共查询到18条相似文献,搜索用时 453 毫秒
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生物质是自然界中最丰富的可再生资源之一,将生物质转化为高附加值化工产品首先要进行生物质预处理,即利用物理、化学和生物等手段削弱细胞壁分子之间的作用,使生物质更容易降解。离子液体具有诸多优异的物理和化学性质,在众多领域引起了广泛关注,近年来在生物质预处理过程中同样展现出良好的效果。综述了近年来离子液体作为木质纤维素溶剂的主要研究成果,重点介绍了溶解机理方面相关研究。介绍了阴阳离子种类及氢键的影响,总结了木质纤维素与离子液体在分子水平上的相互作用机制,最后探讨了离子液体溶解生物质方面的发展前景。 相似文献
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《化工进展》2016,(10)
生物质资源的开发利用是解决资源危机和能源危机的重要途径,但传统的生物质组分分离工艺效率较低且污染严重,极大地制约了生物质资源的高值化利用。作为一类新型溶剂,离子液体可以溶解纤维素、木质素和天然生物质材料,为生物质的组分分离及加工转化提供了有力的工具。本文简述了离子液体在生物质组分分离中的应用,包括离子液体作为溶剂直接从木质纤维素类生物质中提取分离纤维素和木质素,以及在离子液体介质中通过化学反应降解生物质来分离主要组分的方法。从离子液体优选、反应路径设计、生物质预处理、溶解条件和再生剂等方面分析了生物质组分分离工艺。成本高、效率低且容易引起二次污染是阻碍离子液体用于生物质组分分离的主要因素。为了提高生物质组分分离的经济性和绿色性,今后应着力设计低成本、低黏度、热稳定性强和低毒的离子液体,研发绿色高效的生物质组分分离工艺和离子液体再生方法。 相似文献
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木质素是自然界中含量仅次于纤维素、唯一含有苯环结构的可再生生物质资源,对其进行有效的开发利用具有较高的经济价值和社会价值。离子液体作为一种新型绿色溶剂,在木质纤维素溶解方面展现了良好性能,本文粗略地概述了木质素的基本结构和性质,对木质素在离子液体中的溶解及改性等方面的研究进行了总结和综述,并在离子液体在木质素溶解降解方面应用研究的发展前景进行了分析讨论。 相似文献
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生物质是自然界中含量丰富且唯一可再生的有机碳资源,可以经过化学反应转化为高附加值碳基化学品和燃料,被认为是传统化石资源的理想替代品。催化材料的设计开发是生物质资源开发和利用的关键所在,离子液体因其独特的可设计性,在生物质资源利用过程中得到广泛应用。鉴于金属活性中心的催化活性以及离子液体的可设计性,将金属活性中心引入离子液体中制备金属基离子液体催化剂在生物质领域受到广泛关注,并取得一定进展。基于上述背景,本文综述了近年来金属基离子液体催化剂在生物质催化转化过程中的研究进展,重点介绍金属氯化物型、多金属氧酸盐型金属基离子液体在生物质基碳水化合物、木质素催化转化制备平台化学品,以及油脂催化(转)酯化制备生物柴油方面的研究进展;同时还综述了金属螯合物型金属基离子液体以及离子液体金属盐在生物质催化转化方面的研究工作。此外,对金属基离子液体在生物质资源方面的应用进行了总结和展望,并对金属基离子液体催化剂的设计提出建议,以期有助于生物质资源的开发和利用。 相似文献
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植物基因工程对生物燃料生物质特征的改进 总被引:2,自引:1,他引:1
全球每年有多达10~50Gt的廉价植物纤维素可再生利用。美国年产40亿加仑的乙醇,大多数是以玉米为原料生产的。目前多数利用微生物产生的纤维素酶对植物纤维素进行降解预处理,去除木质素,转化为可发酵的糖,进而生产乙醇。发酵前预处理及微生物反应器产酶成本都比较高。最新的植物基因工程研究致力于改善这种状况,降低成本,利用植物自身产纤维素酶和木质素酶来降解纤维素和木质素,或者提高生物质总产量或在植株中增产纤维素。 相似文献
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The separation of cellulose hydrolyzate and ionic liquids (ILs) as well as the recycling of ILs is very plagued and needs to be resolved urgently in cellulose hydrolysis. In this study, a temperature-sensitive phase-variable IL was employed to develop a new conversion method for cellulose. It was found that the IL exhibited favorable catalytic activity over six repeated runs, which only decreased by 9.10%. Additionally, a mechanism for this alcoholysis system was proposed. The study is aimed to provide a new scientific way for the cellulose conversion and extend the application of temperature-sensitive ILs in biomass field. 相似文献
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Ananda S. Amarasekara 《Israel journal of chemistry》2019,59(9):789-802
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. 相似文献
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Pablo Domínguez de María 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2014,89(1):11-18
Recent years have witnessed the use of different ionic liquids for biomass processing, either at the level of lignocellulose pre‐treatment, to fractionate biomass in its main components, separating hemicellulose and lignin from cellulose, or directly in cellulose decrystallization by dissolving it in the ionic liquid and subsequent precipitation by adding anti‐solvents. Yet, most of the ILs employed in these strategies (e.g. imidazolium‐based solvents) are (still) expensive for such applications, and provide discussable ecological footprints. In an attempt to combine the highly useful generated knowledge