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Pages in category "Monomers"
The following 110 pages are in this category, out of 110 total. This list may not reflect recent changes (learn more).
|Wikimedia Commons has media related to Polymer chemistry.|
The following 110 pages are in this category, out of 110 total. This list may not reflect recent changes (learn more).
1. Acrylamide – Acrylamide is a chemical compound with the chemical formula C3H5NO. It is a white crystalline solid, soluble in water, ethanol, ether. Acrylamide decomposes in the presence of acids, bases, oxidizing agents, iron and it decomposes non-thermally to form ammonia, and thermal decomposition produces carbon monoxide, carbon dioxide, and oxides of nitrogen. Acrylamide can be prepared by the hydrolysis of acrylonitrile by nitrile hydratase, in industry, most acrylamide is used to synthesize polyacrylamides, which find many uses as water-soluble thickeners. These include use in treatment, gel electrophoresis, papermaking, ore processing, tertiary oil recovery. Some acrylamide is used in the manufacture of dyes and the manufacture of other monomers, the discovery of acrylamide in some cooked starchy foods in 2002 prompted concerns about the carcinogenicity of those foods. As of 2016 it is not clear whether acrylamide consumption affects peoples risk of developing cancer. Acrylamide is classified as a hazardous substance in the United States as defined in Section 302 of the U. S. Emergency Planning and Community Right-to-Know Act, and is subject to reporting requirements by facilities which produce, store. Polyacrylamide was first used in a setting in the early 1950s. In 1959, the groups of Davis and Ornstein and of Raymond, the technique is widely accepted today, and remains a common protocol in molecular biology labs. Acrylamide has many uses in molecular biology laboratories, including the use of linear polyacrylamide as a carrier. Many laboratory supply companies sell LPA for this use, the majority of acrylamide is used to manufacture various polymers. In the 1970s and 1980s, the proportionately largest use of polymers was in water treatment. Polyacrylamide is also used in potting soil. Another use of polyacrylamide is as an intermediate in the production of N-methylol acrylamide and N-butoxyacrylamide. US demand for acrylamide was 253,000,000 pounds as of 2007, acrylamide is considered a potential occupational carcinogen by U. S. government agencies and classified as a Group 2A carcinogen by the IARC. The Occupational Safety and Health Administration and the National Institute for Occupational Safety, in animal models, exposure to acrylamide causes tumors in the adrenal glands, thyroid, lungs, and testes
2. 2-Acrylamido-2-methylpropane sulfonic acid – 2-Acrylamido-2-methylpropane sulfonic acid is a reactive, hydrophilic, sulfonic acid acrylic monomer used to alter the chemical properties of wide variety of anionic polymers. In the 1970s, the earliest patents using this monomer were filed for acrylic fiber manufacturing, AMPS is made by the Ritter reaction of acrylonitrile and isobutylene in the presence of sulfuric acid and water. Polarity and hydrophilicity, The sulfonate group gives the monomer a high degree of hydrophilicity, in addition, AMPS is absorbing water readily and also imparts enhanced water absorption and transport characteristics to polymers. Solubility, AMPS is very soluble in water and dimethylformamide and also shows limited solubility in most polar organic solvents, inhibition of divalent cation precipitation, Sulfonic acid in AMPS is a very strong ionic group and ionizes completely in aqueous solutions. The result is a significant reduction in the precipitation of a variety of mineral salts, including calcium, magnesium, iron, aluminum, zinc. Determining viscosity-average molecular weight Reactivity ratio, AMPS reacts well with a variety of vinyl monomers, coating and adhesive, Its sulfonic acid group gives the monomers ionic character over a wide range of pH. Anionic charges from AMPS fixed on polymer particles enhance the chemical and shear stabilities of polymer emulsion and it improves the thermal and mechanical properties of adhesives, and increases the adhesive strength of pressure-sensitive adhesive