MECHANISM OF PALLADIUM-CATALYZED ALTERNAT ING COPOLYMERIZATION OF CO WITH ETHYLENE - IN-SITU P-31 NMR-STUDIES ON PALLADIUM-PHOSPHINE COORDINATE STRUCTURE UNDER REACTION CONDITIONS

Palladium-phosphine catalyst with different DPPP/Pd(OAc)(2) ratio has been studied with in situ P-31 NMR spectroscopy under reaction conditi ons(C2H4/CO 1:1, 2.0 MPa). The results showed that the reaction of DPP P with Pd(OAc)(2) produced a stable six-membered ring complex which ha d efficient catalytic activity. When the reaction temperature was abov e 100 degrees C, the complex began to decompose. When the reaction tem perature was above 260 degrees C,the complex decomposed completely. No free DPPP was found in the experiment. The active complex (DPPP) Pd(O COCF3)(2) was formed when DPPP/Pd = 1. The unactive complex (DPPP)(2)P d(OCOCF3)(2) was formed when DPPP/Pd greater than or equal to 2.