Optimization and kinetic study of biodiesel production through esterification of oleic acid applying ionic liquids as catalysts

Abstract

In this study, 1-methylimidazolium hydrogen sulfate, [HMIM]HSO 4 , ionic liquid, was successfully applied as a catalyst in the biodiesel production through the esterification reaction of oleic acid with methanol. A response surface methodology (RSM) known as Box-Behnken Design (BBD) was applied to optimize the main experimental reaction conditions, using a set of 27 experiments. This optimization was based on the maximization of both the conversion of oleic acid and the Fatty Acid Methyl Esters (FAME) content of the obtained biodiesel samples. It was concluded that the two most relevant parameters for both the conversion and the FAME content were the molar ratio between oleic acid and methanol and the catalyst dosage. Accordingly to the model, the optimum condition for the maximum conversion was determined as being 8 h, 110 ± 2°C, 15:1 M ratio methanol/oleic acid and a catalyst dosage of 15 wt%, resulting in a 95% conversion and for the maximum FAME content were 8 h, 110 ± 2°C, 14:1 M ratio and a catalyst dosage of 14 wt%, leading to a FAME content of 90%. The kinetics of the esterification reaction was also evaluated, and the experimental results were well described using a third-order reaction model. The kinetic parameters were experimentally determined, and the value of the activation energy was 6.8 kJ/mol and the pre-exponential factor was 0.0765 L 2 .mol −2 .min −1 confirming that the ionic liquid, [HMIM]HSO 4 , is a good alternative for replacing traditional catalysts for biodiesel production through esterification reaction.

Characterization of Dolomite Promoted by NaAlO2 and Application as Catalyst in Transesterification by Response Surface Methodology

“…Based on the fitting results in RSM‐BBD, the quadratic model shows the highest lack of fit p‐value (>0.05) and adjusted R 2 of 0.9847, which means the model can explain nearly 99% of variation in experimental values and only 1% of values are out of the predicted range. It is thus concluded to be significant and appropriate . Subsequently, the best fitting encoded equation of biodiesel yield and the four factors is expressed as Eq.…”

A kinetic study of the ultrasonically assisted ethyl esterification of fatty acids using an immobilized lipase catalyst and deep eutectic solvent

“…Considering the excessive addition of ethanol in the reaction system, the concentration of ethanol C b was much greater than the concentration of free fatty acid C a . Assuming that the reaction was irreversible, the reaction rate Equation (3) can be simplified as follows, consider $${k^{\prime}}C_b^\beta $$ as a constant term k 22 . According to the acid value and relative density of the raw oil, the amount and volume of free fatty acids were determined respectively, and then the concentration of free fatty acids in the raw oil was solved.…”

Advances in Enzyme and Ionic Liquid Immobilization for Enhanced in MOFs for Biodiesel Production

“…To confirm the effect of the IL acidic strength on biodiesel production, the potential of 1-methylimidazolium hydrogen sulfate ( ] loading to 15 wt % and the methanol/acid ratio to 15:1, the conversion of oleic acid increased to 95% after 8 h at 110 • C. A slight reduction in enzyme loading to 14 wt % reduced the biodiesel yield to 90% under the same operating conditions [153].…”