NSF-BSF: Mechanism-Guided Design of Deoxydehydration Catalysts

生物质衍生资源的化学反应可以提供平台分子，这些分子既可以用作生产，也可以进一步转化为一系列化学品或燃料，这是将碳排放降至最低的可持续化学工业的关键。催化在生物质的增值过程中起着关键作用。脱氧脱水（DODH）是一类很有前途的化学反应，可将生物质衍生的二醇类化学品转化为烯烃。烯烃在化学制造中有广泛的应用，目前主要从化石资源中生产。目前，该领域缺乏高效的DODH催化剂。该研究将促进对DODH催化的基本理解，并利用这些理解设计更有效的催化剂，以及在实际化学制造过程中最佳部署这些催化剂的方法。该项目的目标将通过与以色列海法以色列理工学院的研究人员合作来实现。该项目的目标是获得机械知识，从而设计用于各种底物和还原剂的催化材料，开发先进的支撑，可以有效地“嵌套”活性部分而不会浸出，并探索创新的方法来桥接均相和非均相催化并结合它们的优点。具体而言，该项目将在催化和动力学、有机金属和无机合成以及催化剂表征等领域利用互补的专业知识，培养国际团队之间的协同效应。协作实验方法包括四个工作包：(i)一种新的详细的催化剂评估方法，该方法通过脱氧脱水循环中关键步骤的单独测量动力学来取代总体产量，并通过原位光谱分析活性金属的状态，从而提供深入的机理见解；设计和合成具有强络合配体的新型稳定铼催化剂，这些配体可以是可溶和固定化催化剂的有机氧化还原稳定配体，也可以是属于表面相修饰载体的无机配体；（iii）所开发的分子催化剂和负载催化剂的表征；（iv）探索暂时和部分固定活性基团作为达到具有多相催化分离特征的均相过程的手段。综上所述，该研究将确定用于脱氧脱水的新型可溶性和固体催化剂，以及在复杂的多步循环中对催化剂性能进行基准测试的新方法。更广泛地说，这些结果将推进目标应用的商业前景，即生物质原料的脱氧脱水。新的载体及其合成方法将适用于其他催化剂和其他化学物质，以及动力学分析的新方法。除了技术方面，该项目还将为研究生和本科生提供催化和反应工程、材料合成和材料表征等前沿方法的培训。国际学生交换将促进两组之间在材料设计和合成、均相和非均相催化和动力学以及原位和操作方法方面的交流。研究人员将把最先进的信息整合到他们的正式教学中。扩大未被充分代表的学生的参与将包括招收女本科生，并为麻省理工大学的两个项目——SENGI和工程与计算机女性职业日——做出贡献，以及以色列合作者向海法当地高中进行推广。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。

Chemical reaction of biomass-derived resources to give platform molecules that can be used either as produced, or further converted into a range of chemicals or fuels, is key to a sustainable chemical industry that minimizes carbon emissions. Catalysis plays a key role in the valorization of biomass. Deoxydehydration (DODH) is a promising class of chemical reactions for converting biomass-derived diol chemicals to olefins – the latter having wide application in chemical manufacturing, and currently produced primarily from fossil resources. At present, the field lacks efficient DODH catalysts. The study will advance fundamental understanding of DODH catalysis, and use that understanding to design more efficient catalysts and ways of best deploying those catalysts in real-world chemical manufacturing processes. The project objectives will be achieved through collaboration with researchers at the Technion – Israel Institute of Technology in Haifa, Israel.The objectives of the project are to gain mechanistic knowledge and thereupon design catalytic materials for use with various substrates and reductants, to develop advanced supports that can efficiently "nest" the active moiety with no leaching, and to explore innovative approaches to bridge homogeneous and heterogeneous catalysis and combine their benefits. Specifically, the project will leverage complementary expertise and cultivate synergies between the international teams in the areas of catalysis and kinetics, organometallic and inorganic synthesis, and catalyst characterization. The collaborative experimental approach consists of four work packages: (i) A new and detailed catalyst evaluation approach that replaces overall yields by separately measured kinetics of the key steps in the deoxydehydration cycle and incorporates analysis of the state of the active metal by in situ spectroscopy, thus providing deep mechanistic insights; (ii) design and synthesis of new, stable rhenium catalysts with strongly complexing ligands, which may be organic redox-stable ligands for both soluble and immobilized catalysts, or inorganic ligands belonging to a surface-phase modified support; (iii) characterization of the developed molecular and supported catalysts; and (iv) exploration of temporary and partial immobilization of active moieties as a means to arrive at a homogeneous process with the separation characteristics of heterogeneous catalysis. Taken together, the research will identify new soluble and solid catalysts for deoxydehydration, and new methods for benchmarking catalyst performance in complex multistep cycles. More broadly, the results will advance the commercial prospects of the target application, deoxydehydration of biomass-derived feedstocks. The new supports and the methods to synthesize them will be applicable for other catalysts and other chemistries, as will novel approaches to kinetics analysis. Beyond the technical aspects, the project will provide training to both graduate and undergraduate students in cutting-edge methods of catalysis and reaction engineering, materials synthesis, and materials characterization. International student exchange will foster cross-fertilization between the groups with respect to materials design and synthesis, homogeneous and heterogeneous catalysis and kinetics, and in situ and operando methods. The researchers will integrate the state-of-the art information into their formal teaching. Broadened participation of underrepresented students will include recruiting of female undergraduate students and contributions to two programs at UMass - SENGI and the Women in Engineering and Computing Career Day - as well as outreach by the Israeli collaborator to local high schools in Haifa.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.