Glycerol transesterification with ethyl acetate to synthesize acetins using ethyl acetate as reactant and entrainer

Document Type: Research Paper

Authors

1 Department of Chemistry, Isfahan University of Technology, Isfahan, 84156-83111, Iran.

2 R&D Department, Farzin Chemicals Sepahan Co., Montazerie Industrial Complex, Villashahr, Isfahan, 85131-14461, Iran.

Abstract

Transesterification of glycerol with ethyl acetate was performed over acidic catalysts in the batch and semi-batch systems. Ethyl acetate was used as reactant and entrainer to remove the produced ethanol during the reaction, through azeotrope formation. Since the azeotrope of ethyl acetate and ethanol forms at 70 oC, all the experiments were performed at this temperature. Para-toluene sulfonic acid, sulfuric acid, and Amberlyst 36 were used as catalyst. The effect of process parameters including ethyl acetate to glycerol molar ratio (6-12), reaction time (3-9 h), and the catalyst to glycerol weight (2.5-9.0%), on the conversion and products selectivities were investigated. Under reflux conditions, 100% glycerol conversion was obtained with 45%, 44%, and 11% selectivity to monoacetin, diacetin, and triacetin, respectively. Azeotropic reactive distillation led to 100% conversion of glycerol with selectivities of 3%, 48% and 49% for monoacetin, diacetin, and triacetin. During the azeotropic reactive distillation, it was possible to remove ethanol to shift the equilibrium towards diacetin and triacetin. Therefore, the total selectivity to diacetin and triacetin was increased from 55% to 97% through azeotropic distillation. 

Graphical Abstract

Glycerol transesterification with ethyl acetate to synthesize acetins using ethyl acetate as reactant and entrainer

Highlights

  • Novel strategy for biodiesel glycerol valorization was introduced.
  • Transesterification of glycerol with ethyl acetate was investigated using ethyl acetate as reactant and entrainer.
  • Removal of ethanol from the reaction medium increased triacetin selectivity by about 39%.
  • Sulfuric acid showed the highest selectivity to the most desirable products, i.e., diacetin and triacetin.

Keywords