Ethers of Glycerol and Isoamylenes as Biodiesel Additives: Synthesis and Characterization

Abstract

The influence of reactants, solvents (tert-amyl alcohol, dioxane, glyme and diglyme) and temperature on the etherification reaction of glycerol with isoamylenes in the liquid phase catalyzed by a strong acid ion- exchange resin was studied. Reactions were carried out in a batch reactor autoclave at 1.5 MPa in the temperature range from 298 K to 373 K. It has been developed several methods for separation and isolation of products and various techniques of structural characterization (RMN, GC-MS, etc.) have been employed in order to obtain patterns that were used in the calculation of the conversion of glycerol and the composition of the final reaction mixture. It was found that there is a strong temperature influence on the process due to the polarity of employed solvents, resulting in a better conversion of glycerol for the most polar solvent (TAA) at low temperatures (313 K) and in a greater yield of di- and tri-ethers for the less polar solvent (dioxane) at higher temperatures (348 K), leading to different compositions of the products in the final mixture reaction depending on the initial molar ratio of solvents.