1.
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
2.
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
3.
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
4.
E number
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E numbers are codes for substances that are permitted to be used as food additives for use within the European Union and Switzerland. Commonly found on labels, their safety assessment and approval are the responsibility of the European Food Safety Authority. Having a single unified list for food additives was first agreed upon in 1962 with food colouring, in 1964, the directives for preservatives were added,1970 for antioxidants and 1974 for the emulsifiers, stabilisers, thickeners and gelling agents. They are increasingly, though rarely, found on North American packaging. In some European countries, E number is used informally as a pejorative term for artificial food additives. This is incorrect, because many components of foods have E numbers, e. g. vitamin C. NB, Not all examples of a fall into the given numeric range. Moreover, many chemicals, particularly in the E400–499 range, have a variety of purposes, the list shows all components that have or had an E-number assigned. Not all additives listed are still allowed in the EU, but are listed as they used to have an E-number, for an overview of currently allowed additives see here. Includes Lists of authorised food additives Food additives database
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.
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
7.
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
8.
Boiling point
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The boiling point of a substance is the temperature at which the vapor pressure of the liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. The boiling point of a liquid varies depending upon the environmental pressure. A liquid in a vacuum has a lower boiling point than when that liquid is at atmospheric pressure. A liquid at high pressure has a boiling point than when that liquid is at atmospheric pressure. For a given pressure, different liquids boil at different temperatures, for example, water boils at 100 °C at sea level, but at 93.4 °C at 2,000 metres altitude. The normal boiling point of a liquid is the case in which the vapor pressure of the liquid equals the defined atmospheric pressure at sea level,1 atmosphere. At that temperature, the pressure of the liquid becomes sufficient to overcome atmospheric pressure. The standard boiling point has been defined by IUPAC since 1982 as the temperature at which boiling occurs under a pressure of 1 bar, the heat of vaporization is the energy required to transform a given quantity of a substance from a liquid into a gas at a given pressure. Liquids may change to a vapor at temperatures below their boiling points through the process of evaporation, evaporation is a surface phenomenon in which molecules located near the liquids edge, not contained by enough liquid pressure on that side, escape into the surroundings as vapor. On the other hand, boiling is a process in which molecules anywhere in the liquid escape, a saturated liquid contains as much thermal energy as it can without boiling. The saturation temperature is the temperature for a corresponding saturation pressure at which a liquid boils into its vapor phase, the liquid can be said to be saturated with thermal energy. Any addition of energy results in a phase transition. If the pressure in a system remains constant, a vapor at saturation temperature will begin to condense into its liquid phase as thermal energy is removed, similarly, a liquid at saturation temperature and pressure will boil into its vapor phase as additional thermal energy is applied. The boiling point corresponds to the temperature at which the pressure of the liquid equals the surrounding environmental pressure. Thus, the point is dependent on the pressure. Boiling points may be published with respect to the NIST, USA standard pressure of 101.325 kPa, at higher elevations, where the atmospheric pressure is much lower, the boiling point is also lower. The boiling point increases with increased pressure up to the critical point, the boiling point cannot be increased beyond the critical point. Likewise, the point decreases with decreasing pressure until the triple point is reached
9.
Partition coefficient
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In the physical sciences, a partition-coefficient or distribution-coefficient is the ratio of concentrations of a compound in a mixture of two immiscible phases at equilibrium. This ratio is therefore a measure of the difference in solubility of the compound in two phases. In the chemical and pharmaceutical sciences, both phases usually are solvents, most commonly, one of the solvents is water while the second is hydrophobic such as 1-octanol. Hence the partition coefficient measures how hydrophilic or hydrophobic a chemical substance is, partition coefficients are useful in estimating the distribution of drugs within the body. Hydrophobic drugs with high octanol/water partition coefficients are distributed to hydrophobic areas such as lipid bilayers of cells. Conversely hydrophilic drugs are primarily in aqueous regions such as blood serum. If one of the solvents is a gas and the other a liquid, for example, the blood/gas partition coefficient of a general anesthetic measures how easily the anesthetic passes from gas to blood. Partition coefficients can also be defined one of the phases is solid, for instance, when one phase is a molten metal. The partitioning of a substance into a solid results in a solid solution, partition coefficients can be measured experimentally in various ways or estimated via calculation based on a variety of methods. Despite formal recommendation to the contrary, the partition coefficient remains the predominantly used term in the scientific literature. In contrast, the IUPAC recommends that the term no longer be used, rather. When one of the solvents is water and the other is a non-polar solvent, for measurements of distribution coefficients, the pH of the aqueous phase is buffered to a specific value such that the pH is not significantly perturbed by the introduction of the compound. In addition, since log D is pH-dependent, the pH at which the log D was measured must be specified. In areas such as drug discovery—areas involving partition phenomena in systems such as the human body—the log D at the physiologic pH,7.4, is of particular interest. It is often convenient to express the log D in terms of P I, defined above, the values in the following table are from the Dortmund Data Bank. They are sorted by the coefficient, smallest to largest. Values for other compounds may be found in a variety of available reviews, critical discussions of the challenges of measurement of log P, and related computation of its estimated values, appear in several reviews. Hence, the log P of a molecule is one used in decision-making by medicinal chemists in pre-clinical drug discovery, for example
10.
Acid dissociation constant
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An acid dissociation constant, Ka, is a quantitative measure of the strength of an acid in solution. It is the constant for a chemical reaction known as dissociation in the context of acid–base reactions. In the example shown in the figure, HA represents acetic acid, and A− represents the acetate ion, the chemical species HA, A− and H3O+ are said to be in equilibrium when their concentrations do not change with the passing of time. The definition can then be more simply H A ⇌ A − + H +, K a = This is the definition in common usage. A weak acid has a pKa value in the approximate range −2 to 12 in water, pKa values for strong acids can, however, be estimated by theoretical means. The definition can be extended to non-aqueous solvents, such as acetonitrile and dimethylsulfoxide. Denoting a solvent molecule by S H A + S ⇌ A − + S H +, K a = When the concentration of solvent molecules can be taken to be constant, K a =, as before. The value of pKa also depends on structure of the acid in many ways. For example, Pauling proposed two rules, one for successive pKa of polyprotic acids, and one to estimate the pKa of oxyacids based on the number of =O and −OH groups. Other structural factors that influence the magnitude of the dissociation constant include inductive effects, mesomeric effects. Hammett type equations have frequently applied to the estimation of pKa. The quantitative behaviour of acids and bases in solution can be only if their pKa values are known. These calculations find application in different areas of chemistry, biology, medicine. Acid dissociation constants are essential in aquatic chemistry and chemical oceanography. In living organisms, acid–base homeostasis and enzyme kinetics are dependent on the pKa values of the acids and bases present in the cell. According to Arrheniuss original definition, an acid is a substance that dissociates in solution, releasing the hydrogen ion H+. The equilibrium constant for this reaction is known as a dissociation constant. Brønsted and Lowry generalised this further to an exchange reaction
11.
