PROCESS FOR PREPARING ACYLPHOSPHANES AND THEIR OXIDES AND SULPHIDES

摘要

A process for the preparation of bis-acylphosphanes of formula R¹P(COR²)₂ wherein R¹ is unsubstituted phenyl or phenyl substituted by one to five halogen, C₁-C₈-alkyl, C₁-C₈-alkylthio and/or C₁-C₈-alkoxy; R² is C₁-C₁₈-alkyl or C₂-C₁₈-alkenyl ; C₁C₁₈-alkyl or C₂-C₁₈-alkenyl substituted once or more than once by halogen -OR¹⁰, -OCO-R¹⁰, -OCO-Hal, -COO-R¹⁰, -N(R¹¹)-CO-R¹⁰, -N(R¹¹)-CO-Hal, -CO-NR¹¹R¹⁰, -CH=CH-CO-OR¹⁰ or -CH=CH-phenyl; -C(C₁-C₄alkyl)=C(C₁-C₄alkyl)-CO-OR¹⁰ or -C(C₁-C₄alkyl)=C(C₁-C₄alkyl)-phenyl; C₅-C₁₂cycloalkyl, C₂-C₁₈alkenyl, phenyl-C₁-C₄alkyl, phenyl, naphthyl, biphenyl or a 5- or 6-membered -0-, S- or N-containing heterocyclic ring, the radicals phenyl, naphthyl, biphenyl or the 5- or 6-membered -0-, S- or N-containing heterocyclic ring being unsubstituted or substituted by one to five halogen, C₁-C₈alkyl, C₁-C₈alkoxy and/or C₁-C₈alkylthio; the process comprises the steps in a) selective reduction of dichlorophenylphosphanes of the formula R¹P(CI)₂ by means of hydrogen at a temperature in the range from 20 to 200°C and under hydrogen pressure of atmospheric pressure to 20bar in the presence of a hydrogenation catalyst, a tert. 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 (R¹P)_n (n = 4 to 6); or b) selective reduction of R¹P(CI)₂ by means of hydrogen at a temperature in the range from 80 to 25O°C and under hydrogen pressure of 25 to 250bar in the presence of a hydrogenation catalyst, a tert. aliphatic amine or an aromatic amine and in the presence of a non protic solvent which is unreactive under the hydrogenation conditions to obtain R¹PH₂; c) subsequent reaction with an acid halide of formula in the presence of an apropriate base R²COHal wherein R² is as defined above.