BISACYLPHOSPHINOXIDE, IHRE HERSTELLUNG UND VERWENDUNG

Bisacylphosphine oxides of the general formula wherein R1 stands, for example, for a straight-chain or branched C1-18 alkyl radical, a cyclohexyl, cyclopentyl, phenyl, naphthyl, or biphenylyl radical, a cyclopentyl, cyclohexyl, phenyl, naphthyl, or biphenylyl radical substituted by F, Cl, Br, I, C1-C12 alkyl and/or C1-C12 alkoxyl, or an S or N-containing 5-membered or 6-membered heterocyclic ring, and R2 and R3, which are the same or different, stand for a cyclohexyl, cyclopentyl, phenyl, naphthyl, or biphenylyl radical, a cyclopentyl, cyclohexyl, phenyl, naphthyl, or biphenylyl radical substituted by F, Cl, Br, I, C1-4 alkyl and/or C1-4 alkoxyl, or an S or N-containing 5-membered or 6-membered heterocyclic ring; or R2 and R3 are joined to form a ring which contains from 4 to 10 carbon atoms and which may be substituted by 1 to 6 C1-4 alkyl radicals. The compounds are prepared by oxidation of the corresponding bisacylphosphines. The compounds are suitable for use as initiators for the photopolymerization of compounds containing ethylenically unsaturated bonds.