Esterification of Coconut Fatty Acid Distillate (COFAD) Using Hydrochloric Acid as Homogeneous Acid Catalyst: A Kinetic and Thermodynamic Analysis

Abstract:

Refined Coconut oil (RCNO) is the most used feedstock for biodiesel production, which undergoes alkali-catalyzed transesterification to produce fatty acid alkyl esters due to its low free-fatty acids (FFA) content. This study utilized coconut oil fatty acid distillate (COFAD) as an alternative feedstock to RCNO. As it contains high amounts of FFA, it is pretreated through acid-catalyzed esterification to derive fatty acid methyl esters. The kinetics of the hydrochloric acid catalyzed esterification was investigated with the conditions of 10:1 methanol-to-COFAD molar ratio, 5wt% acid catalyst loading (0.4729N with respect to reaction mixture), reaction temperatures at 45°C, 55°C and 65°C, and 2 hours reaction time. It was found that temperature had a positive effect on the reaction. The highest FFA conversion was observed when the reaction temperature was set to 65°C, where it reached 87%, and the activation energy of the reaction was 29690.96 J^.mol^-1. The highest conversion predicted by the kinetic model is approximately equal to 89%. A good fit of the experimental and calculated data was observed with r² > 0.96. Moreover, the spontaneity of the reaction, as well as the effect of water on the reaction, were identified through the determination of thermodynamic parameters. The esterification reaction was found to be spontaneous only at high temperatures.

• Periodical: Engineering Chemistry (Volume 12)
• Pages: 49-71
• DOI: https://doi.org/10.4028/p-6kVCnm
• Online since: December 2025
• Authors: Ian Dominic F. Tabanag*, Jae Michelle N. Cabo, Carla Bren S. Legarde, Sam Anthonette L. Suico, Jayhiel S. Malila
• Keywords: Acid-Catalyzed Esterification, Biodiesel, Coconut Oil Fatty Acid Distillate (COFAD/CFAD), Kinetics, Thermodynamics

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