Patent GB-719430-A (GB)
Title: A process for the manufacture of powdered siloxanes and/or silica
IPC: C01B33/18
Filed: 1952-08-28
Abstract: Powdered siloxanes and/or silica are produced by mixing one or more chlorosilanes of the general formula RnSiCl4-n, where n has an average value of from 0 to 1.5 and R is an alkyl radical having less than 7 carbon atoms, a phenyl radical or a hydrogen atom, there being not more than one hydrogen atom per silicon, with an inert gas in amount such that the percentage volume of chlorosilane vapour in the silane-gas mixture is less than 80 per cent., and contacting the silane-gas mixture with water in the liquid phase.  There are specified: silanes-tetra-, tri-(H.SiCl3), methyltri-, dimethyldi-, trimethyl:, phenyltri-, diethyldi-, triphenyl-, hexyltri-, monomethyldi-, diphenyldi-phenylhexyldi-, phenylethyldi-, and propyl-trichlorosilanes; inert gasses-air, nitrogen, oxygen, hydrogen, carbon dioxide, carbon monoxide sulphurdioxide, nitrogendioxide, phosphine, tri-methylamine, argon, helium, hydrogen chloride, methane, butadiene, ethane, methyl chloride, dimethyl ether, and vapours of hydrocarbons, hydrocarbon halides, ethers, nitriles, nitro compounds and tertiary amines.  The mixing may be effected (1) by passing the inert gas through the liquid silane, e.g. at room temperature with low boiling silanes and at elevated temperatures with higher boiling silanes, (2) by vapourising (by heating) the silanes and mixing the vapours with the inert gas, or (3) by spraying the silane into a stream of the inert gas. Hydrolysis of the silane(s) may be effected, at temperatures ranging from the freezing point up to the boiling point of the hydrolysis medium (which may be aqueous hydrogen chloride), either by passing the silane-gas mixture through water, or by spraying water into the silane-gas mixture.  The powdered products may be collected by filtering or skimming off the surface of the hydrolysis bath, with subsequent washing and drying.  A finely divided hydrophilic silica is obtained from SiCl4 or SiHCl3, and a hydrophobic powder is obtained from alkyl and phenyl chlorosilanes either alone or mixed with SiCl4 or H.SiCl3.  Some of the products may be used as moulding powders.  Examples are given.ALSO:Powdered siloxanes and/or silica are produced by mixing one or more chloro-silanes of the general formula RnSiCl4-n where n has an average value of from 0 to 1.5 and R is an alkyl radical having less than 7 carbon atoms, a phenyl radical or a hydrogen atom, there being not more than one hydrogen atom per silicon, with an inert gas in amount such that the percentage volume of the chlorosilane vapour in the silane-gas mixture is less than 80 per cent., and contacting the silane-gas mixture with water in the liquid phase.  There are specified: silanestetra-, tri-(HSiCl3),methyl-tri-, dimethyldi-, trimethyl-, phenyltri-, diethyldi-, triphenyl-, hexyltri-, monomethyldi-, diphenyldi-, phenylhexyldi-, phenylethyldi-, and propyltri-chlorosilanes; inert gases-air, nitrogen, oxygen, hydrogen, carbon dioxide, carbon monoxide, sulphur-dioxide, nitrogen dioxide, phosphine, trimethylamine, argon, helium, hydrogen chloride, methane, butadiene, ethane, methyl chloride, dimethyl ether and vapours of hydrocarbons hydrocarbon halides, ethers, nitriles, nitro compounds and tertiary amines.  The mixing may be effected (1) by passing the inert gas through the liquid silane, e.g. at room temperature with low boiling silanes and at elevated temperatures with high boiling silanes, (2) by vaporizing (by heating) the silanes and mixing the vapours with the inert gas, or (3) by spraying the silane into a stream of the inert gas. Hydrolysis of the silane(s) may be effected, at temperatures ranging from the freezing point up to the boiling point of the hydrolysis medium (which may be aqueous hydrogen chloride), either by passing the gaseous mixture through water, or by spraying water into the gaseous mixture.  The powdered products may be collected by filtering or skimming off the surface of the hydrolysis bath, with subsequent washing and drying.  A finely divided hydrophilic silica is obtained from SiCl4 or SiHCl3, and a hydrophobic powder is obtained from alkyl and phenyl chlorosilanes either alone or mixed with SiCl4 or H.SiCl3.  Examples are given.