formulations. Detergents, Enhances the washing performance of surfactants by binding multivalent cations, personal care, Strong polar and hydrophilic properties introduced to a high molecular weight AMPS homopolymer are exploited as a very efficient lubricant characteristic for skin care. Medical hydrogel, High water-absorbing and swelling capacity when AMPS is introduced to a hydrogel are keys to medical applications, in addition, polymers derived from AMPS are used as the absorbing hydrogel and the tackifier component of wound dressings. Is used due to its high water absorption and retention capability as a monomer in superabsorbents e. g. for baby diapers. Oil field applications, Polymers in oil field applications have to stand hostile environments and require thermal and hydrolytic stability, water treatment applications, The cation stability of the AMPS-containing polymers are very useful for water treatment processes. Such polymers with low molecular weights cannot only inhibit calcium, magnesium, and silica scale in cooling towers and boilers, when high molecular weight polymers are used, they can be used to precipitate solids in the treatment of industrial effluent stream. Crop protection, increases in dissolved and nanoparticulate polymer formulations bioavailability of pesticides in aqueous-organic formulations, construction applications, Superplasticizers with AMPS are used to reduce water in concrete formulations. Benefits of these additives include improved strength, improved workability, improved durability of cement mixtures, coating formulations with AMPS-containing polymers prevent calcium ions from being formed as lime on concrete surface and improve the appearance and durability of coating. PolyAMPS Hydrogel Composition analysis of AMPS-vinyl amide copolymers, materials 8287-289 Synthesis and characterization of AMPS copolymers with vinylamides by Solution and thermal studies J. polym. High Temperature Molecular relaxations in EMA-AMPS copolymers, thermoluminescence in probing molecular relaxations and degradation studies of MMA-AMPS copolymers. Bulletin of Electro Chemistry 9 feb
3. Acrylate – Acrylates are the salts, esters, and conjugate bases of acrylic acid and its derivatives. They are also known as propenoates, the acrylate ion has the molecular formula CH2=CHCOO−. Acrylates contain vinyl groups, that is, two carbon atoms bonded to each other, directly attached to the carbonyl carbon. Acrylates and methacrylates are common monomers in polymer plastics, forming the acrylate polymers, acrylates easily form polymers because the double bonds are very reactive. Acrylates are industrially prepared by reacting acrylic acid with the alcohol in presence of a catalyst. The reaction with lower alcohols takes place at 100-120 °C with acidic heterogeneous catalysts, the reaction of higher alcohols is catalysed with sulfuric acid in homogeneous phase. Acrylates of even higher alcohols are obtainable by transesterification of lower esters catalysed by titanium alcoholates or organic tin compounds, acrylate has been suggested to be used by marine phytoplankton as a poisonous defense against predators such as protozoa. When attacked, DMSP lyase breaks down dimethylsulfoniopropionate into dimethylsulfide and acrylate, acrylate polymer Sodium polyacrylate thickeners Methacrylate acrylate
4. Acrylic acid – Acrylic acid is an organic compound with the formula CH2=CHCOOH. It is the simplest unsaturated carboxylic acid, consisting of a group connected directly to a carboxylic acid terminus. This colorless liquid has a characteristic acrid or tart smell and it is miscible with water, alcohols, ethers, and chloroform. More than a million tons are produced annually, Acrylic acid is produced from propylene which is a byproduct of ethylene and gasoline production. CH2=CHCH3 + 3⁄2 O2 → CH2=CHCO2H + H2O Ethylene can be carboxylated to acrylic acid under supercritical carbon dioxide condition, because acrylic acid and its esters have long been valued commercially, many other methods have been developed but most have been abandoned for economic or environmental reasons. An early method was the hydrocarboxylation of acetylene, HCCH + CO + H2O → CH2=CHCO2H This method requires nickel carbonyl and it was once manufactured by the hydrolysis of