A process for preparing linear organohydrogensiloxanes. The process comprises contacting an organohydrogendichlorosilane in the presence of trimethylchlorosilane with water to form an M-stopped hydrolyzate. The hydrolyzate is optionally preheated prior to being contacted with an acidic rearrangement catalyst to effect formation of linear organohydrogensiloxanes. The linear organohydrogensiloxanes are separated from cyclic organohydrogensiloxanes and recovered. The cyclic organohydrogensiloxanes may then be recycled to the process for further contact with the acidic rearrangement catalyst for maximum overall conversion rate.
Process For Preparing A Mixture Of Alkoxyacyloxy Silane And Alkyltriacyloxsilane
Luisito A. Tolentino - Clifton Park NY Lewis O. Slocum - Mecanicville NY Russell L. Wilt - Clifton Park NY
Assignee:
General Electric Company - Waterford NY
International Classification:
C07F 702
US Classification:
556442
Abstract:
A continuous method is provided for making a mixture of alkylpolyacyloxysilane and alkoxyacyloxysilane which is useful as a curing catalyst for a one part moisture curable silicone RTV. A steady-state mixture of alkylpolyacyloxysilane and alkoxyacyloxysilane is established in the reboiler of a distillation system having a reboiler, a distillation column, and a condenser as a result of the continuous introduction into the distillation column of a mixture of an alkyltrichlorosilane and silicon tetrachloride and the direct feeding of an alcohol such as tertiary butanol into the reboiler. A mixture comprising alkylpolyacyloxysilane and alkoxyacyloxysilane and aliphatic carboxylic is continuously pumped to a collection vessel. The continuous stripping and recycling of the aliphatic carboxylic from the collection vessel results in the continuous production of the desired silane mixture.
Acyloxysilanes are prepared by reacting a chlorosilane with an aliphatic carboxylic acid in a column at an elevated temperature wherein the aliphatic carboxylic acid in the vapor phase reacts with the chlorosilane in the column. The improvement comprises introducing the carboxylic acid into the column in a plurality of feed streams preferably at such a rate that the carboxylic acid exceeds 1. 3 moles per gram atom of silicon-bonded chlorine in the column and removing low boiling reaction by-products and hydrogen chloride gas from the top of the column while collecting the acyloxysilane product dissolved in the aliphatic carboxylic acid at the bottom of the column. At least one feed stream of aliphatic carboxylic acid must be located above the chlorosilane feed stream. Aliphatic carboxylic acid is also provided from at least one source located below the chlorosilane feed stream, for example, from at least one feed stream located below the chlorosilane feed stream or from aliphatic carboxylic acid in a reboiler at the bottom of the column or both. In a preferred embodiment, methyltriacetoxysilane is prepared by reacting methyltrichlorosilane with acetic acid in a heated fractionation column.
Process For Co-Alkoxylation Of Halosilanes And Separation Of The Resulting Products
A process for converting a mixture of at least two different halosilanes having the general formula, R. sub. n SiX. sub. 4-n, which are difficult to separate, to at least two different alkoxysilanes having the formula, R. sub. n Si(OR'). sub. 4-n, where R and R' are saturated or unsaturated alkyl groups of 1 to about 8 carbon atoms or aromatic; X is halogen; and n is 0-3; and separating the alkoxysilanes, is disclosed. The co-alkoxylation of the halosilanes is carried out by charging a reboiler equipped with a reflux column with an alkoxylating agent, such as, an aliphatic alcohol, and, optionally, at least one of the halosilanes being alkoxylated; feeding at least two halosilanes to be co-alkoxylated into the upper section of the column; introducing the alkoxylating agent, such as, an aliphatic alcohol, into the upper section of the column to react with the halosilanes in a reaction zone in the column and thereby form alkoxysilanes and hydrogen halide; removing the hydrogen halide; collecting at least two alkoxysilanes formed in the column and separating the alkoxysilanes. In one preferred embodiment, the alkoxysilanes are separated and collected at two different points in the column in a distillation zone below the rection zone. Two halosilanes, which are co-methoxylated and thereafter separated, are dimethyldichlorosilane and methyltrichlorosilane which form dimethyldimethoxysilane and methyltrimethoxysilane, respectively, when heated in the presence of the alkoxylating agent, methanol.
Silicone Rubber Compositions For Liquid Injection Molding Machines
A SiH-olefin platinum catalyzed composition having a Durometer Hardness of at least 60 where the novel ingredients are a combination of 10 to 50 parts by weight of fumed silica and 5 to 50 parts by weight of calcined diatomaceous earth per 100 parts of the base vinyl-containing compound. Such a composition is useful for forming molded parts in liquid injection molding machines, both of the plunger type and of the reciprocating screw type.
Siloxane Fluid From Methylchlorosilane Residue Waste
Robert G. Stank - Ballston Spa NY Luisito A. Tolentino - Clifton Park NY Alan Ritzer - Sand Lake NY Frank J. Traver - Troy NY
Assignee:
General Electric Company - Waterford NY
International Classification:
C07F 708
US Classification:
556430
Abstract:
Siloxane fluids containing novel siloxane polymers prepared from mixtures of disilanes, disiloxanes and silylmethylenes, and a method for recovering fully alkylated linear and cyclic siloxanes with disilane, disiloxane and silylmethylene bonds, such as from methylchlorosilane residue cleavage bottoms, are disclosed.
Method Of Making Organosiloxanes And Alkyl Halides From Dialkyldialkoxysilanes
An improved process for making an alkyl halide and organosiloxanes from a dialkyldialkoxysilane and a hydrogen halide is disclosed. Dialkyldialkoxysilane and hydrogen halide are simultaneously introduced at respective feed points into a column containing hydrogen halide under reflux in such proportions that the amount of hydrogen halide introduced into the column is at a stoichiometric excess over the dialkyldialkoxysilane. In preferred embodiments, the hydrogen halide is hydrogen chloride; the dialkyldialkoxysilane is dimethyldimethoxysilane; the alkyl halide is methyl chloride; and the organosiloxanes are predominantly of the cyclic type.
Method For Preparing Acrylic Functional Halosilanes And Halosiloxanes
The instant invention provides a method for making acrylate-functional halosilanes or halosiloxanes comprising reacting an organic acrylate and a halosilane or halosiloxane having at least one silicon-bonded hydrogen atom in the presence of a hydrosilation catalyst and an amount of inhibitor effective for inhibiting the thermal free radical polymerization of said organic acrylate. Acrylate-functional halosilanes and halosiloxanes prepared in accordance with the present method are also provided.