Catalytic conversion of lignocellulosic biomass to fine chemicals and fuels

Abstract

Lignocellulosic biomass is the most abundant and bio-renewable resource with great potential for sustainable production of chemicals and fuels. This critical review provides insights into the state-of the-art accomplishments in the chemocatalytic technologies to generate fuels and value-added chemicals from lignocellulosic biomass, with an emphasis on its major component, cellulose. Catalytic hydrolysis, solvolysis, liquefaction, pyrolysis, gasification, hydrogenolysis and hydrogenation are the major processes presently studied. Regarding catalytic hydrolysis, the acid catalysts cover inorganic or organic acids and various solid acids such as sulfonated carbon, zeolites, heteropolyacids and oxides. Liquefaction and fast pyrolysis of cellulose are primarily conducted over catalysts with proper acidity/basicity. Gasification is typically conducted over supported noble metal catalysts. Reaction conditions, solvents and catalysts are the prime factors that affect the yield and composition of the target products. Most of processes yield a complex mixture, leading to problematic upgrading and separation. An emerging technique is to integrate hydrolysis, liquefaction or pyrolysis with hydrogenation over multifunctional solid catalysts to convert lignocellulosic biomass to value-added fine chemicals and bio-hydrocarbon fuels. And the promising catalysts might be supported transition metal catalysts and zeolite-related materials. There still exist technological barriers that need to be overcome (229 references).

Quantitative Insights into the Fast Pyrolysis of Extracted Cellulose, Hemicelluloses, and Lignin

“…However, a number of concerns with regard to the quality of fast pyrolysis bio‐oil have been raised (i.e., instability, high variability in chemical composition, high water content, immiscibility with petroleum‐derived fuels, changing viscosity, phase separation) that prevent its upgrading for commercial applications 3. In particular, the high level of oxygen in fast pyrolysis oils requires the application of intensive post‐treatments to deoxygenate these liquids selectively, which has resulted in intense scientific activity in the field of catalytic fast pyrolysis4 and bio‐oil upgrading in the last decade 5. A considerable number of catalysts has been developed as a result of the chemical diversity of the components in bio‐oils 4.…”

Pre-treatment of biomasses using magnetised sulfonic acid catalysts

“…In addition, solid acid catalysts allow for simple separation from products by vacuum filtration or magnetic separation (Lai et al, 2011;Guo et al, 2013;Peña et al, 2014). Further, the catalysts may be used repeatedly for the reaction without neutralisation, therefore decreasing energy consumption and waste (Zhou et al, 2011). Hence, there is a growing interest in developing solid catalysts for pre-treatment of biomass.…”

“…In addition to being inexpensive, lignocellulosic biomass offers sustainability and a high potential to reduce greenhouse gas emissions (Perlack et al, 2005;Zhou et al, 2011). However, one of the main challenges in converting biomass into alcohols involves disruption of the complex structure of the biomass to obtain fermentable monomeric sugars (Kumar et al, 2009;Agbor et al, 2011).…”

Paper-like composites of cellulose acetate–organo-montmorillonite for removal of hazardous anionic dye in water

“…In addition, biopolymers are degradable in the natural system [24]. Among various biopolymers, cellulose is the most abundant one on earth [25]. Moreover, it can be converted into various derivatives through chemical reactions.…”