precursor of anthraquinones in Morinda citrifolia. 0. 5g of plant extract is shaken with 10 ml of benzene, 5ml of 10% ammonia is added to the filtrate. The mixture is shaken and the presence of pink, red or violet colour indicates the presence of anthraquinones, hypericin and fagopyrin are naphthodianthrones, anthraquinone-derivatives. Many quinones are stable in multiple states, as such they can absorb electrons when appropriate counterions are available to maintain the bulk neutrality of the material. As such,2, 6-dihydroanthraquinone can be used as a negative electrolyte reservoir in a flow battery to store electrons when a current is applied at an ion-selective membrane. Anthraquinones are also used as such as in the drug Senna glycoside
11.
Natural dye
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Natural dyes are dyes or colorants derived from plants, invertebrates, or minerals. The majority of natural dyes are vegetable dyes from plant sources—roots, berries, bark, leaves, archaeologists have found evidence of textile dyeing dating back to the Neolithic period. In China, dyeing with plants, barks and insects has been traced more than 5,000 years. The essential process of dyeing changed little over time, typically, the dye material is put in a pot of water and then the textiles to be dyed are added to the pot, which is heated and stirred until the color is transferred. Textile fibre may be dyed before spinning, but most textiles are yarn-dyed or piece-dyed after weaving, many mordants, and some dyes themselves, produce strong odors, and large-scale dyeworks were often isolated in their own districts. 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 such as cochineal and logwood were brought to Europe by the Spanish treasure fleets, the discovery of man-made synthetic dyes in the mid-19th century triggered a long decline in the large-scale market for natural dyes. Natural dyeing techniques are preserved by artisans in traditional cultures around the world. In the early 21st century, the market for natural dyes in the industry is experiencing a resurgence. Western consumers have become concerned about the health and environmental impact of synthetic dyes in manufacturing. The European Union, for example, has encouraged Indonesian batik cloth producers to switch to natural dyes to improve their market in Europe. Protein fibres require vat, acid, or indirect/mordant dyes, that require a bonding agent, each synthetic fibre requires its own dyeing method, for example, nylon requires acid, disperse and pigment dyes, rayon acetate requires disperse dyes, and so on. The earliest surviving evidence of textile dyeing was found at the large Neolithic settlement at Çatalhöyük in southern Anatolia, polychrome or multicolored fabrics seem to have been developed in the 3rd or 2nd millennium BCE. Textiles with a warp and an ochre-yellow weft were discovered in Egyptian pyramids of the Sixth Dynasty. His contributions to refining the process and his theories on colour brought much praise by the well known poet. Some dyestuffs, such as indigo and lichens, will give good color when used alone, the majority of plant dyes, however, also require the use of a mordant, a chemical used to fix the color in the textile fibres. These dyes are called adjective dyes, by using different mordants, dyers can often obtain a variety of colors and shades from the same dye. Fibres or cloth may be pretreated with mordants, or the mordant may be incorporated in the dyebath, salt helps to fix or increase fastness of colors, vinegar improves reds and purples, and the ammonia in stale urine assists in the fermentation of indigo dyes
12.
Anthraquinone
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Anthraquinone, also called anthracenedione or dioxoanthracene, is an aromatic organic compound with formula C 14H 8O2. Several isomers are possible, each of which can be viewed as a quinone derivative, the term anthraquinone, however, almost invariably refers to one specific isomer,9, 10-anthraquinone wherein the keto groups are located on the central ring. It is a block of many dyes and is used in bleaching pulp for papermaking. It is a highly crystalline solid, poorly soluble in water. For instance, it is almost completely insoluble in ethanol near room temperature but 2.25 g will dissolve in 100 g of boiling ethanol,9, 10-Anthraquinone is obtained industrially by the oxidation of anthracene, a reaction that is localized at the central ring. It is also prepared by the Friedel-Crafts reaction of benzene and phthalic anhydride in presence of AlCl3, the resulting o-benzoylbenzoic acid then undergoes cyclization, forming anthraquinone. This reaction is useful for producing substituted anthraquinones, the Diels-Alder reaction of naphthoquinone and butadiene followed by oxidative dehydrogenation will also produce 9, 10-anthraquinone. Lastly, BASF has developed a process proceeds via the acid-catalyzed dimerization of styrene to give a 1, 3-diphenylbutene. It also arises via the Rickert-Alder reaction, a retro-Diels-Alder reaction, in a classic organic reaction called the Bally–Scholl synthesis, named after Oscar Bally and Roland Scholl, anthraquinone condenses with glycerol forming benzanthrone. In this reaction, the quinone is first reduced with copper metal in sulfuric acid after which the glycerol is added, synthetic dyes are often derived from 9, 10-anthraquinone, such as alizarin. Important derivatives are 1-nitroanthraquinone, anthraquinone-1-sulfonic acid, and the dinitroanthraquinone, natural pigments that are derivatives of anthraquinone are found, inter alia, in aloe latex, senna, rhubarb, and cascara buckthorn, fungi, lichens, and some insects. 9, 10-Anthraquinone is used as an additive in production of paper pulp by alkaline processes, like the Kraft. The anthraquinone is a redox catalyst, the reaction mechanism may involve single electron transfer. The anthraquinone is oxidizing the reducing end of polysaccharides in the pulp, i. e. cellulose and hemicellulose, the anthraquinone is reduced to 9, 10-dihydroxyanthracene which then can react with lignin. The lignin is degraded and becomes more water-soluble and thereby more easy to wash away from the pulp and this process gives an increase in yield of pulp, typically 1-3% and a reduction in kappa number. Sodium 2-anthraquinonesulfonate is an anthraquinone derivative that was the first anthraquinone derivative discovered to have a catalytic effect in the alkaline pulping processes. A large industrial application of anthraquinones is for the production of hydrogen peroxide, 2-Ethyl-9, 10-anthraquinone or a related alkyl derivatives is used, rather than anthraquinone itself. 9, 10-Anthraquinone is used as a bird repellant on seeds and it has also been mixed with lanolin and used as a wool spray to protect sheep flocks against kea attacks in New Zealand
13.
