Experimental Isolation of Single Impact, Cumulative Energy, Aging, and Liquid‐Assisted Grinding Effects in Mechanochemical Reactions

Mechanochemical reactivity arises from a complex interplay between single impact energy, cumulative energy input, and secondary effects such as aging or liquid-assisted grinding (LAG). Here, we experimentally isolate these factors across two fundamentally different all-solid reactions-the Finkelstein halogen exchange and the Wittig olefination-using a standardized single-ball mixer mill setup. Systematic variation of milling parameters revealed that both reactions are impact-driven but differ in how mechanical energy translates into chemical conversion. The halogen exchange exhibited pronounced aging, where the transformation continues after mechanical activation, highlighting the contribution of post-impact reactivity. In contrast, the Wittig olefination, free of such secondary effects, showed an almost ideal linear correlation between yield and cumulative energy (E_total). LAG additives were found to modulate but not replace the impact-driven regime, providing mechanistic insight into the frequently observed sweet spot in LAG-assisted reactions.