Study On Catalysts For Electro-catalytic Oxidation Carbonylation Of Methanol To Dimethyl Carbonate

Dimethyl carbonate （DMC） is considered as an environmentally benign chemical, itsapplication field and consumption are increasing year by year. The electro-catalyticoxidation carbonylation method at atmospheric pressure and room temperature has theadvantage of mild reaction condition, clean synthesis process, easily controlled operatingparameters, good reaction selectivity and high purity of the product. But the catalyticactivity of the Cu（bipy）Cl complex is low, and CuCl unstable in air, its solubility inmethanol is low and the irritation to the skin is strong, thus, Cu（bipy）Cl is not suitable forindustrial production. Therefore, this paper mainly focuses on the catalyst of theelectro-catalytic method, to study the reaction process.In this paper, firstly, CuCl₂was employed to instead of CuCl to take part in theelectro-catalytic oxidation carbonylation of methanol to DMC at atmospheric pressure androom temperature. The electrochemical properties of the synthesis system were tested bycyclic voltammetry, the content of DMC in the anolyte and the selectivity of the reactionwere analysed by gas chromatography. In addition, the influence factors, such assupporting electrolyte, anode potential, the concentration of supporting electrolyte andCu（bipy）Cl₂were evaluated. Finally, a new reaction mechanism was proposed.Then, in order to improve the catalytic activity, based on the study of the complexcatalyst Cu（bipy）Cl₂, Phen was used to instead of bipy, to carry out the electro-catalyticoxidation carbonylation of methanol to DMC reaction at atmospheric pressure and roomtemperature. Similar to the Cu（bipy）Cl₂section, cyclic voltammetry was employed to testthe electrochemical properties of the catalytic system, FT-IR and UV spectra were used foranalyzing the coordination between CuCl₂and Phen. Moreover, the influence factors, suchas the concentration of Phen, reaction time, reaction temperature and the surface area of theworking electrode were studied.Experiments show that the electro-catalytic oxidation carbonylation of methanol toDMC can be achieved with high selectivity at atmospheric pressure and room temperaturewith Cu（bipy）Cl₂complexes as catalyst. When using Phen instead of bipy, the catalyticactivity of the complex is significantly improved. But in the process of the reaction, Phenwas degraded, thus result in the catalyst deactivation. The IR, UV characterization results of the complex catalyst showed that a copper ion was coordinated by nitrogen atoms ofPhen, the maximum coordination number between Phen and CuCl₂was2.