SusChEM: The development of recyclable catalysts and reagents using mechanochemistry.

University Of Cincinnati Main Campus, Cincinnati OH

Investigators

Abstract

With this award, the Chemical Synthesis Program is supporting Professor James Mack at the University of Cincinnati Department of Chemistry to explore a solvent-free method known as mechanochemistry to discover new synthetic pathways that are not observed in solution. This research seeks to develop mechanochemical methods for many common synthetic reactions, with a goal of reducing hazardous waste. One major focus is on the development of recyclable catalysts through the use of polymer supported reagents and metal reaction vials, which act as catalysts. The ability to recycle expensive catalysts will significantly reduce the overall cost to conduct many reactions. Professor Mack will integrate the research and educational components of this project through the introduction of students to principles of environmentally benign chemistry. His program fosters a research and learning environment with overlapping experiences among high school, undergraduate, and graduate students. In this environment, high school students are mentored by undergraduates, who are in turn mentored by graduate students. These connections introduce younger students to graduate education, as well as providing role models for success. The mentorship experienced by students is especially beneficial to first generation college students, many of whom have had no prior knowledge about graduate education. This process is intended to increase the pipeline of STEM students, especially women and underrepresented minorities This research seeks to further develop a solvent-free synthetic method known as ball-milling (a type of mechanochemistry) to improve the efficiency of chemical reactions and to reduce hazardous solvent waste. Ball-milling is a procedure in which solid chemical reactants are first placed inside a reaction vessel along with a ball bearing. The vessel is sealed and placed inside a milling apparatus where it is agitated at high speed. This agitation provides energy through the steel ball to initiate a reaction. The present research focuses on the development of recyclable catalysts through the use of polymer supported reagents and metal reaction vials. The planned research will demonstrate new activation pathways for polymer supported reagents as well as new mechanisms for the activation of metal catalysts. Because mechanochemistry is a relatively new field, many of the rules that govern reactions are not well understood. This research will use metal reaction vials to facilitate metal catalyzed chemical reactions. This will lead to greater understanding of the reactivity of metal catalysts in a ligand and solvent-free environment. Additionally, the use of polymer supported reagents under solvent-free conditions will provide new mechanistic insights on the activation of polymer supports. Typically these types of reactions are limited by the slow rate of diffusion; however, under mechanochemical conditions this limitation is expected to be easily overcome. Mechanochemical reactions will be compared to their solution counterparts.