Rhone-Poulenc Specialites Chimiques

Gerard Simon

Christian Prud'Homme

Jean-Luc Lepage

Andre Soldat

Trichlorosilane, SiHCl.sub.3, is facilely prepared by (i) thermally reducing silicon tetrachloride, SiCl.sub.4, with hydrogen to produce reaction admixture comprising SiHCl.sub.3 and hydrochloric acid, said thermal reduction being carried out in a thermal plasma while tempering the reaction medium with a cooling gas, (ii) reacting said step (i) reaction admixture with elemental silicon at a temperature of from about 250.degree. to 350.degree. C. to produce SiHCl.sub.3 and hydrogen therefrom, and thence (iii) separating (iiia) the plasma-creating, hydrogen and cooling gases, and (iiib) product silicon chlorides therefrom.

Plasma production of trichorosilane, SiHCl.sub.3

Dimethyldichlorosilane is directly prepared from methyl chloride and silicon, in high productivity, selectivity and degree of silicon conversion, by reacting methyl chloride with a solid contact mass comprising silicon and a catalytically effective amount of a catalyst which includes (1) elemental copper or a copper compound, (2) from about 30 to 1,000 ppm (calculated as metallic tin and/or antimony) of at least one of the metals tin and antimony, or at least one compound of at least one of the metals tin and antimony, and (3) from about 0.05 to 4% by weight, (calculated as cesium metal) of cesium or a cesium compound, or admixture of cesium with up to 90% by weight of the admixture of lithium, sodium, potassium or rubidium, the amounts of said components (2) and (3) being based upon the total weight of said solid contact mass.

Direct catalytic synthesis of dimethyldichlorosilane from methyl

Dimethyldichlorosilane is directly prepared from methyl chloride and silicon, in high productivity, selectivity and degree of silicon conversion, by reacting methyl chloride with a solid contact mass comprising silicon and a catalytically effective amount of a catalyst which includes (1) elemental copper or a copper compound, (2) from about 30 to 1,000 ppm (calculated as metallic tin and/or antimony) of at least one of the metals tin and antimony, or at least one compound of at least one of the metals tin and antimony, and (3) from about 0.05 to 2% by weight, (calculated as alkali metal) of at least one of the alkali metals lithium, sodium, potassium and rubidium, or compound thereof, the amounts of said components (2) and (3) being based upon the total weight of said solid contact mass.

The dismutation/redistribution of halogenosilanes into silane is carried out by contacting at least one halogenosilane comprising at least one Si-H function with a compound comprising at least one .alpha.-oxoamine group, then by contacting the products of such reaction with a compound also comprising at least one .alpha.-oxoamine group, to selectively dissolve all products of reaction except for the silane therein, and then separating the desired silane therefrom.

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Villeurbanne, France

Gerard Simon