Processes in the H 2 PtCl 6 ·6H 2 O–Solvent Systems. Part 2: Methylvinylsiloxane Solutions

Redox processes in the H 2 PtCl 6 ·6H 2 O–1,1,3,3-tetramethyl-1,3-divinyldisiloxane system both in the presence of ethanol and trimethylchlorosilane, and in the absence thereof were studied by 1 Н, 13 С, and 29 Si NMR spectroscopy and gas–liquid chromatography. It was found for the first time that Pt(IV) and Pt(II) chlorides catalyze the reactions of hydrochlorination of vinyl groups with their transformation into β-chloroethyl groups and the elimination of the latter to form ethylene and dimethylchlorosilanes. Based on the results obtained, it was assumed that Pt(0) is coordinated to the siloxane group. A method to produce a high-temperature hydrosilylation catalyst consisting of nanosized Pt(0) and trimethylsilylsilicate was proposed and successfully tested in practice for curing SIEL-type compounds.