Feasibility studies on Kinetics, thermodynamics, thermal analysis and physicochemical Characterization of Anacardium occidentale kernel oil methyl ester epoxidation-esterification, for use as bio-transformer fluid

Abstract

Epoxidation-esterification of fatty acid methyl ester obtained from Anacardium occidentale kernel oil (AOKO), its characterization, kinetics and thermodynamics were the main focus of this study. The methyl ester obtained via base catalyzed transesterification was used for epoxidation-esterification modification process. Epoxidation kinetics and thermodynamics constants were also investigated. The properties of the AOKO and epoxidized-esterified Anacardium occidentale kernel oil (AOKO) methyl ester (MAOKO^e) were determined using standard methods. Rate constant k for the epoxidation process was found to be in the range 4.15 ×${10}^{-5}$Lmol⁻¹s⁻¹ to 19.7 ×${10}^{-5}$Lmol⁻¹s⁻¹; while the activation energy Ea was 35.69 kJ/mol. ΔG, ΔH, and ΔS values for the epoxidation process were (131.59 to 144.40 kJ mol⁻¹), 32.97 kJ mol⁻¹, and $--$320.20 J mol⁻¹ K⁻¹, respectively, indicating non-spontaneous, endothermic, and endergonic nature of the process. The physicochemical characteristics of MAOKO^e were: 2 °C, 293 °C, 815 Kg/dm³, 7.54 mm²/s, 0.78 mgKOH/g, 0.92 mg/Kg and 42.23 KV, for pour point, flash point, density, viscosity, acid value, moisture content and dielectric strength, respectively. The MAOKO^e properties indicated its potential for use as bio-transformer fluid.