Abstract: The present invention provides a method for preparing alkenylsilanes whereby a gaseous mixture consisting essentially of an acetylenic hydrocarbon and a silane containing a silicon-bonded hydrogen atom is directed into contact with a reaction medium in the form of a relatively thin moving liquid layer or film. The reaction medium comprises a solubilized hydrosilylation catalyst and the alkenylsilane produced as a product of the reaction. The reaction medium can optionally include an organic liquid that is a solvent for the catalyst, alkenylsilane and acetylenic hydrocarbon reactant.

Abstract: A process in which the residual chloride impurities in crude alkoxysilanes with atmospheric boiling points below 130.degree. C. are reduced in order to render the resultant alkoxysilanes more suitable as a starting intermediate for the preparation of other chemical compounds and for use in electronics applications is described. The essence of the process is contacting the alkoxysilane with an alkaline metal compound using superatmospheric pressure to achieve a treatment temperature of greater than 130.degree. C.