- Siloxanes from the hydrolysis of isopropyltrimethoxysilane
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The behavior of isopropyltrimethoxysilane (1) in the presence one equivalent of water and a dibutyltin dilaurate catalyst has been investigated.Under these conditions, partial hydrolysis of the methoxy groups of 1 occurred, followed by condensation reactions leading to the formation of low molecular-weight oligomers.Disiloxane 4, trisiloxane 6 and cyclic siloxanes 7 and 8 have been isolated and fully characterized.Transient reaction intermediates silanol 3 and hydroxydisiloxane 5 have been characterized spectroscopically.The time evolution of these species was followed by gas chromatography and 29Si NMR.A reaction scheme for the hydrolytic condensation of 1 is proposed to accommodate these results. Keywords: Silicon; Siloxanes; Hydrolysis; Nuclear magnetic resonance
- Crandall, Jack K.,Morel-Fourrier, Christophe
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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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- PROCESS FOR MAKING HALOORGANOALKOXYSILANES
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A haloorganoalkoxysilane is prepared by reacting an olefinic halide with an alkoxysilane in which the alkoxy group(s) contain at least two carbon atoms in a reaction medium to which has been added a catalytically effective amount of ruthenium-containing catalyst and a reaction-promoting effective amount of an electron-donating aromatic compound promoter. The process can be used to prepare, inter alia, chloropropyltriethoxysilane, which is a key intermediate in the manufacture of silane coupling agents.
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Page/Page column 24
(2008/06/13)
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- Process for making haloorganoalkoxysilanes
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A haloorganoalkoxysilane is prepared by reacting an olefinic halide with an alkoxysilane in which the alkoxy group(s) contain at least two carbon atoms in a reaction medium to which has been added a catalytically effective amount of ruthenium-containing catalyst and a reaction-promoting effective amount of an electron-donating aromatic compound promoter. The process can be used to prepare, inter alia, chloropropyltriethoxysilane, which is a key intermediate in the manufacture of silane coupling agents.
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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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