Renewable Resources Robert-Jan van Putten,†,‡ Jan C. van der Waal,† Ed de Jong,*,† Carolus B. Rasrendra,‡,⊥ Hero J. Heeres,*,‡ and Johannes G. de Vries* †Avantium Chemicals, Zekeringstraat 29, 1014 BV Amsterdam, the Netherlands ‡Department of Chemical Engineering, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands Stratingh Institute for Chemistry, University of Groningen, Nijenborgh 4, 9747 AG Groningen, the Netherlands DSM Innovative Synthesis BV, P.O. Box 18, 6160 MD Geleen, the Netherlands Department of Chemical Engineering, Institut Teknologi Bandung, Ganesha 10, Bandung 40132, Indonesia

Hydroxymethylfurfural, A Versatile Platform Chemical Made from Renewable Resources

In pursuit of more sustainable and competitive biorefineries, the effective valorisation of lignin is key. An alluring opportunity is the exploitation of lignin as a resource for chemicals. Three technological biorefinery aspects will determine the realisation of a successful lignin-to-chemicals valorisation chain, namely (i) lignocellulose fractionation, (ii) lignin depolymerisation, and (iii) upgrading towards targeted chemicals. This review provides a summary and perspective of the extensive research that has been devoted to each of these three interconnected biorefinery aspects, ranging from industrially well-established techniques to the latest cutting edge innovations. To navigate the reader through the overwhelming collection of literature on each topic, distinct strategies/topics were delineated and summarised in comprehensive overview figures. Upon closer inspection, conceptual principles arise that rationalise the success of certain methodologies, and more importantly, can guide future research to further expand the portfolio of promising technologies. When targeting chemicals, a key objective during the fractionation and depolymerisation stage is to minimise lignin condensation (i.e. formation of resistive carbon–carbon linkages). During fractionation, this can be achieved by either (i) preserving the (native) lignin structure or (ii) by tolerating depolymerisation of the lignin polymer but preventing condensation through chemical quenching or physical removal of reactive intermediates. The latter strategy is also commonly applied in the lignin depolymerisation stage, while an alternative approach is to augment the relative rate of depolymerisation vs. condensation by enhancing the reactivity of the lignin structure towards depolymerisation. Finally, because depolymerised lignins often consist of a complex mixture of various compounds, upgrading of the raw product mixture through convergent transformations embodies a promising approach to decrease the complexity. This particular upgrading approach is termed funneling, and includes both chemocatalytic and biological strategies.

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Chemicals from lignin: an interplay of lignocellulose fractionation, depolymerisation, and upgrading

Lignin is an abundant biopolymer with a high carbon content and high aromaticity. Despite its potential as a raw material for the fuel and chemical industries, lignin remains the most poorly utilised of the lignocellulosic biopolymers. Effective valorisation of lignin requires careful fine-tuning of multiple "upstream" (i.e., lignin bioengineering, lignin isolation and "early-stage catalytic conversion of lignin") and "downstream" (i.e., lignin depolymerisation and upgrading) process stages, demanding input and understanding from a broad array of scientific disciplines. This review provides a "beginning-to-end" analysis of the recent advances reported in lignin valorisation. Particular emphasis is placed on the improved understanding of lignin's biosynthesis and structure, differences in structure and chemical bonding between native and technical lignins, emerging catalytic valorisation strategies, and the relationships between lignin structure and catalyst performance.

Paving the Way for Lignin Valorisation: Recent Advances in Bioengineering, Biorefining and Catalysis.

Recent advancements in supercapacitor technology

Sustainable solvents are a topic of growing interest in both the research community and the chemical industry due to a growing awareness of the impact of solvents on pollution, energy usage, and contributions to air quality and climate change. Solvent losses represent a major portion of organic pollution, and solvent removal represents a large proportion of process energy consumption. To counter these issues, a range of greener or more sustainable solvents have been proposed and developed over the past three decades. Much of the focus has been on the environmental credentials of the solvent itself, although how a substance is deployed is as important to sustainability as what it is made from. In this Review, we consider several aspects of the most prominent sustainable organic solvents in use today, ionic liquids, deep eutectic solvents, supercritical fluids, switchable solvents, liquid polymers, and renewable solvents. We examine not only the performance of each class of solvent within the context of the...

