Synergistic effect of active metal–acid sites on hydrodeoxygenation of lignin-derived phenolic compounds under mild conditions using Ru/C-HPW catalyst

Profitability and sustainability of future biorefineries are dependent on efficient feedstock utilization. It is essential to valorize lignin when using wood. We have developed an integrated biorefinery that converts 78 wt.% of birch into xylochemicals. Reductive catalytic fractionation of wood gives a carbohydrate pulp amenable to bioethanol production and a lignin oil. After extraction of lignin oil, the crude, unseparated mixture of phenolic monomers is catalytically funneled into 20 wt.% of phenol and 9 wt.% of propylene (on lignin basis) by gas-phase hydroprocessing/dealkylation, whereas the residual phenolic oligomers (30 wt.%) are used in printing ink as replacements for controversial para -nonylphenol. Techno-economic analysis predicts an economically competitive production, and life-cycle assessment estimates a lower CO 2 footprint relative to fossil-based production.

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). This journal is © The Royal Society of Chemistry 2011

This review provides critical analysis on various downstream processes to convert lignin derived feedstock into fuels, chemicals and materials. Despite the enormous research efforts in recent years regarding lignin depolymerisation and functionalisation, few commercial products are available. This review provides a summary and viewpoint of extensive research in the lignin-to-product valorisation chain, with an emphasis on downstream processing of lignin derived feedstock into end products. It starts with an introduction of available platform chemicals and polymeric derivatives generated from lignin via existing depolymerisation and functionalisation technologies. Following that, detailed analyses of various strategies for the downstream processing of lignin derived platform chemicals and materials into fuels, valued-added chemicals and functional polymers are provided. A concise techno-economic analysis of various downstream processes is conducted based on the market demand of the end product, economic potential and technological readiness, enabling the identification of processes that are potentially both economically competitive and commercially feasible, and shedding light on processes which deserve further technological development. We wish this review will stimulate further advances in the sustainable production of value-added products from lignin to integrate this invaluable “bio-waste” into the chemical/materials supply chain.