木质素催化解聚的研究进展

木质素是一种芳环结构来源丰富且价格低廉的可再生资源。从木质素出发催化解聚制备单酚类高附加值精细化学品和芳香烃烷烃等高品位生物燃料,可以部分替代以化石燃料为原料的生产过程,是生物质资源全组分高效综合利用的重要组成部分。在木质素催化解聚方法中,催化氢解可以直接将木质素转化为低氧含量的液体燃料,在生物燃料利用方面展现出巨大的潜力。本文详细总结了木质素的催化解聚方法,从催化剂类型、溶剂种类、反应机理及催化剂循环使用性等方面介绍了国内外的主要研究进展,着重阐述了木质素催化氢解方法。最后总结了当前木质素催化解聚过程中存在的难题,并对未来的技术发展提出了建议和展望。     

木质素制备生物液体燃料进展

木质素中含有丰富的芳环结构,可以作为可持续再生的原料用于生产高值能源及化工品。但由于木质素结构复杂,现阶段用于制备生物液体燃料仍处于探索阶段。本文首先介绍了木质素通过催化热解、催化氢解、催化氧化3种解聚方式制备生物液体燃料的进展,分析了当前解聚产物存在低碳原子数、高氧含量的不足而导致其难以投入生产使用的现状,指出应通过C—C偶联方法（包括羟醛缩合、烷基化反应、寡聚反应以及Diels-Alder 反应）增加产物碳原子数、使用加氢脱氧（hydrodeoxygenation, HDO）工艺以降低产物氧含量,从而实现由木质素制备高密度生物液体燃料。最后对当前木质素制备高密度燃料所面临的挑战以及未来研究趋势进行了总结与展望,指出构建高效催化体系,耦合解聚、C—C偶联和HDO过程,将是该领域未来研究重点。     

The Role of Electrochemistry in Future Dynamic Bio‐Refineries: A Focus on (Non‐)Kolbe Electrolysis

The vision of a circular economy with closed carbon dioxide cycles is inevitably connected to a change of raw materials. Non‐edible biomass is an attractive carbon source for chemical industry. Brought together with renewable energy, the electrocatalytic transformation of biomass‐based feedstocks enables to directly integrate renewable electrical energy into chemical value chains. Considering the major role of natural carboxylic acids, the well‐known Kolbe and non‐Kolbe electrolysis attract increasing interest as versatile tools to valorize renewable feedstocks providing access to both biofuels and bulk or fine chemicals. They allow via decarboxylation access either to the corresponding dimerization product or the terminal alkene. Here, the electrochemical valorization of biomass is discussed with special emphasis on the possible role of (non‐)Kolbe electrolysis in a future electrified biorefinery.     

木质素解聚和液相催化降解研究进展

木质纤维生物质作为地球上最丰富的可再生资源, 不仅储量巨大而且在利用过程中具有碳平衡的显著优势, 已逐渐成为最具发展前景的可再生能源之一。木质纤维中的木质素是自然界最大且唯一的可再生芳香族化合物原料, 在生物质燃料转化, 尤其是解聚生产苯系化工产品等领域具有极为重要的作用和意义。本文在简述木质素化学结构的基础上, 综述了近年来木质素高温热解聚, 生物酶解聚, 催化热解聚, 光催化解聚和溶剂热解聚等解聚方法, 深入分析了液相催化过程中酸、碱催化体系, 加氢和氧化催化体系的机理及优缺点, 总结了现阶段木质素解聚方法中存在的问题, 并对未来的发展方向进行了展望。     

Integrated chemo- and biocatalytic processes: a new fashion toward renewable chemicals production from lignocellulosic biomass

