Glycerol carbonylation with CO2 to form glycerol carbonate: A review of recent developments and challenges

The utilization of CO2 as a feedstock to produce valuable chemical products is an important area of research in the field of sustainable chemistry and climate change. It addresses the challenge of rising CO2 atmospheric levels and also the concern that the fossil fuels which are the major source of carbon-based raw materials used in the chemical industry are predicted to be depleted in the near future. This review examines the advances and challenges in the glycerol carbonylation with CO2 to produce glycerol carbonate. Glycerol is the main by-product of the biodiesel industry and its surplus is creating a lot of disposal challenges to this budding industry. Thus, its reaction with CO2 is very attractive because the process converts two wastes into a high value-added product. In this review, the nature and performance of different homogeneous and heterogeneous catalysts are discussed with respect to the attendant process conditions and their effects on conversion and selectivity in the reaction of CO2 and glycerol. Metal free catalyst systems for the same process have also been explored and their efficiency discussed. The presence of dehydrating agents has been found to play a key role in improving selectivity of glycerol carbonate formation when using a variety of catalyst systems. The role of other key reaction parameters such as solvent, pressure and temperature have also been highlighted. Mechanistic insights for the production of glycerol carbonate from CO2 and glycerol have been presented.