Copolymerization of CO2 and cyclohexene oxide

Generation of high value polymers from carbon dioxide is of general technological interest given that C02 is both inexpensive and relatively easy to handle on an industrial scale. Previous work on the use of C02 as a comonomer has focused primarily on development of new catalysts, and the effects of conventional process variables such as temperature and concentration on the polymerization outcome have not been examined in great detail. Recently, we, as well as Darensbourg and colleagues, have shown that one can generate zinc-based catalysts for the polymerization of C02 and cyclohexene oxide which produce over 400 grams of polymer per gram of metal. In this paper, we use a product of the reaction between zinc oxide and the fluorinated half-ester of maleic anhydride to generate copolymers of C02 and cyclohexene oxide where C02 is both reactant and sole solvent. In general, we found that the outcome of the polymerization depends greatly on the proximity to the ceiling temperature and the critical cyclohexene oxide concentration, and also on the phase behavior of the cyclohexene oxide-CO2 binary.