SGER - Fundamental Understanding of Catalytic Cleavage of Lignin in Ionic Liquids

SGER - 对离子液体中木质素催化裂解的基本了解

• 批准号: 0849342
• 负责人: John Ekerdt
• 金额: --
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-09-15 至 2010-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0849342&HistoricalAwards=false
• 关键词: SGER; Fundamental; Understanding; Catalytic; Cleavage

0849342EkerdtIntellectual Merit Lignin is one of the major components in lignocellulosic biomass. The recalcitrant nature of lignin toward microbial breakdown is a highly beneficial feature in guarding natural forestry from rapid degradation by nature itself. Even though nature has evolved a number of enzymes that collectively are efficient in hydrolytically cleaving cellulose and hemicelluloses into their building units, the presence of lignin has been known to severely inhibit such activities. This research addresses this most pressing of issues in biomass conversion and seeks to develop processes and insight into key steps in lignin depolymerization, which are first steps in efficient biomass conversion. The research builds on previous studies and literature that demonstrate lignin can be dissolved in ionic liquids and that lignin is attacked by bases. Lignin has a complicated but poorly characterized composition and architecture, which also depend on the plant species and conditions in which the lignocellulosic biomass are produced. To avoid analytical complication for the purposes of understanding the mechanisms involved in base catalyzed hydrolysis of lignin oxygen linkages, this research will study model compounds that contain oxygen linkages found in lignin. The research investigates neutral ionic liquids and basic ionic liquids, each with an optimized amount of water, and with and without using a catalyst. The pH and the temperature of the test media will be controlled and followed. The effects of reaction time, process pressure, base catalyst type and concentration will all be examined. The research will employ aromatic alkali, of which the basicity can be tuned by the alkalinity of the metal ion, the type and the size of aromatic moiety, and polybasicity. Basic aromatic carboxylates will be included in the study to leverage their strong affinity toward lignin structure in a suitable carrier solvent, such as ionic liquids. By selecting catalysts of varying basicity and by varying operating conditions, we propose to target selectively oxygen linkages of different bond strength in different bonding networks. Broader Impacts By working with a number of model compounds that simulate the oxygen linkages in lignin, this research seeks to achieve a fundamental understanding of the mechanisms involved in lignin hydrolytic cleavage. Ionic liquid solvents that dissolve lignin will be used as media to carry out the reactions. Base catalysts with varying basicity will be used to study the effect of base strength in their activity toward the hydrolytic cleavage of oxygen linkages in ionic liquid solvents. The types of oxygen linkages in the model lignin compounds will be ranked according to their ease of cleavage in the presence of a base in ionic liquids. The knowledge to be gained through this research will help design processes for the rapid fragmentation nature of lignin in ionic liquids. Further, building upon an understanding in the hydrolytic cleavage of oxygen linkages in lignin, the model lignin compounds will be further studied in ionic liquids for selective cracking to produce aromatic molecules as potential fuels and chemicals.

0849342EKERDTINTELLECTUAL优异木质素是木质纤维素生物量的主要成分之一。木质素对微生物分解的顽固性是保护天然林体自然界自然降解的一个非常有益的特征。即使大自然已经进化了许多酶，这些酶在水解裂解的纤维素和半纤维素中有效地进化为建筑单元，但众所周知，木质素的存在严重抑制了这种活性。这项研究探讨了生物质转化中最紧迫的问题，并试图开发过程并深入了解木质素去聚合的关键步骤，这是有效生物量转化的第一步。该研究基于先前的研究和文献，证明木质素可以溶解在离子液体中，并且木质素受到碱的攻击。木质素具有复杂但特征不佳的组成和建筑，这也取决于产生木质纤维素生物量的植物物种和条件。为了避免分析并发症，以理解木质素氧链接中基础催化水解的机制，该研究将研究包含木质素中氧链接的化合物。该研究调查了中性离子液体和碱性离子液体，每种液体都有优化量的水，并且有和不使用催化剂。测试介质的pH和温度将受到控制并遵循。反应时间，过程压力，基础催化剂类型和浓度的影响都将被检查。这项研究将采用芳香族碱，其中碱性可以通过金属离子的碱度，芳香族部分的类型和大小和多重异位调节来调节。研究中将包括基本的芳族羧酸盐，以利用其在合适的载体溶剂（例如离子液体）中对木质素结构的强亲和力。通过选择不同碱性的催化剂并通过不同的工作条件，我们建议靶向不同键合网络中不同键强度的选择性氧连接。通过使用模拟木质素中氧链接的多种模型化合物，该研究旨在实现对木质素水解裂解涉及的机制的基本理解，从而更广泛的影响。溶解木质素的离子液体溶剂将用作培养基进行反应。具有不同碱性的碱催化剂将用于研究基础强度对离子液体溶剂中氧链接水解裂解的活性的影响。模型木质素化合物中的氧链接的类型将根据其在离子液体中碱的存在下的裂解方便进行排名。通过这项研究获得的知识将有助于设计离子液体中木质素快速分裂性质的过程。此外，基于在木质素中氧连接的水解裂解的理解，将在离子液体中进一步研究木质素化合物，以选择性裂纹以产生芳族分子作为潜在的燃料和化学物质。