RSC Mechanochemistry最新文献

The ability to achieve a series of photoreactive solids using dry-vortex grinding that contains trans-1,2-bis(2-pyridyl)ethylene along with 2,4,6-trifluorophenol at different molar ratios is reported. In all cases, mechanochemical grinding generates a three-component hydrogen-bonded co-crystal that undergoes a [2 + 2] cycloaddition reaction. Curiously, the solids formed with a substoichiometric ratio of the template also reached a nearly quantitative yield, since the formation of the photoproduct causes a cascade-like reaction within the solid which shifts the remaining reactant molecules into a suitable position to photoreact.

The bark of Juglans mandshurica (BJM) is a Chinese herbal medicine containing a variety of nutrients and pharmacologically active compounds. Juglone, one of the important active ingredients in BJM, has been shown by many pharmacological studies to have antioxidant, antibacterial, antiviral, anti-tumor, immunoregulatory and other pharmacological properties. Mechanochemistry assisted aqueous two-phase extraction (MAATPE) was successfully established to extract juglone from BJM, combining the purification effect of an alcohol/salt aqueous two-phase system (ATPS) with the high efficiency of mechanochemistry. The key parameters of MAATPE were systematically optimized through single factor analysis and response surface methodology. Under the optimal conditions of an ethanol/NaH₂PO₄ aqueous two-phase system as the liquid reagent, 21.5% (w/w) ethanol concentration, 28% (w/w) NaH₂PO₄ concentration, 458 rpm milling speed, 14 min milling time and 59 mL g⁻¹ reagent–material ratio, the maximum yield of juglone was 15.36 ± 0.16 mg g⁻¹ with a purity of 9.82 ± 0.12% in dry extracts. Compared with other extraction methods, it was found that MAATPE can not only improve the extraction efficiency of juglone, but also achieve higher juglone purity in the products. Finally, the mechanism of action, recyclability and industrial scalability of MAATPE are discussed. In conclusion, MAATPE is an appropriate alternative for the efficient preparation of high-purity products from natural resources.

Per- and poly-fluoroalkyl substances (PFAS) pose a significant environmental and health threat due to their persistence and widespread contamination of water sources. To address this challenge, this study explores the mechanochemical synthesis of two isoreticular highly interpenetrated MOFs, TPPM-mCPW(Ph) and TPPM-mCPW(p-FPh), and investigates the influence of fluorine atoms decorating the framework on the affinity towards these pollutants. Furthermore, the dynamic structural responsiveness of these frameworks to external stimuli has been investigated. Adsorption experiments further highlighted the effect of framework fluorination on PFAS uptake, demonstrating its role in tuning material properties while maintaining structural connectivity. These results underline the potential of mechanochemistry in the discovery of novel metal–organic materials with promising applications in selective guest uptake.

The presented work sets out to investigate the dehydrogenation behaviour of Ca(AlH₄)₂ + 2MCl (M = Li, Na) mixtures. In contrast to the by-product NaCl, which does not affect the decomposition of Ca(AlH₄)₂, LiCl influences its dehydrogenation onward from the formation of CaAlH₅. Thermodynamic calculations were used to support and explain these findings as well as to investigate the potential of Ca(AlH₄)₂ and CaAlH₅ for reversible hydrogen storage applications. For this purpose, their heat capacity functions and absolute entropies were determined in this study.

We present a direct mechanocatalytic approach for the Mizoroki–Heck coupling of aryl iodides with olefins using palladium milling balls as catalyst under elevated temperatures in a ball milling reactor. The high chemoselectivity for C(sp²)–I bonds ensures a single product when employing multi-halogenated arenes. Additionally, a one-pot Wittig olefination/Heck cross-coupling enables direct access to stilbene derivatives from aldehydes and aryl iodides without intermediate isolation.

A free-flowing, homogeneous and non-pyrophoric powder of Na/NaCl is prepared via planetary ball-milling. The mechanochemically micronised Na/NaCl serves as a highly activated source of sodium and was used to prepare [(^ArBDI)Mg]₂ (BDI = HC{(Me)CNAr}₂; Ar = Dipp, 2,6-i-Pr₂C₆H₃; Mes, 2,4,6-CH₃C₆H₂) via ball milling in 75 and 45 minutes, respectively.

