Titania impregnated mesoporous MCM-48 as a solid photo-catalyst for the synthesis of methyl palmitate: Reaction mechanism and kinetics

Abstract

The alarming rate of depletion in diesel resources, has led us in developing an energy efficient route for the synthesis of biodiesel that not only utilizes a substantially lower amount of energy but is also economical. Herein, a mesoporous MCM-48 based photo-catalyst impregnated with titania, was synthesized employing a one pot synthesis method to produce methyl palmitate which is known to be a major component of biodiesel.The reaction was carried out at room temperature, with 3% (w/v) of catalyst loading and 1:20 acid to alcohol molar ratio leading to a conversion of 95.9% in 4.5 h. The catalysts were analysed through FESEM-EDS, Mapping, BET, XRD, FTIR, TGA and UV-DRS with 0.5TMS5 demonstrating a high surface area of 219 m2/g along with 0.985 mmol/g of active acid sites. Furthermore, a detailed kinetic study of the reaction proved that it was kinetically controlled with an activation energy of 25.1 kJ/mol and also formed a basis for configuring a feasible reaction mechanism. The catalyst was also checked for its reusability showing its effectiveness up to 3 reaction cycles when used without activation and up to 10 cycles after activation. Hence, the catalyst manifested to be highly capable in achieving high conversions at minimal energy exhaustion.