1073-06-9Relevant articles and documents
A green environmental protection of the bromobenzene [...] preparation method (by machine translation)
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Paragraph 0025-0056, (2018/11/26)
The present invention provides a green environmental protection of the bromobenzene [...] preparation method, comprises the following steps: sulfuric acid and [...] aniline added in a reaction kettle, stirring cooling to 5 - 10 °C, thermal insulation and slowly instillment bromide, dropping after the completion of the slow heating to 15 - 20 °C, thermal insulation and dropping hydrogen peroxide solution, the constant temperature reaction, again lowering the temperature to 0 - 5 °C, thermal insulation and dropping nitroso sulfuric acid, thermal insulation reaction, slow heating to 35 - 40 °C, thermal insulation and dropping isopropyl alcohol and water mixture, after dropping the stirring, heating up to 55 - 60 °C, thermal insulation, layered, separation [...] and oil reservoir; the oil reservoir is arranged in the rectification apparatus, first heating up to 65 - 70 °C, after the heat preservation, heating up to 83 - 85 °C, distillation separation, to obtain [...] bromobenzene and 3, 5 - dibromide fluoride; the water through distillation, obtained from the isopropyl alcohol, a mixture of water and acetone and sulfuric acid, the isopropanol, water and the mixture for catalytic hydrogenation, to obtain the isopropanol-water solution. (by machine translation)
An intramolecular: Ortho -assisted activation of the silicon-hydrogen bond in arylsilanes: An experimental and theoretical study
Durka, Krzysztof,Urban, Mateusz,Czub, Maja,D?browski, Marek,Tomaszewski, Patryk,Luliński, Sergiusz
, p. 3705 - 3716 (2018/03/21)
An intramolecular activation of the Si-H bond in arylsilanes by selected ortho-assisting functional groups based on boron, carbon and phosphorus was investigated experimentally and by means of theoretical calculations. The major conclusion drawn is that the presence of a negatively charged oxygen atom in the functional group is essential for providing effective chelation to the silicon atom which in turn results in the increased hydridic character of a resulting five-coordinated species. In contrast, an intermolecular attack of hydroxide on the silicon atom in aryldimethylsilane results in the activation of the silicon-aryl bond. This increased reactivity of the Si-H bond in intramolecularly coordinated arylsilanes can be ascribed to a significant trans effect which operates in the preferred configuration. Hydrolytic cleavage of the Si-H bond results in dihydrogen elimination and the formation of various silicon heterocyclic systems such as benzosiloxaboroles, spiro-bis(siloxa)borinate, benzosilalactone and benzophosphoxasilole. In addition, intermolecular reduction of benzaldehydes with ortho-boronated arylsilane was observed whereas compounds bearing other reducible functional groups (COMe, COOEt, CN and NO2) were inert under comparable conditions. Specifically, an intramolecular reduction of the CN group in an ortho-silylated benzonitrile derivative was observed. The mechanism of Si-H bond activation was investigated by the DFT theoretical calculations. The calculations showed that the intramolecular coordination of the silicon atom effectively prevents the cleavage of the Si-aryl bond. Furthermore, the reaction is favored in anionic systems bearing COO-, B(OH)3- or CH2O- groups, while in the case of neutral functional groups such as PO(OEt)2 the process is much slower.
Fluorination of aromatic compounds with xenon difluoride in the presence of boron trifluoride etherate
Fedorov,Zubarev,Mortikov, V. Yu.,Rodinovskaya,Shestopalov
, p. 1049 - 1052 (2016/02/09)
Fluorination of benzene with the XeF2 - BF3?Et2O system in acetonitrile at low temperatures affords fluorobenzene in 18% yield, the conversion of benzene being 92%. The rest products are di-, tri-, tetra-, and polyphenyls with different fluorination pattern. Toluene and chloro- and bromobenzenes are fluorinated predominantly at the ortho and para positions. Fluorination of 4-nitroanisole affords 2-fluoro-4-nitroanisole in 73% yield.