Hydrogen
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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
14.
Hydroxy group
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A hydroxy or hydroxyl group is the entity with the formula OH. It contains oxygen bonded to hydrogen, in organic chemistry, alcohol and carboxylic acids contain hydroxy groups. The anion, called hydroxide, consists of a hydroxy group, according to IUPAC rules, the term hydroxyl refers to the radical OH only, while the functional group −OH is called hydroxy group. Water, alcohols, carboxylic acids, and many other hydroxy-containing compounds can be deprotonated readily and this behavior is rationalized by the disparate electronegativities of oxygen and hydrogen. Hydroxy-containing compounds engage in hydrogen bonding, which causes them to stick together, organic compounds, which are often poorly soluble in water, become water soluble when they contain two or more hydroxy groups, as illustrated by sugars and amino acid. The hydroxy group is pervasive in chemistry and biochemistry, many inorganic compounds contain hydroxy groups, including sulfuric acid, the chemical compound produced on the largest scale industrially. Hydroxy groups participate in the reactions that link simple biological molecules into long chains. The joining of a fatty acid to glycerol to form a triacylglycerol removes the −OH from the end of the fatty acid. The joining of two aldehyde sugars to form a disaccharide removes the −OH from the group at the aldehyde end of one sugar. The creation of a bond to link two amino acids to make a protein removes the −OH from the carboxy group of one amino acid. Hydroxyl radicals are highly reactive and undergo chemical reactions that make them short-lived, when biological systems are exposed to hydroxyl radicals, they can cause damage to cells, including those in humans, where they react with DNA, lipids, and proteins. In 2009, Indias Chandrayaan-1 satellite, NASAs Cassini spacecraft and the Deep Impact probe have each detected the presence of water by evidence of hydroxyl fragments on the Moon. As reported by Richard Kerr, A spectrometer detected an infrared absorption at a wavelength of 3.0 micrometers that only water or hydroxyl—a hydrogen, NASA also reported in 2009 that the LCROSS probe revealed an ultraviolet emission spectrum consistent with hydroxyl presence. The Venus Express orbiter sent back Venus science data from April 2006 until December 2014, results from Venus Express include the detection of hydroxyl in the atmosphere. Hydronium Ion Oxide Reece, Jane, Urry, Lisa, Cain, Michael, Wasserman, Steven, Minorsky, Peter, Jackson, berge, Susan, Golden, Brandy, Triglia, Logan
15.
Lake pigment
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A lake pigment is a pigment manufactured by precipitating a dye with an inert binder, or mordant, usually a metallic salt. Unlike vermilion, ultramarine, and other pigments made from ground minerals, manufacturers and suppliers to artists and industry frequently omit the lake designation in the name. Many lake pigments are fugitive because the involved are not lightfast. Red lakes were important in Renaissance and Baroque paintings, they were often used as translucent glazes to portray the colors of rich fabrics. This sense of lake is unconnected with lake meaning body of water and it has the same root as the word lacquer, and comes originally from the Hindi word lakh, through the Arabic word lakk and the Persian word lak. Many lake pigments are azo dyes and they characteristically have sulfonate and sometimes carboxylate substituents, which confer negative charge to the chromophore. The metallic salt or binder used must be inert and insoluble in the vehicle, the organic component of the dye determines which wavelengths are absorbed and reflected by the resulting precipitate. In ancient times chalk, white clay, and crushed bones were used as sources of the calcium salts. The salts that are used today include barium sulfate, calcium sulfate, aluminium hydroxide. Lake pigments have a history in decoration and the arts. Some have been produced for thousands of years and traded over long distances. The red lakes were important in the history of art, because they were translucent, they were often used in layers of glazes over a more opaque red to create a deep. They were very often used by Titian and other Venetian artists of the 16th century to depict fine draperies, indigo lake was originally produced from the leaves of woad, and was known in ancient Egypt. In the late Middle Ages, a fashion for woad as a textile dye led to overplanting, after trade routes opened to the east, indigo was imported from India as a substitute for woad, and the cultivation of woad became uneconomical in Europe. Today, the blue dye known as indigo once produced from woad. The dye and pigment are both fugitive, rose madder lake, originally from the root of the madder plant, is also known as alizarin crimson in its synthetic form. Since rose madder is fugitive when exposed to light, its use has largely superseded, even in synthetic form. Carmine lake was produced from the cochineal insect, native to Central
16.
