GB906617A - Process for highly purifying liquid or gaseous organic or inorganic silicon compounds - Google Patents

Abstract

Silicon compounds, containing 10-3% to 106% by weight of impurities are purified by contacting them in the liquid state with a carboxylic acid amide and/or a dithiocarbamate and/or a salt of ethylene diamine tetracetic acid, at a temperature below the carbonization point of the purifying agent, and then not more than 90% of the silicon compound is isolated from the mixture, for example by distillation or by passing a carrier gas, for example nitrogen, hydrogen, carbon monoxide, inert gases, and gases which are reacted at a later stage with the purified compound, through the mixture. The mixture may be agitated or refluxed at 0-50 atmospheres gauge. The purifying agent may be present in an amount of 0,1% by weight, or less, although more may be present. Suitable purifying agents include thioglycolic acid (b -naphthyl)-amide, sodium and ammonium pyrrolidine dithiocarbamate. For dealing with very impure silicon compounds, inert porous contact materials, for example hydrogen-containing silica, brown silicon, highly active graphite, or porous quartz glass or quartz ware, may also be present. The reaction vessel may be made of quartz glass or ware, glass, noble metals or alloys, or synthetic resins, for example, polymethacrylates, polytetrafluorethylene, polyvinyl chloride or polytrifluorethylene. In examples, silicon tetrachloride and trichlorsilane were purified.ALSO:Organic silicon compounds (only monomethyl trichlorosilane and monomethyl monochlorsilane are exemplified), containing 10-3%-10-6% by weight of impurities, are purified by contacting them in the liquid state with a carboxylic acid amide and/or a dithiocarbamate and/or a salt of ethylene diamine tetracetic acid, at a temperature below the carbonization point of the purifying agent, and then not more than 90% of the silicon compound is isolated from the mixture, for example by distillation or by passing a carrier gas, such as hydrogen, nitrogen carbon monoxide, inert gases, and gases which are reacted with the silicon compound at a later stage, through the mixture. The mixture may be agitated or refluxed at 0-50 atmospheres guage. The purifying agent may be present in amounts of less or more than 0,1% by weight. Suitable agents include thioglycolic acid (b -naphthyl)-amide, sodium and ammonium pyrrolidine dithiocarbamate. For dealing with very impure silicon compounds inert porous contact materials, such as hydrogen-containing silica, brown silicon, highly active graphite or porous quartz glass or ware may also be present. The reaction vessel may be made of quartz glass or ware, glass, noble metals and alloys, or synthetic resins, for example polymethacrylates, polyvinyl chloride, polytetrafluorethylene or polytrifluorethylene.