USE OF PROTIC IONIC LIQUID ([DETA][Hx]) AS CO-SOLVENT IN BIODIESEL PRODUCTION

Abstract

The need to develop sustainable alternative energy resources becomes an imperative as conventional energy sources are depleted. Ionic liquids (ILs) have acquired notoriety in several applications because of their interesting characteristics, such as favoring solubilization in organic substances, and presenting low surface tension and volatility. Aprotic ionic liquids (AILs) are used commonly as catalysts in biodiesel production. To achieve good results, considerable amounts of these compounds must be used in the reaction, which may affect the feasibility of the process due to its high cost. In this context, protic ionic liquids (PILs) may represent a less expensive alternative to traditional catalysts. When examining the surfactant activity of the ILs, one can observe that low concentrations can be applied to improve the yield of the reaction. Therefore, this study evaluates the use of diethylenetriammonium hexanoate ([DETA][Hx]), a protic ionic liquid, as a co-solvent in the alkaline transesterification of soybean oil. The research presented satisfactory results, indicating that the use of small amounts of co-solvents enhances biodiesel yield in 8.14%, reaching around 96% with only 3% (w/w) of [DETA][Hx] in 60 minutes of reaction, meeting the specifications of European (EN 14214), American (ASTM D6751), and Brazilian (ANP 45/2014) standards.