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Vinylation
in organic chemistry, vinylation is the process of attaching a vinyl group () to a substrate. Many organic compounds contain vinyl groups, so the process has attracted significant interest, especially since the reaction scope includes substituted vinyl groups. The reactions can be classified according to the source of the vinyl group. Nucleophilic vinyl reagents Vinyl lithium and vinyl magnesium bromide are sources of "", which add to ketones and aldehydes. Vinylsiloxane and vinylboranes have also been used as sources of vinyl anion equivalents.These types of reactions require catalysts such as those based on palladium. Vinylation with alkenes The Heck reaction couples an unsaturated halide with an alkene. Base and a palladium catalyst are required. This reaction is a way to substitute alkenes. In hydrovinylation, ethylene adds "across" an alkene double bond: : This kind of reaction requires a metal catalyst. In principle, alkenes other than ethylene could be employed. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organic Chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, J.; Greeves, N. and Warren, S. (2012) ''Organic Chemistry''. Oxford University Press. pp. 1–15. . Study of structure determines their structural formula. Study of properties includes physical and chemical properties, and evaluation of chemical reactivity to understand their behavior. The study of organic reactions includes the chemical synthesis of natural products, drugs, and polymers, and study of individual organic molecules in the laboratory and via theoretical ( in silico) study. The range of chemicals studied in organic chemistry includes hydrocarbons (compounds containing only carbon and hydrogen) as well as compounds based on carbon, but also containing other elements, especially oxygen, nitrogen, sulfur, phosphorus (included in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walter Reppe
Walter Julius Reppe (29 July 1892 in Göringen – 26 July 1969 in Heidelberg) was a German chemist. He is notable for his contributions to the chemistry of acetylene. Education and career Walter Reppe began his study of the natural sciences University of Jena in 1911. Interrupted by the First World War, he obtained his doctorate in Munich in 1920. In 1921, Reppe worked for BASF's main laboratory. From 1923, he worked on the catalytic dehydration of formamide to prussic acid in the indigo laboratory, developing this procedure for industrial use. In 1924, he left research for 10 years, only resuming it in 1934. Acetylene chemistry Reppe began his interest in acetylene in 1928. Acetylene is a gas which can take part in many chemical reactions. However, it is explosive and accidents often occurred. Because of this danger, small quantities of acetylene were used at a time, and always without high pressures. In fact, it was forbidden to compress acetylene over 1.5 bar at BASF. To w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vinyl Acetate
Vinyl acetate is an organic compound with the formula CH3CO2CH=CH2. This colorless liquid is the precursor to polyvinyl acetate and ethene-vinyl acetate copolymers, important industrial polymers. Production The worldwide production capacity of vinyl acetate was estimated at 6,969,000 tonnes/year in 2007, with most capacity concentrated in the United States (1,585,000 all in Texas), China (1,261,000), Japan (725,000) and Taiwan (650,000). The average list price for 2008 was US$1600/tonne. Celanese is the largest producer (ca 25% of the worldwide capacity), while other significant producers include China Petrochemical Corporation (7%), Chang Chun Group (6%), and LyondellBasell (5%). It is a key ingredient in furniture glue. Preparation Vinyl acetate is the acetate ester of vinyl alcohol. Since vinyl alcohol is highly unstable (with respect to acetaldehyde), the preparation of vinyl acetate is more complex than the synthesis of other acetate esters. The major industrial route i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transesterification
In organic chemistry, transesterification is the process of exchanging the organic group R″ of an ester with the organic group R' of an alcohol. These reactions are often catalyzed by the addition of an acid or base catalyst. The reaction can also be accomplished with the help of other enzymes, particularly lipases (one example is the lipase E.C.3.1.1.3). Strong acids catalyse the reaction by donating a proton to the carbonyl group, thus making it a more potent electrophile, whereas bases catalyse the reaction by removing a proton from the alcohol, thus making it more nucleophilic. If the alcohol produced by the reaction can be separated from the reactants by distillation this will drive the equilibrium toward the products, this means that esters with larger alkoxy groups can be made from methyl or ethyl esters in high purity by heating the mixture of ester, acid/base, and large alcohol. Mechanism In the transesterification mechanism, the carbonyl carbon of the starting e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iridium
