Kinetic study of the esterification process catalyzed by ionic liquids for fatty acid methyl esters production
Conference Paper
Overview
Overview
abstract
Due to the massive use of energy from non-renewable sources, as well as to environmental problems, it is important to find green alternatives to energy production. In this context, biodiesel arises as a possible diesel substitute which can be produced using basic or acid catalysts. Despite these traditional catalysts allow high production yields, problems related to its use and the environmental impacts associated, result in the need to search for more sustainable alternatives. Ionic liquids (ILs), used as possible catalysts, represent an interesting alternative because they can be recovered and reused, being environmentally friendly.
The kinetics of the esterification of free fatty acids (FFA) using oleic acid and methanol, and 1-buthyl-3-methylimidazolium methyl sulfate, [BMIM][MeSO4], IL as catalyst is presented. All kinetics measurements were carried out for 8 hours, with a catalyst quantity of 10% w/w, and a molar ratio oleic acid/methanol of 1:10, using four different reaction temperatures (60, 80, 100 and 110°C), under stirring, temperature control and reflux. Throughout the reaction, and at predetermined times (0, 15, 30, 60, 90, 120, 180, 240, 300, 360, 420 and 480 min), 1 mL of sample was collected from the reaction vessel. The acidity value, expressed in mg KOH/g biodiesel, was determined immediately after the sampling using the experimental procedure according to European Standard EN 14104. The conversion of oleic acid, in percentage, was estimated by comparing the initial and final acidity values. It was considered for the calculation of the initial acidity value, the sample collected at time 0 min. The integral method was applied considering 0th, 1st, 2nd and 3rd order kinetics relating to oleic acid, for all temperatures. Therefore, the coefficients of determination (R2) were compared and the order of reaction was selected taking into account the highest value attained. Finally, the Arrhenius theory was used to predict the activation energy value.
