Synergy between Palladium and Potassium Species for Efficient Activation of Carbon Monoxide in the Synthesis of Dimethyl Carbonate

A potassium ion containing Pd/NaY catalyst is introduced that effectively activates the CO molecule for the carbonation of methyl nitrite to synthesize dimethyl carbonate. The potassium ions play a dual role during the activation of CO. Doping the catalyst with potassium enhances the electron density of Pd active species, which strengthens the Pd-C atoms interaction and thus more strongly activates the CO molecule. Further, the charge-balancing potassium cations in the zeolite interact with the O atom of linear adsorbed carbonyls to form a PdCOK+ structure, which further activates the CO bond. Both experimental analyses and density functional theory calculations indicated that the combination of potassium and Pd species facilitates the activation of CO in the carbonylation reaction.