In this work, we study the dynamics of single balls inside the jars of the most common oscillating ball mills. Our methodology combines experimental measurements with numerical simulations. We use piezoelectric sensors to detect individual impacts and record long sequences of time intervals between consecutive impacts, which are used to characterize in detail the ball dynamics with and without powder in the jar. Experimental findings are used as the benchmark for numerical simulations, which reconstruct ball trajectories in three-dimensional jars, with flat or rounded ends, that undergo realistic oscillations. We systematically change the impact elasticity until experimental data are best reproduced by numerical data, achieving remarkable agreement. This suggests that calculations provide realistic estimates of impact frequencies, velocities and angles. We use these quantities to compare the performances of the different ball mills under working conditions. We test the reliability of our results by studying the kinetics of two mechanically induced transformations, namely the comminution of quartz powders and the dechlorination of chlorobenzene. The specific milling intensity, defined as the product between impact frequency and impact energy divided by the total mass of powder, is shown to be a scaling factor for transformation rates. Accordingly, the kinetic curves for transformations induced at different milling intensity collapse on a single curve when plotted versus the total energy delivered to powders. We created a website to give interested researchers the opportunity of running autonomously numerical simulations using our codes to deepen the insight into the mechanical processing conditions in their ball mills.

Mechanochemical methodologies are reshaping synthetic organic chemistry by enhancing practicality and reducing environmental impact. This review presents a comprehensive account of mechanochemical methods for amide bond formation, arguably the most developed and industrially relevant area within mechanochemical organic synthesis. Covering literature from early contributions to the present (September 2025), the review organization follows key substrate classes and methodological strategies: amide bond formation via coupling of carboxylic acids or their activated derivatives with amines (Section 2), followed by unconventional approaches (Section 3) employing carboxylic acid and amine surrogates, redox chemistry, rearrangements, and transition metal-mediated reactions leading to amide products through alternative bond-forming pathways. Mechanoenzymatic transformations are treated separately (Section 4), with stereochemistry-related issues, such as the preservation of enantiomeric purity, discussed in Section 5. Section 6 highlights the use of amide bond formation as a model system for probing mechanochemical driving forces. Special attention is given to scalability and successful scale-up examples, alignment with green chemistry principles, limitations, unexplored areas, and challenges requiring further development. This review is intended as an accessible and thorough resource for synthetic chemists in both academia and industry, including those newly exploring the field of mechanochemistry, and it provides practical guidance for process optimization and scale-up.

The modulation of physicochemical properties through the discovery of new solid forms has attracted significant interest in the pharmaceutical industry. Herein, a novel cocrystal of lenalidomide with quercetin was designed upon crystal engineering principles. Bearing in mind the importance of developing sustainable methods for the pharmaceutical industry, the synthesis of the novel cocrystals was explored by different mechanochemical approaches and slurry techniques for comparison purposes. Thus, the cocrystal was produced by liquid-assisted grinding in ball milling, liquid-assisted resonant acoustic mixing, and the slurry method. All the methods yielded the same final form with similar properties. From the point of view of properties enhancement, solubility studies showed that the cocrystal exhibited lower solubility than that of pure lenalidomide under simulated conditions of gastric and intestinal fluids, suggesting that the cocrystal may function as an extended-release form of lenalidomide. Furthermore, this cocrystal remained stable under accelerated stability conditions, indicating that atmospheric relative humidity does not represent a risk for the handling or storage of these compounds in the solid state.