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 Pd-CO⋯K⁺ structure, which further activates the C-O 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.