- Selective Catalytic Hydrosilylation of Ethylene. Preparation of Ethyltrimethoxysilane by H2O Promoted RuCl3 ? 3H2O Catalyst
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Abstract: The work describes an efficient one-step solvent-free synthesis of ethyltrimethoxysilane through hydrosilylation reaction catalyzed by RuCl3 ? 3H2O–H2O. The procedure involves time point and dose of adding additive water. Excellent yields, short reaction times, and easy reaction handling under solvent-free and mild conditions are the most important advantages of the present protocol. A possible reaction mechanism was discussed by empirical method.
- Han, G.,Li, X.,Liu, L.,Ma, Y.,Wu, C.
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- Kinetic study on hydrosilylation of ethylene with trimethoxysilane by RuCl3·3H2O doped with iodine
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The hydrosilylation reaction of ethylene gas with trimethoxysilane was investigated and various factors such as the temperature, the reaction time, the dosage of catalyst and the promoter iodine on conversion of trimethoxysilane, and the yield and selectivity of the target product were carefully examined. Ethyltrimethoxysilane was obtained in excellent yields and selectivities in the presence of iodine. A kinetic model on the basis of the consumption of trimethoxysilane was built up for the hydrosilylation reaction catalyzed either by ruthenium trichloride hydrate alone or by ruthenium trichloride hydrate doped with iodine. Kinetic parameters were regressed from the experimental data. The results indicated that the hydrosilylation reaction of ethylene gas with trimethoxysilane was a first order reaction process. With the addition of iodine, the apparent activation energy of this reaction significantly decreased from 56.93 to 29.97 kJ mol-1, which is in good agreement with the results observed in the reaction.
- Liu, Ling,Li, Xiaonian,Dong, Hong,Wu, Chuan
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- Metastable Ion Studies: Ethyl(methoxy)(chloro)silanes
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Metastable ion scanning was used to investigate the fragmentation patterns of ethyl(trimethoxy)silane, ethyl(dimethoxy)chlorosilane and ethyl(methoxy)dichlorosilane, their deuterated counterparts and ethyltrichlorosilane.For these compounds the molecule ion has a low abundance using 70 eV electron impact ionization.In all cases the base peak corresponds to the loss of neutral C2H5.When chemical ionization is employed with isobutane, usable peaks representative of the molecule ions are observed.
- Hagen, Arnulf P.,Hodge, Shelly J.,Randolph, Bruce B.,Laing, John L.
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- COSMETIC TREATMENT METHOD COMPRISING THE APPLICATION OF A COATING BASED ON AN AEROGEL COMPOSITION OF LOW BULK DENSITY
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The present invention relates to a cosmetic treatment method comprising the formation of a coating on keratin fibres characterized in that it comprises: 1) the preparation of an aerogel precursor composition comprising:—at least one organic solvent chosen from acetone, C1-C4 alcohols, C1-C6 alkanes, C1-C4 ethers, which may or may not be perfluorinated, and mixtures thereof and at least one precursor compound that contains:—at least one atom chosen from silicon, titanium, aluminium and zirconium,—at least one hydroxyl or alkoxy function directly attached to the atom chosen from silicon, titanium, aluminium and zirconium by an oxygen atom, and,—optionally an organic group directly attached to the atom chosen from silicon, titanium, aluminium and zirconium by a carbon atom, 2) the removal of the solvent or solvents resulting in the formation of an aerogel composition having a bulk density less than or equal to 0.35 g/cm3, 3) the application to the keratin fibres of the aerogel composition resulting from step 2) or of the aerogel precursor composition resulting from step 1). Advantageously, the molar ratio between the precursor compounds and the solvent is at most 1/20.
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Paragraph 0067
(2014/02/15)
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- Hydrosilylation of ethylene
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Hydrosilylation of ethylene with trialkoxysilanes in the presence of Pt(0) complexes as catalysts affords ethyltrialkoxysilanes in almost quantitative yields. No impurities of vinyltrialkoxysilanes were detected. Experiments and ab initio calculations showed that the Pt(0) catalysts are considerably more active in ethylene hydrosilylation than Pt(II) catalysts. Pleiades Publishing, Inc., 2006.
