A variety of catalyst have been developed for the cyclo-addition of CO2 to an epoxide. In few cases the role of the catalyst in the reaction of propene oxide with CO2 have been investigated by DFT calculations. The present study describes the mechanistic investigation of the cyclo-addition of CO2 to AGE catalyzed by iodide and formic acid/acetic acid by DFT calculations at B3LYP/6-31G(d,p) level. Being an electrophile, CO2 is assumed to participate in the ring opening of the epoxide and iodide ion released by the ionization of KI. A reactant complex could be optimized in which CO2 interacts at the epoxide-O, iodide ion at the CH2 carbon and formic acid forms H-bond with ether oxygen of AGE. The transition states (TS) for the ring opening by breaking the O-CH2 bond is 75 kJ/mol in presence of iodide which is significantly lower than that of the uncatalyzed reaction, 226 kJ/mol. Further lowering of the TS energy occurs in the presence of formic acid/acetic acid. Based on DFT calculations a two-step mechanism in which CO2 acts as an electrophile in the ring opening has been proposed.
Allyl glycidyl ether, Carbon dioxide, Cycloaddition, DFT calculations, Cyclic carbonates