Chapter 12 - Sustainable approaches to selective hydrolysis of cellulose with robust crystalline structure into glucose promoted by heterogeneous acid catalysts

Abstract

With a progressive increase in global energy crisis and environmental concerns, sustainable resources for production of energy and chemicals have been much in emergent demands. Lignocellulosic biomass acts as one of various renewable and sustainable resources; it is available in abundance, is inexpensive, and has diverse advantages, because of which it is gained much attention as an alternative to fossil-based fuels, potent medical agents, or intermediate and industry chemicals. Cellulose isolated from cytoderm of vascular plants acts as a renewable and sustainable lignocellulosic biomass and has been developed into predominant sustainable biomass source. This has made biochemists pay much more attention to the process of cellulose hydrolyzed selectively into glucose under mild conditions, with excellent performance in selectivity and yield. Cellulose is regarded as a water-insoluble saccharide polymer; it has a robust crystalline structure and is composed of β-1,4-glycosidic bonds of D-glucose. In the last few years, the conversion of cellulose into various small organic molecules, especially for glucose or its derivatives, has received massive attention in the domain of sustainable and selective degradation. In selective degradation of cellulose into glucose, solid acid acting as potent catalysts is defined as heterogeneous catalyst in hydrothermal reactions. As compared to homogeneous catalysts, such as enzymes, dilute acids and supercritical water, a heterogeneous catalyst performs better separation of products and catalysts, flexibly recycles waste fluids, and has ease in reaction-based operation conditions.