Microwave Assisted Solvent-Free Catalytic Transesterification of Glycerol to Glycerol Carbonate

Authors: Wai Keng Teng, Gek Cheng Ngoh, Rozita Yusoff, Mohamed Kheireddine Aroua, Joe Shen Heng

Abstract:

As a by-product of the biodiesel industries, glycerol has been vastly generated which surpasses the market demand. It is imperative to develop an efficient glycerol valorization processes in minimizing the net energy requirement and intensifying the biodiesel production. In this study, base-catalyzed transesterification of glycerol with dimethyl carbonate using microwave irradiation as heating method to produce glycerol carbonate was conducted by varying grades of glycerol, i.e. 70%, 86% and 99% purity, that is obtained from biodiesel plant. Metal oxide catalysts were used with varying operating parameters including reaction time, DMC/glycerol molar ratio, catalyst weight %, temperature and stirring speed. From the study on the effect of different operating parameters it was found that the type of catalyst used has the most significant effect on the transesterification reaction. Amidst the metal oxide catalysts examined, CaO gave the best performance. This study indicates the feasibility of producing glycerol carbonate using different grade of glycerol in both conventional thermal activation and microwave irradiation with CaO as catalyst. Microwave assisted transesterification (MAT) of glycerol into glycerol carbonate has demonstrated itself as an energy efficient route by achieving 94.2% yield of GC at 65°C, 5 minutes reaction time, 1 wt% CaO and DMC/glycerol molar ratio of 2. The advantages of MAT transesterification route has made the direct utilization of bioglycerol from biodiesel production without the need of purification. This has marked a more economical and less-energy intensive glycerol carbonate synthesis route.

Keywords: Biodiesel, glycerol, glycerol carbonate, microwave irradiation.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1108839

References:

[1] Yang, F., M.A. Hanna, and R. Sun, Value-added uses for crude glycerol- -a byproduct of biodiesel production. Biotechnology for Biofuels, 2012. 5(1): p. 1-10.
[2] Quispe, C.A.G., C.J.R. Coronado, and J.A. Carvalho Jr, Glycerol: Production, consumption, prices, characterization and new trends in combustion. Renewable and Sustainable Energy Reviews, 2013. 27(0): p. 475-493.
[3] Nguyen, N., Economic Analysis of Biodiesel and Glycerol Carbonate Production Plant by Glycerolysis. Journal of Sustainable Bioenergy Systems, 2013. 3(03): p. 209.
[4] Teng, W.K., et al., A review on the performance of glycerol carbonate production via catalytic transesterification: Effects of influencing parameters. Energy Conversion and Management, 2014. 88(0): p. 484- 497.
[5] Patil, P.D., et al., Microwave-Assisted Catalytic Transesterification of Camelina Sativa Oil. Energy & Fuels, 2009. 24(2): p. 1298-1304.
[6] SDA. Glycerine—An Overview. The Soap and Detergent Association, Glycerine and Oleochemical Division, 1990, 27.
[7] Perry, R. H., Green, D. W., & Maloney, J. O., 2008. Perry's chemical engineers' handbook (Vol. 7): McGraw-Hill New York.
[8] Gude, V., et al., Microwave energy potential for biodiesel production. Sustainable Chemical Processes, 2013. 1(1): p. 5-36.
[9] Pan, S., et al., Transesterification of Glycerol with Dimethyl Carbonate to Glycerol Carbonate over Na–based Zeolites. Chinese Journal of Catalysis, 2012. 33(11–12): p. 1772-1777.
[10] Ochoa-Gómez, J.R., et al., Synthesis of glycerol carbonate from glycerol and dimethyl carbonate by transesterification: Catalyst screening and reaction optimization. Applied Catalysis A: General, 2009. 366(2): p. 315-324.
[11] Simanjuntak, F.S.H., et al., CaO-catalyzed synthesis of glycerol carbonate from glycerol and dimethyl carbonate: Isolation and characterization of an active Ca species. Applied Catalysis A: General, 2011. 401(1–2): p. 220-225.
[12] Islam, A., et al., Advances in solid-catalytic and non-catalytic technologies for biodiesel production. Energy Conversion and Management, 2014. 88(0): p. 1200-1218.
[13] Khayoon, M.S. and B.H. Hameed, Mg1+xCa1−xO2 as reusable and efficient heterogeneous catalyst for the synthesis of glycerol carbonate via the transesterification of glycerol with dimethyl carbonate. Applied Catalysis A: General, 2013. 466(0): p. 272-281.