Selectivity Control of Carbonylation of Methanol to Dimethyl Oxalate and Dimethyl Carbonate over Gold Anode by Electrochemical Potential

摘要

Carbonylation of methanol to dimethyl carbonate (DMC, 1) and dimethyl oxalate (DMO, 2) are currently very important key reactions. 1 is expected to be a safe carbonylation reagent to substitute for highly toxic phosgene for the synthesis of polycarbonate and isocyanates.1,2 2 is an intermediate for oxalic acid and is expected to reduce to ethylene glycol. Pd catalysis for the carbonylation of methanol is well-known.3 UBE Industries developed the chemical processes for the production of 1 and alkyl oxalate with Pd-catalyst and alkyl nitrite.4 The selectivities to 1 and 2 were drastically changed with additives and reaction conditions.5 We have recently reported the selective electrochemical carbonylation to 1 over a Pd/carbon anode.6 2 was a minor product, and its selectivity could not be controlled over the Pd anode.6,7 We have found new electrocatalysis of gold during the carbonylation studies. The selectivities to 2 and 1 could be controlled over the gold anode by an electrochemical potential.