Heteropolyacids Based Heterogeneous Catalysts for the Transesterification of Triglycerides

Abstract

The energy requirement is essential for human life, and the majority of need had been placed on non-renewable materials such as carbon fuels. Within that scenario, biofuel has become a feasible substitute for traditional diesel fuel which is also environmentally beneficial. In essence, biodiesel is made by transesterifying triglycerides throughout the presence of solid heterogeneous, homogeneous, or enzyme catalysts to produce methyl esters of fatty acid. NaOH and KOH, ordinary and conventional homogeneous basic catalysts, are incredibly effective for commercial-scale biodiesel generation. Though, that method delays the products that are contaminated with catalyst while producing a significant amount of waste material during the washing and refining procedures. As a result of their tolerance for water and free fatty acid, homogeneous alkali catalysts cannot be used to transesterify waste oils, necessitating the use of costly refined oil that has had free fatty acids and moisture freed from it. Supported heteropolyacids reusable and stable catalysts have gained enormous interest recently in an effort to circumvent the problems associated with uniphasic catalysts. In present thesis, three different heterogeneous catalysts K/TPA/Al2O3, K/TPA/SiO2, and K/TPA/GO were prepared. These catalysts were prepared utilising a wet impregnation process under normal air conditions rather than a severe hydrothermal method. The synthesized catalysts were characterised using a variety of analytical techniques, including powder XRD, FTIR, Raman, CO2 and NH3-TPD, TGA, FE-SEM, XPS, SEM-EDS, HRTEM, and Hammett indicator investigations. These catalysts were successfully applied to the generation of biodiesel from used cottonseed oil. Due to the generation of acidic and basic sites on its surface, the catalyst (K/TPA/Al2O3) was able to carry out the simultaneous esterification and transesterification reaction, and it took 1.25 h at 65 °C to complete the trans - esterification of used cottonseed oil (gt 97 0% biodiesel yield).