Conjugate acid
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A conjugate acid, within the Brønsted–Lowry acid–base theory, is a species formed by the reception of a proton by a base—in other words, it is a base with a hydrogen ion added to it. On the other hand, a base is merely what is left after an acid has donated a proton in a chemical reaction. Hence, a base is a species formed by the removal of a proton from an acid. A proton is a particle with a unit positive electrical charge, it is represented by the symbol H+ because it constitutes the nucleus of a hydrogen atom, that is. A cation can be an acid, and an anion can be a conjugate base, depending on which substance is involved. In an acid-base reaction, an acid plus a base reacts to form a conjugate base plus a conjugate acid, refer to the following figure, We say that the water molecule is the conjugate acid of the hydroxide ion after the latter received the hydrogen proton donated by ammonium. On the other hand, ammonia is the base for the acid ammonium after ammonium has donated a hydrogen ion towards the production of the water molecule. The strength of an acid is directly proportional to its dissociation constant. If a conjugate acid is strong, its dissociation will have an equilibrium constant. The strength of a base can be seen as the tendency of the species to pull hydrogen protons towards itself. If a conjugate base is classified as strong, it will hold on to the hydrogen proton when in solution, if a chemical species is classified as a weak acid, its conjugate base will be strong in nature. This can be observed in ammonias reaction with water, the reaction proceeds until most of the ammonia has been transformed to ammonium. This shift to the right in the equilibrium of the reaction means that ammonium does not dissociate easily in water. On the other hand, if a species is classified as a strong acid, an example of this case would be the dissociation of Hydrochloric acid HCl in water. Since HCl is an acid, its conjugate base will be a weak conjugate base. Therefore, in system, most H+ will be in the form of a Hydronium ion H 3O+ instead of attached to a Cl anion. To summarize, the stronger the acid or base, the weaker the conjugate, the acid and conjugate base as well as the base and conjugate acid are known as conjugate pairs. When finding a conjugate acid or base, it is important to look at the reactants of the chemical equation, to identify the conjugate acid, look for the pair of compounds that are related
12.
Halonium ion
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A halonium ion in organic chemistry is any onium compound containing a halogen atom carrying a positive charge. This cation has the general structure R–X+–R where X is any halogen and R any organic residue, halonium ions formed from fluorine, chlorine, bromine, and iodine are called fluoronium, chloronium, bromonium, and iodonium, respectively. The simplest halonium ions are of the structure H–X+–H, in almost all cases, the halonium ion is attacked by a nucleophile within a very short time. Even a weak nucleophile, such as water will attack the halonium ion, on occasion, a halonium atom will rearrange to a carbocation. This usually occurs only when that carbocation is an allylic or a benzyllic carbocation, halonium ions were first postulated in 1937 by Roberts and Kimball to account for observed diastereoselectivity in halogen addition reactions to alkenes. They also asserted that a positively charged atom is isoelectronic with oxygen. After evaporation of sulfur dioxide this procedure left crystals of CH3–X+–CH3SbF−6, stable at room temperature, compounds containing trivalent or tetravalent halonium ions do not exist but for some hypothetical compounds stability has been computationally tested
13.
Chloride
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The chloride ion /ˈklɔəraɪd/ is the anion Cl−. It is formed when the element chlorine gains an electron or when a compound such as chloride is dissolved in water or other polar solvents. Chloride salts such as sodium chloride are often soluble in water. It is an essential electrolyte located in all body fluids responsible for maintaining acid/base balance, transmitting nerve impulses and regulating fluid in, less frequently, the word chloride may also form part of the common name of chemical compounds in which one or more chlorine atoms are covalently bonded. For example, methyl chloride, with the standard name chloromethane is a compound with a covalent C−Cl bond in which the chlorine is not an anion. A chloride ion is much larger than an atom,167 and 99 pm. The ion is colorless and diamagnetic, in aqueous solution, it is highly soluble in most cases, however, some chloride salts, such as silver chloride, lead chloride, and mercury chloride are slightly soluble in water. In aqueous solution, chloride is bound by the end of the water molecules. Some chloride-containing minerals include the chlorides of sodium, potassium, and magnesium, called serum chloride, the concentration of chloride in the blood is regulated by the kidneys. A chloride ion is a component of some proteins, e. g. it is present in the amylase enzyme. The chlor-alkali industry is a consumer of the worlds energy budget. This process converts sodium chloride into chlorine and sodium hydroxide, which are used to make many other materials and chemicals, in the petroleum industry, the chlorides are a closely monitored constituent of the mud system. An increase of the chlorides in the mud system may be an indication of drilling into a high-pressure saltwater formation and its increase can also indicate the poor quality of a target sand. Chloride is also a useful and reliable chemical indicator of river / groundwater fecal contamination, as chloride is a non-reactive solute, many water regulating companies around the world utilize chloride to check the contamination levels of the rivers and potable water sources. Chloride salts such as sodium chloride are used to preserve food, chloride is an essential electrolyte, trafficking in and out of cells through chloride channels and playing a key role in maintaining cell homeostasis and transmitting action potentials in neurons. Characteristic concentrations of chloride in model organisms are, in both E. coli and budding yeast are 10-200mM, in mammalian cell 5-100mM and in blood plasma 100mM, chloride can be oxidized but not reduced. The first oxidation, as employed in the process, is conversion to chlorine gas. Chlorine can be oxidized to other oxides and oxyanions including hypochlorite, chlorine dioxide, chlorate
14.
Safety data sheet
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A safety data sheet, material safety data sheet, or product safety data sheet is an important component of product stewardship, occupational safety and health, and spill-handling procedures. SDS formats can vary from source to source within a country depending on national requirements, SDSs are a widely used system for cataloging information on chemicals, chemical compounds, and chemical mixtures. SDS information may include instructions for the use and potential hazards associated with a particular material or product. The SDS should be available for reference in the area where the chemicals are being stored or in use, there is also a duty to properly label substances on the basis of physico-chemical, health and/or environmental risk. Labels can include hazard symbols such as the European Union standard symbols, a SDS for a substance is not primarily intended for use by the general consumer, focusing instead on the hazards of working with the material in an occupational setting. It is important to use an SDS specific to country and supplier, as the same product can have different formulations in different countries. The formulation and hazard of a product using a name may vary between manufacturers in the same country. Safety data sheets have made an integral part of the system of Regulation No 1907/2006. The SDS must be supplied in a language of the Member State where the substance or mixture is placed on the market. The 16 sections are, SECTION1, Identification of the substance/mixture, relevant identified uses of the substance or mixture and uses advised against 1.3. Details of the supplier of the safety data sheet 1.4, Emergency telephone number SECTION2, Hazards identification 2.1. Classification of the substance or mixture 2.2, Other hazards SECTION3, Composition/information on ingredients 3.1. Mixtures SECTION4, First aid measures 4.1, Description of first aid measures 4.2. Most important symptoms and effects, both acute and delayed 4.3, indication of any immediate medical attention and special treatment needed SECTION5, Firefighting measures 5.1. Special hazards arising from the substance or mixture 5.3, advice for firefighters SECTION6, Accidental release measure 6.1. Personal precautions, protective equipment and emergency procedures 6.2, methods and material for containment and cleaning up 6.4. Reference to other sections SECTION7, Handling and storage 7.1, conditions for safe storage, including any incompatibilities 7.3. Specific end use SECTION8, Exposure controls/personal protection 8.1, Exposure controls SECTION9, Physical and chemical properties 9.1
15.
