Mechanochemistry presents many advantages over traditional synthetic methods, namely the elimination of side reactions, removal of solvent-waste, and the shortening of reaction times. However, research in the field of powder milling relies on the parameters used in commercially available ball mills (frequency, milling media, milling vessel material) as an indirect means of controlling force in mechanochemical reactions. In order to better understand the relationship between frequency and force, a series of Diels-Alder reactions with substituted anthracenes were performed mechanochemically in both a commercially available ball mill and a novel controlled force reactor (CFR), which both controls and records the amount of force applied over the course of a reaction. We provide an examination of the role of activation energy, reactor vessel hardness, and frequency in altering reactivity. Use of the CFR allows us to isolate the effects of force as a fundamental parameter and determine the force-dependence of these reactions. We confirm that for reactions with activation energy below a certain threshold, reactions will proceed to competition regardless of reaction conditions, and that for higher activation energies reactions will not proceed. This work introduces insight into the correlation between reactor vessel hardness and frequency to reactivity in force-dependent reactions.

Force-driven kinetics of mechanochemical pericyclic reactions

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.