Patent ID: 7470819

Claim:
A process for the preparation of bis-acylphosphanes of formula I R 1 P(COR 2 ) 2 wherein R 1 is unsubstituted phenyl or phenyl substituted by one to five halogen, C 1 -C 8 -alkyl, C 1 -C 8 -alkylthio and/or C 1 -C 8 -alkoxy; R 2 is C 1 -C 18 -alkyl or C 2 -C 18 -alkenyl; C 1 -C 18 -alkyl or C 2 -C 18 -alkenyl substituted once or more than once by halogens, —OR 10 , —OCO—R 10 , —OCO-Hal, —COO—R 10 , —N(R 11 )—CO—R 10 , —N(R 11 )—CO-Hal, —CO—NR 11 R 10 , —CH═CH—CO—OR 10 or —CH═CH-phenyl; —C(C 1 -C 4 -alkyl)=C(C 1 -C 4 -alkyl)-CO—OR 10 or —C(C 1 -C 4 -alkyl)=C(C 1 -C 4 -alkyl)-phenyl; C 5 -C 12 -cycloalkyl, C 2 -C 18 -alkenyl, phenyl-C 1 -C 4 -alkyl, phenyl, naphthyl, biphenyl or a 5- or 6-membered —O—, S— or N-containing heterocyclic ring, the radicals phenyl, naphthyl, biphenyl or the 5- or 6-membered —O—, S— or N-containing heterocyclic ring being unsubstituted or substituted by one to five halogen, C 1 -C 8 -alkyl, C 1 -C 8 -alkoxy and/or C 1 -C 8 -alkylthio; R 10 is hydrogen, C 1 -C 18 -alkyl, or C 2 -C 18 -alkyl which is interrupted by one or more non-successive —O-atoms, C 5 -C 12 -cycloalkyl, phenyl-C 1 -C 4 -alkyl, C 2 -C 18 -alkenyl, phenyl, naphthyl or biphenyl being unsubstituted or substituted by one to five C 1 -C 8 -alkyl, C 1 -C 8 -alkoxy, C 1 -C 8 -alkylthio and/or halogen; R 11 is hydrogen, C 1 -C 18 -alkyl, C 2 -C 18 -alkyl which is interrupted by one or more non-successive O atoms, C 5 -C 12 -cycloalkyl, C 2 -C 18 -alkenyl, phenyl-C 1 -C 4 -alkyl, phenyl, naphthyl, pyridyl, the radicals phenyl, naphthyl or pyridyl being unsubstituted or substituted by one to five C 1 -C 8 -alkyl, C 1 -C 8 -alkoxy, C 1 -C 8 -alkylthio and/or halogen; which process comprises a) selective reduction by hydrogenation of dichlorophenylphosphanes of the formula II R 1 P(Cl) 2 by means of hydrogen at a temperature in the range from 20 to 200° C. and under hydrogen pressure of atmospheric pressure to 20 bar in the presence of a hydrogenation catalyst, a tertiary aliphatic amine or an aromatic amine and in the presence of a non-protic solvent which is unreactive under the hydrogenation conditions to obtain cyclic phenylphosphanes (R 1 P) n (n=4 to 6); or b) selective reduction by hydrogenation of R 1 P(Cl) 2 by means of hydrogen at a temperature in the range from 80 to 250° C. and under hydrogen pressure of 25 to 250 bar in the presence of a hydrogenation catalyst, a tertiary aliphatic amine or an aromatic amine and in the presence of a non-protic solvent which is unreactive under the hydrogenation conditions to obtain R 1 PH 2 ; c) subsequent reaction with an acid halide of formula III in the presence of an appropriate base R 2 COHal wherein R 2 is as defined above.