GHS hazard pictograms
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Hazard pictograms form part of the international Globally Harmonized System of Classification and Labelling of Chemicals. Two sets of pictograms are included within the GHS, one for the labelling of containers and for workplace hazard warnings, either one or the other is chosen, depending on the target audience, but the two are not used together. The two sets of use the same symbols for the same hazards, although certain symbols are not required for transport pictograms. Transport pictograms come in variety of colors and may contain additional information such as a subcategory number. It has still to be implemented by the European Union in 2009, the following pictograms are included in the Worldwide Model Using but have not been incorporated into the GHS, ICZ and Catwallsh Hazcom Labelling because of the nature of the hazards. Globally Harmonized System of Classification and Labelling of Chemicals, New York and Geneva, United Nations,2007, ISBN 978-92-1-116957-7, ST/SG/AC. 10/30/Rev. Model Regulations, New York and Geneva, United Nations,2007, ISBN 978-92-1-139120-6, manual of Tests and Criteria, New York and Geneva, United Nations,2002, ISBN 92-1-139087-7, ST/SG/AC. 10/11/Rev.4 GHS pictogram gallery from the United Nations Economic Commission for Europe
16.
Hydrofluoric acid
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Hydrofluoric acid is a solution of hydrogen fluoride in water. It is a precursor to almost all compounds, including pharmaceuticals such as fluoxetine, diverse materials such as PTFE. It is a solution that is highly corrosive, capable of dissolving many materials. Its ability to dissolve glass has been known since the 17th century, because of its high reactivity toward glass and moderate reactivity toward many metals, hydrofluoric acid is usually stored in plastic containers. Hydrogen fluoride gas is a poison that may immediately and permanently damage lungs. Aqueous hydrofluoric acid is a contact-poison with the potential for deep, initially painless burns, by interfering with body calcium metabolism, the concentrated acid may also cause systemic toxicity and eventual cardiac arrest and fatality, after contact with as little as 160 cm2 of skin. Hydrofluoric acid is classified as an acid because of its lower dissociation constant compared to the strong acids. Hydrofluoric acid is produced by treatment of the mineral fluorite with concentrated sulfuric acid, apatite sources typically contain a few percent of fluoroapatite, acid digestion of which releases a gaseous stream consisting of sulfur dioxide, water, and HF, as well as particulates. After separation from the solids, the gases are treated with sulfuric acid, owing to the corrosive nature of HF, its production is accompanied by the dissolution of silicate minerals, and, in this way, significant amounts of fluorosilicic acid are generated. Hydrofluoric acid has a variety of uses in industry and research and it is used as a starting material or intermediate in industrial chemistry, mining, refining, glass finishing, silicon chip manufacturing, and in cleaning. In a standard oil refinery known as alkylation, isobutane is alkylated with low-molecular-weight alkenes in the presence of the strong acid catalyst derived from hydrofluoric acid. The catalyst protonates the alkenes to produce reactive carbocations, which alkylate isobutane, the reaction is carried out at mild temperatures in a two-phase reaction. The principal use of acid is in organofluorine chemistry. Many organofluorine compounds are prepared using HF as the source, including Teflon, fluoropolymers, fluorocarbons. Most high-volume inorganic fluoride compounds are prepared from hydrofluoric acid, foremost are Na3AlF6, cryolite, and AlF3, aluminium trifluoride. A molten mixture of these serves as a high-temperature solvent for the production of metallic aluminium. Given concerns about fluorides in the environment, alternative technologies are being sought, other inorganic fluorides prepared from hydrofluoric acid include sodium fluoride and uranium hexafluoride. In metalworking, hydrofluoric acid is used as an agent to remove oxides and other impurities from stainless
17.
Hydroiodic acid
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Hydroiodic acid is a highly acidic aqueous solution of hydrogen iodide. It is the strongest hydrohalic acid, hydroiodic acid is a commonly used chemical reagent and is one of the strong acids that ionize completely in an aqueous solution. Concentrated hydroiodic acid has a pH of less than 0, hydroiodic acid is currently listed as a Federal DEA List I Chemical. Owing to its usefulness as an agent, reduction with HI. Clandestine chemists react pseudoephedrine with hydroiodic acid and red phosphorus under heat, HI reacts with pseudoephedrine to form iodoephedrine, an intermediate which is reduced primarily to methamphetamine. This reaction is stereospecific, producing only -methamphetamine, due to its listed status and closely monitored sales, clandestine chemists now use red phosphorus and iodine to generate hydroiodic acid in situ. International Chemical Safety Card 1326 European Chemicals Bureau
18.
Refractive index
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In optics, the refractive index or index of refraction n of a material is a dimensionless number that describes how light propagates through that medium. It is defined as n = c v, where c is the speed of light in vacuum, for example, the refractive index of water is 1.333, meaning that light travels 1.333 times faster in a vacuum than it does in water. The refractive index determines how light is bent, or refracted. The refractive indices also determine the amount of light that is reflected when reaching the interface, as well as the angle for total internal reflection. This implies that vacuum has a index of 1. The refractive index varies with the wavelength of light and this is called dispersion and causes the splitting of white light into its constituent colors in prisms and rainbows, and chromatic aberration in lenses. Light propagation in absorbing materials can be described using a refractive index. The imaginary part then handles the attenuation, while the real part accounts for refraction, the concept of refractive index is widely used within the full electromagnetic spectrum, from X-rays to radio waves. It can also be used with wave phenomena such as sound, in this case the speed of sound is used instead of that of light and a reference medium other than vacuum must be chosen. Thomas Young was presumably the person who first used, and invented, at the same time he changed this value of refractive power into a single number, instead of the traditional ratio of two numbers. The ratio had the disadvantage of different appearances, newton, who called it the proportion of the sines of incidence and refraction, wrote it as a ratio of two numbers, like 529 to 396. Hauksbee, who called it the ratio of refraction, wrote it as a ratio with a fixed numerator, hutton wrote it as a ratio with a fixed denominator, like 1.3358 to 1. Young did not use a symbol for the index of refraction, in the next years, others started using different symbols, n, m, and µ. For visible light most transparent media have refractive indices between 1 and 2, a few examples are given in the adjacent table. These values are measured at the yellow doublet D-line of sodium, with a wavelength of 589 nanometers, gases at atmospheric pressure have refractive indices close to 1 because of their low density. Almost all solids and liquids have refractive indices above 1.3, aerogel is a very low density solid that can be produced with refractive index in the range from 1.002 to 1.265. Moissanite lies at the end of the range with a refractive index as high as 2.65. Most plastics have refractive indices in the range from 1.3 to 1.7, for infrared light refractive indices can be considerably higher
19.
