Dow Corning Corporation

Case Western Reserve University

Gary N Bokerman

John Patrick Cannady

Larry Herbert Wood

Charles S Kuivila

Ollie W Marko

Vishu D Dosaj

David E Puckett

David J Gordon

Malcolm Edward Kenney

Steven K Freeburne

Robert D Steinmeyer

Joseph A Colquhoun

John D Oleson

Neal Roger Langley

John G Uhlmann

Alvin W Rauchholz

Dennis G VanKoevering

Martin D Young

Ann E Ogilvy

Douglas H Lenz

Lawrence M Schuelke

Li-Tain Yeh

James E Hampton

The present invention is a process for the preparation of organofunctional-terminated polydiorganosiloxane polymers and organofunctional polydiorganosiloxane copolymers. The process comprises reacting a hydroxyl-terminated polydiorganosiloxane polymer with: (1) an organofunctional chlorosilane end-blocker to form an organofunctional terminated polydiorganosiloxane polymer and (2) a mixture of organochlorosilane end-blocker and organofunctional dichlorosilane to form an organofunctional polydiorganosiloxane copolymer. The process can be conducted in the presence of an aqueous solution of hydrogen chloride, where the water is present in stoichiometric excess in relation to the hydrolyzable silicon-bonded chlorine. The present process is particularly useful for producing 5-hexenyl-terminated polydimethylsiloxane polymers and for producing siloxane copolymers comprising poly-5-hexenylmethylsiloxy and polydimethylsiloxy blocks.

Condensation process for preparation of organofunctional siloxanes

The present invention is an anhydrous process for preparing organosiloxy end-blocked polyorganosiloxanes from chlorine end-terminated polyorganosiloxanes. The process comprises contacting an anhydrous mixture comprising a chlorine end-terminated polyorganosiloxane and an organodisiloxane with a rearrangement catalyst, where the rearrangement catalyst facilitates a chlorine and organosiloxy exchange between the chlorine end-terminated polyorganosiloxane and the organodisiloxane forming a organochlorosilane as a by-product. The organochlorosilane is continuously removed from the process providing a means by which the chlorine displaced from the chlorine end-terminated polyorganosiloxane can be effectively removed from the organosiloxy end-blocked polyorganosiloxanes in a useable form. The present process is especially useful for the rearrangement of chlorine end-terminated polyorganosiloxanes having one or more hydrogen atoms bonded to silicon to organosiloxy end-blocked polyorganohydrosiloxanes.

Anhydrous process for preparation of polyorganosiloxanes

The present invention is a process for converting chlorine end-terminated polyorganosiloxanes to polyorganocyclosiloxanes. The process comprises forming a mixture comprising chlorine end-terminated polyorganosiloxanes, aqueous hydrogen chloride, and a heterogeneous reequilibrium catalyst. The mixture is heated at a temperature within a range of about 70.degree. C. to 150.degree. C. to effect reequilibrium of the chlorine end-terminated polyorganosiloxanes to form polyorganocyclosiloxanes which are removed from the process as they are formed.

Process for converting chlorine end-terminated polyorganosiloxanes to

The present invention relates to a novel method of preparing alkoxysilanes and oligomeric alkoxysiloxanes. The method comprises reacting a metal silicate with an acid selected from the group consisting of sulfurous acid and acids with a pKa greater than about 2.5 in the presence of an alcohol. The resultant product is then reacted with an alcohol to form the alkoxysilane or oligomeric alkoxysiloxane, depending on the starting silicate. This method is particularly valuable since the reaction conditions are mild and the reactants are readily available.

Alkoxysilanes and oligomeric alkoxysiloxanes by a silicate-acid route

The present invention is a process for the production of organosilanes from the high-boiling residue resulting from the reaction of organohalides with silicon metalloid in a process typically referred to as the 'direct process.' The present process comprises forming a mixture comprising a organotrihalosilane and the high-boiling residue in the presence of hydrogen gas, a hydrogenolysis catalyst, and a redistribution catalyst. The organotrihalosilane and high-boiling residue are converted into commercially useful di- and triorganosilanes and organohydrosilanes. The present process results in consumption of the organotrihalosilane rather than the net increase which typically occurs in the absence of the redistribution catalyst.