Concerns over climate change and environmental pollution resulting from petroleum refining has spurred the exploitation of green replacements for producing chemicals and fuels. Valorization of lignocellulosic biomass into chemicals represents a promising alternative to petroleum refining. Biological and chemical catalysis are two leading routes for lignocellulose variolization, but strategies relying simply on biological or chemical conversion have shown limitations. Integrating biocatalysts with chemocatalysts could leverage the inherent strengths of both while circumventing their respective disadvantages, benefiting product yield and selectivity, and reducing cost and waste generation. This review focuses on the coupled chemocatalytic and biocatalytic synthesis of renewable chemicals from polysaccharides and their derived platform chemicals. In addition, strategies for producing value-added products from lignin via integrated chemical depolymerization and biological conversion are highlighted. The techno-economics of integrating chemocatalysts and biocatalysts in producing chemicals in the context of biorefinery are also discussed. Finally, perspectives on designing integrated chemical and biological catalysis for renewable chemicals production are provided. © 2022 Society of Chemical Industry (SCI).     

Catalysis in biomass processing

Biomass has in recent years been considered as a raw material for the production of fuels and chemicals. This work discusses the reasons for the increased interest in mainly lignocellulosic biomass. Gasification, pyrolysis, and depolymerization by hydrolysis are analyzed as key biomass technology. We also discuss which of the sugars obtained via depolymerization by hydrolysis can be processed into fuel or key intermediates of the chemical industry. Lignocellulosic biomass contains such extractants as fatty acids and terpenes, and we therefore describe the catalytic reactions of these substances for the synthesis of fuels and chemicals. Some typical reactions of biomass processing (oxidation, hydrogenation, cracking, etc.) are conceptually close to the process widely known in the refining and chemical industries. There are, however, other considerations due to, e.g., the large number of functional (hydroxyl and other) groups, and the processing of biomass components therefore requires dehydration, aldol condensation, ketonization, decarboxylation, etc. We cover the fundamentals of the approaches to selecting catalysts for these reactions.     

Innovative and intensified technology for the biological pretreatment of agro waste for ethanol production

Lignocellulosic biomass is an abundant, renewable resource, but the structural and chemical complexity of biomass acts as a hindrance in its effective utilization for cellulosic ethanol production. Hence, effective pretreatment is always necessary to remove the surrounding matrix of lignin prior to the enzymatic hydrolysis. Pretreatment of rice straw by Pleurotus florida was found to be effective and resulted in 49% lignin degradation, whereas fungus along with grape leaves resulted in 99% lignin degradation. This method not only explores a pathway for utilizing the solid agro waste but also results in a value-added product of edible mushrooms that has proved to be the best pretreatment technology for ethanol production. FTIR and SEM analysis confirmed the structural transformation taking place during the pretreatment. The components of grape leaves were also analyzed using GC-MS.     

木质素的催化加氢转化

木质素是来源于木质纤维素的一种重要的可再生生物质资源,可用于制备化学品和燃料。由于木质素本身结构的复杂性和稳定性使其难以有效利用。目前大量的制浆和造纸工业的木质素没有得到有效利用,大部分用于燃烧供能,并且造成了一定程度的环境污染。为了保护环境、实现可持续发展,催化转化木质素制备高附加值化学品成为了研究的热点。木质素转化的研究众多,但是进展依然相对缓慢。目前主要的转化方法包括碱催化解聚、酸催化解聚、热化学转化、加氢处理解聚、氧化解聚等。由于加氢处理解聚木质素可以获得低聚木质素、酚类等有价值的化学品和制备烃类燃料,是目前研究的热点和最有效的方法之一。但是,催化剂失活和解聚产物产率不高等依然是需要进一步解决的问题。基于此,梳理了近年来木质素加氢处理主要的催化体系和相关结果,提出了尚待解决的问题,以期为今后建立有效的木质素解聚体系并实现其高值化利用的相关研究提供参考。     

生物质的电化学转化反应及反应器

生物质通过电化学转化合成燃料和高附加值化学品是未来化学工业发展的一个重要方向，也是现代社会实现可持续发展的重要保障。在可再生能源产能不断提升，而现阶段暂无成熟的大规模能源存储技术的背景下，如何有效地利用可再生能源所产电能进行生物质的电化学转化是目前学术界和工业界关注的一个热点。本文介绍了近年来该领域的研究进展，着重阐释了关键的电化学反应和相关反应器的设计。从生物质衍生的平台分子的电化学转化取得了一定的进展，然而从生物质到平台分子的电化学转化还面临较大的挑战。提高平台分子和生物质电化学反应的选择性有赖于合适的电极材料和催化剂，而将原位分离与电极反应耦合的设计能够提高产物的收率，特别是在生物质直接电化学转化的过程中。     