acrylonitrile which is derived from propene by ammoxidation, but was abandoned because the method cogenerates ammonium derivatives. Other now abandoned precursors to acrylic acid include ethenone and ethylene cyanohydrin, dow Chemical Company and a partner, OPX Biotechnologies, are investigating using fermented sugar to produce 3-hydroxypropionic acid, an acrylic acid precursor. The goal is to reduce gas emissions. Acrylic acid undergoes the reactions of a carboxylic acid. When reacted with an alcohol, it forms the corresponding ester, the esters and salts of acrylic acid are collectively known as acrylates. The most common alkyl esters of acrylic acid are methyl, butyl, ethyl, as a substituent acrylic acid can be found as an acyl group or a carboxyalkyl group depending on the removal of the group from the molecule. More specifically these are, The acryloyl group, with the removal of the –OH from carbon-1, the 2-carboxyethenyl group, with the removal of a –H from carbon-3. This substituent group is found in chlorophyll, Acrylic acid is severely irritating and corrosive to the skin and the respiratory tract. Eye contact can result in severe and irreversible injury, low exposure will cause minimal or no health effects, while high exposure could result in pulmonary edema. Methacrylic acid Acryloyl chloride Acrylamide Acrylate polymer Sodium polyacrylate National Pollutant Inventory, Acrylic acid CDC - NIOSH Pocket Guide to Chemical Hazards - Acrylic acid
5. Acrylonitrile – Acrylonitrile is an organic compound with the formula CH2CHCN. It is a volatile liquid, although commercial samples can be yellow due to impurities. In terms of its structure, it consists of a vinyl group linked to a nitrile. It is an important monomer for the manufacture of plastics such as polyacrylonitrile. It is reactive and toxic at low doses, Acrylonitrile was first synthesized by the French chemist Charles Moureu in 1893. Acrylonitrile is produced by ammoxidation of propylene, also known as the SOHIO process. In 2002, world production capacity was estimated at 5 million tonnes per year, acetonitrile and hydrogen cyanide are significant byproducts that are recovered for sale. In fact, the 2008–2009 acetonitrile shortage was caused by a decrease in demand for acrylonitrile. 2CH3-CH=CH2 + 2NH3 + 3O2 → 2CH2=CH-C≡N + 6H2O In the SOHIO process, propylene, ammonia, the reactants pass through the reactor only once, before being quenched in aqueous sulfuric acid. Excess propylene, carbon monoxide, carbon dioxide, and dinitrogen that do not dissolve are vented directly to the atmosphere, the aqueous solution consists of acrylonitrile, acetonitrile, hydrocyanic acid, and ammonium sulfate. A recovery column removes bulk water, and acrylonitrile and acetonitrile are separated by distillation, historically, one of the first successful catalysts was bismuth phosphomolybdate supported on silica as a heterogeneous catalyst. Further improvements have since been made, various green chemistry routes are being developed for the synthesis of acrylonitrile from renewable feedstocks, such as lignocellulosic biomass, glycerol, or glutamic acid. The lignocellulosic route involves fermentation of the biomass to propionic acid, the glycerol route begins with pyrolysis to acrolein, which undergoes ammoxidation to give acrylonitrile. The glutamic route employs oxidative decarboxylation to 3-cyanopropanoic, followed by a decarbonylation-elimination to acrylonitrile, of these the glycerol route is broadly considered to be the most viable, although current methods are still unable to compete with the SOHIO process in terms of cost. Dimerization of acrylonitrile affords adiponitrile, used in the synthesis of certain polyamides, small amounts are also used as a fumigant. Acrylonitrile and derivatives, such as 2-chloro-acrylonitrile, are dienophiles in Diels-Alder reactions, Acrylonitrile is also a precursor in the industrial manufacture of acrylamide and acrylic acid. Acrylonitrile is highly flammable and toxic at low doses, the burning material releases fumes of hydrogen cyanide and oxides of nitrogen. It evaporates quickly at room temperature to reach dangerous concentrations, skin irritation, respiratory irritation, Acrylonitrile increases cancer in high dose tests in male and female rats and mice