Production of organosilanes from polysilanes

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 described invention is a process for producing silanes and polysiloxanes. The process comprises contacting silica with a preformed alkylaluminum compound in the presence of a catalyst effective in facilitating the reaction. Preferred catalysts are copper, tin, zinc, phosphorous, and compounds thereof.

Metal assisted alkylation of silica

The instant invention is a one-step process for producing polydiorganosiloxanes (siloxanes). In the described process, a mixture comprising diorganodichlorosilane and a source of triorganosilyl groups is contacted with excess water essentially saturated with hydrogen chloride. Product siloxanes are isolated as well as saturated aqueous hydrogen chloride and anhydrous hydrogen chloride. The amount of triorganosilyl groups present in the mixture is controlled to set the degree of polymerization of product siloxanes. The isolated saturated aqueous hydrogen chloride is recycled to the process. Excess chloride generated in the process is collected as anhydrous hydrogen chloride.

Anhydrous hydrogen chloride evolving one-step process for producing

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.

Silane products from reaction of silicon monoxide with organic halides

The instant invention is a process for the removal of hydrogen-containing silane impurities from organosilanes with similar boiling points. In the instant invention, the hydrogen-containing silane is reacted with a hydrogen halide to replace the hydrogen on the silane with a halide and create a modified silane. The substitution of the heavier halide for the hydrogen, increases the boiling point of the modified silane. This increase in boiling point facilitates separation by distillation of the modified silane impurity from the desired organosilanes.

Removal of hydrogen-containing silanes from organosilane mixtures

What is described is a process for the production of silicon via the carbothermic reduction of silicon dioxide in which silicon carbide is fed as the total reductant source or as a portion of the reductant input. The process also includes recovery and recycle to the furnace silicon monoxide and other silicon-containing materials from the by-produced gases from the furnace to maximize raw material efficiency. Finally, the process includes the recovery of value from the by-produced gases via the use of the gases as a chemical intermediate or the use of the gases as a fuel for a combustion process.

Silicon carbide as a raw material for silicon production

A process for purifying alkylhalosilanes to reduce the content of olefinic impurities is described. The process comprises (A) contacting crude alkylhalosilanes, containing as a minor portion the olefinic impurities, with a hydrogen-containing halosilane and a soluble compound of a Group VIII metal; (B) facilitating reaction of the olefins with the hydrogen-containing silicon compound in contact with the Group VIII metal compound to form linear or branched silalkanes, said silalkanes having the formula,

Removal of olefins from organohalosilanes

What is disclosed is an improvement in a process for the carbothermic reduction of silicon dioxide to form silicon, the improvement comprising (a) contacting the by-produced gases from the silicon furnace with a cooling medium such as a vaporizing liquified hydrocarbon-containing gas or an expanding compressed hydrocarbon-containing gas to cool the by-produced gases and to cause silicon-containing materials to completely condense and to form agglomerated solids; (b) removing the agglomerated, solid materials from the gases, and (c) recovering value from the solids-free by-produced gases as an energy source or as a chemical intermediate.

Handling of by-product gases from a silicon furnace

A method of polymerizing hydroxyl-endblocked polydiorganosiloxane in the presence of filler, including acidic filler such as fumed silica, through the use of basic diorganosilanolates as catalysts is claimed. Preferred diorganosilanolates are tetra-n-butylphosphonium dimethylsilanolate and potassium dimethylsilanolate. The silicone polymer-filler mixture produced is useful in silicone greases and elastomers. Methods of combining the silicone polymer-filler mixture with various curing agents to yield curable compositions are claimed.

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Madison, IN, United States of America

Gary N Bokerman