Quantum-Chemical Study of Reactions between Dimethyl Carbonate and Methylamine Proceeding through an Addition–Elimination Mechanism on Zinc Oxide Catalysts

Abstract—Quantum-chemical means wB97XD/6-311++G(df,p), M06/6-311++G(df,p), and PBE0/6-311++G(df,p) are used to study the mechanism and thermodynamic parameters of the activation and reactions between dimethyl carbonate and methylamine and its hydrogen-bonded complexes with methanol through an addition–elimination mechanism on a cubic zinc oxide tetramer catalyst. It is shown that the transformations proceed through cyclic transition states, and the formation of a complex of dimethyl carbonate and dimethoxy(methylamino)methanol with zinc oxide results in considerable orbital interactions, compared to non-catalytic reactions. Calculated data indicate that transformations occurring through the addition–cleavage mechanism are preferential with respect to the S_N2 mechanism of nucleophilic substitution.