Abstract: 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.

Abstract: Dimethyldichlorosilane is selectively and efficiently prepared by reacting methyl chloride with a solid contact mass comprising silicon and a catalytically effective amount of copper or a copper compound, said copper catalyst comprising (i) from about 10 to 1000 ppm of tin, antimony, or admixture thereof, or of a tin or antimony compound, or admixture thereof, (ii) from about 0.01 to 2% by weight of at least one of the metallic additives barium and strontium, or compound thereof, and, optionally, (iii) from about 0.01 to 3% by weight of zinc or a zinc compound.

Abstract: Novel organopolysiloxane/polyurethane block copolymers which are thermoplastic elastomers and which possess good thermomechanical properties, are comprised of the following recurring units (A) and (B): ##STR1## wherein Z is a divalent radical which comprises a polysiloxane block and has the formula: ##STR2## in which Y and Y' are each a divalent radical having one of the formulae: ##STR3## wherein T and T' comprise the divalent or trivalent residue having from 1 to 20 carbon atoms of an unsaturated isocyanate or alcohol having one of the formulae:OCN--T--CR.sub.1 .dbd.CR.sub.2 R.sub.3HO--T--CR.sub.1 .dbd.CR.sub.2 R.sub.3 ##STR4## or an oxygen, sulfur, silicon, nitrogen, ester or amide interrupted such T or T' residue, and further wherein R.sub.1, R.sub.2 and R.sub.3 are each hydrogen, alkyl or aryl, with the proviso that two of the radicals R.sub.1 and R.sub.

Abstract: Thermoplastic, elastomeric polystyrene/diorganopolysiloxane block copolymers having the structural formula: ##STR1## wherein each R, which may be the same or different, is selected from the group consisting of methyl, ethyl, n-propyl, phenyl and 3,3,3-trifluoropropyl; each R', all of which are the same, is hydrogen or methyl; A is a divalent hydrocarbon radical, free of aliphatic unsaturation, having from 6 to 45 carbon atoms; each G, which may be the same or different, is a radical selected from the group consisting of those of the structural formulae: ##STR2## wherein b is 0, 1, 2 or 3, ##STR3## wherein R" is hydrogen, methyl or --Si R.sub.3, c is 0, 1 or 2 and R is as above defined; each a, all of which are the same, is 0 or 1; and n and n', which may be the same or different, represent any numbers, the sum of which is between 20 and 500, and m is any number between 1 and 1,500, are prepared by anionic "styrene" polymerization, chain extension with a vinylchlorosilane, and, ultimately, hydrosilylation.

Abstract: Thermoplastic, crystalline block copolymers are disclosed, each comprising a plurality of recurring units selected from the group consisting of those of the structural formulae F.sub.1 and F'.sub.1, and combinations thereof:F.sub.1 : --A [SiR.sub.2 (GSiR.sub.2).sub.a ASiR.sub.2 G'SiR.sub.2 A].sub.p SiR.sub.2 (GSiR.sub.2).sub.a ASiR.sub.2 (OSiR.sub.2).sub.n ]andF'.sub.1 : --A [SiR.sub.2 G'SiR.sub.2 ASiR.sub.2 (GSiR.sub.2).sub.a A].sub.p SiR.sub.2 G'SiR.sub.2 ASiR.sub.2 (OSiR.sub.2).sub.