Green Chemistry最新文献

Fluoroform (CHF₃) is a byproduct of CHF₂Cl with high global warming potential and long atmospheric lifetime, and its efficient utilization is a great challenge. The mechanochemical reaction between CHF₃ and AlCl₃ was studied for the first time, and the resultant ACFs (AlCl_xF_3−x, x ≈ 0.1) were characterized by ion chromatography, X-ray photoelectron spectroscopy and X-ray diffraction. The reaction mechanism is revealed via experiments and DFT calculation. Here, the reactivity of AlCl₃ is slightly higher than that of AlCl₂F and AlClF₂, while the reactivity of CHF₂Cl and CHFCl₂ is 2 to 6 orders of magnitude higher than that of CHF₃. The reaction is self-accelerated until CHF₃ is fully converted to CHCl₃ and ACFs with controllable F-content. The present work provides a viable approach to convert CHF₃ to CHCl₃ and ACFs at ambient temperature and pressure, which is superior to the mainstream incineration technique with great energy demand and environmental pollution, and sacrifice of the precious F-resource.

Derived from lignocellulosic biomass, sustainable hard carbon has emerged as a promising low-cost anode material for sodium-ion batteries (SIBs). However, the intricate formation process of the hard carbon microstructure remains unclear. This study investigates the structural differences and pyrolysis behaviors of pine lignin and its graded variants obtained through a lignin molecular sieving engineering strategy. Moreover, it delves into the relationship between the microstructure of lignin-derived hard carbon and its sodium-ion storage characteristics. Pristine pine lignin, along with ethanol-isolated lignin, acetone-isolated lignin, and residual lignin, serves as a precursor for synthesizing hard carbon materials. Quantitative analysis via³¹P NMR spectroscopy reveals the highest content of polar functional groups in ethanol-isolated lignin. Interestingly, hard carbon derived from ethanol-isolated lignin exhibits the smallest closed pore volume, leading to the lowest plateau capacity of sodium-ion storage. Conversely, hard carbon derived from acetone-dissolved lignin displays the highest plateau capacity owing to its largest closed pore volume formed in the carbonization process. The origin of open and closed pore structures of hard carbons is thoroughly analyzed.

Selective oxidation of alcohols to aldehydes/ketones is an important reaction in the fine and bulk chemicals fields. However, the classical alcohol oxidation methods are often performed under unfriendly conditions or use stoichiometric oxidants. Herein, we report an ingenious system that enables high selectivity (up to 99%) and high conversion (up to 97%) with high reaction rates in the aerobic oxidation of alcohols to aldehydes/ketones for a broad range of alcohols, proceeding smoothly via mixing the solvent ethyl acetate and HBr under ambient conditions with visible light irradiation. Experimental characterization and theoretical calculations reveal that solvated dispersion intermediates are formed spontaneously in situ through noncovalent interactions among the molecules in the reaction system, which is proposed to be the origin of the high selectivity and high activity of this reaction. The dispersion system provides a feasible activation approach for aerobic oxidation of alcohols to aldehydes/ketones with high performance under visible light.