6. Acryloyl chloride – Acryloyl chloride, also known as 2-propenoyl chloride or acrylic acid chloride, is a clear, light yellow, flammable liquid with an acrid smell. It belongs to the acid group of compounds and is therefore a derivative of acrylic acid. Acryloyl chloride can be prepared by reacting acrylic acid with benzoyl chloride, oxalyl chloride, when preparing this compound adding a small amount of an inhibitor such as hydroquinone can help to avoid light induced polymerisation of acryloyl chloride. Reactions with alcohols will result in the formation of esters and reactions with amines will generate amides
7. Adipic acid – Adipic acid or hexanedioic acid is the organic compound with the formula 42. Adipic acid otherwise rarely occurs in nature, adipic acid is produced from a mixture of cyclohexanol and cyclohexanone called KA oil, the abbreviation of ketone-alcohol oil. The KA oil is oxidized with nitric acid to give adipic acid, nitrous oxide is produced as well, via the intermediacy of a nitrolic acid. Related processes start from cyclohexanol, which is obtained from the hydrogenation of phenol, several methods have been developed by carbonylation of butadiene. For example, the proceeds as follows, CH2=CH−CH=CH2 +2 CO +2 H2O → HO2C4CO2H Another method is oxidative cleavage of cyclohexene using hydrogen peroxide. Historically, adipic acid was prepared by oxidation of various fats, adipic acid is a dibasic acid. The pKa values for their successive deprotonations are 4.41 and 5.41, with the carboxylate groups separated by four methylene groups, adipic acid is suited for intramolecular condensation reactions. Upon treatment with barium hydroxide at elevated temperatures, it undergoes ketonization to give cyclopentanone, about 60% of the 2.5 billion kg of adipic acid produced annually is used as monomer for the production of nylon by a polycondensation reaction with hexamethylene diamine forming nylon 66. Other major applications also involve polymers, it is a monomer for production of polyurethane and its esters are plasticizers, adipic acid has been incorporated into controlled-release formulation matrix tablets to obtain pH-independent release for both weakly basic and weakly acidic drugs. It has also incorporated into the polymeric coating of hydrophilic monolithic systems to modulate the intragel pH. The disintegration at intestinal pH of the enteric polymer shellac has been reported to improve when adipic acid was used as a pore-forming agent without affecting release in the acidic media, other controlled-release formulations have included adipic acid with the intention of obtaining a late-burst release profile. Adipic acid is used to make bisobrin an antifibrinolytic, small but significant amounts of adipic acid are used as a food ingredient as a flavorant and gelling aid. It is used in some calcium carbonate antacids to make them tart, as an acidulant in baking powders, it avoids the undesireable hygroscopic properties of tartaric acid. Adipic acid, rare in nature, does occur naturally in beets, adipic acid, like most carboxylic acids, is a mild skin irritant. It is mildly toxic, with an LD50 of 3600 mg/kg for oral ingestion by rats, the production of adipic acid is linked to emissions of N 2O, a potent greenhouse gas and cause of stratospheric ozone depletion. At adipic acid producers DuPont and Rhodia, processes have been implemented to convert the nitrous oxide to innocuous products,2 N2O →2 N2 + O2 E-number E355
8. Adipoyl chloride – Adipoyl chloride is a di-acyl chloride, with formula C6H8Cl2O2. It is a chemical that evolves HCl when reacted with water. It should be handled with full protection under a fume hood, adipoyl chloride can be reacted with hexamethylenediamine to form nylon 6,6. Adipoyl chloride can be prepared from adipic acid
