Wacker-chemie Gmbh

Willi Streckel

Herbert Straussberger

Wilfried Kalchauer

Bernd Pachaly

Rudolf Riedle

Anton More

Jochen Gross

Winfried Lang

Ralph Ottlinger

Johann Muschi

Markus Reindl

Process for preparing silanes

Dust recirculation in the direct synthesis of chlorosilanes and methylchlorosilanes in a fluidized bed

Methylchlorosilanes are prepared by reacting methyl chloride with a contact catalyst which comprises silicon, copper catalyst, zinc promoters and tin promoters and/or antimony promoters, in which hydrogen chloride is added in the course of from 1% to 45% of the duration of the production campaign.

Process for preparing organochlorosilanes

In the direct synthesis of methylchlorosilanes by reacting methyl chloride with a catalyst composition which comprises silicon, copper catalyst, zinc promoters and tin promoters and/or antimony promoters, a catalyst composition is used which was activated in advance by treatment with HCl under specific activation conditions.

In a process for the direct synthesis of methylchlorosilanes by reacting methyl chloride with a catalytic composition comprising silicon, copper catalyst and promoters, where at least some of the catalytic composition is comprised of the catalytic composition from a prior production campaign.

Process for preparing methylchlorosilanes

Methylchlorosilanes are prepared by reaction of methyl chloride with silicon in the presence of a catalyst combination of copper oxide, zinc oxide and metallic antimony.

Finely divided copper powder suitable for the preparation of copper catalyst for the synthesis of methylchlorosilane is prepared by adding an aqueous copper salt solution to an aqueous suspension of iron powder. Copper salt solutions obtained as process residues from the synthesis of methylchlorosilane can be used in the process of this invention.

Process for the preparation of copper powder

Organopolysiloxanes containing triorganosiloxy terminal units are obtained by a continuous process in which an organopolysiloxane mixture containing organo(poly)siloxanes having triorganosiloxy terminal units and cyclic organopolysiloxanes are introduced into a tube reactor that has been heated to at least 80.degree. C. and which contains a static catalyst bed. The organopolysiloxane composition containing triorganosiloxy terminal units, which exits from the tube reactor is different from the organo(poly)siloxanes containing triorganosiloxy terminal units which were introduced into the reactor. The contents of the reactor in the area between one-third and two-thirds of the distance between the point where the organopolysiloxanes are introduced into the tube reactor and the point where the organopolysiloxanes exit from the reactor, are maintained at a temperature which is at least 50.degree. C. below that which is immediately upstream from the outlet of the reactor.

Continuous process for preparing organopolysiloxanes containing

The invention relates to a process for treating elemental silicon and ferrosilicon with slag having the following analytical composition:

Process for treating silicon and ferrosilicon with slag

A method for utilizing a residue containing elemental silicon in the form of particles having a maximum diameter of 50 microns which comprises heating the residue for at least 15 hours at a temperature of from 100.degree. to 350.degree. C. in the presence of atmospheric air and/or an inert gas and thereafter recycling the treated residue into a process for preparing halosilanes.

Method for reactivating a residue containing elemental silicon

A process for preparing trimethylchlorosilane which comprises reacting methyldichlorosilane with methyl chloride and metallic aluminum.

Process for preparing trimethylchlorosilane

A process of melting down and purifying silicon, which comprises melting silicon in at least half of the amount up to double of the amount of a silicate melt heated by resistance heating up to a temperature of at least 1,420.degree. C., said melt consisting of 2-30% by weight of calcium oxide, 5-35% by weight of magnesium oxide, wherein the sum of calcium oxide and magnesium oxide will be 15-38% by weight, 0.5-28% by weight of aluminum oxide and 45-70% by weight of silicon dioxide, and wherein, to the melt are added at least 0.29% by weight of elementary and/or chemically bound copper, preferably 0.50-3% by weight, calculated on the silicon amount.

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Mehring/Od, Germany

Willi Streckel