Development of solid catalyst solid substrate reactions for efficient utilization of biomass

Abstract

The efficient catalytic conversion of lignocellulose is a formidable issue, but it is worth studying in terms of the high potential as renewable chemical feedstock. In this account, we describe our approach to convert solid cellulose with solid catalysts. We found that carbons bearing weak acid sites were active for the hydrolysis of cellulose. The catalyst produced glucose in up to 88% yield after the formation of good solidsolid contact, due to selective enhancement of the solidsolid interfacial reaction. We also developed a cyclic system to efficiently convert real lignocellulosic biomass. Mechanistic study has revealed that polycyclic carbon aromatics attract cellulose by CHp interactions mainly consisting of dispersion forces and hydrophobic interactions. The adsorbed cellulose molecules diffuse on the surface, rapidly penetrate even micropores, and undergo hydrolysis by weak acid sites such as carboxylic acids. Phenolic or carboxylic groups adjacent to the weak acid increase the frequency factor by forming hydrogen bonds. The combined functions of carbon derived from both polar and nonpolar groups achieve the hydrolysis of cellulose. Finally, we comment on future perspective to apply these findings.