Rose madder
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Rose madder is the commercial name sometimes used to designate a paint made from the pigment madder lake, a traditional lake pigment extracted from the common madder plant Rubia tinctorum. Madder lake contains two red dyes, alizarin and purpurin. Madder has been cultivated as a dyestuff since antiquity in Central Asia, South Asia, and Egypt, where it was grown as early as 1500 BC. Cloth dyed with madder root dye was found in the tomb of the Pharaoh Tutankhamun and on an Egyptian tomb painting from the Graeco-Roman period and it was also found in ancient Greece, and in Italy in the Baths of Titus and the ruins of Pompeii. In Spain, madder was introduced and then cultivated by the Moors, the production of a lake pigment from madder seems to have been first invented by the ancient Egyptians. Ideal color was said to come from plants 18 to 28 months old that had grown in calcareous soil. The resulting madder lake had a less fugitive color and could be used more efficaciously, for example by blending it into a paint. Over the following years, other salts, including those containing chromium, iron. In 1827, the French chemists Pierre-Jean Robiquet and Colin began producing garancine and they then found that madder lake contained two colorants, the red alizarin and the more rapidly fading purpurin. Purpurin is only present in the form of madder and gives a distinctive orange/red generally warmer tone that pure synthetic alizarin does not. Purpurin fluoresces yellow to red under ultraviolet light, while synthetic alizarin slightly shows violet, alizarin was discovered before purpurin, by heating the ground madder with acid and potash. A yellow vapor crystallized into bright red needles, alizarin and this alizarin concentrate comprises only 1% of the madder root. Natural rose madder supplied half the world with red, until 1868, however, their recipe was not feasible for large-scale production, it required expensive and volatile substances, specifically bromine. William Perkin, the inventor of mauve, filed a patent in June 1869 for a new way to produce alizarin without bromine. Gräbe, Liebermann, and Heinrich Caro filed a patent for a similar process just one day before Perkin did - yet both patents were granted, as Perkins had been sealed first. They divided the market in half, Perkin sold to the English market, because this synthetic alizarin dye could be produced for a fraction of the cost of the natural madder dye, it quickly replaced all madder-based colorants then in use. In turn, alizarin itself has now largely replaced by the more light-resistant quinacridone pigments originally developed at DuPont in 1958. It is still manufactured in traditional ways to meet the demands of the art market
17.
Pierre Jean Robiquet
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Pierre Jean Robiquet was a French chemist. He laid founding work in identifying amino acids, the building blocks of proteins. He was at first a pharmacist in the French armies during the French Revolution years and became a professor at the École de pharmacie in Paris, some of these discoveries were made in collaboration with other scientists. Distinguished with the order of the Légion dHonneur, in the fall of 1805, Robiquet, then a young help working in the laboratory of Louis Nicolas Vauquelin, started analyses, with what rudimentary methods were then available, with asparagus juice. Duly convinced this is something new, they call this matter asparagin. Asparagine will turn out to be one of the 22 amino acids that build-up all living matter on earth, progress in isolating the other amino acids will be very slow, with less than a handful in total during the whole 19th century. Even until the middle of 19th century, all used for colouring cloth were natural substances. Furthermore, many lacked stability through washing or exposure to sunlight and its extraction was variable and complicated, and dependent on the availability of the very specific type of shell from which it was extracted. Another type of red dye used from times immemorial was obtained from madder root in Central Asia and Egypt. Cloth dyed with madder root pigment was found in the tomb of the Pharaoh Tutankhamun and in the ruins of Pompeii, in the Middle Ages, Charlemagne encouraged madder cultivation. It grew well in the soils of the Netherlands and became an important part of the local economy. By 1804, the English dye maker George Field had introduced new techniques known as lake madder and it is one of the most effective orally-administered opioid analgesics and has a wide safety margin. It is from 8 to 12 percent of the strength of morphine in most people, differences in metabolism can change this figure as can other medications, depending on its route of administration. While codeine can still be extracted from opium, its original source. Thus, in 1809, Robiquet extracts from liquorice root a sweetish matter which he dubs glycyrrhizine, from Glycirrhiza, Robiquet likewise analysed a variety of animal tissues. In the frame of that investigation, Robiquet in addition evidences the presence of uric acid within insects feeding on plant tissues. Over a period of fifteen years, Pierre Robiquet will also conduct a series of investigations on bitter almonds oil. In 1816, together with Jean-Jacques Colin, they obtain a new component which they call éther hydrochlorique and this discovery was opening the door to the huge family of aromatic molecules, that are based on the cyclic 6 carbon benzenoic structure
18.
Carl Theodore Liebermann
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Carl Theodore Liebermann was a German chemist and student of Adolf von Baeyer. Liebermann first studied at the University of Heidelberg where Robert Wilhelm Bunsen was teaching and he then joined the group of Adolf von Baeyer at the University of Berlin where he received his Ph. D. in 1865. Together with Carl Gräbe, Liebermann synthesized the dye alizarin in 1868. After his habilitation in 1870 he became professor at the University of Berlin after Adolf von Baeyer left for the University of Strasbourg, shortly after Liebermann retired, in 1914, he died. In 1826, the French chemist Pierre Jean Robiquet had isolated from the root of a plant, madder, and defined the structure of, alizarin, a remarkable red dye. Liebermanns 1868 discovery that alizarin can be reduced to form anthracene, the patent of Liebermann and Carl Gräbe for the synthesis of alizarin from anthracene was filed one day before the patent of William Henry Perkin. The synthesis is a chlorination or bromination of anthracene with a subsequent oxidation forming the alizarin, Pierre Jean Robiquet Carl Gräbe William Henry Perkin
19.
Heinrich Caro
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Heinrich Caro, was a German chemist. He started his study of chemistry at the Friedrich Wilhelms University and later chemistry, during this time he improved the analysis of madder lake. After he returned to Germany he conducted his military service in 1857 and 1858 and he worked in the laboratory of Jacques Meyer the father of Viktor Meyer in Berlin. In 1858 he was able to return to Mühlheim where he was not able to conduct his work and he joined the chemical firm Roberts, Dale in Manchester which he knew from his former visit. During his time in England he improved the extraction of Mauveine from the residues of the synthesis and developed a synthesis for aniline red, in 1861 Caro returned to Germany and stayed at the laboratory of Robert Bunsen until he joined the Chemische Fabrik Dyckerhoff Clemm & Co. This chemical company later became BASF, Caro was responsible for indigo research at BASF and he and Adolf von Baeyer synthesised the first indigo dye in 1878. Caro also patented the dye alizarin on behalf of BASF and he was the first to isolate acridine and Caros acid is named after him. Nikodem Caro, co-inventor of the Frank-Caro process to produce calcium cyanamide Linde-Frank-Caro process, heinrich Caro and the creation of modern chemical industry. Heinrich Caro at scienceandsociety. co. uk Indigo at uni-bayreuth. de Indigo at econdoc. de
20.
