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

Abstract 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.