The recent growth of the biodiesel industry has produced excess glycerol for which there is no market. This surplus glycerol offers an interesting opportunity to produce biomass-derived raw materials and chemical intermediates that have previously been manufactured from petroleum. If the surplus glycerol can be converted into a higher value product, the economics biodiesel production would be enhanced. This project aims to convert glycerol to glycerol carbonate, a versatile chemical that may be used as a solvent or additive by itself or as a platform chemical for other industries.

Lipases, which catalyze ester synthesis reactions in low water environments, were evaluated as biocatalysts for a reaction between glycerol and a dialkyl carbonate. Several lipases, dialkyl carbonate reactants, and solvents were considered. The conversion of glycerol to glycerol carbonate can be effectively catalyzed by lipases, particularly Candida antarctica lipase B. A solvent is not required for this reaction, but it can positively affect lipase activity. The rate of reaction as well as the product specificity differs for different dialkyl carbonate substrates.

When reacting with dimethyl carbonate in the presence of tert-butanol, glycerol conversion reached 72% with over 99% of the product being glycerol carbonate. The effects of dialkyl carbonate choice and solvent selection on lipase activity and product selectivity will be presented.