CAS: Reaction and Deactivation Implications of Pore structure, Nodal Identity, and Coordination Environment on Small-molecule Oxidations by Metal-organic Frameworks

在化学系化学催化项目的支持下，普林斯顿大学的Michele L.Sarazen正在研究选择性氧化反应，这些反应在各种制药、精细化工和其他化学工业过程中是核心的。具体地说，这项工作旨在设计具有高反应性、选择性和稳定性的先进催化剂，通过组合合成、表征和反应分析，有效和可持续地满足我们日益增长的能源和产品需求。金属有机骨架(MOF)是一类对包括氧化在内的许多化学过程都具有吸引力的材料。本提案旨在提供对MOF在模拟操作条件下的行为、其失活途径以及其重新激活的理解。如果成功，这些研究的结果将有助于指导进一步的研究，不仅在催化方面，而且在其他应用方面，如气体捕获和分离、能量存储、药物输送和传感器。了解材料限制对商业可持续性的其他影响可以在热化学稳定性和稳定性方面改进现有材料，并减少废催化剂的浪费。同样，这项工作优先考虑可持续实践，因为与许多当前的工业过程相比，它考虑了更便宜、更丰富的金属和更良性的氧化剂。PiSarazen将继续参与科学推广和教育项目，旨在通过在校内外推广活动中展示这些催化剂在废水中发现的染料分子的氧化中利用这些催化剂，提供令人兴奋的、充满活力的颜色变化，以促进催化剂应用的力量和公众对可持续工业化学的科学素养，从而增加科学界的多样性。本项目通过实验和计算表征，研究具有工业应用价值的液相氧化反应。开放晶体MOF网络中规则分布的金属中心将被用来建立结构-功能关系，阐明1-辛烯典型氧化反应中的反应和失活机理，其中严格的动力学实验将与表征技术和计算模拟相结合。具体地说，这项拟议的工作将研究过氧化氢辅助构象和合成模数1-辛烯氧化过程中物理化学可调的铁基MIL MOF，以量化孔疏水性、酸度和Fe活性中心配位球扰动对观察到的反应性、选择性和稳定性的影响。这项实验研究的结果将通过利用MOF的结晶性质来推动密度泛函理论的计算研究，并可能开发出预测有前景的材料组成或方法来改进现有材料以实现预期应用的趋势。这里描述的研究整个催化生命周期的框架，包括Fe-羧酸盐MOF上氧化反应的具体机理细节，有可能提供一个基础，可以扩展到提高不同MOF架构上的碳升级(石油/生物质/废物精炼)以及甚至不同能源(即电催化、光催化)输入的碳氢化合物和含氧物加工相关的各种原料的催化剂效率。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。

With the support of the Chemical Catalysis program in the Division of Chemistry, Michele L. Sarazen of Princeton University is studying selective oxidation reactions that are central in a variety of pharmaceutical, fine chemical, and other chemical industry processes. Specifically, this work is directed at the design of advanced catalysts with high reactivity, selectivity, and stability that can efficiently and sustainably address our growing energy and product demands through combined synthesis, characterization, and reaction analysis. Metal-organic frameworks (MOFs) are a class of materials attractive for many chemistries, including oxidations. This proposal aims to provide understanding of how MOFs behave under model operating conditions, their deactivation pathways, and their reactivation. If successful, the results of these studies will help guide further research, not only in catalysis but also for other applications such as gas capture and separations, energy storage, drug delivery, and sensors. Additional implications for commercial sustainability from understanding material limitations can improve existing materials in terms of thermochemical robustness and stability, and reducing waste from spent catalysts. Similarly, this work prioritizes sustainable practices by considering cheaper and more abundant metals and more benign oxidants compared to many current industrial processes. PI Sarazen will continue her engagement in scientific outreach and educational programs that aim to increase diversity within the scientific community through demonstrations in on-/off-campus outreach events that utilize these catalysts in the oxidation of dye molecules found in wastewater, offering exciting, vibrant color changes that can be used to promote the power of catalyst applications and public scientific literacy on sustainable industrial chemistry. This project involves the study of liquid-phase oxidation reactions valuable for industrial applications through experimental and computational characterizations. The regularly distributed metal centers in open crystalline MOF networks will be used to build structure-function relations and elucidate reaction and deactivation mechanisms during representative oxidation reactions of 1-octene, where rigorous kinetic experiments will be coupled with characterization techniques and computational modelling. Specifically, this proposed work will investigate physicochemically tunable Fe-based MIL MOFs during hydrogen peroxide-assisted oxidation of conformationally and synthetically modular 1-octene to quantify the impacts of pore hydrophobicity, acidity, and Fe active site coordination sphere perturbations on observed reactivity, selectivity, and stability. The results of this experimental study will motivate computational investigations with density functional theory by taking advantage of the crystalline nature of MOFs and could develop trends that predict promising material compositions or methods to improve existing materials for a desired application. The framework described here for studying entire catalytic lifecycles, including specific mechanistic details for oxidation reactions on Fe-carboxylate MOFs, has the potential to provide a foundation that can be extended to improve catalyst efficiency for other reactions of various feedstocks related to hydrocarbon and oxygenate processing from carbon upgrading (petroleum/biomass/waste refining) over different MOF architectures and even different energy (i.e., electrocatalytic, photocatalytic) inputs.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.