Rubia tinctorum
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Rubia tinctorum, the common madder or dyers madder, is a herbaceous perennial plant species belonging to the bedstraw and coffee family Rubiaceae. The common madder can grow up to 1.5 m in height, the evergreen leaves are approximately 5–10 cm long and 2–3 cm broad, produced in whorls of 4–7 starlike around the central stem. It climbs with tiny hooks at the leaves and stems, the flowers are small, with five pale yellow petals, in dense racemes, and appear from June to August, followed by small red to black berries. The roots can be over a long, up to 12 mm thick. It prefers loamy soils with a constant level of moisture, Madder is used as food plants for the larvae of some Lepidoptera species including the Hummingbird Hawk Moth. It has been used since ancient times as a red dye for leather, wool, cotton. For dye production, the roots are harvested in the first year, the outer brown layer gives the common variety of the dye, the lower yellow layer the refined variety. The dye is fixed to the cloth with help of a mordant, Madder can be fermented for dyeing as well. In France, the remains were used to produce a spirit as well, the roots contain the acid ruberthyrin. By drying, fermenting or a treatment with acids, this is changed to sugar, alizarin and purpurin, purpurin is normally not coloured, but is red when dissolved in alkaline solutions. Mixed with clay and treated with alum and ammonia, it gives a brilliant red colourant, the pulverised roots can be dissolved in sulfuric acid, which leaves a dye called garance after drying. Another method of increasing the yield consisted of dissolving the roots in sulfuric acid after they had used for dyeing. This produces a dye called garanceux, by treating the pulverized roots with alcohol, colorin was produced. It contained 40–50 times the amount of alizarin of the roots, the chemical name for the pigment is alizarin, of the anthraquinone-group, and was used to make the alizarine ink in 1855 by the Professor Leonhardi of Dresden, Germany. In 1869, the German chemists Graebe and Liebermann synthesised artificial alizarin, which was produced industrially from 1871 onwards, in the 20th century, madder was only grown in some areas of France. The plants roots contain several compounds, such as 1, 3-Dihydroxyanthraquinone,1, 4-Dihydroxyanthraquinone,1,2, 4-Trihydroxyanthraquinone and 1. This last compound gives it its red colour to a textile dye known as Rose madder and it was also used as a colourant, especially for paint, that is referred to as Madder lake. The substance was derived from another species, Rubia cordifolia
21.
Alizarin
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Alizarin or 1, 2-dihydroxyanthraquinone is an organic compound with formula C 14H 8O4 that has been used throughout history as a prominent red dye, principally for dyeing textile fabrics. Historically it was derived from the roots of plants of the madder genus, in 1869, it became the first natural pigment to be duplicated synthetically. Alizarin is the ingredient for the manufacture of the madder lake pigments known to painters as Rose madder. A notable use of alizarin in modern times is as an agent in biological research because it stains free calcium. Alizarin continues to be used commercially as a red textile dye, Madder has been cultivated as a dyestuff since antiquity in central Asia and Egypt, where it was grown as early as 1500 BC. Cloth dyed with madder root pigment was found in the tomb of the Pharaoh Tutankhamun and in the ruins of Pompeii, in the Middle Ages, Charlemagne encouraged madder cultivation. Madder was widely used as a dye in Western Europe in the Late Medieval centuries, in 17th century England, alizarin was used as a red dye for the clothing of the parliamentary New Model Army. The distinctive red color would continue to be worn for centuries, giving English, the madder dyestuff is combined with a dye mordant. According to which mordant used, the color may be anywhere from pink through purple to dark brown. In the 18th century the most valued color was a bright red known as Turkey Red, the combination of mordants and overall technique used to obtain the Turkey Red originated in the Middle East or Turkey. It was a complex and multi-step technique in its Middle Eastern formulation, the process was simplified in late 18th-century Europe. This resulting madder lake has a color, and can be used more efficaciously. This general method of preparing lakes has been known for centuries but was simplified in the late 18th, in 1826, the French chemist Pierre-Jean Robiquet found that madder root contained two colorants, the red alizarin and the more rapidly fading purpurin. About the same time, the English dye chemist William Henry Perkin independently discovered the same synthesis, the subsequent discovery that anthracene could be abstracted from coal tar further advanced the importance and affordability of alizarins artificial synthesis. The synthetic alizarin could be produced for a fraction of the cost of the product. The principal synthesis entailed oxidation of anthraquinone-2-sulfonic acid with sodium nitrate in concentrated sodium hydroxide, Alizarin itself has been in turn largely replaced today by the more light-resistant quinacridone pigments developed at DuPont in 1958. Alizarin is one of ten dihydroxyanthraquinone isomers and its molecular structure can be viewed as being derived from anthraquinone by replacement of two neighboring hydrogen atoms by hydroxyl groups. It is soluble in hexane and chloroform, and can be obtained from the latter as red-purple crystals, Alizarin changes color depending on the pH of the solution it is in, thereby making it a pH indicator
22.
