Formation of glycerol carbonate from glycerol and urea catalysed by metal monoglycerolates

Polymeric monoglycerolate complexes of zinc and cobalt can act as homogeneous catalysts for the one-pot synthesis of glycerol carbonate from glycerol and urea. Effects of reaction temperature, time and glycerol to urea molar ratios on glycerol carbonate selectivity and glycerol conversion have been analysed, with yields reaching 83% at 98% glycerol conversion. The proposed mechanism involves competing catalysed and uncatalysed pathways. In the catalysed pathway, an intermediate isocyanate complex, formed from reaction of urea with the metal monoglycerolate, undergoes rearrangement to form glycerol carbonate and ammonia.