Relative permittivity
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The relative permittivity of a material is its permittivity expressed as a ratio relative to the permittivity of vacuum. Permittivity is a property that affects the Coulomb force between two point charges in the material. Relative permittivity is the factor by which the field between the charges is decreased relative to vacuum. Likewise, relative permittivity is the ratio of the capacitance of a capacitor using that material as a dielectric, relative permittivity is also commonly known as dielectric constant, a term deprecated in physics and engineering as well as in chemistry. Relative permittivity is typically denoted as εr and is defined as ε r = ε ε0, where ε is the complex frequency-dependent absolute permittivity of the material, and ε0 is the vacuum permittivity. Relative permittivity is a number that is in general complex-valued, its real and imaginary parts are denoted as. The relative permittivity of a medium is related to its electric susceptibility, χe, in anisotropic media the relative permittivity is a second rank tensor. The relative permittivity of a material for a frequency of zero is known as its relative permittivity. The historical term for the relative permittivity is dielectric constant and it is still commonly used, but has been deprecated by standards organizations, because of its ambiguity, as some older authors used it for the absolute permittivity ε. The permittivity may be quoted either as a property or as a frequency-dependent variant. It has also used to refer to only the real component εr of the complex-valued relative permittivity. In the causal theory of waves, permittivity is a complex quantity, the imaginary part corresponds to a phase shift of the polarization P relative to E and leads to the attenuation of electromagnetic waves passing through the medium. By definition, the relative permittivity of vacuum is equal to 1. The relative static permittivity, εr, can be measured for static electric fields as follows, first the capacitance of a test capacitor, then, using the same capacitor and distance between its plates, the capacitance Cx with a dielectric between the plates is measured. The relative dielectric constant can be calculated as ε r = C x C0. For time-variant electromagnetic fields, this quantity becomes frequency-dependent, an indirect technique to calculate εr is conversion of radio frequency S-parameter measurement results. A description of frequently used S-parameter conversions for determination of the frequency-dependent εr of dielectrics can be found in this bibliographic source, alternatively, resonance based effects may be employed at fixed frequencies. The relative permittivity is a piece of information when designing capacitors
20.
Infrared spectroscopy
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Infrared spectroscopy involves the interaction of infrared radiation with matter. It covers a range of techniques, mostly based on absorption spectroscopy, as with all spectroscopic techniques, it can be used to identify and study chemicals. Sample may be solid, liquid, or gas, the method or technique of infrared spectroscopy is conducted with an instrument called an infrared spectrometer to produce an infrared spectrum. An IR spectrum is essentially a graph of infrared light absorbance on the vertical axis vs. frequency or wavelength on the horizontal axis, typical units of frequency used in IR spectra are reciprocal centimeters, with the symbol cm−1. Units of IR wavelength are commonly given in micrometers, symbol μm, a common laboratory instrument that uses this technique is a Fourier transform infrared spectrometer. Two-dimensional IR is also possible as discussed below, the infrared portion of the electromagnetic spectrum is usually divided into three regions, the near-, mid- and far- infrared, named for their relation to the visible spectrum. The higher-energy near-IR, approximately 14000–4000 cm−1 can excite overtone or harmonic vibrations, the mid-infrared, approximately 4000–400 cm−1 may be used to study the fundamental vibrations and associated rotational-vibrational structure. The far-infrared, approximately 400–10 cm−1, lying adjacent to the region, has low energy. The names and classifications of these subregions are conventions, and are loosely based on the relative molecular or electromagnetic properties. Infrared spectroscopy exploits the fact that molecules absorb frequencies that are characteristic of their structure and these absorptions occur at resonant frequencies, i. e. the frequency of the absorbed radiation matches the vibrational frequency. The energies are affected by the shape of the potential energy surfaces, the masses of the atoms. In particular, in the Born–Oppenheimer and harmonic approximations, i. e, the resonant frequencies are also related to the strength of the bond and the mass of the atoms at either end of it. Thus, the frequency of the vibrations are associated with a normal mode of motion. In order for a mode in a sample to be IR active. A permanent dipole is not necessary, as the rule requires only a change in dipole moment, a molecule can vibrate in many ways, and each way is called a vibrational mode. For molecules with N number of atoms, linear molecules have 3N –5 degrees of vibrational modes, as an example H2O, a non-linear molecule, will have 3 ×3 –6 =3 degrees of vibrational freedom, or modes. Simple diatomic molecules have only one bond and only one vibrational band, if the molecule is symmetrical, e. g. N2, the band is not observed in the IR spectrum, but only in the Raman spectrum. Asymmetrical diatomic molecules, e. g. CO, absorb in the IR spectrum, more complex molecules have many bonds, and their vibrational spectra are correspondingly more complex, i. e. big molecules have many peaks in their IR spectra
21.
Nuclear magnetic resonance spectroscopy
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Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy, is a research technique that exploits the magnetic properties of certain atomic nuclei. This type of spectroscopy determines the physical and chemical properties of atoms or the molecules in which they are contained and it relies on the phenomenon of nuclear magnetic resonance and can provide detailed information about the structure, dynamics, reaction state, and chemical environment of molecules. Suitable samples range from small compounds analyzed with 1-dimensional proton or carbon-13 NMR spectroscopy to large proteins or nucleic acids using 3 or 4-dimensional techniques. The impact of NMR spectroscopy on the sciences has been substantial because of the range of information, NMR spectra are unique, well-resolved, analytically tractable and often highly predictable for small molecules. Thus, in organic chemistry practice, NMR analysis is used to confirm the identity of a substance, different functional groups are obviously distinguishable, and identical functional groups with differing neighboring substituents still give distinguishable signals. NMR has largely replaced traditional wet chemistry tests such as reagents or typical chromatography for identification. A disadvantage is that a large amount, 2–50 mg, of a purified substance is required. Preferably, the sample should be dissolved in a solvent, because NMR analysis of solids requires a dedicated MAS machine, the timescale of NMR is relatively long, and thus it is not suitable for observing fast phenomena, producing only an averaged spectrum. NMR spectrometers are relatively expensive, universities usually have them, modern NMR spectrometers have a very strong, large and expensive liquid helium-cooled superconducting magnet, because resolution directly depends on magnetic field strength. There are even benchtop NMR spectrometers, the Purcell group at Harvard University and the Bloch group at Stanford University independently developed NMR spectroscopy in the late 1940s and early 1950s. Edward Mills Purcell and Felix Bloch shared the 1952 Nobel Prize in Physics for their discoveries, when placed in a magnetic field, NMR active nuclei absorb electromagnetic radiation at a frequency characteristic of the isotope. The resonant frequency, energy of the absorption, and the intensity of the signal are proportional to the strength of the magnetic field, for example, in a 21 Tesla magnetic field, protons resonate at 900 MHz. It is common to refer to a 21 T magnet as a 900 MHz magnet, spinning the sample is necessary to average out diffusional motion. Whereas, measurements of diffusion constants are done the sample stationary and spinning off, the vast majority of nuclei in a solution would belong to the solvent, and most regular solvents are hydrocarbons and would contain NMR-reactive protons. The most used deuterated solvent is deuterochloroform, although deuterium oxide and deuterated DMSO are used for hydrophilic analytes, the chemical shifts are slightly different in different solvents, depending on electronic solvation effects. NMR spectra are often calibrated against the known solvent residual proton peak instead of added tetramethylsilane, to detect the very small frequency shifts due to nuclear magnetic resonance, the applied magnetic field must be constant throughout the sample volume. High resolution NMR spectrometers use shims to adjust the homogeneity of the field to parts per billion in a volume of a few cubic centimeters. In order to detect and compensate for inhomogeneity and drift in the magnetic field, in modern NMR spectrometers shimming is adjusted automatically, though in some cases the operator has to optimize the shim parameters manually to obtain the best possible resolution
22.
