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TMXDI
Tetramethylxylylene diisocyanate (TMXDI) is an organic compound is an organic compound with the formula C6H4(CMe2NCO)2 (Me = CH3). The molecule features two isocyanate groups. It was introduced in the 1980s by American Cyanamid. TMXDI is generally classified as an aliphatic isocyanate. Aliphatic isocyanates generally exhibit enhanced UV stability compared to their aromatic counterparts. Production Many isocyanates are produced by phosgenation of amines, but TMXDI is not. It is produced by the reaction of diisopropenylbenzene with hydrogen chloride followed by isocyanic acid: :C6H4(C(Me)=CH2)2 + 2 HCl → C6H4(CMe2Cl)2 :C6H4(CMe2Cl)2 + 2 HNCO → C6H4(CMe2NCO)2 + 2 HCl Uses A key use for TMXDI is in manufacturing polyurethane prepolymers. It is also used to manufacture polyurethane dispersions (PUDs). These materials are then further used to manufacture coatings, adhesives, sealants and elastomers. TMXDI has been considered as a replacement for Isophorone diisocyana ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Compound
In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The study of the properties, reactions, and syntheses of organic compounds comprise the discipline known as organic chemistry. For historical reasons, a few classes of carbon-containing compounds (e.g., carbonate salts and cyanide salts), along with a few other exceptions (e.g., carbon dioxide, hydrogen cyanide), are not classified as organic compounds and are considered inorganic. Other than those just named, little consensus exists among chemists on precisely which carbon-containing compounds are excluded, making any rigorous definition of an organic compound elusive. Although organic compounds make up only a small percentage of Earth's crust, they are of central importance because all known life is based on organic compounds. Living t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isocyanate
In organic chemistry, isocyanate is the functional group with the formula . Organic compounds that contain an isocyanate group are referred to as isocyanates. An organic compound with two isocyanate groups is known as a diisocyanate. Diisocyanates are manufactured for the production of polyurethanes, a class of polymers. Isocyanates should not be confused with cyanate esters and isocyanides, very different families of compounds. The cyanate (cyanate ester) functional group () is arranged differently from the isocyanate group (). Isocyanides have the connectivity , lacking the oxygen of the cyanate groups. Structure and bonding In terms of bonding, isocyanates are closely related to carbon dioxide (CO2) and carbodiimides (C(NR)2). The C−N=C=O unit that defines isocyanates is planar, and the N=C=O linkage is nearly linear. In phenyl isocyanate, the C=N and C=O distances are respectively 1.195 and 1.173 Å. The C-N=C angle is 134.9° and the N=C=O angle is 173.1°. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Cyanamid
American Cyanamid Company was a leading American conglomerate which became one of the nation's top 100 manufacturing companies during the 1970s and 1980s, according to the Fortune 500 listings at the time. It started in fertilizer, but added many other lines of business. In merged with American Home Products in 1994. The combined company sold off most of its lines of business except pharmaceuticals, adopted the name of its remaining Wyeth division, and was bought by Pfizer in 2009, becoming defunct as a separate concern. History The company was founded by engineers Frank S. Washburn and Charles H. Baker in New York City in 1907, to capitalize on a German patent they had licensed for the manufacture of nitrogen products for fertilizer. The company's name is derived from the chemical ''calcium cyanamide'', the fertilizer they would manufacture. They soon set up headquarters in Nashville, investing a million dollars in several corporations underpinning the manufacturing operati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosgenation
Phosgene is the organic chemical compound with the formula COCl2. It is a toxic, colorless gas; in low concentrations, its musty odor resembles that of freshly cut hay or grass. Phosgene is a valued and important industrial building block, especially for the production of precursors of polyurethanes and polycarbonate plastics. Phosgene is extremely poisonous and was used as a chemical weapon during World War I, where it was responsible for 85,000 deaths. It was a highly potent pulmonary irritant and quickly filled enemy trenches due to it being a heavy gas. It is classified as a Schedule 3 substance under the Chemical Weapons Convention. In addition to its industrial production, small amounts occur from the breakdown and the combustion of organochlorine compounds, such as chloroform. Structure and basic properties Phosgene is a planar molecule as predicted by VSEPR theory. The C=O distance is 1.18 Å, the C−Cl distance is 1.74 Å and the Cl−C−Cl angle is 111 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Chloride
The compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chloride gas and hydrochloric acid are important in technology and industry. Hydrochloric acid, the aqueous solution of hydrogen chloride, is also commonly given the formula HCl. Reactions Hydrogen chloride is a diatomic molecule, consisting of a hydrogen atom H and a chlorine atom Cl connected by a polar covalent bond. The chlorine atom is much more electronegative than the hydrogen atom, which makes this bond polar. Consequently, the molecule has a large dipole moment with a negative partial charge (δ−) at the chlorine atom and a positive partial charge (δ+) at the hydrogen atom. In part because of its high polarity, HCl is very soluble in water (and in other polar solvents). Upon contact, and HCl combine to form hydronium cations and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isocyanic Acid
Isocyanic acid is a chemical compound with the structural formula HNCO, which is often written as . It is a colourless, volatile and poisonous substance, with a boiling point of 23.5 °C. It is the predominant tautomer of cyanic acid (). The derived anion of isocyanic acid is the same as the derived anion of cyanic acid, and that anion is , which is called cyanate. The related functional group is isocyanate; it is distinct from cyanate (), fulminate (), and nitrile oxide (). Isocyanic acid was discovered in 1830 by Justus von Liebig and Friedrich Wöhler. Isocyanic acid is the simplest stable chemical compound that contains carbon, hydrogen, nitrogen, and oxygen, the four most commonly found elements in organic chemistry and biology. It is the only fairly stable one of the four linear isomers with molecular formula HOCN that have been synthesized, the others being cyanic acid (cyanol, ) and the elusive fulminic acid () and isofulminic acid .William R. Martin and Dav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyurethane Dispersion