Glycoside
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In chemistry, a glycoside /ˈɡlaɪkəsaɪd/ is a molecule in which a sugar is bound to another functional group via a glycosidic bond. Glycosides play numerous important roles in living organisms, many plants store chemicals in the form of inactive glycosides. These can be activated by enzyme hydrolysis, which causes the part to be broken off. Many such plant glycosides are used as medications, in animals and humans, poisons are often bound to sugar molecules as part of their elimination from the body. In formal terms, a glycoside is any molecule in which a group is bonded through its anomeric carbon to another group via a glycosidic bond. Glycosides can be linked by an O-, N-, S-, according to the IUPAC, the name C-glycoside is a misnomer, the preferred term is C-glycosyl compound. The given definition is the one used by IUPAC, which recommends the Haworth projection to correctly assign stereochemical configurations, many authors require in addition that the sugar be bonded to a non-sugar for the molecule to qualify as a glycoside, thus excluding polysaccharides. The sugar group is known as the glycone and the non-sugar group as the aglycone or genin part of the glycoside. The glycone can consist of a sugar group or several sugar groups. The first glycoside ever identified was amygdalin, by the French chemists Pierre Robiquet and Antoine Boutron-Charlard, molecules containing an N-glycosidic bond are known as glycosylamines and are not discussed in this article. Glycosylamines and glycosides are grouped together as glycoconjugates, other glycoconjugates include glycoproteins, glycopeptides, peptidoglycans, glycolipids, much of the chemistry of glycosides is explained in the article on glycosidic bonds. For example, the glycone and aglycone portions can be separated by hydrolysis in the presence of acid. There are also numerous enzymes that can form and break glycosidic bonds, the most important cleavage enzymes are the glycoside hydrolases, and the most important synthetic enzymes in nature are glycosyltransferases. Genetically altered enzymes termed glycosynthases have been developed that can form glycosidic bonds in excellent yield, there are many ways to chemically synthesize glycosidic bonds. Fischer glycosidation refers to the synthesis of glycosides by the reaction of unprotected monosaccharides with alcohols in the presence of an acid catalyst. The Koenigs-Knorr reaction is the condensation of glycosyl halides and alcohols in the presence of salts such as silver carbonate or mercuric oxide. Glycosides can be classified by the glycone, by the type of glycosidic bond, in the body, toxic substances are often bonded to glucuronic acid to increase their water solubility, the resulting glucuronides are then excreted. Depending on whether the glycosidic bond lies below or above the plane of the sugar molecule
23.
Crystal
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A crystal or crystalline solid is a solid material whose constituents are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macroscopic single crystals are usually identifiable by their geometrical shape, the scientific study of crystals and crystal formation is known as crystallography. The process of crystal formation via mechanisms of crystal growth is called crystallization or solidification, the word crystal derives from the Ancient Greek word κρύσταλλος, meaning both ice and rock crystal, from κρύος, icy cold, frost. Examples of large crystals include snowflakes, diamonds, and table salt, most inorganic solids are not crystals but polycrystals, i. e. many microscopic crystals fused together into a single solid. Examples of polycrystals include most metals, rocks, ceramics, a third category of solids is amorphous solids, where the atoms have no periodic structure whatsoever. Examples of amorphous solids include glass, wax, and many plastics, Crystals are often used in pseudoscientific practices such as crystal therapy, and, along with gemstones, are sometimes associated with spellwork in Wiccan beliefs and related religious movements. The scientific definition of a crystal is based on the arrangement of atoms inside it. A crystal is a solid where the form a periodic arrangement. For example, when liquid water starts freezing, the change begins with small ice crystals that grow until they fuse. Most macroscopic inorganic solids are polycrystalline, including almost all metals, ceramics, ice, rocks, solids that are neither crystalline nor polycrystalline, such as glass, are called amorphous solids, also called glassy, vitreous, or noncrystalline. These have no periodic order, even microscopically, there are distinct differences between crystalline solids and amorphous solids, most notably, the process of forming a glass does not release the latent heat of fusion, but forming a crystal does. A crystal structure is characterized by its cell, a small imaginary box containing one or more atoms in a specific spatial arrangement. The unit cells are stacked in three-dimensional space to form the crystal, the symmetry of a crystal is constrained by the requirement that the unit cells stack perfectly with no gaps. There are 219 possible crystal symmetries, called space groups. These are grouped into 7 crystal systems, such as cubic crystal system or hexagonal crystal system, Crystals are commonly recognized by their shape, consisting of flat faces with sharp angles. Euhedral crystals are those with obvious, well-formed flat faces, anhedral crystals do not, usually because the crystal is one grain in a polycrystalline solid. The flat faces of a crystal are oriented in a specific way relative to the underlying atomic arrangement of the crystal. This occurs because some surface orientations are more stable than others, as a crystal grows, new atoms attach easily to the rougher and less stable parts of the surface, but less easily to the flat, stable surfaces
24.
Ethanol
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Ethanol, also called alcohol, ethyl alcohol, and drinking alcohol, is the principal type of alcohol found in alcoholic beverages. It is a volatile, flammable, colorless liquid with a characteristic odor. Its chemical formula is C 2H 6O, which can be written also as CH 3-CH 2-OH or C 2H 5-OH, ethanol is mostly produced by the fermentation of sugars by yeasts, or by petrochemical processes. It is a psychoactive drug, causing a characteristic intoxication. It is widely used as a solvent, as fuel, and as a feedstock for synthesis of other chemicals, the eth- prefix and the qualifier ethyl in ethyl alcohol originally come from the name ethyl assigned in 1834 to the group C 2H 5- by Justus Liebig. He coined the word from the German name Aether of the compound C 2H 5-O-C 2H5, according to the Oxford English Dictionary, Ethyl is a contraction of the Ancient Greek αἰθήρ and the Greek word ύλη. The name ethanol was coined as a result of a resolution that was adopted at the International Conference on Chemical Nomenclature that was held in April 1892 in Geneva, Switzerland. The term alcohol now refers to a class of substances in chemistry nomenclature. The Oxford English Dictionary claims that it is a loan from Arabic al-kuḥl, a powdered ore of antimony used since aniquity as a cosmetic. The use of alcohol for ethanol is modern, first recorded 1753, the systematic use in chemistry dates to 1850. Ethanol is used in medical wipes and most common antibacterial hand sanitizer gels as an antiseptic, ethanol kills organisms by denaturing their proteins and dissolving their lipids and is effective against most bacteria and fungi, and many viruses. However, ethanol is ineffective against bacterial spores, ethanol may be administered as an antidote to methanol and ethylene glycol poisoning. Ethanol, often in high concentrations, is used to dissolve many water-insoluble medications, as a central nervous system depressant, ethanol is one of the most commonly consumed psychoactive drugs. The amount of ethanol in the body is typically quantified by blood alcohol content, small doses of ethanol, in general, produce euphoria and relaxation, people experiencing these symptoms tend to become talkative and less inhibited, and may exhibit poor judgment. Ethanol is commonly consumed as a drug, especially while socializing. The largest single use of ethanol is as a fuel and fuel additive. Brazil in particular relies heavily upon the use of ethanol as an engine fuel, gasoline sold in Brazil contains at least 25% anhydrous ethanol. Hydrous ethanol can be used as fuel in more than 90% of new gasoline fueled cars sold in the country, Brazilian ethanol is produced from sugar cane and noted for high carbon sequestration
25.