- Chernyshev,Belyakova,Knyazev,Turkel'taub,Parshina,Serova,Storozhenko
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p. 225 - 228
(2008/02/08)
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- Process for preparing low-chloride or chloride-free alkoxysilanes
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A process for preparing an alkoxysilane with an acidic chloride content of less than 10 ppm by weight, comprising: reacting a chlorosilane with an alcohol in a water-free and solvent-free phase to form a product mixture containing alkoxysilane and residual acidic chloride, with removal of resultant hydrogen chloride from the product mixture, then adding liquid or gaseous ammonia, in an amount corresponding to a stoichiometric excess, based on the content of acidic chloride, to form an ammonia-containing product mixture, treating the ammonia-containing product mixture at a temperature between 10 and 50 DEG C., wherein the ammonia and acidic chloride undergo neutralization, to form a crude product, and optionally, then separating off a salt formed in the course of neutralization, from the crude product, and recovering the alkoxysilane by distilling the crude product.
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- Generation and reactivities of ethylmethoxysilylene
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Vacuum pyrolysis of 1,2-diethyl-1,1,2,2-tetramethoxydisilane (II) in the presence of 2,3-dimethyl-1,3-butadiene resulted in the formation of 1-ethyl-1-methoxy-(III), 1-ethyl-(IV), and 1-methoxy-3,4-dimethyl-1-silacyclopent-3-ene(V) along with ethyltrimethoxysilane. The observed products might be formed from the addition of ethylmethoxysilylene, ethylsilylene and methoxysilylene into 2,3-dimethyl-1,3-butadiene respectively under thermal conditions. A labelling experiment employing a deuterated precursor of 1,2-diethyl-1,1,2,2-tetramethoxy-d12-disilane (II-d12) was performed for the purpose of elucidating the conversion of ethylmethoxysilylene into ethylsilylene. Ethylsilylene might be generated from [3 → 2 + 1] cyclo-elimination of an intermediate of 2-ethyloxasilacyclopropane (EtHSi-O-CH2) which can arise from a possible intramolecular silylene insertion into a C-H bond of the methoxy group of ethylmethoxysilylene. The methoxysilylene might be formed from elimination of ethylene of 1-methoxy-1-silacyclopropane (HMeOSi-CH2-CH2) derived from intramolecular silylene insertion into a C-H bond of the ethyl group of ethylmethoxysilylene. The temperature dependence of the trapped adduct distribution from the pyrolysis of 1,2-diethyl,1,2,2-tetramethoxydisilane was examined.
- Kwak, Young-Woo,Lee, Kyung-Koo
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p. 219 - 225
(2007/10/03)
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- Direct synthesis of ethylmethoxysilanes by the liquid-phase reaction of silicon, methanol and ethylene
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The liquid-phase reactions of silicon, methanol and ethylene in an autoclave gave ethylmethoxysilanes (HSi(C2H5)(OCH3)2 and Si(C2H5)(OCH3)3) besides HSi(OCH3)3 and Si(OCH3)4.The reaction conditions for obtaining a high selectivity for the ethylmethoxysilanes were examined.With the use of a high pressure of ethylene and a small amount of methanol in toluene as a solvent at 433 K, ethylmethoxysilanes were obtained in 26percent selectivity at silicon conversion of 59percent.The direct reaction of silicon with ethanol and ethylene gave HSi(C2H5)(OC2H5)2 and Si(C2H5)(OC2H5)3.Keywords: Silylene; Alkene; Silane; Methanol; Liquid-phase reaction; Silicon
- Okamoto, Masaki,Watanabe, Naoto,Suzuki, Eiichi,Ono, Yoshio
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p. C12 - C16
(2007/10/02)
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