木质纤维生物质精炼中木质素的分离及高值化利用

木质纤维素作为最有前途的可再生资源,可替代现有的液体燃料。因此,木质素作为木质纤维生物质细胞壁的主要成分之一,由其开发的高附加值产品将大大提高从可循环利用生物质生产能源的经济性。本文回顾了自催化乙醇精炼技术的优势,相对于其他制浆技术不仅可以高效地从木质纤维生物质中分离出高活性的木质素,还可以获得高附加值的副产品(如糠醛、低聚糖、乙酰丙酸、甲酸、乙酸等)。同时,抽提液可循环利用。基于自催化乙醇精炼木质纤维生物质的特点,介绍了用自催化乙醇精炼所分离出的高活性木质素进行高值化利用的优势,以及用木质素生产高附加值产品的研究及利用,从而为木质纤维生物质中木质素在工业上大量开发利用提供了一条新的途径。     

化学法降解木质素为酚类化合物的研究进展

木质素是一种具有潜在巨大应用前景的可再生资源,其降解的酚类化合物产物是可替代部分仅依靠石油能源为主要来源的化工原料,故可缓解一定的石油能源压力。主要从化学法降解木质素的方法和防止降解物重聚两个角度综述木质素降解的研究现状,总结木质素降解存在的主要问题及对其未来的发展提出了展望。     

The Scent of Change: Sustainable Fragrances Through Industrial Biotechnology

Current environmental and safety considerations urge innovation to address the need for sustainable high-value chemicals that are embraced by consumers. This review discusses the concept of sustainable fragrances, as high-value, everyday and everywhere chemicals. Current and emerging technologies represent an opportunity to produce fragrances in an environmentally and socially responsible way. Biotechnology, including fermentation, biocatalysis, and genetic engineering, has the potential to reduce the environmental footprint of fragrance production while maintaining quality and consistency. Computational and in silico methods, including machine learning (ML), are also likely to augment the capabilities of sustainable fragrance production. Continued innovation and collaboration will be crucial to the future of sustainable fragrances, with a focus on developing novel sustainable ingredients, as well as ethical sourcing practices.     

Study on the catalytic degradation of sodium lignosulfonate to aromatic aldehydes over nano-CuO: Process optimization and reaction kinetics

As one of the few renewable aromatic resources, the research of depolymerization of lignin into high-value chemicals has attracted extensive attention in recent years. Catalytic wet aerobic oxidation (CWAO) is an effective technology to convert lignin like sodium lignosulfonate (SL), a lignin derivative, into aromatic aldehydes such as vanillin and syringaldehyde. However, how to improve the yield of aromatic aldehyde and conversion efficiency is still a challenge, and many operating conditions that significantly affect the yield of these aromatic compounds have rarely been investigated systematically. In this work, we adopted the stirred tank reactor (STR) for the CWAO process with nano-CuO as catalyst to achieve the conversion of SL into vanillin and syringaldehyde. The effect of operating conditions including reaction time, oxygen partial pressure, reaction temperature, SL concentration, rotational speed, catalyst amount, and NaOH concentration on the yield of single phenolic compound was systematically investigated. The results revealed that all these operating conditions exhibit a significant effect on the aromatic aldehyde yield. Therefore, they should be regulated in an optimal value to obtain high yield of these aldehydes. More importantly, the reaction kinetics of the lignin oxidation was explored. This work could provide basic data for the optimization and design of industrial operation of lignin oxidation.     

