Dow Corning Corporation

Dow Silicones Corporation

David Clay Miller

Jonathan David Wineland

Ora L Flaningam

Charles S Kuivila

Christopher James Kozenski

The invention pertains to a method of passivating direct process solids and to passivated and quenched compositions resulting from said method. The method of passivating direct process solids according to the invention comprises combining direct process solids with a passivating composition comprising clay, base, and water. The passivated composition of the invention comprises direct process solids and a passivating composition comprising clay, base, and water. The quenched composition of the invention comprises the passivated composition, wherein the passivated composition has been held for a sufficient period of time for the reactive species from the direct process solids to be substantially quenched and/or oxidized.

Solids passivation

Crude chlorosilane streams containing lower-boiling chlorosilanes and higher-boiling chlorosilanes are separated by contacting them with a distillation aid. The lower-boiling chlorosilanes are separated from the crude chlorosilane stream, and then the distillation aid and the higher-boiling chlorosilanes are separated from one another. The distillation aid is a mono-cyano-substituted organic compound, a nitro-substituted organic compound, a mono-cyano-substituted organosilicon compound, a nitro-substituted organosilicon compound, or a mixture thereof. These distillation aids increase the relative volatility of crude chlorosilane streams such as methyltrichlorosilane and dimethyldichlorosilane resulting in improved separation at lower capital and/or fixed costs.

Separation of chlorosilanes

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.

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Madison, IN, United States of America

David Clay Miller