Mechanochemistry of Gaseous Reactants.

In recent years, the application of mechanical energy to chemical systems has repeatedly proven beneficial to facilitate chemical transformations in various areas in chemistry. Today, a systematic body of evidence indicates that mechanochemistry holds great promise to become a game-changer in chemical synthesis. Not only does mechanochemistry permit access to products that are inaccessible by established means (e.g. purely thermal activation), mechanochemical reactions often outperform their solution-based counterparts in terms of sustainability. Most mechanochemical reactions carried out by ball milling techniques involve transformations of solids and liquids, but the number of mechanochemical reactions with gaseous reactants is increasing. The aim of this Minireview is to provide an overview of recent chemical reactions involving gaseous samples by ball milling techniques and to highlight advances in ball milling technology for the safe handling of gaseous reagents. Examples of reactions proceeding at the interface of solid-/liquid-/gas-gas systems that led to significant improvements in reactivity or selectivity will also be highlighted.