(49d) Intensification of Biofuel Synthesis by Microwave Irradiation

 The threats posed by the recent climate changes along with increasing global demand for energy call for environmentally benign and economically viable alternatives to fossil-derived fuels. Biodiesel and biomass-derivable ethyl tert-butyl ether (ETBE) are seriously being pursued as potential alternatives. In this regard, development of efficient and energy-saving methods for the production of these two most promising biofuels had been a subject of intensive global research in recent years.

 The application of microwave irradiation to intensify synthesis of the two above mentioned biofuels offer benefits including energy efficiency, development of a compact process, rapid heating and instant on-off process (instant heating-cooling process), among others. Unlike the conventional heating, the heat is generated within the material, thus rapid heating occurs. Besides, microwave effects on reaction also likely occur, thus obtaining dramatic increase in the yield even at low bulk temperatures.

  In this work, application of microwave for the intensification of heterogeneously catalyzed syntheses of the two biofuels was investigated. Results showed a significant increase in the yield of biodiesel even at short time less than 1 min, in which the attained bulk temperature did not reach 60^oC. For ETBE production, at a microwave power of 350W, and irradiation time of 1 min, the mixture reached solvothermal conditions obtaining EtOH conversion closed to 90%. The conversion and yield were found to be dependent on operating parameters such as temperature, microwave irradiation power, time and amount of catalysts.