Toxic solvents and catalysts, tedious monomer synthesis, as well as long reaction time significantly limit the sustainable and large-scale preparation and practical application of microporous polyimides (MPIs). In this work,...

ILs with reversible construction of ionic networks, which mainly consist of cooperative hydrogen bonds (CHBs) were designed for sigmoidal ammonia (NH3) absorption isotherm, which leads to efficient absorption, energy-saving desorption, and high reversibility. Combined with NH3 absorption–desorption experiments, spectroscopic investigations, NH3–TPD measurement, and quantum-chemical calculations, NH3 absorption mechanism was proposed as the hydrogen bond interaction with IL by overcoming the heat for disorganizing ionic networks, including CHBs breakage and the phase change of IL from solid to liquid. Reversely, the NH3 desorption would be promoted by the heat release for the reformation of ionic networks. Thereinto, [BzAm]­[Tf2N] with ionic networks showed NH3 absorption with threshold pressure at 0.28 bar and NH3 capacity of 2.8 mol NH3/mol IL at 1 bar as well as be desorpted completely just through pressure swing, calorimetric test indicated the exothermic reformation of ionic networks provided 31.8% of energy for NH3 desorption from [BzAm]­[Tf2N]. Furthermore, the ammonia capacity as well as the threshold pressure would be changed by varying the CHBs interaction in IL, that [2PyH]­[Tf2N] with weaker interaction of CHBs indicating decreased threshold pressure at 0.04 bar and enhanced NH3 capacity of 3.8 mol NH3/mol IL at 1 bar. We believe this highly efficient and reversible process by reversible construction of absorbents can provide a potential alternative for NH3 as well as other gas absorption.

Hyper-crosslinking polymers and its immobilized acid ionic liquid catalyst were prepared using cheap pitch, as a monomer, through hyper-crosslinking reactions and allyl chloride, as a chlorine source, for chloromethylation and further grafting with imidazole and functionalizing with sulfonic acid. The polymers were characterized by FE-SEM, FTIR, TG, and nitrogen sorption. The grafting ratios of the chloromethylated pitch-based hyper-crosslinked polymer (HCPpitch–CH2–Cl) and immobilized acid ionic liquid [HCPpitch–Im–Pros][Tos] were 3.5 mmol/g and 3.0 mmol/g, and the BET specific surface areas were 520 m2/g and 380 m2/g, respectively. This strategy provides an easy approach to preparing highly stable and acid functionalized mesoporous catalysts. The immobilized acidic ionic liquid was used as a catalyst for the esterification of oleic acid and methanol to synthesize biodiesel. The results demonstrated that under the optimal conditions of an alcohol to acid molar ratio of 7:1, ionic liquid to oleic acid molar ratio of 0.12, and a reaction time of 3 h at atmospheric pressure, the yield of methyl oleate can reach up to 93%. Moreover, the catalyst was reused five times without the yield decreasing significantly. This study shows that [HCPpitch–Im–Pros][Tos] is a robust catalyst for the synthesis of biodiesel.

An efficient strategy for enhancing CO2 capture performance based on 2-hydroxyl pyridium anion-functionalized ILs was reported via the reduction of cation–anion interactions in ILs.

The effective conversion of carbon dioxide (CO2) into cyclic carbonates requires porous materials with high ionic content and large specific surface area. Herein, we developed a new systematic post-synthetic modification strategy for synthesizing imidazolium-based hypercrosslinked ionic polymers (HIPs) with high ionic content (up to 2.1 mmol g−1) and large specific surface area (385 m2 g−1) from porous hypercrosslinked polymers (HCPs) through addition reaction and quaternization. The obtained HIPs were efficient in CO2 capture and conversion. Under the synergistic effect of high ionic content, large specific surface area, and plentiful micro/mesoporosity, the metal-free catalyst [HCP-CH2-Im][Cl]-1 exhibited quantitative selectivities, high catalytic yields, and good substrate compatibility for the conversion of CO2 into cyclic carbonates at atmospheric pressure (0.1 MPa) in a shorter reaction time in the absence of cocatalysts, solvents, and additives. High catalytic yields (styrene oxide, 120 °C, 8 h, 94% yield; 100 °C, 20 h, 93% yield) can be achieved by appropriately extending the reaction times at low temperature, and the reaction times are shorter than other porous materials under the same conditions. This work provides a new strategy for synthesizing an efficient metal-free heterogeneous catalyst with high ionic content and a large specific surface area from HCPs for the conversion of CO2 into cyclic carbonates. It also demonstrates that the ionic content and specific surface area must be coordinated to obtain high catalytic activity for CO2 cycloaddition reaction.

The development of simple and highly effective desulfurization technology is attracting more and more interest in both industrial and academic fields. Here, a new family of precursors was prepared based on hyper-cross-linked asphalt and coal tar building blocks. Thanks to the preintroduced porous structure, the precursors were converted into carbons with high surface area and large micropore volume via a uniform carbonization process. The synergistic effects of high surface area, abundant microporous structure, and the introduced polar functional groups endow the carbon materials with high desulfurization performance. The results of repeated experiments show that the adsorption capacities of five carbonized samples are higher than 40 mg S g −1 , and the theoretical maximum adsorption capacity reaches 44.7 mg S g −1 . Particularly, the adsorption equilibrium of all the carbonized samples can be reached in 5 min. Moreover, the recycle adsorption performance was also studied. Toluene exhibits the best elution effect among three eluents (isooctane, para-xylene, and toluene) and the adsorption capacity remains 89% of the initial adsorption capacity after two adsorption− desorption cycles. It is believed that both innocent treatment of byproducts from petroleum industry and their high-value application for deep desulfurization in liquid hydrocarbon fuels benefit environmental protection and sustainable development.

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