NSF-BSF: Mechanism-Guided Design of Deoxydehydration Catalysts

University Of Massachusetts Amherst, Amherst MA

Investigators

Abstract

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.