Understanding low-pressure CO2 insertion chemistry in epoxide–CO2 copolymerization catalysis

Abstract Despite many CO 2 use strategies being reliant on fast and selective CO 2 insertion reactions into metal-alkoxide bonds, in-depth studies into this chemistry remain rare. Here the effect of CO 2 pressure on the CO 2 insertion chemistry is studied using epoxide–CO 2 copolymerizations. Five high-performance literature catalysts are investigated under systematically varied CO 2 pressures, revealing kinetic profiles indicative of CO 2 insertion equilibria. For each catalyst, two key parameters describing the CO 2 insertion chemistry are determined: the equilibrium constant, K eq , and the saturation CO 2 pressure above which catalytic performance is maximized, P threshold . Generalizable correlations between copolymerization activity, K eq and P threshold are uncovered and used to predict performances for four further catalyst–monomer combinations. These correlations are a direct link between CO 2 insertion chemistry and process operating conditions, providing a mechanistic framework and testing protocols to accelerate future catalyst development. These results should help deliver efficient scalable CO 2 use technologies, operating with minimal energy.