Application of Biomass-Derived Catalyst

Abstract

Due to the high cost and complex synthesis of existing heterogeneous-base catalysts such as supported alkaline catalysts, alkali earth oxides, mixed metal oxides, dolomites, perovskite-type catalysts, zeolites, hydrocalcites etc., carbon-based sulfonated catalyst (CBSC) was widely studied and showed high catalytic activities in many chemical reactions, including hydrolysis, dehydration, esterification, alkylation, condensation, oxathioketalization, dimerization, benzylation, and trimethylsilylation. The enhanced activity of heterogeneous CBSC ascribed to the high stability of its acid sites, high density, carbon sheets hydrophobic property, existence of –OH and –COOH groups in its molecular structure and loose irregular network are some of the structural properties that are usually not present in the homogeneous catalyst. A variety of technique is used to characterize the catalysts structure. As both transesterification and esterification reactions are being simultaneously catalyzed by these catalysts, hence it is considered as a viable alternative for the production of biodiesel from the waste cooking oil or any feedstock having high free fatty acid (FFA) concentrations. Performance of various solid acid catalysts is influenced by method of preparation such as calcinations temperature within 500–800 °C range. The best way to produce biodiesel is provided by solid acid biomass-derived sulfonated catalyst. These solid acid catalysts are found to be recoverable and reusable which are more eco-friendly and greener than a catalyst in a liquid phase. Many research nowadays focused on production of biodiesel involving renewable “green catalyst” prepared either from biomass or from waste generated in the households.