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

木质素是木本和草本植物细胞壁的三种主要成分之一，其化学组成不仅富含碳，而且类似于许多石油基化学前体。 该项目解决了木质素催化分解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族化学品。 具体地，目的是了解催化剂如何与易于裂解的木质素部分相互作用。 该催化剂含有分散在多孔固体载体上的铜纳米颗粒，并且在超临界甲醇（sc-MeOH）中，它催化固体木质素裂解为富含能量的有机液体而不形成炭。两个关键问题是大体积、难溶性聚合物的移动和进入催化剂的内表面。通过调节反应条件和催化材料的性质，将优化催化剂与木质素的相互作用以增强解聚并使得能够经济地生产可再生芳香族化学品。其目标是开发创新的，可持续的和可扩展的转化工艺，使用由地球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品。该项目将测试两个主要假设：1）木质素吸收到多孔催化剂中及其吸附到催化剂表面上引起构象变化，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最大化关键芳基醚键与催化活性位点的相互作用。研究将涉及：1）具有受控和系统变化的孔结构和表面官能度的有序中孔催化剂（即，疏水性）; 2）木质素二聚体和低聚物模型系统，其具有受控的和系统地改变的链长、为芳基醚的键的比例和芳基醚键之间的间隔基，和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模型系统和模板化的中孔催化剂，其具有受控的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-催化剂相互作用;并使用先进的光谱方法，探索木质素和催化剂之间的界面相互作用，以了解它们如何通过芳基氢解促进选择性木质素解聚，醚键 该研究小组将与学校伙伴关系研究所合作，为圣路易斯社区代表性不足和弱势的八年级学生开展外联和教育活动。具体而言，外展工作将包括通过校园访问，校园参观和实验室演示为当地代表性不足的少数民族学生提供年度研究员日计划。加州大学圣巴巴拉分校的SciTrek外展计划将提供类似的活动。

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 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 using advanced spectroscopic methods, to probe interfacial interactions between lignin and catalyst 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 eighth grade students in the St. Louis community. Specifically, the outreach efforts will include an annual Researcher for a Day program for local underrepresented minority 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.