Microwave-assisted Catalytic Transformation of Biomass to Platform Chemicals

Abstract

Lignocellulosic biomass is an emerging and renewable feedstock for biorefineries. Biomass valorization to platform chemicals through microwave technology, which offers a relatively mild and convenient protocol, has a futuristic demand towards a sustainable future. Thus, microwave (MW) conversion of biomass to bioenergy, biopolymers, and chemicals may be a promising approach to replace conventional and other thermochemical reactions in pressurized reactors. As a rising technology, MW heating reduces energy consumption and enables fast conversion processes with improved product quality and yield. MW heating was documented for its direct dielectric interaction with biomass substrates, providing advantages over conventional heating. In this chapter, we highlight the catalytic upgradation of biomass and biomass-derived molecules to platform chemicals, including furans (HMF and EMF), levulinic acid, levulinates (ML and EL), as well as xylitol and sorbitol as low-calorie sugars, employing metal nanoparticles, single metal atoms, metal oxides, and graphene oxide as catalysts. Eventually, we also discuss the significant challenges and drawbacks of MW-mediated reactions, including poor interactions of substrates with low-dielectric properties and the scope of large-scale applications, compared to pyrolysis and hydrothermal processes. Ultimately, this chapter concludes that waste biomass is the benchmark raw material for a controlled circular bioeconomic route.