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Triphenylboron
Triphenylborane, often abbreviated to BPh3 where Ph is the phenyl group C6H5-, is a chemical compound with the formula B(C6H5)3. It is a white crystalline solid and is both air and moisture sensitive, slowly forming benzene and triphenylboroxine. It is soluble in aromatic solvents. Structure and properties The core of the compound, BC3, has a trigonal planar structure. The phenyl groups are rotated at about a 30° angle from the core plane. Even though triphenylborane and tris(pentafluorophenyl)borane are structurally similar, their Lewis acidity is not. BPh3 is a weak Lewis acid while B(C6F5)3 is a strong Lewis acid due to the electronegativity of the fluorine atoms. Other boron Lewis acids include BF3 and BCl3. Synthesis Triphenylborane was first synthesized in 1922. It is typically made with boron trifluoride diethyl etherate and the Grignard reagent, phenylmagnesium bromide. : BF3•O(C2H5)2 + 3 C6H5MgBr → B(C6H5)3 + 3 MgBrF + (C2H5)2O Triphenylborane can also be s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triphenylmethyl
The triphenylmethyl radical (often shorted to trityl radical) is an organic compound with the formula (C6H5)3C. It is a persistent radical. It was the first radical ever to be described in organic chemistry. Because of its accessibility, the trityl radical has been heavily exploited. Preparation and properties It can be prepared by homolysis of triphenylmethyl chloride 1 by a metal like silver or zinc in benzene or diethyl ether. The radical 2 forms a chemical equilibrium with the quinoid-type dimer 3 ( Gomberg's dimer). In benzene the concentration of the radical is 2%. Solutions containing the radical are yellow; when the temperature of the solution is raised, the yellow color becomes more intense as the equilibrium is shifted in favor of the radical (in accordance with Le Chatelier's principle). When exposed to air, the radical rapidly oxidizes to the peroxide, and the color of the solution changes from yellow to colorless. Likewise, the radical reacts with iodine to tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Boron Trifluoride Diethyl Etherate
Boron trifluoride etherate, strictly boron trifluoride diethyl etherate, or boron trifluoride–ether complex, is the chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ... with the formula BF3O(C2H5)2, often abbreviated BF3OEt2. It is a colorless liquid, although older samples can appear brown. The compound is used as a source of boron trifluoride in many chemical reactions that require a Lewis acid. The compound features tetrahedral boron coordinated to a diethylether ligand. Many analogues are known, including the methanol complex. Reactions Boron trifluoride etherate serves as a source of boron trifluoride according to the equilibrium: :BF3OEt2 BF3 + OEt2 The BF3 binds to even weak Lewis bases, inducing reactions of the resulting adducts with nucleophil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Haloaromatic
In organic chemistry, an aryl halide (also known as haloarene) is an aromatic compound in which one or more hydrogen atoms, directly bonded to an aromatic ring are replaced by a halide. The haloarene are different from haloalkanes because they exhibit many differences in methods of preparation and properties. The most important members are the aryl chlorides, but the class of compounds is so broad that there are many derivatives and applications. Preparation The two main preparatory routes to aryl halides are direct halogenation and via diazonium salts. Direct halogenation In the Friedel-Crafts halogenation, Lewis acids serve as catalysts. Many metal chlorides are used, examples include iron(III) chloride or aluminium chloride. The most important aryl halide, chlorobenzene is produced by this route. Monochlorination of benzene is always accompanied by formation of the dichlorobenzene derivatives. Arenes with electron donating groups react with halogens even in the absence of Le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium
Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable isotope is 23Na. The free metal does not occur in nature, and must be prepared from compounds. Sodium is the sixth most abundant element in the Earth's crust and exists in numerous minerals such as feldspars, sodalite, and halite (NaCl). Many salts of sodium are highly water-soluble: sodium ions have been leached by the action of water from the Earth's minerals over eons, and thus sodium and chlorine are the most common dissolved elements by weight in the oceans. Sodium was first isolated by Humphry Davy in 1807 by the electrolysis of sodium hydroxide. Among many other useful sodium compounds, sodium hydroxide (lye) is used in soap manufacture, and sodium chloride (edible salt) is a de-icing agent and a nutrient for animals including h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nylon
Nylon is a generic designation for a family of synthetic polymers composed of polyamides ( repeating units linked by amide links).The polyamides may be aliphatic or semi-aromatic. Nylon is a silk-like thermoplastic, generally made from petroleum, that can be melt-processed into fibers, films, or shapes. Nylon polymers can be mixed with a wide variety of additives to achieve many property variations. Nylon polymers have found significant commercial applications in fabric and fibers (apparel, flooring and rubber reinforcement), in shapes (molded parts for cars, electrical equipment, etc.), and in films (mostly for food packaging). History DuPont and the invention of nylon Researchers at DuPont began developing cellulose based fibers, culminating in the synthetic fiber rayon. DuPont's experience with rayon was an important precursor to its development and marketing of nylon. DuPont's invention of nylon spanned an eleven-year period, ranging from the initial research pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adiponitrile
Adiponitrile is an organic compound with the chemical formula (CH2)4(CN)2. This viscous, colourless dinitrile is an important precursor to the polymer nylon 66. In 2005, about one million tonnes of adiponitrile were produced.M. T. Musser, "Adipic Acid" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. Production Early methods Because of the industrial value of adiponitrile, many methods have been developed for its synthesis. Early industrial methods started from furfural and later by the chlorination of butadiene to give 1,4-dichloro-2-butene, which with sodium cyanide, converts to 3-hexenedinitrile, which in turn can be hydrogenated to adiponitrile: :ClCH2CH=CHCH2Cl + 2 NaCN → NCCH2CH=CHCH2CN + 2 NaCl :NCCH2CH=CHCH2CN + H2 → NC(CH2)4CN Adiponitrile has also been produced from adipic acid, by dehydration of the diamide, but this is rarely employed. Modern methods After patent application in 2004, the majority of adiponitrile is prepar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Butadiene