Chloroform
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Chloroform, or trichloromethane, is an organic compound with formula CHCl3. It is a colorless, sweet-smelling, dense liquid that is produced on a scale as a precursor to PTFE. It is also a precursor to various refrigerants and it is one of the four chloromethanes and a trihalomethane. The molecule adopts tetrahedral molecular geometry with C3v symmetry, the total global flux of chloroform through the environment is approximately 7005660000000000000♠660000 tonnes per year, and about 90% of emissions are natural in origin. Many kinds of seaweed produce chloroform, and fungi are believed to produce chloroform in soil and its half-life in air ranges from 55 to 620 days. Biodegradation in water and soil is slow, chloroform does not significantly bioaccumulate in aquatic organisms. Justus von Liebig carried out the cleavage of chloral. Eugène Soubeiran obtained the compound by the action of chlorine bleach on both ethanol and acetone, in 1834, French chemist Jean-Baptiste Dumas determined chloroforms empirical formula and named it. In 1835, Dumas prepared the substance by the cleavage of trichloroacetic acid. Regnault prepared chloroform by chlorination of chloromethane, in 1842 Dr Robert Mortimer Glover in London discovered the anaesthetic qualities of chloroform on laboratory animals. In 1847, Scottish obstetrician James Y. Simpson was the first to demonstrate the properties of chloroform on humans. By the 1850s, chloroform was being produced on a basis by using the Liebig procedure. Today, chloroform — along with dichloromethane — is prepared exclusively, in industry, chloroform is produced by heating a mixture of chlorine and either chloromethane or methane. CDCl3 is a solvent used in NMR spectroscopy. Deuterochloroform is produced by the reaction, the reaction of acetone with sodium hypochlorite or calcium hypochlorite. The haloform process is now obsolete for the production of ordinary chloroform, deuterochloroform can also be prepared by the reaction of sodium deuteroxide with chloral hydrate, or from ordinary chloroform. The haloform reaction can also occur inadvertently in domestic settings, bleaching with hypochlorite generates halogenated compounds in side reactions, chloroform is the main byproduct. Chlorodifluoromethane is then converted into tetrafluoroethylene, the precursor to Teflon
26.
Aluminium sulfate
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Aluminium sulfate is a chemical compound with the formula Al23. It is soluble in water and is used as a flocculating agent in the purification of drinking water and waste water treatment plants. Aluminium sulfate is referred to as a type of alum. Alums are double sulfate salts, with the formula AM 2·12H 2O, the anhydrous form occurs naturally as a rare mineral millosevichite, found e. g. in volcanic environments and on burning coal-mining waste dumps. Aluminium sulfate is rarely, if ever, encountered as the anhydrous salt and it forms a number of different hydrates, of which the hexadecahydrate Al23•16H2O and octadecahydrate Al23•18H2O are the most common. The heptadecahydrate, whose formula can be written as 23•5H2O, occurs naturally as the mineral alunogen, in water purification, it causes impurities to coagulate into larger particles and then settle to the bottom of the container more easily. This process is called coagulation or flocculation, research suggests that in Australia, aluminium sulfate used this way in drinking water treatment is the primary source of hydrogen sulfide gas in sanitary sewer systems. An improper and excess application incident in 1988 polluted the water supply of Camelford in Cornwall, when dissolved in a large amount of neutral or slightly alkaline water, aluminium sulfate produces a gelatinous precipitate of aluminium hydroxide, Al3. In dyeing and printing cloth, the gelatinous precipitate helps the dye adhere to the fibers by rendering the pigment insoluble. Aluminium sulfate is used to reduce the pH of garden soil, as it hydrolyzes to form the aluminium hydroxide precipitate. An example of changing the pH level of soil can do to plants is visible when looking at Hydrangea macrophylla. The gardener can add aluminium sulfate to the soil to reduce the pH which in turn result in the flowers of the Hydrangea turning a different color. The aluminium is what makes the flowers blue, at a higher pH, thus, both the aluminium and sulfur keep the plants blue. Despite this, several countries, primarily in Asia, still use the widely available, aluminium potassium sulfate is usually found in baking powder. In the construction industry, it is used as waterproofing agent, another use is a foaming agent in fire fighting foam. It is also used in pencils, and pain relief from stings. It can also be effective as a molluscicide, killing spanish slugs. It is used in dentistry because of its astringent and hemostatic properties and it combines with water forming hydrated salts of various compositions
27.