with novel neoteric solvents with improved properties, economics, availability and ecology, several new trends have appeared in these areas during recent years. They comprise the use of switchable ILs, based on strong organic bases and CO2, the application of distillable ILs, as well as the use of bio‐based and low‐cost ILs and deep‐eutectic‐solvents (DES), e.g. choline chloride‐based derivatives. Apart from other emerging uses, for all these solvents some preliminary applications in biomass processing involving pretreatments, cellulose dissolution and other applications have been successfully reported. This Minireview contextualizes these recent trends and discusses them with emphasis on future use of them in biorefineries and biomass valorization. © 2013 Society of Chemical Industry 相似文献
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F. Sáez M. Ballesteros I. Ballesteros P. Manzanares J. M. Oliva M. J. Negro 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2013,88(5):937-941
BACKGROUND: Lignocellulosic biomass offers many potential advantages in comparison with the traditionally used sugars or starchy biomass since it is very widely available and does not compete with food and feed production. The abundance and high carbohydrates content of barley straw make it a good candidate for bioethanol production in Europe. Since biomass must be pretreated before enzymatic hydrolysis to improve the digestibility of both the cellulose and the hemicellulose biomass, the use of ionic liquids (IL) has been proposed as an environment‐friendly pretreatment of biomass. RESULTS: Different pretreatment conditions were investigated to determine the effects of the experimental conditions (temperature and time) on the enzymatic digestibility of pretreated material. The pretreatment of barley straw with 1‐ethyl‐3‐methyl imidazolium acetate treatment resulted in up to a 9‐fold increase in the cellulose conversion and a 13‐fold increase in the xylan conversion when compared with the untreated barley straw. CONCLUSION: Ionic liquid pretreatment of barley straw at 110°C for 30 min, followed by enzymatic hydrolysis, leads to a sugar yield of 53.5 g per 100 g raw material. It is then ready available for conversion into ethanol and is equivalent to more than 86% from potential sugars. The increase in saccharification was possible due to rupture of the lignin–hemicellulose linkages by treatment with 1‐ethyl‐3‐methyl imidazolium acetate. © 2012 Society of Chemical Industry 相似文献
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木质纤维素转化燃料乙醇一般需要经过原料预处理、酶水解和发酵过程。由于木质纤维原料化学结构复杂、直接酶解效率非常低,一般在酶水解之前需要进行适当的预处理以打破其致密结构,增加纤维表面积,提高后续纤维素酶的可及性。预处理程度直接影响纤维底物后续酶水解的效果。本文在木质纤维素常用预处理技术分析的基础上,重点讨论了3种相对高效的预处理技术:微波辅助离子液体预处理、两阶段深度共熔溶剂(DES)预处理和氯化铁预处理技术,分析了它们的优势、不足及发展现状。文中指出微波辅助离子液体预处理可有效解构木质素和半纤维素,破坏纤维素结晶区域,利于后续酶解,但微波加热过程会使离子液体分解和部分底物碳化。两阶段DES预处理可有效提高酶水解效率,但是预处理后原料中残留的DES可能会对后续反应中纤维素酶和微生物产生抑制作用。氯化铁预处理可有效破坏木质素与碳水化合物间的结合键,脱除底物中的半纤维素,而对木质素和纤维素降解较少,具有很好的发展前景。由于单一预处理技术的局限性,寻求低成本高效的联合预处理技术将是未来重点发展的方向。 相似文献
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木质纤维素生物质转化为生物燃料或化工产品一般需经历预处理、酶解及发酵过程,因其复杂的化学结构,在酶解前通常进行预处理以破坏其致密结构,提高酶与纤维素的可及性。深度共熔溶剂(DES)是一类新型的“绿色”溶剂,具有制备简单、价格低廉、性质可调、可生物降解、可循环使用等优势,可有效去除木质素组分,同时保留大部分纤维素,在生物质预处理方面具有巨大的潜力。本文介绍了DES的构成、分类及理化性质,总结了DES预处理对生物质组分的影响,并对预处理效果的影响因素如底物和DES的类型、溶剂黏度、温度、生物载量、微波及超声波辅助工艺和两阶段处理工艺等方面进行分析,探讨了DES和生物的相容性,最后针对DES存在的问题及缺点,提出了理性设计和大规模利用DES的机遇与挑战,本文可为实现生物质的低成本预处理和高价值利用提供新的思路。 相似文献