Mass spectrometry
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Mass spectrometry is an analytical technique that ionizes chemical species and sorts the ions based on their mass-to-charge ratio. In simpler terms, a mass spectrum measures the masses within a sample, mass spectrometry is used in many different fields and is applied to pure samples as well as complex mixtures. A mass spectrum is a plot of the ion signal as a function of the mass-to-charge ratio, in a typical MS procedure, a sample, which may be solid, liquid, or gas, is ionized, for example by bombarding it with electrons. This may cause some of the molecules to break into charged fragments. The ions are detected by a capable of detecting charged particles. Results are displayed as spectra of the abundance of detected ions as a function of the mass-to-charge ratio. The atoms or molecules in the sample can be identified by correlating known masses to the masses or through a characteristic fragmentation pattern. Goldstein called these positively charged anode rays Kanalstrahlen, the translation of this term into English is canal rays. Wien found that the charge-to-mass ratio depended on the nature of the gas in the discharge tube, thomson later improved on the work of Wien by reducing the pressure to create the mass spectrograph. The word spectrograph had become part of the international scientific vocabulary by 1884, a mass spectroscope is similar to a mass spectrograph except that the beam of ions is directed onto a phosphor screen. A mass spectroscope configuration was used in early instruments when it was desired that the effects of adjustments be quickly observed, once the instrument was properly adjusted, a photographic plate was inserted and exposed. The term mass spectroscope continued to be used though the direct illumination of a phosphor screen was replaced by indirect measurements with an oscilloscope. The use of the mass spectroscopy is now discouraged due to the possibility of confusion with light spectroscopy. Mass spectrometry is often abbreviated as mass-spec or simply as MS, modern techniques of mass spectrometry were devised by Arthur Jeffrey Dempster and F. W. Aston in 1918 and 1919 respectively. Sector mass spectrometers known as calutrons were used for separating the isotopes of uranium developed by Ernest O. Lawrence during the Manhattan Project, calutron mass spectrometers were used for uranium enrichment at the Oak Ridge, Tennessee Y-12 plant established during World War II. In 1989, half of the Nobel Prize in Physics was awarded to Hans Dehmelt, a mass spectrometer consists of three components, an ion source, a mass analyzer, and a detector. The ionizer converts a portion of the sample into ions, there is a wide variety of ionization techniques, depending on the phase of the sample and the efficiency of various ionization mechanisms for the unknown species. An extraction system removes ions from the sample, which are then targeted through the mass analyzer, the differences in masses of the fragments allows the mass analyzer to sort the ions by their mass-to-charge ratio
23.
Inorganic chemistry
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Inorganic chemistry deals with the synthesis and behavior of inorganic and organometallic compounds. This field covers all chemical compounds except the myriad organic compounds, the distinction between the two disciplines is far from absolute, as there is much overlap in the subdiscipline of organometallic chemistry. It has applications in every aspect of the industry, including catalysis, materials science, pigments, surfactants, coatings, medications, fuels. Many inorganic compounds are compounds, consisting of cations and anions joined by ionic bonding. Examples of salts are magnesium chloride MgCl2, which consists of magnesium cations Mg2+ and chloride anions Cl−, or sodium oxide Na2O, in any salt, the proportions of the ions are such that the electric charges cancel out, so that the bulk compound is electrically neutral. The ions are described by their state and their ease of formation can be inferred from the ionization potential or from the electron affinity of the parent elements. Important classes of compounds are the oxides, the carbonates, the sulfates. Many inorganic compounds are characterized by high melting points, inorganic salts typically are poor conductors in the solid state. Other important features include their high meilting point and ease of crystallization, where some salts are very soluble in water, others are not. The simplest inorganic reaction is double displacement when in mixing of two salts the ions are swapped without a change in oxidation state, in redox reactions one reactant, the oxidant, lowers its oxidation state and another reactant, the reductant, has its oxidation state increased. The net result is an exchange of electrons, electron exchange can occur indirectly as well, e. g. in batteries, a key concept in electrochemistry. When one reactant contains hydrogen atoms, a reaction can take place by exchanging protons in acid-base chemistry, as a refinement of acid-base interactions, the HSAB theory takes into account polarizability and size of ions. Inorganic compounds are found in nature as minerals, soil may contain iron sulfide as pyrite or calcium sulfate as gypsum. Inorganic compounds are also found multitasking as biomolecules, as electrolytes, the first important man-made inorganic compound was ammonium nitrate for soil fertilization through the Haber process. Inorganic compounds are synthesized for use as such as vanadium oxide and titanium chloride. Subdivisions of inorganic chemistry are organometallic chemistry, cluster chemistry and bioinorganic chemistry and these fields are active areas of research in inorganic chemistry, aimed toward new catalysts, superconductors, and therapies. Inorganic chemistry is a highly practical area of science, traditionally, the scale of a nations economy could be evaluated by their productivity of sulfuric acid. The manufacturing of fertilizers is another application of industrial inorganic chemistry
24.
Pungency
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Pungency is the condition of having a strong, sharp smell or taste that is often so strong that it is unpleasant. The term piquancy /ˈpiːkənsi/ is sometimes applied to foods with a degree of pungency that are agreeably stimulating to the palate. Examples of piquant food include mustard and some strongly flavored tomatoes, for instance, a pumpkin pie can be both hot and spicy, but it is not pungent. Conversely, pure capsaicin is pungent, yet it is not naturally accompanied by a hot temperature or spices, pungency is often quantified in scales that range from mild to hot. The Scoville scale measures the pungency of chili peppers, as defined by the amount of capsaicin they contain, pungency is not considered a taste in the technical sense because it is carried to the brain by a different set of nerves. While taste nerves are activated when consuming foods like chili peppers, many parts of the body with exposed membranes that lack taste receptors produce a similar sensation of heat when exposed to pungent agents. The scientific term for the effect of pungency is chemesthesis, substances such as piperine and capsaicin cause a burning sensation by inducing a trigeminal nerve reaction together with normal taste reception. The pungency of chilies may be a response to selection by microbial pathogens
25.
