Zeolite Catalysts for Biomass Valorization: Tuning of active sites for promoting reactivity

Abstract

ABSTRACT Consumer demand for environmentally friendly products, government mandates and incentives have been driving the development of innovative solutions to produce fuels and chemicals using sustainable and renewable resources. As a result, valorization of biomass is increasingly gaining popularity as an alternative route to produce fuels and value-added chemical with lower carbon footprints. Many efforts have been made for the development of materials and processes for biomass valorization into useful intermediates using different bio-based platform molecules. In this context, zeolites, an important class of crystalline materials, have been exploited for biomass valorization, due to their ordered unique structural features and intrinsic acidic properties. The rational design of zeolites by modifying with alkali and alkaline earth metals is distinct to tune the acid-base properties by controlling the material porosity for the guest molecules adsorption aiming at the production of desirable chemicals. This review outlines the key mechanistic studies to consider when developing modified zeolites catalyzed chemical conversions especially involving the utilization of biomass and derived molecules, most of them being platform chemicals. The selected case studies are highlighted based on the mechanistic consideration to understand the involvement of active sites for active and reactive intermediates formation. A deeper understanding of the catalyst chemistry and formed active sites can be instrumental in guiding the development and invention of viable synthetic protocols for biomass transformations.