Chemical Conversion of CO2: Evaluation of Different Ionic Liquids as Catalysts in Dimethyl Carbonate Synthesis

Abstract

Dimethyl carbonate (DMC) synthesis from methanol and CO2was investigated using ionic liquids (ILs) as catalysts. ILs based on 1-alkyl-3-methyl imidazolium and N-alkylpyridine cations and [Cl−], [BF4−], [PF6−], [Tf2N−] anions were used in this study. Selectivity in DMC increased in the anion order: [Tf2N−] < [PF6−] < [Cl−] < [BF4−], following the same behavior for both cations. Methanol conversion was similar for all tested ILs. The best result for DMC selectivity (83%) was obtained when [emim][BF4] was used as catalyst. After 5 recycling tests, a loss of 8.5% in the catalyst activity was observed for [bmim][BF4].