9. 1,3-Butadiene – 1, 3-Butadiene is a simple conjugated diene with the formula C4H6. It is an important industrial chemical used as a monomer in the production of synthetic rubber, the molecule can be viewed as two vinyl groups joined together. The word butadiene usually refers to 1, 3-butadiene, which has the structure H2C=CH−CH=CH2, although butadiene breaks down quickly in the atmosphere, it is nevertheless found in ambient air in urban and suburban areas as a consequence of its constant emission from motor vehicles. The name butadiene can also refer to the isomer,1, 2-butadiene, however, this allene is difficult to prepare and has no industrial significance. This diene is also not expected to act as a diene in a Diels–Alder reaction due to its structure, to effect a Diels–Alder reaction, only a conjugated diene will suffice. The rest of this article concerns only 1, 3-butadiene, in 1863, the French chemist E. Caventou isolated a previously unknown hydrocarbon from the pyrolysis of amyl alcohol. This hydrocarbon was identified as butadiene in 1886, after Henry Edward Armstrong isolated it from among the products of petroleum. In 1910, the Russian chemist Sergei Lebedev polymerized butadiene and obtained a material with rubber-like properties and this polymer was, however, found to be too soft to replace natural rubber in many applications, notably automobile tires. The butadiene industry originated in the leading up to World War II. In 1929, Eduard Tschunker and Walter Bock, working for IG Farben in Germany, worldwide production quickly ensued, with butadiene being produced from grain alcohol in the Soviet Union and the United States and from coal-derived acetylene in Germany. In the United States, western Europe, and Japan, butadiene is produced as a byproduct of the cracking process used to produce ethylene. When mixed with steam and briefly heated to high temperatures, aliphatic hydrocarbons give up hydrogen to produce a complex mixture of unsaturated hydrocarbons. The quantity of butadiene produced depends on the used as feed. Light feeds, such as ethane, give primarily ethylene when cracked, but heavier feeds favor the formation of heavier olefins, butadiene, butadiene can also be produced by the catalytic dehydrogenation of normal butane. The first such post-war commercial plant, producing 65,000 tons per year of butadiene, began operations in 1957 in Houston, today, butadiene from n-butane is commercially practiced using the Houdry catadiene process, which was developed during World War II. In other parts of the world, including South America, Eastern Europe, China, while not competitive with steam cracking for producing large volumes of butadiene, lower capital costs make production from ethanol a viable option for smaller-capacity plants. At the same time this type of manufacture was canceled in Brazil, nowadays there is no industrial production of butadiene from ethanol. Recently, Lanxess announced plans to produce butadiene from ethanol, the process remains in use today in China and India
10. 1,2,4-Butanetriol – 1,2, 4-Butanetriol is a clear or slightly yellow, odorless, hygroscopic, flammable, viscous liquid. It is an alcohol with three hydrophilic alcoholic hydroxyl groups and it is similar to glycerol and erythritol. It is chiral, with two possible enantiomers,1,2, 4-Butanetriol is used in the manufacture of butanetriol trinitrate, an important military propellant. Microbial synthesis of the energetic material precursor 1,2, 4-butanetriol and it is as one of the monomers for manufacture of some polyesters and as a solvent. However, of an increasing importance is the synthesis using genetically engineered Escherichia coli
11. Butene – Butene, also known as butylene, is a series of alkenes with the general formula C4H8. The word butene may refer to any of the individual compounds and they are colourless gases that are present in crude oil as a minor constituent in quantities that are too small for viable extraction. Butene is therefore obtained by cracking of long-chain hydrocarbons left during refining of crude oil. Cracking produces a mixture of products, and the butene is extracted from this by fractional distillation, butene can be used as the monomer for polybutene but this polymer is more expensive than alternatives with shorter carbon chains such as polypropylene. Polybutene is therefore used as a co-polymer, such as in hot-melt adhesives. Among the molecules which have the chemical formula C4H8 four isomers are alkenes, all four of these hydrocarbons have four carbon atoms and one double bond in their molecules, but have different chemical structures. Other organic compounds have the formula C4H8, namely cyclobutane and methylcyclopropane, there