Over the last two decades, complex metal hydrides have attracted attention in various fields such as chemical hydrogen storage, solid state electrolytes and superconductivity. In this context, we determined thermodynamic properties of the complex metal hydride Y(BH₄)₃. Yttrium borohydride was prepared by solid state metathesis yielding a mixture containing three equivalents lithium chloride beside the boranate. The benefit of the mechanochemical preparation procedure compared to the classical wet chemical one is to avoid the desolvation step which can lead to a partial decomposition of the hydride. The heat capacity of the compound as a function of the temperature covering a temperature range from 2 K to 370 K was determined using two different calorimetric techniques. Based on the heat capacity data, the standard entropy at 298.15 K was obtained. From the evaluation of the low temperature heat capacity region the Sommerfeld coefficient and the Debye temperature were derived.

In this work, the lead dodecyl sulfate material (Pb(DS)₂) was successfully synthesized for the first time via a mechanochemical ball milling method. The synthesized material was comprehensively analyzed using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and nuclear magnetic resonance (NMR) spectroscopy. The results demonstrate that the Pb(DS)₂ catalyst, synthesized via solvent-free mechanical ball milling, possesses a distinctive solid nanorod morphology. Furthermore, the catalyst efficiently promotes the synthesis of heterocyclic derivatives in a solvent-free environment within 20 minutes, achieving a target product yield of up to 98%. Specifically, it produced bis(indolyl)methane derivatives with yields ranging from 78% to 98%, and quinoxaline derivatives with yields ranging from 87% to 98% within the same timeframe. The Pb(DS)₂ catalyst also exhibits remarkable catalytic activity in the Biginelli reaction. Notably, the catalyst maintains excellent and stable performance over eight recycling cycles.

The interest in the use of mechanochemistry as a green alternative to conventional solution-based synthesis methods has been steadily growing in recent years. Recently, Dual-Function Materials (DFMs) have been explored for the preparation of multicomponent systems which combine a sorbent and a catalytic phase co-supported on a support oxide for the capture of CO₂ from flue gases and its subsequent conversion into added-value products when exposed to H₂ (or CH₄) in a chemical-looping-type reaction. However, the complexity of setting the right milling parameters, which are interconnected and strongly dependent on the precursor materials, is exacerbated in the multi-component system. In this work, we address this issue by employing a Design of Experiments (DoE) statistical approach for the screening of the most relevant milling parameters for the synthesis of Ru–Na/Al₂O₃ DFMs for integrated CO₂ capture and methanation (ICCU-MET). The milling intensity and the organic precursors proved to be the key factors positively affecting the DFMs' capture capacity and CH₄ conversion, respectively.

The repertoire of established mechanophores has been on a steady rise over the last few years, holding the promise of generating materials capable of delivering programmable, beneficial responses upon mechanical stimulation. However, investigations are usually confined to demonstrating activation within limited and seemingly arbitrary choices of polymer matrices. In contrast, the broader applicability of the mechanophore across various types of polymer materials is rarely explored. The experimental techniques generally used to achieve mechanochemical activation are also a source of discrepancy. Ultrasonication of dilute polymer solutions is a popular method that applies extreme strain rates to isolated, solvated chains. The technique is practical and convenient, but its experimental conditions are not conducive to elucidating the activity of the same mechanophore in a bulk polymer system under tensile strain. Here, we report a comparative study on the mechanochemical behaviour of anthracene–maleimide Diels–Alder adducts in a series of polymeric materials. We embed the mechanophores either in the backbone of linear polymers or as cross-links of polymer networks. We show that the solution-phase ultrasonication efficiently activates the mechanophores, regardless of the design of the linear polymer. In contrast, mechanophore activation in bulk is highly dependent on the polymer matrix, topology, and the connectivity of the mechanophore and the matrix.