Precipitation (chemistry)
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Precipitation is the creation of a solid from a solution. When the reaction occurs in a solution, the solid formed is called the precipitate. The chemical that causes the solid to form is called the precipitant, without sufficient force of gravity to bring the solid particles together, the precipitate remains in suspension. After sedimentation, especially when using a centrifuge to press it into a compact mass, Precipitation can be used as a medium. The precipitate-free liquid remaining above the solid is called the supernate or supernatant, powders derived from precipitation have also historically been known as flowers. When the solid appears in the form of fibers which have been through chemical processing. Sometimes the formation of a precipitate indicates the occurrence of a chemical reaction, if silver nitrate solution is poured into a solution of sodium chloride, a chemical reaction occurs forming a white precipitate of silver chloride. When potassium iodide solution reacts with lead nitrate solution, a precipitate of lead iodide is formed. Precipitation may occur if the concentration of a compound exceeds its solubility, Precipitation may occur rapidly from a supersaturated solution. Precipitation in solids is routinely used to synthesize nanoclusters, an important stage of the precipitation process is the onset of nucleation. The creation of a solid particle includes the formation of an interface, which requires some energy based on the relative surface energy of the solid. If this energy is not available, and no suitable nucleation surface is available, Precipitation reactions can be used for making pigments, removing salts from water in water treatment, and in classical qualitative inorganic analysis. Precipitation is also useful to isolate the products of a reaction during workup, ideally, the product of the reaction is insoluble in the reaction solvent. Thus, it precipitates as it is formed, preferably forming pure crystals, an example of this would be the synthesis of porphyrins in refluxing propionic acid. Thereafter, the precipitate may easily be separated by filtration, decanting, an example would be the synthesis of chromic tetraphenylporphyrin chloride, water is added to the DMF reaction solution, and the product precipitates. Precipitation is also useful in purifying products, crude bmim-Cl is taken up in acetonitrile, and dropped into ethyl acetate, another important application of an antisolvent is in ethanol precipitation of DNA. In metallurgy, precipitation from a solution is also a useful way to strengthen alloys. An example of a reaction, Aqueous silver nitrate is added to a solution containing potassium chloride
28.
Cotton
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Cotton is a soft, fluffy staple fiber that grows in a boll, or protective case, around the seeds of the cotton plants of the genus Gossypium in the family of Malvaceae. The fiber is almost pure cellulose, under natural conditions, the cotton bolls will tend to increase the dispersal of the seeds. The plant is a native to tropical and subtropical regions around the world, including the Americas, Africa. The greatest diversity of wild species is found in Mexico, followed by Australia. Cotton was independently domesticated in the Old and New Worlds, the fiber is most often spun into yarn or thread and used to make a soft, breathable textile. Current estimates for world production are about 25 million tonnes or 110 million bales annually, China is the worlds largest producer of cotton, but most of this is used domestically. The United States has been the largest exporter for many years, in the United States, cotton is usually measured in bales, which measure approximately 0.48 cubic meters and weigh 226.8 kilograms. Cotton cultivation in the region is dated to the Indus Valley Civilization, the Indus cotton industry was well-developed and some methods used in cotton spinning and fabrication continued to be used until the industrialization of India. Between 2000 and 1000 BC cotton became widespread across much of India, for example, it has been found at the site of Hallus in Karnataka dating from around 1000 BC. Cotton fabrics discovered in a cave near Tehuacán, Mexico have been dated to around 5800 BC, the domestication of Gossypium hirsutum in Mexico is dated between 3400 and 2300 BC. Cotton was grown upriver, made into nets, and traded with fishing villages along the coast for supplies of fish. The Spanish who came to Mexico and Peru in the early 16th century found the people growing cotton and this may be a reference to tree cotton, Gossypium arboreum, which is a native of the Indian subcontinent. According to the Columbia Encyclopedia, Cotton has been spun, woven and it clothed the people of ancient India, Egypt, and China. Hundreds of years before the Christian era, cotton textiles were woven in India with matchless skill, in Iran, the history of cotton dates back to the Achaemenid era, however, there are few sources about the planting of cotton in pre-Islamic Iran. The planting of cotton was common in Merv, Ray and Pars of Iran, in Persian poets poems, especially Ferdowsis Shahname, there are references to cotton. Marco Polo refers to the products of Persia, including cotton. John Chardin, a French traveler of the 17th century who visited the Safavid Persia, during the Han dynasty, cotton was grown by Chinese peoples in the southern Chinese province of Yunnan. Mohamed Ali Pasha accepted the proposition and granted himself the monopoly on the sale and export of cotton in Egypt, and later dictated cotton should be grown in preference to other crops
29.
Nature (journal)
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Nature is an English multidisciplinary scientific journal, first published on 4 November 1869. Nature claims a readership of about 3 million unique readers per month. The journal has a circulation of around 53,000. There are also sections on books and arts, the remainder of the journal consists mostly of research papers, which are often dense and highly technical. There are many fields of research in which important new advances, the papers that have been published in this journal are internationally acclaimed for maintaining high research standards. In 2007 Nature received the Princess of Asturias Award for Communications, the enormous progress in science and mathematics during the 19th century was recorded in journals written mostly in German or French, as well as in English. Britain underwent enormous technological and industrial changes and advances particularly in the half of the 19th century. In addition, during this period, the number of popular science periodicals doubled from the 1850s to the 1860s. According to the editors of these popular science magazines, the publications were designed to serve as organs of science, in essence, Nature, first created in 1869, was not the first magazine of its kind in Britain. While Recreative Science had attempted to more physical sciences such as astronomy and archaeology. Two other journals produced in England prior to the development of Nature were the Quarterly Journal of Science and Scientific Opinion, established in 1864 and 1868 and these similar journals all ultimately failed. The Popular Science Review survived longest, lasting 20 years and ending its publication in 1881, Recreative Science ceased publication as the Student, the Quarterly Journal, after undergoing a number of editorial changes, ceased publication in 1885. The Reader terminated in 1867, and finally, Scientific Opinion lasted a mere 2 years, janet Browne has proposed that far more than any other science journal of the period, Nature was conceived, born, and raised to serve polemic purpose. Perhaps it was in part its scientific liberality that made Nature a longer-lasting success than its predecessors and this is what Lockyers journal did from the start. Norman Lockyer, the founder of Nature, was a professor at Imperial College and he was succeeded as editor in 1919 by Sir Richard Gregory. Gregory helped to establish Nature in the scientific community. During the years 1945 to 1973, editorship of Nature changed three times, first in 1945 to A. J. V. Gale and L. J. F. Brimble, then to John Maddox in 1965, and finally to David Davies in 1973. In 1980, Maddox returned as editor and retained his position until 1995, philip Campbell has since become Editor-in-chief of all Nature publications
30.
