Esterification of palmitic acid using facile solid semiconductors and mesoporous 3d framework based catalyst photo catalyst

Abstract

Methyl palmitate, one of the most widely used fatty acid methyl ester, and one of the major components of biofuel, has found its applications in various industrial processes. This research work majorly revolves around the synthesis of methyl palmitate in a batch reactor using palmitic acid and methanol employing various heterogeneous catalysts. The synthesis of ester was primarily subjected by two processes; a conventional thermal synthesis process and by employing a low energy pathway of photocatalytic process. For carrying out conventional thermal esterification reactions, two solid catalysts were synthesized using different combination of Graphene Oxide (GO), mesoporous frameworks like MCM-48 and Chromium based Metal Organic Framework (Cr-MOF). These were, GO and MCM-48 based catalyst and GO and Cr-MOF based catalyst. In case of photocatalytic esterification reactions, four heterogeneous photo-catalysts were employed making use of titanium dioxide (P25 TiO2) in combination with other active species i.e. GO, MCM-48 and Cr-MOF. These were, MCM-48 and P25 TiO2 based catalyst, GO and P25 TiO2 based catalyst, GO-MCM-48 immobilised P25 TiO2 based catalyst and GO-Cr MOF impregnated P25 TiO2 based catalyst. The major reason for introducing photo-catalysts was that the esterification reactions are usually carried out at high thermal conditions which require a lot of energy; henceforth, in order to make the process overall energy efficient, an attempt has been made to carry out the reactions at room temperature (303±2K). Therefore, an attempt has been made to utilise low temperature conditions for the synthesis of methyl palmitate esters, ditching the conventional heat driven methods that require high amount of energy along with greater reaction completion time. Thus, making the overall process highly economical as well as environment friendly with a systematic consumption of power.