Ionic Liquids in Biomass Processing

The ionic liquids have emerged as new solvents and catalysts for processing biomass to value added chemicals and fuels. This review will present the recent developments in applications of ionic liquids in lignocellulosic biomass pretreatments, depolymerization, biodiesel synthesis, dehydration of carbohydrates to renewable feedstock chemicals as well as further transformations of biomass derived feedstocks such as furfural, 5‐hydroxymethylfurfural and levulinic acid to value added chemicals. In addition, the recycling of ionic liquids used in biomass processing is also discussed in the review.     

面向资源与环境的生物基化学品技术创新与展望

生物基化学品是以可再生的生物质为原料,以生物细胞或酶蛋白为催化剂合成的产品。由于摆脱了对化石原料的依赖,同时避免了石油基产品制备过程的高能耗高污染,为了资源和环境的绿色、可持续发展,以可再生的生物质资源为原料,以生物转化技术制备化学品是未来发展的主要趋势。本文对目前国内外生物基化学品研发及生产概况进行综述,预测生物基化学品制造业将朝着为原料多元化、生物转化过程高效化、产品高值化的方向发展,针对生物转化过程高效化的关键科学问题进行深入探讨,提出生物学科与其他学科交叉融合是生物基化学品制造技术未来的发展方向,包括生物技术自身融合、生物与化工技术融合及生物与过程控制技术融合。     

Progress in the hydrolysis of lignocellulosic biomass for fuel-thanol production

以木质纤维素生产燃料乙醇具有原料可再生性和环境友好的优点而备受重视。本文介绍了国内外木质纤维素制取燃料乙醇中的水解工艺过程,包括浓酸水解、稀酸水解和酶水解工艺,分析了各工艺的技术特点,同时指出稀酸预处理-酶水解工艺将成为近几年国内外研究和开发的重点。     

木质素氢解反应溶剂与催化剂研究进展

木质素是由三种苯丙烷单元随机键合形成的复杂大分子物质,是自然界中唯一可直接提供芳环的可再生能源。以木质素为原料制取高品位液体燃料和高附加值化学品,特别是木质素氢解是国内外关注的热门研究领域之一。梳理了近年木质素催化氢解研究进展,针对木质素氢解过程中溶剂体系（水溶剂以及醇类溶剂）和催化剂体系（均相催化剂以及非均相金属催化剂）对木质素氢解效率、产物分布的影响机理,做了较全面的概述和分析。最后,针对木质素催化氢解领域目前尚存在的问题提出建议,期望为木质素高值化利用相关研究提供参考。     

木质纤维素水解制取燃料乙醇研究进展

以木质纤维素生产燃料乙醇具有原料可再生性和环境友好的优点而备受重视.本文介绍了国内外木质纤维素制取燃料乙醇中的水解工艺过程,包括浓酸水解、稀酸水解和酶水解工艺,分析了各工艺的技术特点,同时指出稀酸预处理-酶水解工艺将成为近几年国内外研究和开发的重点.     

农业废弃物转化成能源及高附加值化学品的研究进展

在简单介绍农业废弃生物质主要组分及含量的基础上,概述了当前农业废弃生物质主要组分纤维素、半纤维素及木质素转化为乙醇、丙酮等生物能源以及糠醛、呋喃等高附加值化学品的国内外研究进展,并分析其在研究中存在的问题及未来发展方向。     

苯酚类分子选择性直接脱氧制备芳烃的研究进展

以生物质为原料生产可再生能源和化工产品是未来能源工业的重要发展方向。芳烃,尤其是苯、甲苯和二甲苯是目前运用十分广泛的大宗化学品,同时可作为一种辛烷值很高的汽油添加剂。木质素含有大量苯酚类分子（含氧芳烃）,以其为原料通过选择性直接脱氧制备芳烃具有很高的经济、社会效益,潜力巨大的同时也挑战重重。评述了硫化物、磷（氮、硼）化物、金属、金属氧化物、双金属合金、金属-沸石双功能催化剂等在酚类分子直接脱氧制备芳烃中的性能。综述了包括反应温度、压力、助剂、载体、硫化剂等因素对于催化反应的影响,指出了适合芳烃生产的催化剂和反应条件。