Vinyl chloride
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Vinyl chloride is an organochloride with the formula H2C=CHCl that is also called vinyl chloride monomer or chloroethene. This colorless compound is an important industrial chemical used to produce the polymer polyvinyl chloride. About 13 billion kilograms are produced annually, VCM is among the top twenty largest petrochemicals in world production. The United States currently remains the largest VCM manufacturing region because of its low-production-cost position in chlorine and ethylene raw materials, China is also a large manufacturer and one of the largest consumers of VCM. Vinyl chloride is a gas with a sweet odor and it is highly toxic, flammable, and carcinogenic. It can be formed in the environment when soil organisms break down chlorinated solvents, vinyl chloride that is released by industries or formed by the breakdown of other chlorinated chemicals can enter the air and drinking water supplies. Vinyl chloride is a common contaminant found near landfills, in the past VCM has been used as a refrigerant. Vinyl chloride was first produced in 1835 by Justus von Liebig and they obtained it by treating 1, 2-dichloroethane with a solution of potassium hydroxide in ethanol. In 1912, Fritz Klatte, a German chemist working for Griesheim-Elektron, patented a means to produce vinyl chloride from acetylene and hydrogen chloride using mercuric chloride as a catalyst. While this method was used during the 1930s and 1940s in the West, it has since been superseded by more economical processes based on ethylene in the United States. It remains the production method in China. Vinyl chloride is produced on a substantial scale—approximately 31.1 million tons were produced in 2000, two methods are employed, the hydrochlorination of acetylene and the dehydrochlorination of ethylene dichloride. Numerous attempts have been made to convert directly to vinyl chloride. Vinyl chloride can also be obtained as byproducts in the synthesis of chlorofluorocarbons when saturated chlorofluorocarbons are catalytically dechlorinated by ethylene, ethane sulfochlorination has been proposed as a route to produce vinyl chloride using sulfur instead of oxygen. About 85% of vinyl chloride is produced by a set of reactions starting with chlorine, ethylene. Two processes are used to generate 1, 2-dichloroethane, commonly known by its old name of ethylene dichloride, the expected consumption for raw materials and utilities per 1000 kg VCM product are, EDC is prepared by reacting ethylene and chlorine. In the presence of iron chloride as a catalyst, these compounds react exothermically, CH2=CH2 + Cl2 → ClCH2CH2Cl This process results in high purity EDC, dissolved catalyst and moisture must be removed before EDC enters the vinyl chloride production process. Due to the low cost of ethylene, compared to acetylene
26.
Acid strength
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The strength of an acid refers to its ability or tendency to lose a proton. A strong acid is one that completely ionizes in a solution, in water, one mole of a strong acid HA dissolves yielding one mole of H+ and one mole of the conjugate base, A−. Essentially, none of the non-ionized acid HA remains. Examples of strong acids are hydrochloric acid, hydroiodic acid, hydrobromic acid, perchloric acid, nitric acid, in aqueous solution, each of these essentially ionizes 100%. In contrast, an acid only partially dissociates. Examples in water include carbonic acid and acetic acid, at equilibrium, both the acid and the conjugate base are present in solution. Stronger acids have an acid dissociation constant and a smaller logarithmic constant than weaker acids. The stronger an acid is, the more easily it loses a proton, two key factors that contribute to the ease of deprotonation are the polarity of the H—A bond and the size of atom A, which determines the strength of the H—A bond. Acid strengths also depend on the stability of the conjugate base, while Ka measures the strength of an acidic molecule, the strength of an aqueous acid solution is measured by pH, which is a function of the concentration of hydronium ions in solution. The pH of a solution of an acid in water is determined by both Ka and the acid concentration. For weak acid solutions, it depends on the degree of dissociation, for concentrated solutions of strong acids with a pH less than about zero, the Hammett acidity function is a better measure of acidity than the pH. Sulfonic acids, which are organic oxyacids, are a class of strong acids, a common example is p-toluenesulfonic acid. Unlike sulfuric acid itself, sulfonic acids can be solids, in fact, polystyrene functionalized into polystyrene sulfonate is a solid strongly acidic plastic that is filterable. Superacids are acid solutions that are more acidic than 100% sulfuric acid, examples of superacids are fluoroantimonic acid, magic acid and perchloric acid. Superacids can permanently protonate water to give ionic, crystalline hydronium salts and they can also quantitatively stabilize carbocations. In aqueous solution, an acid is an acid that ionizes completely by losing one proton.74. An example is HCl for which pKa = −6.3 and this generally means that, in aqueous solution at standard temperature and pressure, the concentration of hydronium ions is equal to the concentration of strong acid introduced to the solution. No acid species stronger than H3O+ can exist in aqueous solution, the acidity of the stronger acid is said to be leveled to the acidity of hydronium ion. Strong acids are distinguished from weak acids, in which dissociation is incomplete and is represented as an equilibrium, the typical definition of a weak acid is any acid that does not dissociate completely
27.
Food industry
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The Food Industry is a complex, global collective of diverse businesses that supplies most of the food consumed by the world population. Only subsistence farmers, those who survive on what they grow, the food Industry includes, Agriculture, raising of crops and livestock, and seafood Manufacturing, agrichemicals, agricultural construction, farm machinery and supplies, seed, etc. The Food Standards Agency, a government body in India, describes it thus. the whole food industry – from farming and food production, packaging and distribution, to retail and catering. The Economic Research Service of the USDA uses the food system to describe the same thing, The U. S. food system is a complex network of farmers. Those links include makers of farm equipment and chemicals as well as firms that provide services to agribusinesses, such as providers of transportation and financial services. The system also includes the marketing industries that link farms to consumers, and which include food and fiber processors, wholesalers, retailers. The term food industries covers a series of activities directed at the processing, conversion, preparation, preservation. Many food industries depend almost entirely on agriculture or fishing. Agriculture is the process of producing food, feeding products, fiber and other desired products by the cultivation of certain plants, the practice of agriculture is also known as farming. Scientists, inventors, and others devoted to improving farming methods,1 in 3 people worldwide are employed in agriculture, yet it only contributes 3% to global GDP. Agronomy is the science and technology of producing and using plants for food, fuel, fibre, agronomy encompasses work in the areas of plant genetics, plant physiology, meteorology, and soil science. Agronomy is the application of a combination of sciences, agronomists today are involved with many issues including producing food, creating healthier food, managing environmental impact of agriculture, and extracting energy from plants. Food processing includes the methods and techniques used to transform raw ingredients into food for human consumption, Food processing takes clean, harvested or slaughtered and butchered components and uses them to produce marketable food products. There are several different ways in which food can be produced, one off production, This method is used when customers make an order for something to be made to their own specifications, for example a wedding cake. The making of products could take days depending on how intricate the design is. Batch production, This method is used when the size of the market for a product is not clear, a certain number of the same goods will be produced to make up a batch or run, for example a bakery may bake a limited number of cupcakes. This method involves estimating consumer demand, mass production, This method is used when there is a mass market for a large number of identical products, for example chocolate bars, ready meals and canned food. The product passes from one stage of production to another along a production line, just-in-time, This method of production is mainly used in restaurants
28.
