Diethyl zinc/glycerol catalyzed CO2/PO copolymerization: A combined experimental and DFT study

The copolymerization of carbon dioxide (CO2) and propylene oxide (PO) catalyzed by diethyl zinc/glycerol has been studied by experimental and theoretical approaches. The efficiency of the catalyst is strongly determined by the preparation methods, as the catalyst showed high activity when the catalyst was prepared by dropping glycerol into diethyl zinc. Conversely, the catalyst showed almost no activity when the dropping order was reversed. The order of dropwise addition could change the reaction between diethyl zinc and glycerol, which affects the structure of the catalyst and leads to a change in the catalytic activity. DFT calculations showed that the catalyst is self-assembled and the copolymerization follows a bimetallic coordination-push mechanism.