Quaternaryammoniumsalts were synthesized from ammoniumsalts and dialkyl carbonates over imidazolium ionic liquid catalysts. The reaction gave almost stoichiometric amounts of the quaternaryammoniumsalts for halides and nitrates. It was found that the electron-donating property of the alkyl moieties of ammonium cations, the electrophilic nature of the alkyl group of the carbonate, the acidity of
Pd-NHC catalyzed Suzuki cross-coupling of benzyl ammonium salts
作者:Chuntao Zhong、Huiling Tang、Benqiang Cui、Yanhui Shi、Changsheng Cao
DOI:10.1007/s11164-022-04795-6
日期:2022.10
palladium-catalyzed Suzukicross-coupling of benzyl ammonium triflates via activation of a Csp3–N bond to construct a Csp3–Csp2 bond is described. Various boronicacids can be coupled with a range of benzylamine-derived quaternary ammonium salts in 1:1 molar ratio by the bench-stable N-heterocyclic carbene palladium complex, SIPr-PdCl2-Py to afford diarylmethane derivatives. This reaction exhibits a wide
Charge-controlled Pd catalysis enables the meta-C–H activation and olefination of arenes
作者:Arup Mondal、Marina Díaz-Ruiz、Fritz Deufel、Feliu Maseras、Manuel van Gemmeren
DOI:10.1016/j.chempr.2022.12.019
日期:2023.1
meta-selective activation and olefination of arenes to address these challenges in Pd catalysis. The charged moiety can easily be converted to uncharged simple arenes by hydrogenation or cross-coupling. In-depth mechanisticstudies prove that the charge is responsible for the observed selectivity. We expect our studies to be generalizable and thereby enable further regioselective transformations.
Vinyl ester resin composition thickened by a group II metal oxide or hydroxide
申请人:SHELL INTERNATIONALE RESEARCH
MAATSCHAPPIJ B.V.
公开号:EP0015029A1
公开(公告)日:1980-09-03
Chemically modified thickenable vinyl esters are prepared by reacting an ethylenically unsaturated monocarboxylic acid with a polyepoxide in the presence of a small amount of a dicarboxylic acid. These resins are diluted with a copolymerizable monomer, such as styrene, blended with a Group II metal oxide or hydroxide and other additives, and cured with a free-radical catalyst. The compositions can be used for coating, laminating, moulding, or as adhesive.
Independent analysis of anions and cations using indirect photometric chromatography
申请人:THE DOW CHEMICAL COMPANY
公开号:EP0186037A2
公开(公告)日:1986-07-02
An improved technique and apparatus for the indepen-. dent measurement of anions and cations in solution, wherein the sample ions are chromatographically displaced in a plurality of ion exchange columns by an eluting ion which is or is made light-absorbing and wherein the sample ions are detectable from decrements in absorbance of the eluting ions as revealed by photometric monitoring; and the sample ions, cations and anions, are further detected independently by means for monitoring eluting anion and cation absorbance differences calibrated according to characteristic absorbance ratios of the selected eluting ion species at a plurality of wavelengths.