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广泛化学品和燃料的构件的较小分子方面取得了重大进展。 现在正在研究这种策略，用于废弃塑料聚合物的解构，以提供用于塑料再合成或用于合成其他化学品的构建单元分子。 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催化研究，涉及生物质和废塑料的解构和再合成，以生产一系列产品。 特别是，研究人员将利用他们在生物质催化方面的经验，探索废塑料加工的基本方面。 由此产生的理解将为识别用于处理废弃聚合物塑料原料的具有成本效益和环境友好的化学途径提供重要见解。 除了技术方面，该项目还将在这两个机构开展教育和外联活动，重点是代表性不足的少数民族学生。 设计对多功能有机分子中的特定化学键的活化具有选择性的催化剂是化学品和燃料的可持续和具有成本效益的生产的长期目标，以满足社会需求，同时对环境的影响最小。近年来，碳-氧（C-O）键的选择性断裂尤其变得非常重要，这是由于其在来自生物质和塑料聚合物的多官能有机分子的化学加工中的相关性。氢解是一种广泛应用于活化有机分子中C-X（X = C，H，O）键的方法，在氢的辅助下。然而，大多数氢解催化剂受到多官能有机分子内选择性催化氢辅助的C-O键裂解超过其它C-X（X = C，H）键的能力的挑战。该项目的中心目标是了解如何调整非均相催化剂的整体结构可以影响多功能有机分子中的C-O键通过氢解的选择性裂解。该项目将结合联合收割机的合成，显微镜/光谱表征，动力学研究，以获得基本的了解的机制，管理模型有机底物分子的氢解双中心催化剂。该研究将导致对双中心催化剂上C-O键的选择性裂解的理解，这对于确定催化位点和结构要求以提高多功能有机分子中的产物选择性至关重要。这种理解将为确定用于处理生物质和废弃聚合物塑料原料的具有成本效益和环境友好的化学途径提供重要见解。拟议的研究将对促进代表性不足的少数群体的催化科学和工程培训/教育产生广泛影响。外联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代表性不足的少数群体提供辅导、积极学习和研究机会，以促进途径，并吸引学生攻读科学和工程研究生课程。作为外联活动的一部分，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大都会地区的初中和高中学生介绍，该奖项反映了NSF的法定使命，并被认为是值得支持的，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。

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.