Polyurethane Dispersion, or PUD, is understood to be a polyurethane polymer resin Dispersion (chemistry), dispersed in water, rather than a solvent. Its manufacture involves the synthesis of polyurethanes having carboxylic acid functionality or nonionic hydrophiles like PEG (polyethylene glycol) incorporated into, or pendant from, the polymer backbone. Background There has been a general trend towards converting existing resin systems to waterborne resins, for ease of use and environmental considerations. Particularly, their development was driven by increased demand for solventless systems since the manufacture of coatings and adhesives entailed the increasing release of solvents into the atmosphere from numerous sources. Using VOC exempt solvents is not a panacea as they have their own weaknesses. The problem has always been that polyurethanes in water are not stable, reacting to produce a urea and carbon dioxide. Many papers and patents have been published on the subject. For ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adhesive
Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advantages over other binding techniques such as sewing, mechanical fastenings, or welding. These include the ability to bind different materials together, the more efficient distribution of stress across a joint, the cost-effectiveness of an easily mechanized process, and greater flexibility in design. Disadvantages of adhesive use include decreased stability at high temperatures, relative weakness in bonding large objects with a small bonding surface area, and greater difficulty in separating objects during testing. Adhesives are typically organized by the method of adhesion followed by ''reactive'' or ''non-reactive'', a term which refers to whether the adhesive chemically reacts in order to harden. Alternatively, they can be organized eithe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elastomer
An elastomer is a polymer with viscoelasticity (i.e. both viscosity and elasticity) and with weak intermolecular forces, generally low Young's modulus and high failure strain compared with other materials. The term, a portmanteau of ''elastic polymer'', is often used interchangeably with rubber, although the latter is preferred when referring to vulcanisates. Each of the monomers which link to form the polymer is usually a compound of several elements among carbon, hydrogen, oxygen and silicon. Elastomers are amorphous polymers maintained above their glass transition temperature, so that considerable molecular reconformation is feasible without breaking of covalent bonds. At ambient temperatures, such rubbers are thus relatively compliant ( E ≈ 3 M Pa) and deformable. Their primary uses are for seals, adhesives and molded flexible parts. Application areas for different types of rubber are manifold and cover segments as diverse as tires, soles for shoes, and damping and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isophorone Diisocyanate
Isophorone diisocyanate (IPDI) is an organic compound in the class known as isocyanates. More specifically, it is an aliphatic diisocyanate. It is produced in relatively small quantities, accounting for (with hexamethylene diisocyanate) only 3.4% of the global diisocyanate market in the year 2000.{{cite book , first=David , last=Randall , author2=Lee, Steve , title=The Polyurethanes Book , publisher=Wiley , location=New York , year=2002 , isbn=0-470-85041-8 Aliphatic diisocyanates are used, not in the production of polyurethane foam, but in special applications, such as enamel coatings which are resistant to abrasion and degradation from ultraviolet light. These properties are particularly desirable in, for instance, the exterior paint applied to aircraft. Synthesis IPDI is obtained by phosgenation of isophorone diamine: Chemistry IPDI exists in two stereoisomers, cis and trans. Their reactivities are similar. Each stereoisomer is an unsymmetrical molecule, and thus has ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylene Diphenyl Diisocyanate
Methylene diphenyl diisocyanate (MDI) is an aromatic diisocyanate. Three isomers are common, varying by the positions of the isocyanate groups around the rings: 2,2′-MDI, 2,4′-MDI, and 4,4′-MDI. The 4,4′ isomer is most widely used, and is also known as 4,4′-diphenylmethane diisocyanate. This isomer is also known as Pure MDI. MDI reacts with polyols in the manufacture of polyurethane. It is the most produced diisocyanate, accounting for 61.3% of the global market in the year 2000. Production Total world production of MDI and polymeric MDI is over 7.5 million tonnes per year (in 2017). As of 2019, the largest producer was Wanhua Chemical Group. Other major producers are Covestro, BASF, Dow, Huntsman, Tosoh, Kumho Mitsui Chemicals. All major producers of MDI are members of the International Isocyanate Institute, whose aim is the promotion of the safe handling of MDI and TDI in the workplace, community and environment. The first step of the production of MDI is the rea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toluene Diisocyanate
Toluene diisocyanate (TDI) is an organic compound with the formula CH3C6H3(NCO)2. Two of the six possible isomers are commercially important: 2,4-TDI (CAS: 584-84-9) and 2,6-TDI (CAS: 91-08-7). 2,4-TDI is produced in the pure state, but TDI is often marketed as 80/20 and 65/35 mixtures of the 2,4 and 2,6 isomers respectively. It is produced on a large scale, accounting for 34.1% of the global isocyanate market in 2000, second only to MDI. Approximately 1.4 billion kilograms were produced in 2000. All isomers of TDI are colorless, although commercial samples can appear yellow. Synthesis 2,4-TDI is prepared in three steps from toluene via dinitrotoluene and 2,4-diaminotoluene (TDA). Finally, the TDA is subjected to ''phosgenation'', i.e., treatment with phosgene to form TDI. This final step produces HCl as a byproduct and is a major source of industrial hydrochloric acid. : Distillation of the raw TDI mixture produces an 80:20 mixture of 2,4-TDI and 2,6-TDI, known as TDI (80/20) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
