Ethyl Corporation

Douglas M Richards

Joseph A Bossier, Iii

Robert H Allen

James E Boone

Lloyd T Crasto

The present invention provides a method of removing impurities from a stream of silane, SiH.sub.4. Most notably, the present invention provides a method of removing ethylene from a silane stream by converting the ethylene to ethylsilane in the presence of a molecular sieve and distilling the desired silane from the ethylsilane contaminant.

Removal of ethylene from silane using a distillation step after

A process for continuously preparing silane and a coproduct by reacting a metal hydride such as NaAlH.sub.4 with a silicon halide such as SiF.sub.4, utilizing, in conducting the reaction, equipment which includes, in series, a primary reactor, a secondary reactor and a separation zone. The metal hydride is reacted in the first reactor with less than a stoichiometric amount of the silicon halide, and the unreacted metal hydride is then passed to the second reactor wherein the remainder of the hydride is reacted in the secondary reactor, in which a stoichiometric excess of the silicon halide is added. The rate of silicon halide or metal hydride addition is governed by a temperature differential feed back from the reaction in the secondary reactor so that overall a stoichiometric or substantially stoichiometric operation is achieved. Techniques are also disclosed for splitting the silicon halide feed between the liquid and vapor phases of the secondary reactor to eliminate the hazard of combustible mixtures, and, with variable speed agitation of the liquid, to control the mass transfer characteristics of the reaction. Also, consistant kinetics result from control of residence time by varying the liquid level in the secondary reactor as related to the halide or hydride mass flow rates. These improvements conserve resources, provides improved coproduct and reduce costs.

Process for preparation of silane

A continuous method for preparing silane and a co-product by reacting a metal hydride such as NaAlH.sub.4 with a silicon halide such as SiF.sub.4. The method involves a reactor loop comprising a primary reactor, a secondary reactor and a separation zone. Most of the metal hydride is reacted in the first reactor to which it is added in a substantially constant rate. The remainder of the hydride is reacted in the secondary reactor, in which all or substantially all of the silicon halide is added. The rate of silicon halide addition is governed by feed back from the reaction in the secondary reactor, (.rarw.T so that stoichiometric or substantially stoichiometric operation is achieved. This conserves resources, provides improved co-product and reduces costs.

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Houston, TX, United States of America

Douglas M Richards