Study of glycerol etherification with ethanol in fixed bed reactor under high pressure

The aim of this work was to optimize the reaction parameters for the glycerol etherification with ethanol in a fixed bed pressurized reactor using Amberlyst 15 as a catalyst. A three factor central composite design was proposed to study the effect of reaction temperature (180-250 °C), ethanol/glycerol molar ratio (4-20/1) and amount of catalyst (0-0.80 g) over the glycerol conversion and yield of ethers. Analysis of variance (ANOVA) was used to evaluate the significance of the independent variables and their interactions. The correlations between reaction parameters and response variables were made by regression models. Among the variables screened, the reaction temperature and catalyst amount were statistically significant in glycerol conversion and ethers yield. The optimum levels of the parameters on yield of ethers were: temperature (238 °C), ethanol/glycerol molar ratio (16/1) and catalyst amount (0.61 g). Experimental verification of the predicted optimum conditions for yield of ethers gave the unprecedented response of 56%. These results indicated that the models were capable in describing the actual experimental data. Therefore, a process using a fixed bed high-pressure reactor has the potential to be used in glycerol transformation into ethers.