Method of preparation of polyorganosiloxanes containing unsaturated functions by dehydrogenation / condensation in the presence of complexes of metals of group iv.

摘要

PCT No. PCT/FR94/01047 Sec. 371 Date May 30, 1996 Sec. 102(e) Date May 30, 1996 PCT Filed Sep. 6, 1994 PCT Pub. No. WO95/07312 PCT Pub. Date Mar. 16, 1995Provided is a process for the preparation of polyorganosiloxanes containing unsaturated functions. A polyorganohydrogenosiloxane (A) containing at least 0.1 mol % of hydrogen atoms linked directly to the silicon is reacted with at least a stoichiometric amount of a hydrocarbon compound (B) having at least one ethylenic or acetylenic unsaturation, in the presence of a catalytically effective amount of a dehydrogenative condensation catalyst comprising a metal complex of formula (I): LnMRxYy. M represents a metal chosen from titanium, zirconium and hafnium; the symbols L are the same or different and represent a hydrocarbon ligand of the metal M, the said ligand donating from 3 to 8 pi -electrons to the valence shell of the said metal; n is an integer ranging from 0 to 3; the symbols R are the same or different and represent a hydrocarbon or organosilicon ligand of the metal M, the ligand being a sigma -electron donor; the symbols Y are the same or different and represent a ligand which forms, with the metal M, a covalent bond; x is an integer ranging from 0 to 4; y is an integer ranging from 0 to 4; the respective values of the numbers n, x and y being such that the number of electrons in the valence shell of the completed metal M is less than or equal to 18, wherein at least one of n, x and y does not equal zero.