Methods for Monitoring Milling Reactions and Mechanistic Studies of Mechanochemistry: A Primer

Mechanochemistry by ball milling is garnering significant attention as an efficient and versatile means of chemical synthesis which minimizes the need for solvents and reduces the amount of energy required to conduct many molecular transformations. Understanding milling reactions often requires monitoring the reaction of solid forms, with little or ideally no disruption of the milling process. Herein, we provide a broad but succinct summary of how different ex situ and the more recently developed in situ techniques have been applied to monitor mechanochemical reactions, revealing reaction pathways and the mechanisms driving different solid-state molecular and materials transformations by milling. The rapidly evolving field of monitoring milling reactions has already revolutionized our understanding of mechanochemical reactions, revealing complex self-assembled phases as intermediates in catalytic and other types of synthesis through ball milling. The multitude of recently reported techniques for investigating ball milling reactions, many of which are touched upon in this summary, promise to dramatically increase the pace of mechanochemical reaction development and the understanding of solid-state chemistry.