Reactive distillation for synthesis of glycerol carbonate via glycerolysis of urea

Abstract

This study developed a new process for synthesis of glycerol carbonate via glycerolysis of urea by reactive distillation. Missing thermodynamic parameters were estimated by various group contribution methods. The results of Gibbs free energy showed that Gani's method provided the lowest deviation. Equilibrium and kinetic model parameters of the glycerolysis obtained from batch experiments were employed for the simulation of the reactive distillation using Aspen Plus®software. High conversion of glycerol was achieved by reducing reactant loss in distillate through an increase in the number of stripping and reaction stages and a decrease in the number of rectifying stages. Moreover, glycerol and urea in distillate were recycled to the reactive section by increasing reflux ratio to a reasonable value. The suitable design and operating parameters were achieved at 3 stripping stages, 3 reactive stages, no rectifying stage, reboiler heat duty of 15kW and reflux ratio of 2. This offered 93.6% conversion of glycerol, and 90.0% yield of glycerol carbonate with 100% purity in the final product. Compared with conventional in vacuo process, reactive distillation promoted glycerol conversion by 29.1% and saved in energy consumption by 37.1%. © 2013 Elsevier B.V.