Green and Sustainable Solvents in Chemical Processes

Our severe dependence on fossil resources for the production of fuels and chemicals is responsible for two major global challenges: declining the fuel supply and increasing the anthropogenic greenhouse gas emissions. Conversion of biomass to fuels and chemicals can be a part of the low-carbon solution to both issues. Among various biomass species, inedible biomass such as lignocellulosics is the preferred choice for such applications due to their minimal impact on the food security. While technologies for the conversion of carbohydrates to value-added materials such as pulp, sugar monomers, and ethanol are well-established, lignin upgrading and valorization processes are significantly less-developed, and technical lignins are almost entirely burnt to generate heat and steam. The economic viability of biorefineries – which will receive significant amounts of lignin in future – can potentially improve significantly when advanced technologies are available that aid the conversion of lignin to value-added compounds. In this paper we assess how thermochemical processes can be used to isolate lignin from the lignocellulosic biomass, and subsequently convert it to liquid fuels, hydrogen, and aromatic monomers. To this end, different depolymerization, gasification and upgrading technologies for lignin conversion will be considered. Finally, the foreseeable applications of lignin-based products, the future directions for development, and the potential supportive interventions from policy makers are critically assessed.

Liquid fuels, hydrogen and chemicals from lignin: A critical review

Review of heterogeneous catalysts for sub- and supercritical water gasification of biomass and wastes

Increasing population has posed insurmountable challenges to agriculture in the provision of future food security, particularly in the Middle East and North Africa (MENA) region where biophysical conditions are not well-suited for agriculture. Iran, as a major agricultural country in the MENA region, has long been in the quest for food self-sufficiency, however, the capability of its land and water resources to realize this goal is largely unknown. Using very high-resolution spatial data sets, we evaluated the capacity of Iran's land for sustainable crop production based on the soil properties, topography, and climate conditions. We classified Iran's land suitability for cropping as (million ha): very good 0.4% (0.6), good 2.2% (3.6), medium 7.9% (12.8), poor 11.4% (18.5), very poor 6.3% (10.2), unsuitable 60.0% (97.4), and excluded areas 11.9% (19.3). In addition to overarching limitations caused by low precipitation, low soil organic carbon, steep slope, and high soil sodium content were the predominant soil and terrain factors limiting the agricultural land suitability in Iran. About 50% of the Iran's existing croplands are located in low-quality lands, representing an unsustainable practice. There is little room for cropland expansion to increase production but redistribution of cropland to more suitable areas may improve sustainability and reduce pressure on water resources, land, and ecosystem in Iran.

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Iran's Land Suitability for Agriculture

Catalytic conversion of biomass using solvents derived from lignin

In this study, the catalytic activity and hydrogen selectivity of Ni/α-Al 2 O 3 , Ni/hydrotalcite, Raney nickel, Ru/C and Ru/γ-Al 2 O 3 catalysts for hydrothermal hydrogen production from lignocellulosic biomass have been evaluated. The feedstocks included glucose, cellulose, fructose, xylan, pulp, lignin and bark. The experiments were carried out at 380 °C in a batch reactor with 2 wt% feed concentration. It was found that the gasification of glucose, fructose, cellulose, xylan and pulp resulted in comparable gas yields (±10% at 60 min), whereas lignin was substantially harder to gasify. Interestingly, gasification yield of bark which has a high lignin content was comparable to those of carbohydrates after 60 min reaction time. For a given feedstock, catalyst type affected both the gasification yield and the product distribution. Ni/α-Al 2 O 3 and Ni/hydrotalcite catalysts were not only highly active for the gasification of carbohydrates, but also had better hydrogen selectivity when compared to Raney nickel, Ru/C and Ru/γ-Al 2 O 3 . In particular, gasification of bark in the presence of these catalysts resulted in negligible amounts of alkanes.

Pooya Azadi

Papers

Liquid fuels, hydrogen and chemicals from lignin: A critical review

Review of heterogeneous catalysts for sub- and supercritical water gasification of biomass and wastes

Iran's Land Suitability for Agriculture

Catalytic conversion of biomass using solvents derived from lignin

Hydrogen production from cellulose, lignin, bark and model carbohydrates in supercritical water using nickel and ruthenium catalysts