Patent GB-909950-A (GB)
Title: Improvements in the production of silicon hydrides
IPC: C01B33/04
Filed: 1960-07-15
Abstract: Halogen substituted silanes are hydrogenated by reaction with a hydride of an alkali metal (except lithium) or alkaline earth metal (including magnesium) under oxygen free and anhydrous conditions in the presence of an ether as reaction medium and zinc, a zinc alloy or zinc compound as catalyst.  The hydride may be present in at least the stoichiometric amount required to produce the halogen free silane.  The hydride may be of sodium, calcium, or magnesium.  The halogen substituted silane may be a tetrahalosilane, e.g. SiF4, SiCl4, SiBr4, SiCl3Br, SiI4; a trihalosilane, e.g. SiHCl3, SiHBr3, SiHI3; a dihalo- or monohalosilane, e.g. SiH2Cl2, SiH3Cl; a halopolysilane, e.g. Si2Cl6, Si2I6, Si3Br8, Si6Cl10.  The catalyst may be a zinc halide, a zinc carboxylate, zinc carbonate, zinc oxide, a zinc alkyl or zinc hydride.  The molar ratio of catalyst to halosilane may be from 1:8 to 2:1.  Suitable ethers are tetrahydrofuran, mono-, di-, tri-, or tetra-ethylene glycol dimethyl ether, diethyl ether, 1,4-dioxane, dipropyl ether, diisopropyl ether, dichloro-diethyl ether.  The metal hydride may be in finely divided form as a dry powder or finely dispersed on an inert support, e.g. sodium chloride, or as a powder wetted with an oil.  An attritive agent is preferably added to form a viscous slurry which is then stirred.  The attritive agent may be quartz, ilmenite, sand, salts, e.g. sodium chloride, calcium chloride, metal particles, e.g. steel, aluminium, titanium, zinc (also acts as catalyst). The ether may be diluted with an inert organic liquid, e.g. kerosene, heptane. Specification 659,710 and U.S.A. Specification 2,406,605 are referred to.ALSO:Halogen substituted organo silanes are hydrogenated by reaction with a hydride of an alkali metal (except lithium) or alkaline earth metal (including magnesium) under oxygen-free and anhydrous conditions in the presence of an ether as reaction medium and zinc, a zinc alloy or zinc compound as catalyst.  The hydride may be present in at least the stoichiometric amount required to produce the halogen free organo silane.  The hydride may be sodium hydride, calcium hydride, or magnesium hydride. The halogen substituted organo silane may be an alkyl halosilane, e.g. (CH3)3SiCl, (CH3)2SiCl2, (C2H5)SiBr3; an aryl halosilane, e.g. (C6H5)SiCl3, (C6H5)SiBr3, an alkyl halopolysilane, e.g. Si2Cl4(CH3)2. The catalyst may be a zinc halide, a zinc carboxylate, zinc carbonate, zinc oxide, a zinc alkyl, or zinc hydride.  The molar ratio of catalyst to halogen substituted organo silane may be from 1:8 to 2:1.  Suitable ethers are tetrahydrofuran, mono-, di, tri-, or tetra-ethylene glycol dimethyl ether, diethyl ether, 1,4-dioxane, dipropyl ether, diisopropyl ether, dichloro-diethyl ether.  The metal hydride may be in finely-divided form as a dry powder or finely-dispersed on an inert support, e.g. sodium chloride, or as a powder wetted with an oil.  An attritive agent is preferably added to form a viscous slurry which is then stirred.  The attritive agent may be quartz, ilmerite, sand, salts, e.g. steel, aluminium, titanium, zinc (also acts as catalyst).  The ether may be diluted with an inert organic liquid, e.g. kerosene, heptane.  Specification 659,710 and U.S.A. Specification 2,406,605 are referred to.