Collaborative Research: Engineering Selectivity by Catalyst Architecture Control

近年来，在化学分解生物质以产生更小的分子方面取得了重大进展，这些分子可以用作广泛的化学品和燃料的基础。目前正在研究这种策略，以解构废塑料聚合物，为塑料的重新合成或其他化学品的合成提供构建块分子。在这两种情况下，催化在将化学攻击导向特定化学键方面起着重要作用。该项目继续由研究人员进行有关生物质和废塑料解构和重新合成一系列产品的催化研究。特别是，研究人员将利用他们在生物质催化方面的经验来探索废塑料处理的基本方面。由此产生的理解将为确定具有成本效益和环境友好的废旧聚合物塑料原料处理化学途径提供关键见解。除了技术方面，该项目还将在两所院校开展教育和推广活动，重点关注代表性不足的少数民族学生。设计能够选择性激活多功能有机分子中特定化学键的催化剂是一个长期的目标，以可持续和具有成本效益的方式生产化学品和燃料，以满足社会需求，同时对环境的影响最小。特别是碳氧键的选择性裂解，近年来变得非常重要，因为它与生物质和塑料聚合物的多功能有机分子的化学加工有关。氢解是一种广泛应用于有机分子中C-X （X = C， H， O）键激活的方法，在氢的辅助下。然而，大多数氢解催化剂都面临着在多功能有机分子中选择性催化氢辅助C- o键而不是其他C-X （X = C， H）键的能力的挑战。该项目的中心目标是了解多相催化剂的整体结构如何通过氢解作用影响多功能有机分子中C-O键的选择性裂解。该项目将结合合成、微观/光谱表征和动力学研究，以获得对双位点催化剂上模型有机底物分子氢解机制的基本理解。该研究将有助于了解C-O键在双位点催化剂上的选择性裂解，这对于确定催化位点和结构要求以提高多功能有机分子的产物选择性至关重要。这种理解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见解。拟议的研究将对促进代表性不足的少数民族的催化科学和工程培训/教育产生更广泛的影响。外展活动将侧重于为来自波多黎各大学-马亚圭斯分校和密歇根大学的少数族裔提供指导、主动学习和研究机会，以激发学生攻读科学和工程研究生的途径和参与。作为推广活动的一部分，将开发一个“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都会区的中学生和高中生介绍催化在减少碳排放和促进燃料和化学品制造循环中的重要性。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.