Lithium-ion battery
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A lithium-ion battery or Li-ion battery is a type of rechargeable battery in which lithium ions move from the negative electrode to the positive electrode during discharge and back when charging. Li-ion batteries use an intercalated lithium compound as one electrode material, the electrolyte, which allows for ionic movement, and the two electrodes are the constituent components of a lithium-ion battery cell. Lithium-ion batteries are common in home electronics and they are one of the most popular types of rechargeable batteries for portable electronics, with a high energy density, tiny memory effect and low self-discharge. Beyond consumer electronics, LIBs are also growing in popularity for military, battery electric vehicle, for example, lithium-ion batteries are becoming a common replacement for the lead–acid batteries that have been used historically for golf carts and utility vehicles. Chemistry, performance, cost and safety characteristics vary across LIB types, handheld electronics mostly use LIBs based on lithium cobalt oxide, which offers high energy density, but presents safety risks, especially when damaged. Lithium iron phosphate, lithium ion manganese oxide battery and lithium nickel manganese cobalt oxide offer lower energy density, such batteries are widely used for electric tools, medical equipment and other roles. NMC in particular is a contender for automotive applications. Lithium nickel cobalt aluminum oxide and lithium titanate are specialty designs aimed at particular niche roles, the newer lithium–sulfur batteries promise the highest performance-to-weight ratio. Lithium-ion batteries can pose unique safety hazards since they contain a flammable electrolyte, an expert notes If a battery cell is charged too quickly, it can cause a short circuit, leading to explosions and fires. Because of these risks, testing standards are more stringent than those for acid-electrolyte batteries, there have been battery-related recalls by some companies, including the 2016 Samsung Note 7 recall for battery fires. This article covers just the topics and general principles of lithium-ion batteries. Nearly all facets have elements that are impacted by currently very active development or research, a cell is a basic electrochemical unit that contains the basic components, such as electrodes, separator, and electrolyte. In the case of cells, this is the single cylindrical, prismatic or pouch unit. In this regard, the simplest battery is a cell with perhaps a small electronic circuit for protection. In many cases, distinguishing between cell and battery is not important, however, this should be done when dealing with specific applications, for example, battery electric vehicles, where battery may indicate a high voltage system of 400 V, and not a single cell. The term module is used as an intermediate topology, with the understanding that a battery pack is made of modules. In electrochemistry, the anode is the electrode where oxidation is taking place in the battery, i. e. electrons get free, however, this happens on opposite electrodes during charge vs. discharge. Historically, for lithium cells, which started as single use discharge cells and this is true on discharge, but with a rechargeable system, the negative electrode chemically becomes the cathode while charging
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PubMed Identifier
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PubMed is a free search engine accessing primarily the MEDLINE database of references and abstracts on life sciences and biomedical topics. The United States National Library of Medicine at the National Institutes of Health maintains the database as part of the Entrez system of information retrieval, from 1971 to 1997, MEDLINE online access to the MEDLARS Online computerized database primarily had been through institutional facilities, such as university libraries. PubMed, first released in January 1996, ushered in the era of private, free, home-, the PubMed system was offered free to the public in June 1997, when MEDLINE searches via the Web were demonstrated, in a ceremony, by Vice President Al Gore. Information about the journals indexed in MEDLINE, and available through PubMed, is found in the NLM Catalog. As of 5 January 2017, PubMed has more than 26.8 million records going back to 1966, selectively to the year 1865, and very selectively to 1809, about 500,000 new records are added each year. As of the date,13.1 million of PubMeds records are listed with their abstracts. In 2016, NLM changed the system so that publishers will be able to directly correct typos. Simple searches on PubMed can be carried out by entering key aspects of a subject into PubMeds search window, when a journal article is indexed, numerous article parameters are extracted and stored as structured information. Such parameters are, Article Type, Secondary identifiers, Language, publication type parameter enables many special features. As these clinical girish can generate small sets of robust studies with considerable precision, since July 2005, the MEDLINE article indexing process extracts important identifiers from the article abstract and puts those in a field called Secondary Identifier. The secondary identifier field is to store numbers to various databases of molecular sequence data, gene expression or chemical compounds. For clinical trials, PubMed extracts trial IDs for the two largest trial registries, ClinicalTrials. gov and the International Standard Randomized Controlled Trial Number Register, a reference which is judged particularly relevant can be marked and related articles can be identified. If relevant, several studies can be selected and related articles to all of them can be generated using the Find related data option, the related articles are then listed in order of relatedness. To create these lists of related articles, PubMed compares words from the title and abstract of each citation, as well as the MeSH headings assigned, using a powerful word-weighted algorithm. The related articles function has been judged to be so precise that some researchers suggest it can be used instead of a full search, a strong feature of PubMed is its ability to automatically link to MeSH terms and subheadings. Examples would be, bad breath links to halitosis, heart attack to myocardial infarction, where appropriate, these MeSH terms are automatically expanded, that is, include more specific terms. Terms like nursing are automatically linked to Nursing or Nursing and this important feature makes PubMed searches automatically more sensitive and avoids false-negative hits by compensating for the diversity of medical terminology. The My NCBI area can be accessed from any computer with web-access, an earlier version of My NCBI was called PubMed Cubby
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. PMID 23233879. Retrieved 12 December 2012.
