Inelastic collisions of in ball milling provide energy to drive the chemical transformation which is, for purely mechanically driven reactions, linear with the energy dose received.

Typically induced by the mechanical processing of powders in ball mills, mechanochemical transformations are considered to result from the application of mechanical force to solid reactants. However, the undeniable deep connection between the dynamic compaction of powders during impacts and the overall transformation degree has yet to be disclosed. In the present work, we show that the square planar bis(dibenzoylmethanato)NiII coordination compound undergoes trimerization when its powder experiences even a single ball impact. Based on systematic experiments with individual ball impacts and analysis by Raman spectroscopy, we provide here quantitative mapping of the transformation in the powder compact and deduce bulk reaction kinetics from multiple individual impacts.

Catalyzed reactions of organic substrates that operate continuously by extrusion techniques are rare. In this study, we developed a mechanochemical bromination of unactivated naphthalene (1) with 1,3-dibromo-5,5-dimethylhydantoin (DBDMH), catalyzed by zeolites in a ball mill. The use of DBDMH enabled the atom economy of the reaction to be superior compared to the other brominating agents evaluated. Among the zeolites tested, a FAU-type zeolite demonstrated high catalytic activity and recyclability. The success of the bromination route on a small scale enabled the development of a continuous catalyzed bromination of 1 by twin-screw extrusion.

Solid-state supramolecular complexation of potassium cations enables the reactivity of KOH in mechanochemical organic reactions.

The correlation between kinetics and Hammett constants in a model mechanochemical imine formation indicates that the mechanistic framework of physical–organic chemistry could be used to describe solid-state reactions conducted by ball milling.