- Some regularities of chlorosilanes etherification
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The influence of reagents, solvent polarity, and temperature on the etherification of chlorosilanes ClCH2SiCl3, VinSiCl 3, PrSiCl3, and Ph3SiCl with ethanol was studied. Influence of reaction temperature on the ratio of the synthesized alkoxysilane and related side-product siloxane is revealed. Use of excess alcohol is shown to increase the content of siloxane. Introduction of FeCl 3 does not affect the synthesis. Solvents are shown to influence the reaction rate: the rate constant increases with increasing ε parameter of the solvent. The rate constant of etherification of chlorosilanes with ethanol falls in the series: ClCH2SiCl3 > VinSiCl3 > PrSiCl3. An explanation of the regularities is suggested.
- Belyakova,Komarov,Bykovchenko,Ershov,Chernyshev,Storozhenko
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experimental part
p. 1650 - 1655
(2011/05/13)
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- Utility of trichloroisocyanuric acid in the efficient chlorination of silicon hydrides
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The potential of trichloroisocyanuric acid (TCCA) as a chlorination agent for efficient conversion of Si-H functional silanes and siloxanes to the corresponding Si-Cl functional moieties was explored. In comparison to methods using other chlorinating agents, TCCA is inexpensive, results in a much faster reaction and produces a high purity product with a conversion that is essentially quantitative. A variety of chloro derivatives of linear and cyclic structures have been synthesized from silicon hydrides using this reagent with impressive yields that typically exceed 90%: PhSiCl3 (97.5%); PhMeSiCl2 (95.5%); Ph3SiCl (97.5%); Vi3SiCl (98.7%); (EtO)3SiCl (99.7%); t-Bu3SiCl (~100%); (MeClSiO)4 (86.5%); (MeClSiO)5 (95%); (MeClSiO)7 (96.5%); Ph(OEt)2SiCl (98%); ClMe2SiOSiMe2Cl (98.6%); ClMe2SiOSiMeClOSiMe2Cl (94.6%); ClMe2Si(OSiMeCl)2OSiMe2C l (92.3%); (Me3SiO)3SiCl (97%); Me3SiOSiClPhOSiMe3 (99%); Me3SiO(SiMeClO)3SiMe3 (95.7%); ClSi(OSiMe3)2OSi(OSiMe3) 2Cl (93.6%). For monohydridosilanes, dichloromethane (CH2Cl2) was a suitable solvent in which nearly quantitative conversion was observed within several minutes following the addition of the silanes to TCCA. For certain cyclic and linear siloxanes, and especially silanes containing multiple hydrogen atoms on the same silicon for which the reaction is sluggish in CH2Cl2, tetrahydrofuran (THF) was the preferred solvent. For a sterically demanding silane that did not undergo chlorination even in THF viz., HSi(OSiMe3)2O-Si(OSiMe3)2H, 1,2-dichloroethane was the best solvent.
- Varaprath, Sudarsanan,Stutts, Debra H.
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p. 1892 - 1897
(2007/10/03)
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- Reaction of Tetraalkoxysilanes with Alkyl(aryl)chlorosilanes
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Alkyl(aryl)trichloro- or dialkyl(diaryl)dichlorosilanes react with tetraalkoxysilanes Si(OMe)4, Si(OEt)4, and Si(OBu)4 to give partially etherfied alkyl(aryl)chlorosilanes RSiCl2(OAlk), RSiCl(OAlk)2, and R2SiCl(OAlk).
- Chernyshev, E. A.,Komalenkova, N. G.,Tagachenkov, A. A.,Bykovchenko, V. G.
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p. 241 - 243
(2007/10/03)
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