Gelatin
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Gelatin or gelatine is a translucent, colorless, brittle, flavorless food derived from collagen obtained from various animal body parts. It is commonly used as an agent in food, pharmaceutical drugs, vitamin capsules, photography. Substances containing gelatin or functioning in a way are called gelatinous. It is found in most gummy candy, as well as other such as marshmallows, gelatin desserts, and some ice creams, dips. Gelatin for recipe use comes in the form of sheets, granules, instant types can be added to the food as they are, others need to be soaked in water beforehand. During hydrolysis, the molecular bonds between individual collagen strands are broken down into a form that rearranges more easily. Its chemical composition is, in respects, closely similar to that of its parent collagen. Photographic and pharmaceutical grades of gelatin generally are sourced from beef bones, Gelatin readily dissolves in hot water and sets to a gel on cooling. When added directly to water, it does not dissolve well. Gelatin also is soluble in most polar solvents, Gelatin solutions show viscoelastic flow and streaming birefringence. Solubility is determined by the method of manufacture, typically, gelatin can be dispersed in a relatively concentrated acid. Such dispersions are stable for 10–15 days with little or no changes and are suitable for coating purposes or for extrusion into a precipitating bath. The mechanical properties of gelatin gels are very sensitive to variations, the previous thermal history of the gels. The upper melting point is below human body temperature, a factor that is important for mouthfeel of foods produced with gelatin, the viscosity of the gelatin-water mixture is greatest when the gelatin concentration is high and the mixture is kept cool at about 4 °C. The gel strength is quantified using the Bloom test, the worldwide production amount of gelatin is about 375, 000–400,000 tonnes per year. On a commercial scale, gelatin is made from by-products of the meat, recently, fish by-products also have been considered suitable because they eliminate some of the religious obstacles surrounding gelatin consumption. Gelatin is derived from pork skins, pork, and cattle bones, the raw materials are prepared by different curing, acid, and alkali processes that are employed to extract the dried collagen hydrolysate. These processes may take weeks, and differences in such processes have great effects on the properties of the final gelatin products
29.
Leather
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Leather is a durable and flexible material created by tanning animal rawhide and skin, often cattle hide. It can be produced at manufacturing scales ranging from cottage industry to heavy industry, people use leather to make various goods—including clothing, bookbinding, leather wallpaper, and as a furniture covering. It is produced in a variety of types and styles. Several tanning processes transform hides and skins into leather, Chrome-tanned leather, invented in 1858, is tanned using chromium sulfate and it is more supple and pliable than vegetable-tanned leather and does not discolor or lose shape as drastically in water as vegetable-tanned. It is also known as wet-blue for its color derived from the chromium, more exotic colors are possible when using chrome tanning. The chrome tanning method usually only takes a day to finish, and it is reported that chrome-tanned leather adds up to 80% of the global leather supply. Vegetable-tanned leather is tanned using tannins and other found in different vegetable matter, such as tree bark prepared in bark mills, wood, leaves, fruits. It is supple and brown in color, with the exact shade depending on the mix of chemicals and it is the only form of leather suitable for use in leather carving or stamping. Vegetable-tanned leather is not stable in water, it tends to discolor, so if left to soak and then dried it shrinks, in hot water, it shrinks drastically and partly congeals—becoming rigid, and eventually brittle. Boiled leather is an example of this, where the leather has been hardened by being immersed in hot water, historically, it was occasionally used as armour after hardening, and it has also been used for book binding. Aldehyde-tanned leather is tanned using glutaraldehyde or oxazolidine compounds and this is the leather that most tanners refer to as wet-white leather due to its pale cream or white color. It is the type of chrome-free leather, often seen in shoes for infants. Formaldehyde tanning is another aldehyde tanning method, brain-tanned leathers fall into this category, and are exceptionally water absorbent. Brain tanned leathers are made by a process that uses emulsified oils, often those of animal brains such as deer, cattle. They are known for their softness and washability. Chamois leather also falls into the category of aldehyde tanning, and like brain tanning, produces a porous, chamois leather is made using marine oils that oxidize easily to produce the aldehydes that tan the leather to color it. Rose-tanned leather is a variation of oil tanning and brain tanning. Rose-tanned leather tanned leaves a powerful rose fragrance even years from when it is manufactured and it has been called the most valuable leather on earth, but this is mostly due to the high cost of rose otto and its labor-intensive tanning process
30.
Jabir ibn Hayyan
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Born and educated in Tus, he later traveled to Kufa. He is sometimes referred to as the father of early chemistry, as early as the 10th century, the identity and exact corpus of works of Jabir was in dispute in Islamic circles. In 988 Ibn al-Nadim compiled the Kitab al-Fihrist which mentions Jabir as a follower and as a companion to Jafar as-Sadiq. In another reference al-Nadim reports that a group of philosophers claimed Jabir was one of their own members, another group, reported by al-Nadim, says only The Large Book of Mercy is genuine and that the rest are pseudographical. Their assertions are rejected by al-Nadim, joining al-Nadim in asserting a real Jabir, Ibn-Wahshiyya Rejecting a real Jabir, Abu Sulayman al-Mantiqi claims the real author is one al-Hasan ibn al-Nakad al-Mawili. The 14th century critic of Arabic literature, Jamal al-Din ibn Nubata al-Misri declares all the attributed to Jabir doubtful. Jabir was a philosopher who lived mostly in the 8th century, he was born in Tus, Khorasan, in Persia. Jabir in the sources has been entitled differently as al-Azdi al-Barigi or al-Kufi or al-Tusi or al-Sufi. There is a difference of opinion as to whether he was a Persian from Khorasan who later went to Kufa or whether he was, as some have suggested, of Syrian origin and later lived in Persia and Iraq. His ethnic background is not clear, but most sources reference him as a Persian, in some sources, he is reported to have been the son of Hayyan al-Azdi, a pharmacist of the Arabian Azd tribe who emigrated from Yemen to Kufa during the Umayyad Caliphate. While Henry Corbin believes Geber seems to have been a client of the Azd tribe, Hayyan had supported the Abbasid revolt against the Umayyads, and was sent by them to the province of Khorasan to gather support for their cause. He was eventually caught by the Umayyads and executed and his family fled to Yemen, where Jabir grew up and studied the Quran, mathematics and other subjects. Jabirs fathers profession may have contributed greatly to his interest in alchemy, after the Abbasids took power, Jabir went back to Kufa. He began his practicing medicine, under the patronage of a Vizir of Caliph Harun al-Rashid. His connections to the Barmakid cost him dearly in the end, when that family fell from grace in 803, Jabir was placed under house arrest in Kufa, where he remained until his death. It has been asserted that Jabir was a student of the sixth Imam Jafar al-Sadiq and Harbi al-Himyari, in total, nearly 3,000 treatises and articles are credited to Jabir ibn Hayyan. The 112 Books dedicated to the Barmakids, viziers of Caliph Harun al-Rashid and this group includes the Arabic version of the Emerald Tablet, an ancient work that proved a recurring foundation of and source for alchemical operations. In the Middle Ages it was translated into Latin and widely diffused among European alchemists, the Seventy Books, most of which were translated into Latin during the Middle Ages
31.
