SYNTHESIS OF PROPYLENE CARBONATE BY HETEROGENEOUS CATALYST

Abstract

Propylene carbonate (PC) was synthesized by urea alcoholysis of propylene glycol (PG) in the presence CaO-MgO catalyst in an autoclave reactor. Different precipitating agents and Ca/Mg ratios were used for the catalyst synthesis and their influence on the catalyst performance were examined. The catalysts were characterized by thermogravimetric (TG/DTA) analysis, X-ray diffraction (XRD) analysis, field emission scanning electron microscopy (FE-SEM), Brunauer−Emmett−Teller (BET) analysis and Fourier transform infra-red spectroscopy (FTIR) techniques. The influence of reaction conditions on the synthesis of PC were analysed and the best results were obtained when the reaction temperature was kept at 160˚C for a time of 4 h, a catalyst dosage of 2 wt.% and (PG)/(urea) molar ratio of 4:1 was fed in the reactor. CaOMgO catalyst with the Mg/Ca ratio as 1 and prepared using Na2CO3 as precipitant displayed the best results of 96.8% PC yield, 99.8% PC selectivity and 96% conversion of urea under the optimal reaction conditions. Moreover, this catalyst could be reused up to 5 cycles without much change in the PC yield.