Basic ionic liquids promoted the synthesis of glycerol 1,2-carbonate from glycerol

Glycerol has been subjected to a transesterification process with dialkyl carbonate to generate glycerol 1,2-carbonate (GC) using different ionic liquids as catalysts under solvent-free conditions. The basic ionic liquids 1-butyl-3-methylimidazolium imidazolium ([Bmim]Im), 1-butyl-3- methylimidazolium hydroxide ([Bmim]OH), 1-allyl-3-methylimidazolium imidazolium ([Amim]Im), and 1-allyl-3- methylimidazolium hydroxide ([Amim]OH) worked well as catalysts compared with acidic ionic liquid and inorganic basic catalysts. Subsequent optimization of the reaction conditions using [Bmim]Im as a catalyst led to 98.4% glycerol conversion and up to 100% GC selectivity at 70 °C under ambient pressure. The recovery and reuse of these ionic liquids were also satisfactory. [Bmim]Im could be reused three times (i.e., 92.0% glycerol conversion and near 100% GC selectivity). This method exhibited several special features including a simple product isolation procedure, high product yield, exclusive selectivity, and mild conditions, as well as avoiding the use of any toxic catalysts.

Graphical AbstractThe transesterification of glycerol with DMC to generate glycerol 1,2-carbonate (GC) was investigated using basic IL [Bmim]Im as a catalyst. A glycerol conversion of 98.4% was achieved with up to 100% GC selectivity.Figure optionsDownload full-size imageDownload as PowerPoint slide