Organic-inorganic hybrids of imidazole complexes of zinc (II) for catalysts in the glycerolysis of urea.

Bis(alkylimidazole) complexes of zinc, (RIm)2ZnX2, were prepared by a metal insertion reaction. The synthesized (RIm)2ZnX2 exhibited good catalytic performance during synthesis of glycerol carbonate (GC) from glycerol and urea. (HEIm)2ZnCl2 with a hydroxyl group exhibited the highest GC yield during glycerolysis of urea owing to incorporation of acid-base bifunctional active sites. (EIm)2ZnX2 catalysts based on different halide anions showed increased reactivity as Cl- < Br- < I-, which is the order of nucleophilicity. The effects of reaction parameters such as temperature, reaction time, catalyst loading, and degree of vacuum on the reactivity were also investigated.