are also cyclic alkenes with four carbon atoms overall such as cyclobutene and two isomers of methylcyclopropene, but they do not have the formula C4H8 and are not discussed here. All four of these isomers are gases at room temperature and pressure and these gases are colourless, but do have distinct odours, and are highly flammable. Although not naturally present in petroleum in high percentages, they can be produced from petrochemicals or by catalytic cracking of petroleum, although they are stable compounds, the carbon-carbon double bonds make them more reactive than similar alkanes, which are more inert compounds in various ways. Because of the bonds, these 4-carbon alkenes can act as monomers in the formation of polymers. They are used in the production of synthetic rubber, but-1-ene is a linear or normal alpha-olefin and isobutylene is a branched alpha-olefin. In a rather low percentage, but-1-ene is used as one of the comonomers, along with other alpha-olefins, in the production of high-density polyethylene, butyl rubber is made by cationic polymerisation of isobutylene with about 2 - 7% isoprene. Isobutylene is also used for the production of methyl tert-butyl ether and isooctane, both of which improve the combustion of gasoline
12. Butyl cyanoacrylate – N-Butyl cyanoacrylate, a cyanoacrylate ester, is a butyl ester of 2-cyano-2-propenoic acid. It is a colorless liquid with a sharp, irritating odor. Its chief use is as the component of medical cyanoacrylate glues. It can be encountered under various names, e. g. MediBond, MediCryl, PeriAcryl, GluStitch, Xoin, Gesika, VetGlu, Vetbond, LiquiVet, Indermil, LiquiBand, Histoacryl, IFABond. The generic international nonproprietary name for NBCA is embucrilate, in medical and veterinary applications, NBCA, isobutyl cyanoacrylate, and octyl cyanoacrylate are commonly used. They are bacteriostatic and their use is usually painless, butyl esters provide stronger bond, but are rigid. Octyl esters, while providing weaker bond, are more flexible, blends of octyl cyanoacrylate and n-butyl cyanoacrylate are available which offer both flexibility and a strong bond. N-Butyl cyanoacrylate is used for embolization of cerebral arteriovenous malformations before their surgical treatment. NBCA is soluble in acetone, methyl ethyl ketone, nitromethane, NBCA in monomer form polymerizes rapidly in presence of ionic substances such as moisture, blood, or tissue fluids. NBCA has unique properties compared to other such as octyl cyanoacrylate or isoamyl cyanoacrylate. The polymerized form has excellent tensile strength and is effective in closing surgical or wound incisions. The closure of the wound or cut is quick and the product has inherently some valuable bacteriostatic properties, the cosmetic outcome of the closure is comparable or generally better than an equivalent suture substitute with least amount of scarring visible after three to six months. Also important is the properties of polymerized NBCA within the body. This property of NBCA has made it a very useful polymer to create various nanoparticles for delivery of drugs into the body with sustained release profiles, heating to higher temperatures causes pyrolysis and depolymerization of the cured glue, producing gaseous products strongly irritating to lungs and eyes. The medical applications of butyl cyanoacrylate include its use as an adhesive for lacerations of the skin, butyl cyanoacrylate has been used to treat arteriovenous malformations by application of the glue into the abnormality through angiography. In gastroenterology, butyl cyanoacrylate is used to treat bleeding gastric varices, the gastric varices are accessed by endoscopy, which uses a flexible fibre-optic camera to enter the stomach. They are injected with a needle inserted into the varix through the endoscope. Other sites of varices, including esophageal varices, duodenal varices, gastric varices have also been obliterated with recurrent injection treatment with butyl cyanoacrylate