Halite
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Halite, commonly known as rock salt, is a type of salt, the mineral form of sodium chloride. The mineral is colorless or white, but may also be light blue, dark blue, purple, pink, red, orange, yellow or gray depending on the amount. It commonly occurs with other evaporite minerals such as several of the sulfates, halides. Halite occurs in vast beds of sedimentary evaporite minerals that result from the drying up of enclosed lakes, playas, salt beds may be hundreds of meters thick and underlie broad areas. In the United States and Canada extensive underground beds extend from the Appalachian basin of western New York through parts of Ontario, other deposits are in Ohio, Kansas, New Mexico, Nova Scotia and Saskatchewan. The Khewra salt mine is a deposit of halite near Islamabad. In the United Kingdom there are three mines, the largest of these is at Winsford in Cheshire producing on average a million tonnes per year. Salt domes are vertical diapirs or pipe-like masses of salt that have been squeezed up from underlying salt beds by mobilization due to the weight of overlying rock. Salt domes contain anhydrite, gypsum, and native sulfur, in addition to halite and sylvite and they are common along the Gulf coasts of Texas and Louisiana and are often associated with petroleum deposits. Germany, Spain, the Netherlands, Romania and Iran also have salt domes, salt glaciers exist in arid Iran where the salt has broken through the surface at high elevation and flows downhill. In all of these cases, halite is said to be behaving in the manner of a rheid, unusual, purple, fibrous vein filling halite is found in France and a few other localities. Halite crystals termed hopper crystals appear to be skeletons of the cubes, with the edges present and stairstep depressions on, or rather in. In a rapidly crystallizing environment, the edges of the cubes simply grow faster than the centers, halite crystals form very quickly in some rapidly evaporating lakes resulting in modern artifacts with a coating or encrustation of halite crystals. Halite flowers are rare stalactites of curling fibers of halite that are found in certain arid caves of Australias Nullarbor Plain, halite stalactites and encrustations are also reported in the Quincy native copper mine of Hancock, Michigan. Halite is often used both residentially and municipally for managing ice, because brine has a lower freezing point than pure water, putting salt or saltwater on ice that is near 0 °C will cause it to melt. It is common for homeowners in cold climates to spread salt on their sidewalks and driveways after a snow storm to melt the ice. It is not necessary to use so much salt that the ice is melted, rather. Also, many cities will spread a mixture of sand and salt on roads during, in addition to de-icing, rock salt is occasionally used in agriculture
32.
Iron(II) sulfate
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Iron sulfate or ferrous sulfate denotes a range of salts with the formula FeSO4·xH2O. These compounds exist most commonly as the heptahydrate but are known for several values of x, the hydrated form is used medically to treat iron deficiency, and also for industrial applications. Known since ancient times as copperas and as green vitriol, the blue-green heptahydrate is the most common form of this material, all the iron sulfates dissolve in water to give the same aquo complex 2+, which has octahedral molecular geometry and is paramagnetic. The name copperas dates from times when the copper sulfate was known as blue copperas and it is on the World Health Organizations List of Essential Medicines, the most important medications needed in a basic health system. Industrially, ferrous sulfate is used as a precursor to other iron compounds. It is an agent, and as such is useful for the reduction of chromate in cement to less toxic Cr compounds. Historically ferrous sulfate was used in the industry for centuries as a dye fixative. It is used historically to blacken leather and as a constituent of ink, together with other iron compounds, ferrous sulfate is used to fortify foods and to treat and prevent iron deficiency anemia. Constipation is a frequent and uncomfortable side effect associated with the administration of oral iron supplements, stool softeners often are prescribed to prevent constipation. Ferrous sulfate was used in the manufacture of inks, most notably iron gall ink, chemical tests made on the Lachish letters showed the possible presence of iron. It is thought that oak galls and copperas may have used in making the ink on those letters. It also finds use in dyeing as a mordant. Harewood, a used in marquetry and parquetry since the 17th century, is also made using ferrous sulfate. Two different methods for the application of indigo dye were developed in England in the eighteenth century. One of these, known as blue, involved iron sulfate. After printing an insoluble form of indigo onto the fabric, the indigo was reduced to leuco-indigo in a sequence of baths of ferrous sulfate, the china blue process could make sharp designs, but it could not produce the dark hues of other methods. Sometimes, it is included in canned black olives as an artificial colorant, ferrous sulfate can also be used to stain concrete and some limestones and sandstones a yellowish rust color. Woodworkers use ferrous sulfate solutions to color maple wood a silvery hue, in horticulture it is used for treating iron chlorosis
33.
Basil Valentine
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According to John Maxson Stillman, who wrote on the history of chemistry, there is no evidence of such a name on the rolls in Germany or Rome and no mention of this name before 1600. His putative history, like his portrait, appears to be of later creation than the writings themselves. During the 18th century it was suggested that the author of the attributed to Basil Valentine was Johann Thölde. Modern scholarship now suggests that one author was Thölde, but that others were involved, Thölde published the first five books under Valentines name. Whoever he was, Basil Valentine had considerable chemical knowledge, the Twelve Keys of Basil Valentine is a widely reproduced alchemical book attributed to Basil Valentine, first published in 1599. It contains two parts, the second of which houses the twelve keys and these were accompanied by woodcut engravings from later publications in the early seventeenth century. Numerous publications on alchemy in Latin and German were published under the name Basil Valentine and they have been translated into many European languages, including English, French, Russian and others. The following list is organized in order of translation or publication date. Ein kurtz summarischer Tractat, von dem grossen Stein der Uralten. by Basilius Valentinus, eisleben,1599 Ein kurtz summarischer Tractat, von dem grossen Stein der Uralten. Leipzig,1602 Triumph Wagen Antimonii, by Basil Valentine, Johannes Isaaci Hollandus, Joachim Tank, Georg Phaedro, leipzig, In Verlegung Jacob Apels,1604. De microcosmo deque magno mundi mysterio, et medicina hominis, by Basilius Valentinus, a Latin translation of the text of Ein kurtz summarischer Tractat as Tripus Aureus, hoc est, Tres Tractatus Chymici Selectissimi, nempe I. Basilii Valentini. Practica una cum 12 clavibus & appendice, ex Germanico, Michael Maier, Frankfurt, azoth, ou le moyen de faire lor caché des philosophes, de frère Basile Valentin by Basilius Valentinus, Christofle Perier, Jeremie Perier. Paris, Chez Ieremie & Christofle Perier, au Palais, MDCXXIV1624, Les dovze clefs de philosophie de Frere Basile Valentin. Traictant de la vraye medecine matalique, plus lAzoth, ou Le moyen de faire lor chaché des philosophes. Paris, Chez Ieremie et Christophle Perier,1624, letztes Testament und Offenbahrung der himmlischen und virdischen Geheimnüss, so in einem Altar gefunden, in fünff Bücher abgetheilet. Zuvor nie in Druck aussgangen, jetzt aber. publiciret durch Georgium Claromontanum, by Basile Valentin, Georg Hellberger dit Georgius Claromontanus. Iena, H. Eyrings und J. Perferts Erben,1626, revelation des mysteres des teintures essentieles des sept metaux et de leurs vertus médicinales. By Basile Valentin, translated by Jean Israël, paris, J. De Senlecque et J. Hénault,1645
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