CO2 electro-valorization to dimethyl carbonate from methanol using potassium methoxide and the ionic liquid [bmim][Br] in a filter-press electrochemical cell

BACKGROUNDThe electrochemical valorization of CO2 into added-value products appears a promising strategy for reducing CO2 emissions and mitigating climate change. Dimethyl carbonate (DMC) is an environmentally friendly valuable chemical, with multiple applications, and has been suggested as a potential gasoline additive. However, DMC has traditionally been produced from hazardous phosgene and CO routes, which encourages the interest in developing new processes. The aim of this work is to study the valorization process for the direct electrosynthesis of DMC from CO2 and methanol using CH3OK and the ionic liquid 1-butyl-3-methylimidazolium bromide, avoiding the addition of carcinogenic compounds. RESULTSThe evolution of the concentration of DMC was studied in a filter-press electrochemical cell with anodic and cathodic compartments separated by a Nafion 117 membrane, operating for 48 h. A final DMC concentration of 15.07 mmol L-1 was observed. Analysis of the by-products obtained in the process revealed the formation of tetramethyl orthocarbonate and dimethoxymethane, which were detected and quantified in the liquid phase. A simplified reaction scheme was also proposed based on the results obtained. CONCLUSIONUnlike all previous work that used an undivided cell, the new experimental results of this study using a divided cell can serve as a reference for further research to overcome current limitations. (c) 2014 Society of Chemical Industry