Reaction mixtures, processes for their preparation and their use as polymerization initiators

Claim 1

A process for the preparation of a reaction mixture suitable as an initiator for free radical-initiated polymerisation reactions, which comprises reacting 1 mol of an α-arylketone or of an arylaldehyde of the general formula V or VI respectively ##STR11## wherein R 4 represents an aryl radical optionally substituted by C 1 -C 4 alkyl, methoxy, chlorine or fluorine, and R 6 represents an aryl radical optionally substituted by C 1 -C 4 alkyl, methoxy, chlorine or fluorine, or a C 1 -C 6 -alkyl radical optionally substituted by C 1 -C 4 alkyl, methoxy, chlorine or fluorine, or a C 5 -C 7 -cycloalkyl radical or hydrogen, and approximately the equivalent amount of a base metal in an inert aprotic solvent at -10 to +70° C. with 0.4 to 0.8 mol of a dichloro-organosilane of the general formula VII r.sup.1 r.sup.2' siCl.sub.2 (VII) or with 0.25 to 0.6 mol of a trichloro-organosilane of the general formula VIII r.sup.1 siCl.sub.3 (VIII) wherein R 1 represents a methyl, ethyl, phenyl, benzyl or chloromethyl radical, and R 2 represents a chlorine atom, a hydroxyl, methoxy, or ethoxy radical, or one of the substituents R 1 or with 0.1 to 0.7 mol of tetrachlorosilane, chlorinated polyorganosilanes or -siloxanes having a molecular weight of 150 to 3.000 until the exothermic reaction has ended, hydrolysing the reaction product, separating off the organic phase and stripping off the solvent under a pressure of between 2 and 6 mm Hg.