Copolymerization of CO 2 and epoxides mediated by zinc organyls.

Herein we report the copolymerization of CHO with CO 2 in the presence of various zinc compounds R 2 Zn (R = Et, Bu, i 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 Bu 2 Zn reached a TON up to 269 and an initial TOF up to 91 h -1 . The effect of various parameters on the reaction outcome has been investigated. Poly(ether)carbonates with molecular weights up to 79.3 kg mol -1 and a CO 2 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 Et 2 Zn (0.5 mol%). The reaction of other epoxides ( e.g. 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.