13. Caprolactam – Caprolactam is an organic compound with the formula 5CNH. This colourless solid is a lactam of caproic acid, approximately 4.5 billion kilograms are produced annually. Caprolactam is the precursor to Nylon 6, a widely used synthetic polymer, caprolactam was first described in the late 1800s when it was prepared by the cyclization of ε-aminocaproic acid, the product of the hydrolysis of caprolactam. Given the commercial significance of Nylon-6, many methods have developed for the production of caprolactam. Most of the caprolactam is synthesised from cyclohexanone, which is first converted to its oxime, treatment of this oxime with acid induces the Beckmann rearrangement to give caprolactam, The immediate product of the acid-induced rearrangement is the bisulfate salt of caprolactam. This salt is neutralized with ammonia to release the free lactam, in optimizing the industrial practices, much attention is directed toward minimizing the production of ammonium salts. The other major route involves formation of the oxime from cyclohexane using nitrosyl chloride. The advantage of this method is that cyclohexane is less expensive than cyclohexanone, in earlier times, caprolactam was prepared by treatment of caprolactone with ammonia. Cyclohexanone with hydrazoic acid has also been reported and this is known as a Schmidt ring expansion. Almost all caprolactam produced goes into the manufacture of Nylon-6, the conversion entails a ring-opening polymerization, n 5CNH → n Nylon-6 is widely used in fibers and plastics. In situ anionic polymerization is employed for cast nylon production where conversion from ε-caprolactam to Nylon-6 takes place inside a mold, in conjunction with endless fiber processing the term thermoplastic resin transfer molding is often used. Caprolactam is an irritant and is toxic, with an LD50 of 1.1 g/kg. In 1991, it was included on the list of air pollutants by the U. S. Clean Air Act of 1990. It was subsequently removed from the list in 1996, in water, caprolactam hydrolyzes to aminocaproic acid, which is used medicinally. As of 2016 caprolactam had the status of being the only chemical in the International Agency for Research on Cancers lowest hazard category, Group 4. Currently, there is no official permissible exposure limit set for workers handling caprolactam in the United States, the recommended exposure limit is set at 1 mg/m3 over an eight-hour work shift for caprolactam dusts and vapors. The short-term exposure limit is set at 3 mg/m3 for caprolactam dusts and vapors
14. Caprolactone – ε-Caprolactone or simply caprolactone is a cyclic ester, a member of the lactone family, with a seven-membered ring with the formula 5CO2. This colorless liquid is miscible with most organic solvents and it is produced on a large scale as a precursor to polycaprolactones. The great majority of caprolactone is consumed, often in situ and it is also a monomer used in the manufacture of highly specialised polymers. Ring-opening polymerization, for example, gives polycaprolactone, another polymer is polyglecaprone, used as suture material in surgery. Caprolactone is prepared industrially by Baeyer-Villiger oxidation of cyclohexanone with peracetic acid, the three main manufacturers are BASF in the USA, Daicel in Japan and the largest Perstorp in Sweden. The major use of caprolactone is the production of polycaprolactones, there is published usage for caprolactone is its conversion to caprolactam, billions of kilograms of which are produced annually but not by this route. Carbonylation of caprolactone gives, after hydrolysis, pimelic acid, the lactone ring is easily opened with nucleophiles including alcohols and water to give polylactones and eventually the 6-hydroxyadipic acid. Several other caprolactones are known, although none approaches the technological importance of ε-caprolactone and these isomers include alpha-, beta-, gamma-, delta-caprolactones. Gamma-caprolactone is component of flower aromas and an insect pheromone, delta-Caprolactone is found in heated milk fat. Caprolactone hydrolyses rapidly and the resulting hydroxycarboxylic acid displays unexceptional toxicity and it is known to cause severe eye irritation. Exposure may result in corneal injury
