Hong Meng

Methylbutynol (MB) is a typical propargylic alcohol with both alkynyl and hydroxyl groups, featuring excellent modifiability and broad applications. Currently, it is produced through the reaction of alkaline metallic acetylides and acetone, requiring expensive raw material and harsh reaction conditions. Herein, a novel method was proposed by replacing the metallic acetylide with calcium carbide (CaC₂) as a low-cost industrial acetylide reagent. The effects of solvent, activator, and proton donor on the ball mill reaction, and the defoaming performance of the resultant MB and its oxidative coupling product (2,7-dimethyl-3,5-octadiyn-2,7-diol), were studied. Nucleophilic reactivity of CaC₂ with acetone can be regulated by the activating effect of the ball mill, an appropriate activator, and a proton donor. High yield of MB (~94%) was obtained under synergistic action of TBAF·3H₂O and acetylene, which represents a facile synthesis process of MB under mild conditions. MB exhibits good defoaming performance, and 2,7-dimethyl-3,5-octadiyn-2,7-diol is more promising, being an excellent non-ionic defoamer. The result is of great significance for exploring new chemical reactions of CaC₂ and its high-value utilizations.

Carbon dioxide (CO₂) is a greenhouse gas, and its resource use is vital for carbon reduction and neutrality. Herein, the nucleophilic addition reaction of calcium carbide (CaC₂) to CO₂ was studied for the first time to synthesize propiolic and butynedioic acids by using CuI or AgNO₃ as catalyst, Na₂CO₃ as additive, and triphenylphosphine as ligand in the presence/absence of a hydrogen donor. The effects of the experimental conditions and intensification approach on the reaction were investigated. The reactivity of CaC₂ is closely associated with its synergistic activation by the catalysts, solvent, and external intensification, such as the ultrasound and mechanical force. Ultrasound helps to promote the reaction by enhancing the interfacial mass transfer of CaC₂ particulates. Mechanochemistry can effectively promote the reaction, yielding 29.8% of butynedioic acid and 74.8% of propiolic acid after 2 h ball milling at 150 rpm, arising from the effective micronization and interfacial renewal of calcium carbide. The present study sheds a light on the high-value uses of CO₂ and CaC₂ and is of reference significance for the nucleophilic reaction of CaC₂ with other carbonyl compounds.

A green approach that synergistically addresses the resource utilization of CHF ₃ , reduces disposal energy consumption, and mitigates global warming.

We synthesized nitrogen-doped carbon shell encapsulated Ni ₃ Fe alloy catalyst (Ni ₃ Fe-NC/NF) for high-performance water splitting. It exhibits low overpotentials for the OER and HER at a high current density, along with ultralong stability.

The design of an efficient absorbent is the premise for recovery and resource utilization of hydrogen chloride (HCl) from its industrial tail gases. Herein, a series of 1-butyl-3-methylimidazolium chloride (BmimCl) based-deep eutectic solvents (DESs) were designed and the solubility behavior for HCl was studied in terms of their structure, basicity, free volume, intermolecular interaction energy, and absorption enthalpy. The relationship between the interaction energy and the phase change in the HCl dissolution process was explored in detail. BmimCl-TAA (thioacetamide) (1 : 1) shows high reversible solubility due to its high free volume, suitable absorption enthalpy, and closer H-bonding (HB) interactions between BmimCl and TAA or HCl. The dissolution mechanism of HCl and the dynamic evolution of the HB network were verified by FT-IR and NMR spectra and quantum chemical calculations. The results show that it is the competitive HB interaction that promotes the dissolution of HCl, reduces the absorption enthalpy, and renders a reversible absorption. Compared with BmimCl, the absorption enthalpy of HCl in BmimCl-TAA (1 : 1) is reduced by 25% and the reversible solubility increased 150%. The reversible solubility of HCl in BmimCl-TAA (1 : 1) is as high as 0.51 g g⁻¹ (1.76 mol mol⁻¹) at 303.15 K and 101.3 kPa, and the absorbent can be regenerated facilely by heating under reduced pressure. This work provides new insights into the rational design of DES for efficient and reversible absorption of HCl and other polar gases.

Introducing high strength inorganic nanoparticles has emerged as an effective strategy to optimize the comprehensive properties of polymers, but good dispersion must be maintained to avoid clustering of inorganic nanoparticles. We report a novel phosphazene‐coated ZrO₂ nanoparticles (ZrO₂@PZS) prepared by a simple ultrasonic method to further enhance thermal, mechanical, optical properties and flame retardancy of polythiourethane (PTU). ZrO₂@PZS nanoparticles presented good dispersion in composites, with regular spherical core‐shell structures exhibiting significant enhancement effects for overall performance of PTU composites, through strong interfacial interaction. Studies revealed that regular spherical ZrO₂@PZS strengthened thermal and tensile properties of PTU, which reached 62.8°C and 79.28 MPa respectively. More importantly, PTU composites showed good flame retardancy through catalytic carbonization, condensed phase shielding and gas phase dilution effect of ZrO₂@PZS, where the limiting oxygen index was increased to 25.39% from 20.39%. Moreover, the peak heat release rate, total heat release and smoke production rate could be reduced by 23.5%, 27.7% and 40.0%, respectively. In brief, PTU composites show excellent potential in high strength special fireproof lenses.

Polythiourethane (PTU) has attracted considerable attention in engineering building materials. Here, based on phosphazene nanoparticles (PZS‐1 and PZS‐2) prepared by water‐triggered and ultrasonic self‐assembly method, phosphazene/polythiourethane (PZS/PTU) composites with excellent mechanical strength, high flame retardancy and good transparency was obtained. Then, the comprehensive properties of both composites were evaluated, where PZS‐2 endowed PTU with better overall performance. Due to the good dispersibility of PZS and its strengthed interfacial interaction with PTU matrix, both PZS significantly enhanced mechanical and thermal property of PTU, where the tensile strength and glass transition temperature of PZS/PTU composites reached to 84.34 MPa and 59.94°C respectively. More importantly, compared to pure PTU, the values of peak heat release rate (HRR), total heat release rate (THR), smoke production rate (SPR), and total smoke production (TSP) of composites were decreased by 10.5%, 13.3%, 30.6% and 18.0%, respectively. The limiting oxygen index of composites was improved to 21.39% due to the catalytic carbonization of PZS, the expanded carbon layer and the incombustible gases released during combustion. Meanwhile, the PZS/PTU composite exhibited the high refractive index of 1.6580 and good transparency (not less than 85% at 500 nm). The PZS/PTU composite was promising candidates for optical flame retardant coatings and engineering building materials.

Covalent organic frameworks (COFs) are promising materials for advanced molecular-separation membranes, but their wide nanometer-sized pores prevent selective gas separation through molecular sieving. Herein, we propose a MOF-in-COF concept for the confined growth of metal-organic framework (MOFs) inside a supported COF layer to prepare MOF-in-COF membranes. These membranes feature a unique MOF-in-COF micro/nanopore network, presumably due to the formation of MOFs as a pearl string-like chain of unit cells in the 1D channel of 2D COFs. The MOF-in-COF membranes exhibit an excellent hydrogen permeance (>3000 GPU) together with a significant enhancement of separation selectivity of hydrogen over other gases. The superior separation performance for H₂/CO₂ and H₂/CH₄ surpasses the Robeson upper bounds, benefiting from the synergy combining precise size sieving and fast molecular transport through the MOF-in-COF channels. The synthesis of different combinations of MOFs and COFs in robust MOF-in-COF membranes demonstrates the versatility of our design strategy.