Collaborative Research: Engineering Selectivity by Catalyst Architecture Control

近年来，在化学解构生物质以生产可用作各种化学品和燃料的基石的较小分子方面取得了重大进展。目前正在研究这样一种策略，用于解构废旧塑料聚合物，以提供构建块分子，用于塑料的重新合成或其他化学品的合成。在这两种情况下，催化在引导化学攻击特定化学键方面发挥了重要作用。该项目继续由研究人员进行与生物质和废塑料相关的催化研究，并对一系列产品进行分解和再合成。特别是，研究人员将以他们在生物质催化方面的经验为基础，探索废塑料加工的基本方面。由此产生的理解将为确定处理废旧聚合物塑料原料的成本效益和环境友好的化学途径提供关键的见解。除技术方面外，该项目还将在这两所学校开展教育和外联活动，重点放在代表性不足的少数族裔学生身上。设计选择性地激活多功能有机分子中特定化学键的催化剂是可持续和具有成本效益的化学品和燃料生产的长期目标，以满足社会需求，并将对环境的影响降至最低。尤其是碳-氧(C-O)键的选择性断裂在近年来变得非常重要，因为它与生物质和塑料聚合物中的多官能团有机分子的化学加工有关。氢解是一种在氢的辅助下，有机分子中的C-X(X=C，H，O)键被广泛应用的方法。然而，大多数氢解催化剂面临的挑战是选择性地催化氢辅助的C-O键裂解多官能团有机分子中的其他C-X(X=C，H)键。这个项目的中心目标是了解调整多相催化剂的整体结构如何通过氢解影响多功能有机分子中C-O键的选择性断裂。该项目将结合合成、显微/光谱表征和动力学研究，以获得对双位催化剂上控制模型有机底物分子氢解的机理的基本了解。这项研究将有助于理解C-O键在双位催化剂上的选择性断裂，这将是确定催化剂位置和结构要求以提高多功能有机分子产品选择性的关键。这一认识将为确定处理生物质和废弃聚合物塑料原料的成本效益和环境友好的化学途径提供关键的见解。拟议的研究将对促进催化科学和对代表性不足的少数群体进行工程培训/教育产生更广泛的影响。外联活动将侧重于向波多黎各大学-马亚圭斯大学和密歇根大学代表人数不足的少数族裔提供指导、积极学习和研究机会，以促进和吸引学生攻读科学和工程研究生课程。作为推广活动的一部分，将建立一个“能源、环境和工程”日营，向来自波多黎各西海岸地区和底特律大都市区的初中生和高中生介绍催化在最大限度减少碳排放和促进燃料和化学品制造循环方面的重要性。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Significant progress has been made in recent years in chemically deconstructing biomass to produce smaller molecules that can be used as building blocks for a broad range of chemicals and fuels. Such a strategy is now being investigated for the deconstruction of waste plastic polymers to provide building block molecules either for re-synthesis of plastics or for synthesis of other chemicals. In both cases, catalysis plays an important role in directing chemical attack towards specific chemical bonds. The project continues catalysis research by the investigators relevant to both biomass and waste plastic deconstruction and re-synthesis toward a range of products. In particular, the investigators will build on their experience in biomass catalysis to explore fundamental aspects of waste plastics processing. The resulting understanding will provide critical insights toward identification of cost-effective and environmentally benign chemical pathways for processing of waste polymer plastic feedstocks. Beyond the technical aspects, the project will embrace educational and outreach activities at both institutions focused on underrepresented minority students. Designing catalysts that are selective for the activation of specific chemical bonds in multifunctional organic molecules is a long-standing goal for the sustainable and cost-effective production of chemicals and fuels to meet societal demands with minimal environmental impact. Selective cleavage of carbon-oxygen (C-O) bonds, especially, has become significantly important in recent years due to its relevance in chemical processing of multifunctional organic molecules from biomass and plastic polymers. Hydrogenolysis is an approach widely implemented for the activation of C-X (X = C, H, O) bonds in organic molecules, as aided by hydrogen. However, most hydrogenolysis catalysts are challenged by the ability to selectively catalyze hydrogen-assisted C-O bond cleavage over other C-X (X = C, H) bonds within multifunctional organic molecules. The central objective of this project is to develop an understanding of how tuning the overall architecture of heterogeneous catalysts can affect the selective cleavage of C-O bonds in multifunctional organic molecules through hydrogenolysis. The project will combine synthesis, microscopic/spectroscopic characterization, and kinetic studies to gain fundamental understanding of the mechanisms that govern hydrogenolysis of model organic substrate molecules on dual-site catalysts. The research will lead to an understanding of the selective cleavage of C-O bonds over dual-site catalysts, which will be critical in identifying catalytic site and architecture requirements to enhance product selectivity in multifunctional organic molecules. This understanding will provide critical insights toward identification of cost-effective and environmentally benign chemical pathways for processing both biomass and waste polymer plastic feedstocks. The proposed research will have broader impacts related to the advancement of catalytic science and engineering training/education of underrepresented minorities. Outreach activities will focus on providing mentorship, active learning, and research opportunities to underrepresented minorities from the University of Puerto Rico – Mayaguez and the University of Michigan to foment pathways and engage students towards pursuing graduate studies in science and engineering. As part of the outreach activities an "Energy, Environment, and Engineering" day camp will be developed to introduce middle- and high-school students, from the west coast area of Puerto Rico and the Metro area of Detroit, to the importance of catalysis in minimizing carbon emissions and promoting circularity in the manufacture of fuels and chemicals.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.