CAREER: Molecular imprinting strategy to rationally design porous solid acid catalysts for C-C coupling chemistries

长期以来，催化剂一直被用来加快化学反应的速度，提高能源效率，并指导反应生成所需的产品。沸石是一类纳米多孔固体酸催化剂，特别适合于天然气和石油资源衍生的碳氢化合物的反应。近年来，从化石资源向生物可再生原料的转变引发了人们对改性沸石和其他微孔催化剂的兴趣，以提高它们将生物质原料分子反应成更高价值燃料和化学品的效率。该项目研究了一种用于修饰酸催化剂的新方法，该方法包括通过在狭窄的空间中限制来提高反应速度，同时促进大量产品分子从活性中心扩散。该方法利用分子印迹原子层沉积方法在活性中心附近产生微孔二氧化硅结构，从而在不施加输运限制的情况下诱导限制效应。这些具有可调孔结构的固体酸催化剂将在芳香烷基化和羟醛缩合反应中测试其有效性和稳定性，因为它们在工业化学和提升生物质衍生分子方面得到了广泛应用。该项目将通过将研究结果整合到课堂材料中，为STEM中历史上代表性不足的群体的学生提供研究机会，向当地K-12女性学生展示研究人员的实验室，并通过社交媒体渠道为新接触多相催化研究的研究人员制作和播放教育视频，涉及研究和教育之间的强耦合。在过去的20年里，该领域在了解反应网络、动力学和运输对观察到的速率、选择性和稳定性的影响，以及对发生在受限空间(如微孔酸性沸石)上的化学反应的影响方面取得了重大进展。然而，沸石材料中微孔结构的三维网络经常引入不必要的传输效应，这可能会导致不希望看到的副反应和因孔堵塞而导致的催化剂失活。本项目旨在通过开发和实施分子印迹原子层沉积方法，在介孔铝硅酸盐活性中心附近创建微孔SiO_2结构，从而在不施加输运限制的情况下，在合理设计多孔材料方面增加另一个维度。这些具有可调孔结构的固体酸将被用来结合动力学、光谱和理论方法来评估它们对观察到的速率、选择性和稳定性的详细作用。在这样做的过程中，这项建议旨在为活性中心操纵提供全面的催化剂设计原则，符合C-C偶联化学的具体要求。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。

Catalysts have long been used to enhance the rate of chemical reactions, improve energy efficiency, and direct reactions toward desired products. Zeolites are a class of nanoporous solid-acid catalysts that are particularly well suited to reactions of hydrocarbons derived from natural gas and petroleum resources. The transition from fossil-based resources to bio-renewable feedstocks in recent years has triggered interest in modifying zeolites and other microporous catalysts to increase their effectiveness for reacting raw biomass molecules to higher-value fuels and chemicals. The project investigates a novel approach for modifying acid catalysts that involves promoting reaction rates through confinement in tight spaces while facilitating diffusion of bulky product molecules away from the active sites. The approach utilizes a molecular imprinting atomic layer deposition method to create microporous silica structures near the active sites to induce confinement effects without imposing transport constraints. These solid acids catalysts with tunable porous structures will be tested for their effectiveness and stability in aromatic alkylation and aldol condensation reactions, chosen because of their widespread application in industrial chemistry and in upgrading biomass-derived molecules. The project will involve strong coupling between research and education by integrating the research results into classroom materials, providing research opportunities for students from historically underrepresented groups in STEM, showcasing the investigator’s laboratories to local K-12 female students, and creating and broadcasting educational videos via social media channels for researchers who are new to heterogeneous catalysis research.Over the last two decades, the field has made significant progress in understanding the effects of reaction network, kinetics, and transport on observed rates, selectivities, and stabilities, on chemistries occurring on confined spaces such as microporous acidic zeolites. Yet, the three-dimensional network of microporous structures in zeolitic materials often introduces unwanted transport effects that can lead to undesired side reactions and catalyst deactivation caused by pore blockage. This project aims to add another dimension in rationally designing porous materials by developing and implementing molecular imprinting atomic layer deposition methods to create microporous SiO2 architecture near active sites in mesoporous aluminosilicates to induce confinement effects without imposing transport constraints. These solid acids with tunable porous structures will be used to assess their detailed role on observed rates, selectivities, and stabilities by combining kinetic, spectroscopic, and theoretical methods. In doing so, this proposal aims to provide comprehensive catalyst design principles for active site manipulation that match the specific requirements of C-C coupling chemistries.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.