Synthesis of Glycerol Carbonate from Glycerol and Dimethyl Carbonate Catalyzed by Solid Base Catalyst Derived from Waste Carbide Slag

Jianye Wang,Yifeng Sun,Zhu Wang,Song Wang,Haifeng Liu

doi:10.1155/2021/9300442

Abstract

Na2CO3 was loaded onto waste carbide slag (CS) by impregnation-calcination method to prepare the solid base catalyst, which was used to synthesize glycerol carbonate (GC) by the transesterification of glycerol with dimethyl carbonate (DMC). The prepared catalysts were characterized by a scanning electron microscope (SEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Brunner−Emmet−Teller (BET) techniques. The catalyst 15 wt.% Na2CO3-CS-800, which was prepared by impregnating CS to the Na2CO3 solution with the concentration of 15 wt.% weight of CS and calcined at 800°C for 3 hours, showed an excellent catalytic ability. When it was applied in the catalytic synthesis of GC, 98.1% glycerol conversion and 96.0% GC yield were achieved in 90 mins at 75°C with the catalyst dosage of 3 wt.% to total reactants and the DMC to glycerol molar ratio of 5. More importantly, the loading of Na2CO3 can effectively improve the reusability of catalyst. The 15 wt.% Na2CO3-CS-800 can still achieve 83.6% glycerol conversion and 80.5% GC yield after five-time reuse. Meanwhile, under the same reaction conditions, the CS-800, which was obtained by calcining CS at 800°C for 3 hours, experienced significant activity reduction with only 15.2% glycerol conversion and 14.1% GC yield after five-time reuse. FTIR and XRD characterization revealed that CO32- might play a key role in preserving active catalytic CaO component by forming protective CaCO3 shell on the catalyst surface.

Highlights

The demand of human society for energy is increasing, but the nonrenewable fossil fuels on the earth are decreasing
Taking the catalyst nNa2CO3-CS800 as an example (Figure 1), when the DMC-to-glycerol molar ratio was 4 : 1, the reaction temperature was 75°C, reaction time was 120 mins, and catalyst dosage was wt.%, glycerol conversion, and GC yield increased to the highest point with the increase of Na2CO3 loading from 0 wt.% to 15 wt.%
The conversion of glycerol was 83.6% and the yield of GC was 80.5% even after five cycles of the reaction. This result indicated that the 15 wt.% Na2CO3-CS-800 exhibited a good reusability in the transesterification reaction of glycerol with DMC

Summary

Introduction

The demand of human society for energy is increasing, but the nonrenewable fossil fuels on the earth are decreasing. Catalyst plays an important role in the transesterification of glycerol with DMC Several factors, such as catalytic performance, separation efficiency, and environmental friendliness, should be considered in the selection of catalyst. [38] Since using waste to prepare material has the advantage of low cost, heterogeneous base catalysts derived from waste have attracted extensive attention in the field of GC synthesis [39]. These catalysts exhibit an outstanding catalytic performance in the synthesis of GC and could be recycled and reused.

Materials and Methods

Results and Discussion

Conclusions