Dow Corning Corporation

Charles S Kuivila

Roland L Halm

John Patrick Cannady

Gary N Bokerman

Regie H Zapp

Oliver K Wilding

David Clay Miller

Richard D Daugherty

A method for selecting chemical grade silicon metalloid having improved performance in a direct process for making organohalosilanes. The method comprises (A) heating a chemical grade silicon metalloid sample at a temperature ramp speed controlled to effect a stepwise reduction of oxide impurities present in the chemical grade silicon metalloid to a temperature greater than about 2300.degree. C. in the presence of a carbon source thereby effecting the formation of a reduction product consisting of carbon monoxide and carbon dioxide, (B) determining the amount of the reduction product formed above a temperature of about 1900.degree. C., and (C) selecting a chemical grade silicon metalloid for use in the direct process for making organohalosilanes based upon the amount of the reduction product formed above a temperature of about 1900.degree. C.

Method for selecting silicon metalloid having improved performance in

A method for controlling the direct process to vary the concentrations of trialkylhalosilanes and alkyltrihalosilanes in the product. The method comprises contacting an alkyl chloride with silicon metalloid in the presence of a catalytic amount of a catalyst comprising 0.5 to 10 weight percent copper, 5 to 200 ppm tin, 25 to 2,500 ppm phosphorous, and greater than zero to less than 50 ppm zinc, where the concentration of each of the catalyst components is based on the weight of the silicon, at a temperature within a range of about 250.degree. C. to 400.degree. C. The present inventors have found that by controlling the zinc concentration the concentrations of trialkylhalosilanes and alkyltrihalosilanes in the product can be varied.

Method for controlling the direct process product distribution

The present invention is a method for analyzing silicon for nonmetallic contaminants. The method comprises: (A) forming an alloy comprising silicon and a metal which promotes separation of nonmetallic contaminants present in the alloy, (B) separating the nonmetallic contaminants from the alloy, and (C) analyzing the separated nonmetallic contaminants for chemical content. The present invention is particularly useful for analyzing metallurgical grade silicon intended for use in the direct process for the production of organohalosilanes for the presence of oxides and carbides of calcium, aluminum, and silicon.

Analytical method for nonmetallic contaminates in silicon

The present invention is an improvement of the Direct Process for the manufacture of alkylhalosilanes by the contact of powdered metallurgical grade silicon with an alkyl halide in the presence of a copper catalyst. The improvement reduces lot-to-lot variations in silicon conversion to desired dialkyldihalosilanes. The improvement comprises alloying 0.01 to nine weight percent copper with the silicon to be used in the process and separating slag. In a preferred embodiment of the present process, silicon-copper alloy is pulverized to a powder and mixed with additional copper and other catalysts to form a contact mass reactive with alkylhalides.

Process for manufacture of alkylhalosilanes

The described invention is a process for preparing silanes from the reaction of solid silicon monoxide with aromatic halides. The solid silicon monoxide is reacted with the aromatic halide in the presence of a catalyst which can increase the conversion of silicon monoxide to silanes, and partially select for arylsilane products. The process may employ an activation step in which the solid silicon monoxide is activated by heating in an inert atmosphere. Activation of the solid silicon monoxide can increase silicon conversion and increase selectivity for arylsilane products.

Silane products from reaction of solid silicon monoxide with aromatic

The present invention is processes for preparing silanes from the reaction of silicon monoxide with hydrogen halides. In a first embodiment of the instant invention, silicon monoxide is reacted with a hydrogen halide to produce silanes and halosilanes. In a second embodiment of the instant invention, the silicon monoxide is activated by heating in an inert atmosphere prior to contact with the hydrogen halide. In a third embodiment of the instant invention, a catalyst is employed which enhances conversion of silicon monoxide to silanes and modifies process selectivity for silane products. The catalyzed process can be run with activated or non-activated silicon monoxide.

Silane products from reaction of silicon monoxide with hydrogen halides

The present invention is a process for preparing silanes from the reaction of solid silicon monoxide with organic halides. The solid silicon monoxide is reacted with the organic halide in the presence of a catalyst which can increase the conversion of silicon monoxide to silanes and partially select for the type of silanes produced. The process may employ an activation step in which the solid silicon monoxide is activated by heating in an inert atmosphere. Activation of the silicon monoxide can increase silicon conversion and alter the type of silanes produced.

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LaGrange, KY, United States of America

Charles S Kuivila