Transesterification of soybean oil to biodiesel by anionic and cationic ion exchange resins

Abstract

This work reports the results of the evaluation of the commercial resins Amberlyst 15Wet (cationic resin) and Amberlyst-26OH (anionic resin), both with macroporous structures, on batch transesterification reactions of Brazilian soybean oil with methanol and ethanol. The influence of reaction conditions, such as type and amount of catalyst, reaction time and alcohol to oil molar ratio were investigated. The anionic resin was more efficient than the cationic resin for production of FAME (fatty-acid methyl esters) and FAEE (fatty-acid ethyl esters). The soybean oil conversion into FAME by employing the anionic resin was 100% employing 12.5 mol % of resin, methanol to soybean oil mole ratio of 100:1 and reaction time of 8 h. The methyl esters produced can be classified as biodiesel according to the standards of the Brazilian National Petroleum, Natural Gas and Biofuels Agency (ANP), European Standards (EN) and American Society for Testing and Materials (ASTM): ANP 14 (2012), ANP 07 (2008), ASTM 6751(2008) and EN 14214 (2003). For ethyl esters, some parameters, such as viscosity, water content and total glycerin, need to be optimized.