Process for the synthesis of soluble, condensed hydridosilicon resins containing low levels of silanol
AssigneeDow Corning Corporation
InventorsHoward M. Bank, Martin E. Cifuentes, Theresa E. Martin
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Abstract
This invention relates to an improved method of hydrolyzing hydridosilanes with 2 or more hydrolyzable groups which comprises forming an arylsulfonic acid hydrate containing reaction medium, adding the silane to the hydrolysis medium, facilitating hydrolysis of the silane to form the polyester, settling the hydrolysis medium and polymer into an acid layer and an organic layer containing the polymer, separating the organic layer from the acid layer, contacting the organic layer with a neutralizing agent, and removing the neutrailizing agent from the organic layer.
Claims38
A method of hydrolyzing a silane of the formula H.sub.a SiX.sub.4-a where a is 1 or 2 and X is a hydrolyzable group, to produce polymers containing units of the formula H.sub.a SiO.sub.( 4-a)/2, the method comprising:
- forming a hydrolysis medium containing an arylsulfonic acid hydrate.
- adding a the silane to the agitated hydrolysis medium,
- facilitating hydrolysis of the silane in the hydrolysis medium to form the polymer,
- settling the hydrolysis medium and polymer into immiscible layers comprising an acid layer and an organic layer where the organic layer contains the polymer,
- separating the organic layer from the acid layer,
- contacting the organic layer with a neutralizing agent sufficiently basic to neutralize the remaining acid species but insufficiently basic to catalyze rearrangement of the polymer or solvolysis of silicon hydrides, and
- separating the organic layer from the neutralizing agent.
A method of hydrolyzing a silane of the formula HSiCl.sub.3 to produce a polymer containing units of the formula HSiO.sub.3/2, the method comprising:
- forming a toluenesulfonic acid hydrate hydrolysis medium by combining toluene and concentrated sulfuric acid,
- adding trichlorosilane dissolved in toluene to the agitated hydrolysis medium,
- facilitating hydrolysis of the silane in the hydrolysis medium to form the polymer,
- settling the hydrolysis medium and polymer into immiscible layers comprising an acid layer and an organic layer where the organic layer contains the polymer and toluene,
- separating the organic layer from the acid layer and washing the organic layer with aqueous sulfuric acid,
- contacting the organic layer with calcium carbonate to neutralize the remaining acid species,
- separating the organic layer from the calcium carbonate, contacting the neutralized organic layer with a drying agent, separating the organic layer from the drying agent, and evaporating the solvent.
Dependencies are inferred from the claim text.