Effect of reaction conditions on the etherification between glycerol and tert-butyl alcohol over beta zeolite

Abstract

Introduction: Glycerol tert-butyl ethers (GTBEs) can be used as diesel additives due to their physico-chemical properties, such as flash point, viscosity, and cetane number. GTBEs were produced from the reaction between tert-butyl alcohol and glycerol using a stirred reactor at moderate temperatures. This study aims to discuss the effect of reaction conditions on the etherification between glycerol and tert-butyl alcohol.

Methods: In this work, the etherification of glycerol and tert-butyl alcohol was performed using beta zeolite (SiO2/Al2O3 = 360:1) under different reaction conditions, including different molar ratios, catalyst loadings, reaction times, and reaction temperatures, to evaluate glycerol conversion and product selectivity. Beta zeolite was characterized by infrared spectroscopy, X-ray diffraction, and NH3-TPD.

Results: The results showed that the suitable conditions for the synthesis of GTBEs using beta zeolite were a temperature of 80 °C, a tert-butyl alcohol/glycerol feed ratio of 12:1, a catalyst loading of 1:3 weight of glycerol, and a reaction time of 6 hours. Under these conditions, the highest glycerol conversion was 81.35%, the selectivity of the diether was 32.44%, and the overall yield of the diether was 26.39%.

Conclusion: Reaction conditions are important factors in tailoring glycerol conversion and product selectivity in the reaction between glycerol and tert-butyl alcohol.