Catalytic Cracking of Biomass-Derived Hydrocarbon Tars or Model Compounds To Form Biobased Benzene, Toluene, and Xylene Isomer Mixtures

The gasification of biomass is one of the most prominent technologies for the conversion of the raw material feedstock to polymers, useful chemical substances, and energy. The main engineering challenge during the processing of wastes is the presence of tars in gaseous reaction products, which could make this operation methodology unsuccessfully due to the blockage of separating particle filters, fuel line flow, and substantial transfer losses. Catalytic hydrocarbon cracking appears to be a promising developing approach for their optimal removal. However, it is still highly desirable to enhance the catalysts' activity kinetics, selectivity, stability, resistance to (ir)reversible coke deposition, and regeneration solutions. The purpose of this Review is to provide a comparative systematic evaluation of the various natural, synthetic, and hybrid ways to convert the model molecular compounds into benzene, toluene, xylene, (poly)aromatics, syngas, and others. The recent scientific progress, including calcite, dolomite, lime, magnesite, olivine, char, nonmetallic activated carbons, supported alkali, noble, and transition metals, and (metal-promoted) zeolites, is presented. A special concentrated attention is paid to effectiveness, related to hydrogenation, peculiar pore structure, and formulations' suitable acidity. The role of catalysis is described, recommendations for prospective catalyzed mechanisms are provided, and future technical feasibility is discussed as well.