Collaborative Research: SusChEM: Designing Catalytic Interfaces to Promote Selective Lignin Depolymerization

木质素是木本和禾本科植物细胞壁的三种主要成分之一，其化学组成不仅富含碳，而且与许多基于石油的化学前体相似。该项目解决了催化分解木质素为其组成单元所带来的挑战，以产生可再生和低成本的芳香化学品。具体来说，目的是了解催化剂如何与木质素的部分相互作用，是易被切割。该催化剂含有分散在多孔固体载体上的铜纳米颗粒，在超临界甲醇（sc-MeOH）中催化固体木质素裂解成富含能量的有机液体，而不形成炭。两个关键问题是体积庞大、难溶性聚合物的移动和催化剂内部表面的接近。通过调整反应条件和催化材料的性质，优化催化剂与木质素的相互作用，促进解聚，实现可再生芳香族化学品的经济生产。目标是开发创新的、可持续的、可扩展的转化过程，利用地球上丰富的材料制成的多孔固体催化剂，经济地从木质素中产生平台可再生化学物质。该项目将测试两个主要假设：1)木质素被吸收到多孔催化剂中，并在催化剂表面吸附，引起构象变化，增加木质素和催化剂之间的相互作用；2)具有适当内部结构和组成的多孔催化剂可以最大限度地发挥关键芳醚键与催化活性位点的相互作用。该研究将涉及：1)有序介孔催化剂，具有可控和系统变化的孔隙结构和表面功能（即疏水性）；2)木质素二聚体和低聚物模型系统，具有控制和系统地改变链长，芳香醚键的比例，芳香醚键之间的间隔，以及3)吸附模式和反应动力学的原位评估。实现这些目标和测试这些假设的计划包括合成木质素<e:2> - o -4模型体系和模板介孔催化剂，这些催化剂具有可控和系统变化的结构和组成，以探测溶剂-木质素，溶剂-催化剂和木质素-催化剂的相互作用；2)利用先进的光谱方法探测木质素与催化剂之间的界面相互作用，以了解它们如何通过氢解芳基醚键促进木质素的选择性解聚。研究小组将与学校伙伴关系研究所合作，为圣路易斯社区中代表性不足和贫困的八年级学生开展外展和教育活动。具体地说，拓展工作将包括每年一次的？当一天研究员？通过校园参观、校园游览和实验室演示，为当地未被充分代表的少数民族中学生提供项目。加州大学圣巴巴拉分校的SciTrek外展项目也将提供类似的活动。

Lignin is one of the three major components of woody and grassy plant cell walls, and its chemical make-up is not only carbon-rich but also resembles many petroleum-based chemical precursors. This project addresses challenges presented by the catalytic deconstruction of lignin into its constituent units in an effort to generate renewable and low-cost aromatic chemicals. Specifically, the aims are to understand how the catalyst interacts with portions of lignin that are susceptible to cleavage. The catalyst contains copper nanoparticles dispersed on a porous solid support, and in supercritical methanol (sc-MeOH) it catalyzes the cleavage of solid lignin to energy-rich organic liquids without forming char. Two key problems are movement of the bulky, poorly soluble polymer and access to the internal surfaces of the catalyst. By tuning the reaction conditions and the properties of the catalytic material, the interactions of the catalyst with lignin will be optimized to enhance depolymerization and enable economical production of renewable aromatic chemicals. The goal is to develop innovative, sustainable, and scalable conversion processes that generate platform renewable chemicals from lignin economically using porous solid catalysts made with Earth-abundant materials. This project will test two overarching hypotheses: 1) that lignin absorption into a porous catalyst and its adsorption onto catalyst surfaces induce conformational changes that increase interactions between the lignin and the catalyst; and 2) that porous catalysts with appropriate internal structure and composition maximize interactions of the key aryl ether linkages with catalytically active sites. The research will involve: 1) ordered mesoporous catalysts with controlled and systematically varied pore architecture and surface functionality (i.e., hydrophobicity); 2) lignin dimer and oligomer model systems that have controlled and systematically varied chain length, proportion of linkages that are aryl ethers, and spacers between aryl ether linkages, and 3) in-situ assessment of adsorption modes and reaction kinetics. The plan to achieve these objectives and test these hypotheses involves synthesizing both lignin â-O-4 model systems and templated mesoporous catalysts with controlled and systematically varied structures and compositions to probe solvent-lignin, solvent-catalyst, and lignin-catalyst interactions; and 2) using advanced spectroscopic methods to probe interfacial interactions between lignin and catalyst in order to understand how they promote selective lignin depolymerization by hydrogenolysis of aryl ether linkages. The research team will collaborate with the Institute for School Partnership to develop outreach and education activities for underrepresented and underprivileged 8th grade students in the St. Louis community. Specifically, the outreach efforts will include an annual ?Researcher for a Day? program for local underrepresented minority middle school students through a campus visit, a campus tour, and lab demonstrations. A similar activity will be offered through the SciTrek outreach program at UC Santa Barbara.