Microwave-Assisted Noncatalytic Esterification of Fatty Acid for Biodiesel Production: A Kinetic Study

Abstract

This study developed a microwave-mediated noncatalytic esterification of oleic acid for producing ethyl biodiesel. The microwave irradiation process outperformed conventional heating methods for the reaction. A highest reaction conversion, 97.62%, was achieved by performing esterification with microwave irradiation at a microwave power of 150 W, 2:1 ethanol:oleic acid molar ratio, reaction time of 6 h, and temperature of 473 K. A second-order reaction model (R2 of up to 0.997) was established to describe esterification. The reaction rate constants were promoted with increasing microwave power and temperature. A strong linear relation of microwave power to pre-exponential factors was also established, and microwave power greatly influenced the reaction due to nonthermal effects. This study suggested that microwave-assisted noncatalytic esterification is an efficient approach for biodiesel synthesis.

Biodiesel Production by Heterogeneous Catalysis and Eco‐friendly Routes

“…Through this process, friction and collision occur between molecules, which generate heat. Reaction is achieved quickly under mild operational conditions and with smaller amounts of catalyst [58,[83][84][85][86][87]. Irradiation can be conducted continuously or pulsed [129,130] and applied to different feedstocks.…”

Green Energy Technology

“…Biofuel is one of the solutions for energy shortage and environmental threats. Nguyen et al [1] developed microwave-assisted noncatalytic oleic acid esterification for biodiesel production. The highest reaction conversion (97.62%) was achieved by the microwaveassisted esterification process.…”

“…This Special Issue of Energies on the subject of "Green Energy Technology" contains the successful invited submissions [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. A total of 17 technical papers that cover diversified green energy technology-related research have shown critical results and contributed significant findings in biofuel production [1], energy-saving in buildings [2], wind energy [3], energy policy [4], electricity supply [5], a thermal-hydraulic system [6], fluidized bed reactor [7], green-supply chains [8], SI engine [9], renewable energy grid [10], kinetic energy harvest [11], green hydrogen utilization [12], water conservation [13], hydraulic power [14], Illumination Performance in buildings [15], community renewable energy [16], and heat transfer [17].…”

Bio-Derived Catalysts: A Current Trend of Catalysts Used in Biodiesel Production

“…With an increasing demand for environmental protection, green processes have been rapidly developed for chemical production. Consequently, various ecofriendly processes have been proposed for producing biodiesel to reduce the adverse environmental effects [5,149]. Particularly, the enzyme-catalyzed reaction is one of the most promising processes for biodiesel production due to the ecofriendly and reusable nature of the enzyme.…”

“…Biodiesel is mainly synthesized from oils/fat (derived from plants, animals, and microorganisms) through the (trans)esterification process [3,4]. The efficiency of this process is mainly affected by several factors including the quality of feedstock (level of free fatty acids), the type of acyl acceptor (e.g., alcohols or methyl acetate), and the type of reactions (e.g., noncatalytic reaction, chemical-catalyzed reaction, and enzymatic reaction) [5,6]. To enhance the reaction efficiency, most studies focused on developing efficient catalysts for the (trans)esterification reaction.…”