1,3-Butadiene () is the organic compound with the formula (CH2=CH)2. It is a colorless gas that is easily condensed to a liquid. It is important industrially as a precursor to synthetic rubber. The molecule can be viewed as the union of two vinyl groups. It is the simplest conjugated diene. 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, which is a cumulated diene with structure H2C=C=CH−CH3. This allene has no industrial significance. History In 1863, the French chemist E. Caventou isolated butadiene from the pyrolysis of amyl alcohol. This hydrocarbon was identified as butadiene in 1886, after Henry Edward Armstrong isolated it from among the pyrolysis products of petroleum. In 1910, the Russian chemist Sergei Lebedev polymerized butadiene and obtained a material wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrocyanation
In organic chemistry, hydrocyanation is a process for conversion of alkenes to nitriles. The reaction involves the addition of hydrogen cyanide and requires a catalyst. This conversion is conducted on an industrial scale for the production of precursors to nylon. Hydrocyanation of unactivated alkenes Industrially, hydrocyanation is commonly performed on alkenes catalyzed by nickel complexes of phosphite () ligands. A general reaction is shown:Piet W.N.M. van Leeuwen "Homogeneous Catalysis: Understanding the Art", 2004, Wiley-VCH, Weinheim. :RCH=CH2 + HCN -> RCH2-CH2-CN Stoichiometry and mechanism The reaction involves the addition of and cyanide () to the substrate. Usually the substrate is an alkene and the product is a nitrile. The reaction proceeds via the oxidative addition of HCN to a low-valent metal complex to give a hydrido cyanide complex. Subsequent binding of the alkene gives the intermediate , which then undergoes migratory insertion to give an alkylmetal cya ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DuPont (1802–2017)
DuPont de Nemours, Inc., commonly shortened to DuPont, is an American multinational chemical company first formed in 1802 by French-American chemist and industrialist Éleuthère Irénée du Pont de Nemours. The company played a major role in the development of Delaware and first arose as a major supplier of gunpowder. DuPont developed many polymers such as Vespel, neoprene, nylon, Corian, Teflon, Mylar, Kapton, Kevlar, Zemdrain, M5 fiber, Nomex, Tyvek, Sorona, Corfam and Lycra in the 20th century, and its scientists developed many chemicals, most notably Freon (chlorofluorocarbons), for the refrigerant industry. It also developed synthetic pigments and paints including ChromaFlair. In 2015, DuPont and the Dow Chemical Company agreed to a reorganization plan in which the two companies would merge and split into three. As a merged entity, DuPont simultaneously acquired Dow and renamed itself to DowDuPont on August 31, 2017, and after 18 months spin off the merged entity's ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liebigs Annalen Der Chemie
''Justus Liebigs Annalen der Chemie'' (often cited as just ''Liebigs Annalen'') was one of the oldest and historically most important journals in the field of organic chemistry worldwide. It was established in 1832 and edited by Justus von Liebig with Friedrich Wöhler and others until Liebig's death in 1873. In 1997 the journal merged with ''Recueil des Travaux Chimiques des Pays-Bas'' to form ''Liebigs Annalen/Recueil''. In 1998 it was absorbed by ''European Journal of Organic Chemistry'' by merger of a number of other national European chemistry journals. Title history * ''Annalen der Pharmacie'', 1832–1839 * ''Annalen der Chemie und Pharmacie'', 1840–1873 (, CODEN JLACBF) * ''Justus Liebig's Annalen der Chemie und Pharmacie'', 1873–1874 (, CODEN JLACBF) * ''Justus Liebig's Annalen der Chemie'', 1874–1944 & 1947–1978 (, CODEN JLACBF) * ''Liebigs Annalen der Chemie'', 1979–1994 (, CODEN LACHDL) * ''Liebigs Annalen'', 1995–1996 (, CODEN LANAEM) * ''Liebi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trimethylammonium Tetraphenylborate
Trimethylamine (TMA) is an organic compound with the formula N(CH3)3. It is a colorless, hygroscopic, and flammable tertiary amine. It is a gas at room temperature but is usually sold as a 40% solution in water. (It is also sold in pressurized gas cylinders.) TMA is a nitrogenous base and can be readily protonated to give the trimethylammonium cation. Trimethylammonium chloride is a hygroscopic colorless solid prepared from hydrochloric acid. Trimethylamine is a good nucleophile, and this reaction is the basis of most of its applications. TMA is widely used in industry: it is used in the synthesis of choline, tetramethylammonium hydroxide, plant growth regulators or herbicides, strongly basic anion exchange resins, dye leveling agents, and a number of basic dyes. At higher concentrations it has an ammonia-like odor, and can cause necrosis of mucous membranes on contact. At lower concentrations, it has a "fishy" odor, the odor associated with rotting fish. In humans, ingestion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Decomposition
Thermal decomposition, or thermolysis, is a chemical decomposition caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes. The reaction is usually endothermic as heat is required to break chemical bonds in the compound undergoing decomposition. If decomposition is sufficiently exothermic, a positive feedback loop is created producing thermal runaway and possibly an explosion or other chemical reaction. Decomposition temperature definition A simple substance (like water) may exist in equilibrium with its thermal decomposition products, effectively halting the decomposition. The equilibrium fraction of decomposed molecules increases with the temperature. Examples * Calcium carbonate (limestone or chalk) decomposes into calcium oxide and carbon dioxide when heated. The chemical reaction is as follows: ::CaCO3 → CaO + CO2 :The reaction is used to make Calcium oxide, quick lime, which is an industrially impor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
