Transesterification of used cooking oil (UCO) catalyzed by mesoporous calcium titanate: Kinetic and thermodynamic studies

Abstract

Due to the superior catalytic property of calcium oxide in biodiesel production via transesterification, it is necessary to modify such catalyst to retain the catalytic property while overcoming the disadvantages related to the catalyst application in the process. The present study focused on the kinetic and thermodynamic studies on the transesterification of used cooking oil (UCO) catalyzed by mesoporous calcium titanate (MCT). The experiments were performed at room temperature, 65 °C, and 100 °C. Among the various models being studied, the Pseudo First order is the best model to describe the reaction kinetic. Data analysis showed that the rate constants, k, varied in the range of 0.0233–0.058 s−1, while the activation energy, Ea was determined to be 21.25 kJ·mol−1. The following parameters were also obtained: −24 kJ·mol−1 for enthalpy (ΔH), −0.16 kJ·mol−1.K−1 for entropy (ΔS) and 25.62–35.70 kJ·mol−1 for Gibb's free energy (ΔG). The results showed that the reaction was exothermic (ΔH < 0), and that the biodiesel oxidation reaction is non-spontaneous and endergonic in nature (ΔG > 0). This study demonstrates the potential of MCT catalyst in promoting the conversion UCO into biodiesel with high quality fuel properties.