The value-added utilization of glycerol for the synthesis of glycerol carbonate catalyzed with a novel porous ZnO catalyst

Abstract

In the carbonylation reaction, a novel porous ZnO was prepared by a calcination method, and the raw material Zn glycerolate platelets were prepared via the glycerol approach, which could make use of a by-product of glycerol. To elucidate their composition, morphology, and properties, the resulting materials were characterized by FT-IR, XRD, SEM, BET, XPS, TPD and TG. The results showed that the catalyst was porous and irregularly shaped with appropriate acid and base properties; moreover, it displayed better catalytic performance for the synthesis of glycerol carbonate. The highest glycerol carbonate yield reached 85.97% of ZnO from zinc glycerolate under the optimal reaction conditions of 5.0 wt% of catalyst, 1 : 1.5 molar ratio of glycerol to urea and reacting at 140 °C for 6 h under 1 kPa. Comparing the three catalysts ZnO, zinc glycerolate and ZnO from zinc glycerolate, the maximum glycerol carbonate yield was 85.97% with the ZnO from zinc glycerolate as the catalyst under optimized operating conditions. Compared with the conventional ZnO, the as-prepared catalyst embodied in its porosity, acidity and basicity. The catalyst maintained excellent catalytic performance after 5 cycles with almost no loss of catalytic activity. This study revealed that ZnO from a zinc glycerolate catalyst is highly active, highly recyclable, remarkably stable, and environmental friendly for industrial applications. Overall, this new material overcomes the limitation of glycerol application and will have a good potential for industrial application.