Abstract: This invention relates to a process for the preparation of organosiloxanes, in particular those containing a high proportion of low molecular weight cyclic and chain structured organosiloxanes, preferably cyclic dimethylsiloxanes, by hydrolysis of the corresponding organochlorosilanes, in which a high proportion of gaseous hydrogen chloride is formed at the same time.

Abstract: The present invention relates to a process for the preparation of trioganosilyl-terminated polydiorganosiloxanes by basic polymerization of cyclic diorganopolysiloxanes and triorganosilyl-terminated siloxanes, wherein, before the polymerization, a part of the cyclic diorganosiloxane is distilled off in the presence of the polymerization catalyst at a temperature which is at least 10.degree. C. below the polymerization temperature.

Abstract: In a plastic organosiloxane molding composition which in the absence of water is capable of being stored and in the presence of moisture is cross-linked to a rubber, the composition comprising a hydroxypolydiorganosiloxane, a nitrogen base and heavy metal compound as cross-linking catalyst, and a cross-linking agent, the improvement which comprises employing as the cross-linking agent a compound of the formula ##STR1## or a partial hydrolysis product thereof, wherein R is an optionally substituted alkyl, alkenyl or aryl group,R.sub.1 is hydrogen or R,R.sub.2 is an acyl, carbalkoxy or carbaroxy group or R.sub.1,a is 1-3, andn is 0, 1 or 2 and a+n.ltoreq.3.Upon curing no unpleasant odors are given off upon decomposition of the cross-linking agent.

Abstract: In the preparation and working up of a SiOC-linked polysiloxane/polycarbonate copolymer comprising reacting an .alpha.,.omega.-dihalogenopolysiloxane with an .alpha.,.omega.-dihydroxy-oligocarbonate in the presence of a tertiary amine and a solvent, and subsequently separating off the resulting copolymer from the reaction mixture additionally containing the amine, amine hydrochloride and organic solvent, the improvement which comprises subjecting the reaction mixture to steam distillation whereby the copolymer remains behind. Advantageously, the copolymer reaction solution is added to an aqueous solution having a pH of 7 to 8 whereby the amine and hydrogen chloride also distill over. If a surface active agent is present in the aqueous solution the product will be of very fine particle size.

Abstract: In the preparation of a cyclic diphenylsiloxane of the formula ##STR1## WHEREIN N IS 3 OR 4, BY HYDROLYSIS OF A DIPHENYLDIHALOGENOSILANE, THE IMPROVEMENT WHICH COMPRISES ADDING THE DIPHENYLDIHALOGENOSILANE, IN THE PRESENCE OF AN ORGANIC, APROTIC SOLVENT TO AN AQUEOUS BASIC SOLUTION, THE BASE BEING EMPLOYED IN AN AMOUNT WHICH IS AT LEAST STOICHIOMETRICALLY EQUIVALENT TO THE HALOGEN CONTENT, WHEREBY THE CYCLIC DIPHENYLSILOXANE IS OBTAINED IN HIGH YIELD AND PURITY. The base is preferably lithium hydroxide, potassium hydroxide or sodium hydroxide and is used in the form of an at least 5 molar solution, about 2.1 to 2.5 equivalents being used per mole of diphenyldihalogenosilane.

Abstract: In the preparation of cyclic and linear organosiloxanes by reacting an organohalogenosilane with a compound of the formulaROR'in whichR is an alkyl radical with 1-4 C atoms, andR' is hydrogen or an alkyl radical with 1-4 C atoms,The improvement which comprises effecting the reaction in an aqueous solution of a Lewis acid. Preferably the organohalogenosilane is a di- or tri-organo-chloro or -bromo-silane wherein the organo radical is selected from the group consisting of alkyl or alkenyl of up to 4 C atoms or aryl, especially dimethyldichlorosilane, and the Lewis acid is a 40-90% solution of ZnCl.sub.2, FeCl.sub.3, CdCl.sub.2 or H.sub.2 SO.sub.4. Advantageously ROR' is methanol, ethanol, propanol, dimethyl ether or diethyl ether.

Abstract: A polysiloxane composition which can be cross-linked under atmospheric conditions and which consists essentially of:A. 100 parts by weight of an .alpha.,.omega.-dihydroxymethylphenylpolysiloxane with about 7-15 mole % of diphenylsiloxy units or about 14-28 mole % of methylphenylsiloxy units, and having a viscosity of between about 1,000 and 500,000 cSt (at 20.degree. C),b. about 1 to 40 parts by weight of an uncoated reinforcing filler consisting essentially of SiO.sub.2 having a specific surface area of about 40 to 500 m.sup.2 /g by the BET method, andC. about 1 to 10 parts by weight of a cross-linking agent of the formulaRSiX.sub.3whereinR is an alkyl, halogenoalkyl, aryl, or arylalkyl radical, andX is an alkoxy, acyloxy, oximato or alkylamino radical.A curing catalyst may also be present. The composition is clear as are the silicone rubbers produced upon curing.