15. Chloroprene – Chloroprene is the common name for the organic compound 2-chlorobuta-1, 3-diene, which has the formula CH2=CCl−CH=CH2. This colorless liquid is the monomer for the production of the polymer polychloroprene, polychloroprene is better known to the public as Neoprene, the trade name given by DuPont. Chloroprene is produced in three steps from 1, 3-butadiene, chlorination, isomerization of part of the product stream, chlorine adds to 1, 3-butadiene to afford a mixture of 3, 4-dichlorobut-1-ene and 1, 4-dichlorobut-2-ene. The 1, 4-dichloro isomer is subsequently isomerized to 3,4 isomer and this dehydrohalogenation entails loss of a hydrogen atom in the 3 position and the chlorine atom in the 4 position thereby forming a double bond between carbons 3 and 4. In 1983, approximately 2,000,000 kg was produced in this manner, the chief impurity in chloroprene prepared in this way is 1-chlorobuta-1, 3-diene, which is usually separated by distillation. Until the 1960s, chloroprene production was dominated by the acetylene process, furthermore, the intermediate vinyl acetylene is unstable. This acetylene process has been replaced by a process which adds Cl2 to one of the bonds in 1, 3-butadiene instead. Transportation of uninhibited chloroprene has been banned in the United States by the US Department of Transportation, stabilized chloroprene is in hazard class 3. Its UN number is 1991 and is in packing group 1, international Chemical Safety Card 0133 NIOSH Pocket Guide to Chemical Hazards #0133. National Institute for Occupational Safety and Health
16. Cyanoacrylate – Cyanoacrylates are a family of strong fast-acting adhesives with industrial, medical, and household uses. Cyanoacrylate adhesives have a shelf life if not used, about one year from manufacture if unopened. Cyanoacrylates include methyl 2-cyanoacrylate, ethyl-2-cyanoacrylate, n-butyl cyanoacrylate and 2-octyl cyanoacrylate, Octyl cyanoacrylate was developed to address toxicity concerns and to reduce skin irritation and allergic response. Cyanoacrylate adhesives are sometimes known generically as instant glues, power glues or superglues, the abbreviation CA is commonly used for industrial grades. The original patent for cyanoacrylate was filed in 1942 by Goodrich Company, as an outgrowth of a search for materials suitable for clear plastic gun sights for the war effort. In 1942, a team of scientists headed by Harry Coover Jr. stumbled upon a formulation that stuck to everything with which it came in contact. The team quickly rejected the substance for the application, but in 1951, while working as researchers for Eastman Kodak, Coover. The two realized the commercial potential, and a form of the adhesive was first sold in 1958 under the title Eastman #910. During the 1960s, Eastman Kodak sold cyanoacrylate to Loctite, which in turn repackaged and distributed it under a different brand name Loctite Quick Set 404, in 1971 Loctite developed its own manufacturing technology and introduced its own line of cyanoacrylate, called Super Bonder. Loctite quickly gained market share, and by the late 1970s it was believed to have exceeded Eastman Kodaks share in the North American industrial cyanoacrylate market, National Starch and Chemical Company purchased Eastman Kodak’s cyanoacrylate business and combined it with several acquisitions made throughout the 1970s forming Permabond. Other manufacturers of cyanoacrylate include LePage, the Permabond Division of National Starch and Chemical, together, Loctite, Eastman and Permabond accounted for approximately 75% of the industrial cyanoacrylate market. As of 2013 Permabond continued to manufacture the original 910 formula, in its liquid form, cyanoacrylate consists of monomers of cyanoacrylate molecules. Methyl-2-cyanoacrylate has a weight equal to 111.1, a flashpoint of 79 °C. Ethyl 2-cyanoacrylate has a weight equal to 125 and a flashpoint of >75 °C. To facilitate easy handling, an adhesive is frequently formulated with an ingredient such as fumed silica to make it more viscous or gel-like. More recently, formulations are available with additives to increase shear strength, such additives may include rubber, as in Loctites Ultra Gel, or others which are not specified. In general, cyanoacrylate is a resin that rapidly polymerises in the presence of water, forming long, strong chains. Because the presence of moisture causes the glue to set, exposure to normal levels of humidity in the air causes a thin skin to start to form within seconds, because of this cyanoacrylate is applied thinly, to ensure that the reaction proceeds rapidly for bonding