A scalable strategy for the convenient and rapid preparation of nitrogen-doped carbon-coated iron-based alloy catalysts was developed. By controlling the type and amount of metal salts in the precursor, various types of nitrogen-doped carbon-coated alloy catalysts can be prepared in a targeted manner. Fe₂Ni₂@CN materials with small particle sizes and relatively homogeneous basic sites showed promising results in the N-alkylation reaction of benzyl alcohol with aniline (optimum yield: 99%). It is worth noting that the catalyst can also be magnetically separated and recovered after the reaction, and its performance can be regenerated through simple calcination. Furthermore, it was confirmed by kinetic experiments that the activation of C–H at the benzyl alcohol benzylic position is the rate-determining step (RDS). According to density flooding theory calculations, Fe₂Ni₂@CN catalysts require less energy than other materials (Fe@CN and Ni@CN) for the RDS (dehydrogenation reaction) process. Therefore N-alkylation reactions are more easily carried out on Fe₂Ni₂@CN catalysts, which may be the reason for the best catalytic activity of Fe-Ni alloy materials. These carbon-coated alloy materials will show great potential in more types of heterogeneous catalysis.

The Fe₃O₄/LaNiO₃ composite, synthesised with the sol-gel method, is considered to be an excellent nanocatalyst for the production of high value-added humic acids from oxidised weathered coal under solid phase milling process conditions. Under optimum process conditions (1% catalyst, 10% activator, 60 min grinding), 48.4% of the weathered coal can be oxidised to produce humic acid. The prepared Fe₃O₄/LaNiO₃ catalyst was characterized by HRTEM, XRD, and XPS, etc. The heterojunction structure that can promote the electron transfer between the components of the composite material was formed with the recombination of Fe₃O₄ and LaNiO₃. The activation of surface oxygen species and adsorbed oxygen could be enhanced with the help of electron transfer between components. Compared to the blank sample or the LaNiO₃ catalyst alone, the molecular weight of the humic acid produced using the Fe₃O₄/LaNiO₃ composite catalyst was significantly lower (maximum heavy mean molecular weight decreased from 59.7 kDa to 5.5 kDa) and the number of reactive groups in humic acid increased (to seven times that of the blank sample). Oxygen-free vacuum experiments indicated that O₂ has an indispensable effect on its excellent catalytic performance in the Fe₃O₄/LaNiO₃ system. In addition, Fe₃O₄/LaNiO₃ could be used at least six times by simple magnetic separation. The development and preparation of perovskite composite catalysts provide a promising approach to the environmentally friendly development and application of weathered coal, as well as an effective method to resolve the associated environmental pollution.

Herein we report the multicomponent synthesis of the bis(indolyl)methane derivatives in a ball mill. The reaction was carried out under solvent-free conditions using only the Lewis acid-surfactant-SiO₂ composite nanocatalyst (LASSC) prepared in situ. The unsymmetrical bis(indolyl) methane derivatives containing nitro or fluorine substitution with a yield of 72%–92% were obtained in a short reaction time. Within we verified that under the action of the combined catalyst of AlCl₃·6H₂O + SDS + SiO₂, the method of preparing unsymmetrical bis(indolyl)methane by mechanical grinding without solvent has obvious advantages. Finally, we inspected that the catalysis system can be used eight times without a significant decrease in activity. Graphical Abstract

The use of mechanical ball milling to facilitate the synthesis of organic compounds has attracted intense interest from organic chemists. Herein, we report a new process for the preparation of xanthene and pyrimidinone compounds by a one-pot method using polymeric aluminum chloride (PAC), silica gel, and reaction raw materials under mechanical grinding conditions. During the grinding process, polymeric aluminum chloride and silica gel were reconstituted in situ to obtain a new composite catalyst (PAC-silica gel). This catalyst has good stability (six cycles) and wide applicability (22 substrates). The Al-O-Si active center formed by in situ grinding recombination was revealed to be the key to the effective catalytic performance of the PAC-silica gel composites by the comprehensive analysis of the catalytic materials before and after use. In addition, the mechanism of action of the catalyst was verified using density functional theory, and the synthetic pathway of the xanthene compound was reasonably speculated with the experimental data. Mechanical ball milling serves two purposes in this process: not only to induce the self-assembly of silica and PAC into new composites but also to act as a driving force for the catalytic reaction to take place. From a practical point of view, this "one-pot" catalytic method eliminates the need for a complex preparation process for catalytic materials. This is a successful example of the application of mechanochemistry in materials and organic synthesis, offering unlimited possibilities for the application of inorganic polymer materials in green synthesis and catalysis promoted by mechanochemistry.

With the consumption of fossil fuels, the level of CO₂ in the atmosphere is growing rapidly, which leads to global warming. Hence, the chemical conversion of CO₂ into high value-added products is one of the most important approaches to reducing CO₂ emissions. Due to being simple, inexpensive and environmentally friendly, the direct synthesis of cyclic carbonates from olefins and CO₂ is a promising project for industrial application. In this review, we discuss the design of the homogeneous and heterogeneous catalytic system for the synthesis of cyclic carbonates from the reaction of olefins and CO₂. Usually, the catalyst contains the epoxidation active site and the cycloaddition active site, which could achieve the oxidation of oleifins and the CO₂-insert, respectively. This review will provide a comprehensive overview of the direct synthesis of cyclic carbonates from olefins and CO₂ catalyzed by homogeneous and heterogeneous catalysts. The focus mainly lies on the rational fabrication of multifunctional catalysts, and provides a new perspective for the design of catalysts.

PLASC catalysts have significant green chemistry properties and can be used as new cheap, efficient and green catalysts.