DFT Investigations of the Reaction Mechanism of Dimethyl Carbonate Synthesis from Methanol and CO on Various Cu Species in Y Zeolites

In this study, a density functional theory method is employed to investigate the reaction mechanisms of dimethyl carbonate (DMC) formation, through oxidative carbonylation methanol, on four types Y zeolites doped with Cu+, Cu2+, Cu2O and CuO, respectively. A common chemical route found for these identified as, first, adsorbed CH3OH oxidized CH3O species; subsequently, CO inserts into CH3OCO, which reacts form DMC rapidly; finally, released gas phase. The rate-limiting step Cu2+Y zeolite as oxidation activation barrier 66.73 kJ·mol−1. While Cu+Y, Cu2O-Y CuO-Y zeolites, insertion CH3O, corresponding barriers are 63.73, 60.01 104.64 kJ·mol−1, For presence oxygen, whereas caused by lattice oxygen CuO. order catalytic activities different Cu states follows Cu+Y ≈ > zeolite. Therefore, CuY catalysts Cu+ dominated species beneficial formation DMC.