Sulfonated Hydrothermal Carbon-Based Catalyzed Esterification under Microwave Irradiation: Optimization and Kinetic Study

Laddawan Tumkot (Chemical Engineering Research Unit for Value Adding of Bioresources, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Phayathai Road, Bangkok 10330)
Armando T. Quitain (Department of Applied Chemistry and Biochemistry, Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto 860-8555 International Research Organization for Advanced Science and Technology, Kumamoto University, Kumamoto 860-8555)
Tetsuya Kida (Department of Applied Chemistry and Biochemistry, Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto 860-8555)
Navadol Laosiripojana (The Joint Graduate School of Energy and Environment, King Mongkut’s University of Technology Thonburi, Prachauthit Road, Bangmod, Bangkok 10140)
Artiwan Shotipruk (Chemical Engineering Research Unit for Value Adding of Bioresources, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Phayathai Road, Bangkok 10330)
Panatpong Boonnoun (Chemical Engineering Program, Department of Industrial Engineering, Faculty of Engineering, Naresuan University, Phitsanulok 65000)

Bulletin of Chemical Reaction Engineering & Catalysis
2020: BCREC Volume 15 Issue 2 Year 2020 (August 2020)

In this study, the esterification reaction of oleic acid (OA) with methanol was investigated in the presence of a sulfonated hydrothermal carbon-based catalyst under microwave irradiation. The reaction conditions were optimized using response surface methodology based on a central composite design. Three following variables were studied: methanol to OA molar ratios (2.5:1–7.5:1), reaction time (50–70 min) and catalyst loading (2–5 wt.%) to provide a statistical model with the coefficient of regression (R2) of 0.9407. Based on the model, the optimum OA conversion of 95.6% was predicted at 5.8:1 methanol to OA molar ratio, 60 min and 3.05 wt.% catalyst loading. The experimental validation indicated that the model gave a good prediction of OA conversion (2.8% error). Furthermore, the reaction was found to be reasonably described by the pseudo-first order kinetics. The dependency of the reaction rate constant on temperatures gave a value of the activation energy of 64 kJ/mol. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).