Iridium is a chemical element with the symbol Ir and atomic number 77. A very hard, brittle, silvery-white transition metal of the platinum group, it is considered the second-densest naturally occurring metal (after osmium) with a density of as defined by experimental X-ray crystallography. It is one of the most corrosion-resistant metals, even at temperatures as high as . However, corrosion-resistance is not quantifiable in absolute terms; although only certain molten salts and halogens are corrosive to solid iridium, finely divided iridium dust is much more reactive and can be flammable, whereas gold dust is not flammable but can be attacked by substances that iridium resists, such as aqua regia. Iridium was discovered in 1803 among insoluble impurities in natural platinum. Smithson Tennant, the primary discoverer, named it after the Greek goddess Iris, personification of the rainbow, because of the striking and diverse colors of its salts. Iridium is one of the rarest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vinyl Formate
Vinyl formate is an organic compound with the formula . It is the ester formally derived from formic acid and vinyl alcohol Vinyl alcohol, also called ethenol (IUPAC name; not ethanol), is the simplest enol. With the formula , it is a labile compound that converts to acetaldehyde. It is not a precursor to polyvinyl alcohol. Synthesis Vinyl alcohol can be formed by th .... Although rare commercially, it occurs naturally. It can be prepared by transvinylation, say by treating vinyl versatate with formic acid in the presence of a mercury(II) catalyst..{{cite journal , doi=10.1016/S0040-4020(01)97407-1, title=A novel synthesis of vinyl esters from vinylversatate-10 , year=1974 , last1=Mondal , first1=M.A.S. , last2=Van Der Meer , first2=R. , last3=German , first3=A.L. , last4=Heikens , first4=D. , journal=Tetrahedron , volume=30 , issue=23–24 , pages=4205–4207 References Monomers Vinyl esters Formates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vinyl Acetate
Vinyl acetate is an organic compound with the formula CH3CO2CH=CH2. This colorless liquid is the precursor to polyvinyl acetate and ethene-vinyl acetate copolymers, important industrial polymers. Production The worldwide production capacity of vinyl acetate was estimated at 6,969,000 tonnes/year in 2007, with most capacity concentrated in the United States (1,585,000 all in Texas), China (1,261,000), Japan (725,000) and Taiwan (650,000). The average list price for 2008 was US$1600/tonne. Celanese is the largest producer (ca 25% of the worldwide capacity), while other significant producers include China Petrochemical Corporation (7%), Chang Chun Group (6%), and LyondellBasell (5%). It is a key ingredient in furniture glue. Preparation Vinyl acetate is the acetate ester of vinyl alcohol. Since vinyl alcohol is highly unstable (with respect to acetaldehyde), the preparation of vinyl acetate is more complex than the synthesis of other acetate esters. The major industrial route i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vinyl Ester
left, 144px, Vinyl acetate is a commercially important monomer that is classified as a vinyl ester (i.e. an ester of vinyl alcohol). Vinyl ester refers to esters formerly derived from vinyl alcohol. Commercially important examples of these monomers are vinyl acetate, vinyl propionate, and vinyl laurate Vinyl may refer to: Chemistry * Polyvinyl chloride (PVC), a particular vinyl polymer * Vinyl cation, a type of carbocation * Vinyl group, a broad class of organic molecules in chemistry * Vinyl polymer, a group of polymers derived from vinyl m ....{{cite encyclopedia, author=G. Roscher, title=Ullmann's Encyclopedia of Industrial Chemistry, chapter=Vinyl Esters, encyclopedia=Ullmann's Encyclopedia of Chemical Technology, year=2007, publisher=Wiley-VCH, location=Weinheim, doi=10.1002/14356007.a27_419, isbn=978-3527306732 References Monomers Commodity chemicals Vinyl compounds ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrylic Acid
Acrylic acid (IUPAC: propenoic acid) is an organic compound with the formula CH2=CHCOOH. It is the simplest unsaturated carboxylic acid, consisting of a vinyl group connected directly to a carboxylic acid terminus. This colorless liquid has a characteristic acrid or tart smell. It is miscible with water, alcohols, ethers, and chloroform. More than a million tons are produced annually. History The word "acrylic" was coined in 1843, for a chemical derivative of acrolein, an acrid-smelling oil derived from glycerol. Production Acrylic acid is produced by oxidation of propylene, which is a byproduct of the production of ethylene and gasoline: : 2 CH2=CHCH3 + 3 O2 → 2 CH2=CHCO2H + 2 H2O Historical methods Because acrylic acid and its esters have long been valued commercially, many other methods have been developed. Most have been abandoned for economic or environmental reasons. An early method was the hydrocarboxylation of acetylene (" Reppe chemistry"): : This method re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Monoxide
Carbon monoxide (chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simplest molecule of the oxocarbon family. In coordination complexes the carbon monoxide ligand is called carbonyl. It is a key ingredient in many processes in industrial chemistry. The most common source of carbon monoxide is the partial combustion of carbon-containing compounds, when insufficient oxygen or heat is present to produce carbon dioxide. There are also numerous environmental and biological sources that generate and emit a significant amount of carbon monoxide. It is important in the production of many compounds, including drugs, fragrances, and fuels. Upon emission into the atmosphere, carbon monoxide affects several processes that contribute to climate change. Carbon monoxide has important biological roles across phylogenetic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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