Copolymerization of CO and epoxides mediated by zinc organyls.

Herein we report the copolymerization of CHO with CO in the presence of various zinc compounds RZn (R = Et, Bu, Pr, Cy and Ph). Several zinc organyls proved to be efficient catalysts for this reaction in the absence of water and co-catalyst. Notably, readily available BuZn reached a TON up to 269 and an initial TOF up to 91 h. The effect of various parameters on the reaction outcome has been investigated. Poly(ether)carbonates with molecular weights up to 79.3 kg mol and a CO content of up to 97% were obtained. Under standard reaction conditions (100 °C, 2.0 MPa, 16 h) the influence of commonly employed co-catalysts such as PPNCl and TBAB has been investigated in the presence of EtZn (0.5 mol%). The reaction of other epoxides ( propylene and styrene oxide) under these conditions led to no significant conversion or to the formation of the respective cyclic carbonate as the main product.