Synthesis of Glycerol Carbonate from Glycerol and Dimethyl Carbonate Using Ionic Liquid Catalysts

Acidic, basic and neutral ionic liquids (ILs) were prepared by two-step method. Their IR and NMR spectra showed that their structures were in accordance with their theoretical structure. Then these ILs were used as catalysts in the Glycerol carbonate (GC) of glycerol with dimethyl carbonate (DMC). The results show that basic ILs have high catalytic activity compared with acidic or neutral ILs and inorganic basic catalysts in the reaction. Under the suitable conditions using [Bmin]lm as a catalyst led to the yield of GC reached 94%, glycerol conversion reached 96%, GC selectivity reached 97% at molar ratio of DMC to glycerol at 3: 1, mass fraction of ionic liquid 12% (omega), reaction temperature 80 degrees C and reaction time 70 min. The ionic liquid was stable, and its activity did not decrease after using for 8 times (i. e., 85% glycerol conversion and near 90% GC selectivity). The results showed that the basic ionic liquid is more ideal green catalyst in esterification reaction.