Polymer-supported bimetallic system of PdCl2-4NiCl2-PPH3/PVP [PVP= poly(N-vinyl-2-pyrrolidone)] provided an almost regiospecific conversion of styrene to thebranched methyl 2-propionate at a high conversion. Typical reaction conditions are: 353 K,2.1 MPa of CO pressure (gauge pressure), 10h; styrene (1 mmol); methanol (0. 8 mL) ;benzene (10 mL); PdCl2/PVP(0. 04 mmol Pd, N/Pd= 20 in molar ratio); n (Pd): n(Ni): n(PPh3) = 1: 4:1. A remarkable synergic effect of bimetallic catalyst can be observed.Effects of PVP, amount of triphenylphosphine and temperature on the reaction were studied.The system of PdCl2-4NiCl2-PPh3/PVP gave 100% conversion of styrene and 99% selectivityto the branched chain ester under the typical reaction conditions.
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