RSC Mechanochemistry最新文献

The International Symposium on Mechanochemistry (Mech'cheM 2025) took place in Montpellier (France) June 4-6, 2025, gathering 145 mechanochemists across the disciplines. Ten years after Mech'cheM 2015, it was an occasion to assess new progress and developments in the field. In this article, we highlight the main features of the plenary lectures and oral communications, illustrating the dynamic current cutting-edge research activities together with significant applications across the field of chemistry.

Mechano-chemical activation is of rapidly growing interest for producing cementitious constituents from clays. The chemical reactivity of clay minerals is enhanced during intensive grinding, due to mechano-chemical dehydroxylation and mechanically-induced amorphisation. The most widely used grinding apparatus for laboratory-scale studies is a planetary ball mill. It is still largely unknown whether activation efficacy is critically dependent on any individual milling parameter, or whether trade-offs are possible between different parameters. In this study a first principles approach, previously applied to alloy amorphisation, is adopted to estimate the energy of an individual collision event and the total milling input energy. Using a combination of primary data generated through experiments and secondary data from literature, a set of nearly 100 datapoints was analysed. Rapid increases in chemical reactivity were generally observed for <100 kJ g⁻¹ of modelled milling energy input, with a plateau beyond this value. The relationship between chemical reactivity and modelled energy input was well fitted by an exponential type function. For the same modelled milling energy input, a higher gain in chemical reactivity was achieved for the 1 : 1 clay minerals compared to the 2 : 1 clay minerals or mixtures of different clay minerals. No strong trends were observed with individual collision energy, with no clear evidence for the existence of a threshold collision energy. The modelled milling input energy was more effective for predicting reactivity increase than measured energy consumption by the mill. Within the ranges tested, increasing ball : powder ratio or rotation speed seemed to be more energetically efficient at increasing reactivity, compared to increasing milling duration. Results from this study can also aid in selection of milling equipment for scaling up this process.

A rock tumbler used in the field of geology is developed as an apparatus for mechanochemistry performed in the chemistry laboratory. The apparatus supports the formation of a photoactive organic cocrystal and a metal–organic framework, as well as photochemical reactions to be performed within the confines of the assembly.

Lithium-ion batteries are the most common energy storage system for consumer electronics and electric vehicles, and are now emerging into the market for stationary applications. However, their production depends on critical raw materials, such as lithium, nickel, and cobalt. When reaching the end of their life, spent batteries are regarded as toxic waste, underscoring the need for efficient and inexpensive recycling technologies to enable a circular economy. Current recycling technologies exhibit issues, such as wastewater generation and high consumption of energy and chemicals. While the focus has been on the recovery of valuable transition metals, lithium is often not recovered. In this study, we present a deeper investigation of the solvent-free mechanochemical reduction of LiCoO₂ with Al. The combined analysis using XRD, SEM and EDX, together with the observation of a characteristic temperature and pressure profile, proved the reaction to proceed via a mechanically induced self-propagating reaction pathway. A spike in the pressure, detected by an internal sensor in the milling jar, was used to determine the length of the activation phase, which enables a kinematic analysis and the systematic study of milling parameters. Furthermore, the presence of graphite was found to increase the activation time and with a 20% weight fraction, the self-propagating behavior can be suppressed. This research provides important information regarding the application of this process on a real black mass or on a larger scale.

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In this effort, a solvent-free, media-free, mechanochemical route is used to accelerate the synthesis and exploration of an energetic oxidizer : fuel complex. Using magnesium nitrate hexahydrate and glycine as our example, we demonstrate that water from the metal salt is shed with moderate energy input and drives liquid-assisted mechanochemistry. This route reduces synthesis time from days to hours and shows promise for a host of metal salt complexes.

In an effort to introduce alternative methods of post-synthetic functionalization of zeolites, mechanochemistry was utilized for ion exchange and synthesis of transition metal halide and pseudohalide complexes within FAU-type zeolite cages. Structural characterization of the guest molecules shows a variety of synthesized compounds inside the zeolite cavities.

Chemical reactions are conventionally carried out in solution, wherein solvents assume a pivotal role in facilitating the dissolution of reagents and thereby enabling molecular interactions. However, this conventional approach is associated with substantial solvent consumption, waste production, and environmental and safety concerns, while also necessitating protracted reaction times. In recent years, there has been an increase in the study of various mechanochemical methods, with the flow-through mechanochemical approach via reactive extrusion (REX) emerging as one of the most promising alternatives. This process employs screws (single, twin or multiple) to generate mechanical energy (shear, compression and friction) to drive chemical reactions, offering precise control over temperature, mixing and residence time. Typically, REX is performed with minimal or no solvents, which significantly reduces its environmental impact. Furthermore, it ensures shorter reaction times and higher yields. In this review, a comprehensive analysis is conducted on the role of screw configuration, temperature control, and residence time in optimising the outcomes of various reaction types.

Selective syntheses of known 1D-coordination polymers derived from the combination of 4,4′-bipyridine (bipy) or 1,2-bis-(4-pyridyl)ethylene (dpe) with Zn(OAc)₂·2H₂O were achieved under mechanochemical conditions by carefully controlling the mechanochemical parameters, including reaction stoichiometry and the nature of the solvent used in liquid assisted grinding. Ligand exchange reactions performed under grinding conditions showed the conversion of the dpe-containing polymers into bipy-containing polymers, whereas the reverse reactions proved unfeasible. A computational rationale for the observed reactivity is provided. The dimensionality growth of the dpe-containing 1D-coordination polymers into a three-dimensional pillared metal–organic framework was achieved by reaction with terephthalic acid. The same 3D-MOF was also obtained by a one-pot procedure, involving dpe, Zn(OAc)₂·2H₂O and terephthalic acid simultaneously ground in the presence of a small aliquot of N,N-dimethylformamide. All the reactions occurred in high yields affording pure products with a favorable environmental profile, as evidenced by the environmental factor (EF) and reaction mass efficiency (RME) calculated for selective reactions. This work highlights how mechanochemistry not only allows the efficient synthesis of coordination polymers but also their post-synthetic modifications by environmentally benign protocols.

Mechanochemistry has become a powerful and sustainable approach in synthetic chemistry, yet the fundamental principles governing energy transfer during milling remain poorly understood. In particular, the trajectory of the milling ball has been largely overlooked in mechanistic studies. To address this, we employed high-speed recordings to precisely track ball motion, enabling accurate calculation of kinetic energies and their comparison with theoretical values. The use of hollow and solid balls of varying sizes further allowed us to disentangle the effects of altered trajectories in both the Finkelstein reaction and the direct mechanocatalyzed Suzuki coupling. This work underscores the critical importance of milling ball trajectory in mechanochemistry and highlights the need to consider this parameter in future mechanistic studies and in the development of optimized milling protocols.