Search Results (10)

Strategic utilization of carbon dioxide as both a carbon mitigation tool and a sustainable C1 feedstock represents a pivotal pathway toward green chemistry. Although poly(ionic liquid)s (PILs) exhibit promise in CO₂ conversion, conventional divinylbenzene (DVB) cross-linked architectures are limited by reduced ionic density and limited accessibility of active sites. Herein, we reported a binuclear imidazolium-functionalized PIL catalyst (P-BVIMCl), synthesized through a simple self-polymerization process, derived from rationally designed ionic liquid monomers formed by quaternization of 1,4-bis(chloromethyl)benzene with N-vinylimidazole. The dual active sites in P-BVIMCl-quaternary ammonium cation (N⁺) and nucleophilic chloride anion (Cl⁻) synergistically enhanced CO₂ adsorption/activation and epoxide ring-opening. Under optimal catalyst preparation conditions (100 °C, 24 h, water/ethanol = 1:3 (v/v), 10 wt% AIBN initiator) and reaction conditions (100 °C, 2.0 MPa CO₂, 10 mmol epichlorohydrin, 6.7 wt% catalyst loading, 3.0 h), P-BVIMCl catalyzed the synthesis of glycerol carbonate (GLC) with a yield of up to 93.4% and selectivity of 99.6%, maintaining activity close to 90% after five cycles. Systematic characterization and density functional theory (DFT) calculations confirmed the synergistic activation mechanism. This work established a paradigm for constructing high-ionic-density catalysts through molecular engineering, advancing the development of high-performance PILs for industrial CO₂ valorization. Full article

The reaction of octakis(3-chloropropyl)octasilsesquioxane with four equivalents of 1-hexylimidazole or 1-decylimidazole gave two products labelled as HQ-POSS (hexyl-imidazolium quaternized POSS) and DQ-POSS (decyl-imidazolium quaternized POSS) as regioisomer mixtures. An investigation of the biological activity of these two compounds revealed the higher antimicrobial performances of HQ-POSS against Gram-positive and Gram-negative microorganisms, proving its broad-spectrum activity. Due to its very viscous nature, HQ-POSS was adsorbed in variable amounts on the surface of biologically active oxides to gain advantages regarding the expendability of such formulations from an applicative perspective. Titania and 5 wt% Cu on titania were used as supports. The materials 10HQ-POSS/Ti and 15HQ-POSS/5CuTi strongly inhibited the ability of Pseudomonas PS27 cells—a bacterial strain described for its ability to handle very toxic organic solvents and perfluorinated compounds—to grow as planktonic cells. Moreover, the best formulations (i.e., 10HQ-POSS/Ti and 15HQ-POSS/5CuTi) could prevent Pseudomonas PS27 biofilm formation at a certain concentration (250 μg mL⁻¹) which greatly impaired bacterial planktonic growth. Specifically, 15HQ-POSS/5CuTi completely impaired cell adhesion, thus successfully prejudicing biofilm formation and proving its suitability as a potential antifouling agent. Considering that most studies deal with quaternary ammonium salts (QASs) with long alkyl chains (>10 carbon atoms), the results reported here on hexylimidazolium-based POSS further deepen the knowledge of QAS formulations which can be used as antifouling compounds. Full article

Membranes made up of composite materials have shown promising advantages for application in alkaline fuel cell anion exchange membranes. In this study, a general method is employed to improve the overall performance and properties of alkaline anion exchange membranes by making use of polyethersulfone quaternized with imidazolium groups and blended with imidazolium functionalized graphene oxide inorganic filler (ImGO). The inorganic filler blended with the polymer matrix yielded better ionic transport, with 73.2 mS·cm⁻¹ being the highest ion conductivity for the polymer membrane with 0.5% ImGO content, which is higher than that of the QPES parent material. The 0.5% ImGO content also showed better swelling ratio, water uptake, alkaline stability, ion exchange capacity and alkaline stability in comparison to other membranes. Furthermore, it also exhibited 130 mW·cm⁻² peak power. Full article

The development of bifunctional ionic polymers as heterogeneous catalysts for effective, cocatalyst- and metal-free cycloaddition of carbon dioxide into cyclic carbonates has attracted increasing attention. However, facile fabrication of such polymers having high numbers of ionic active sites, suitable types of hydrogen bond donors (HBDs), and controlled spatial positions of dual active sites remains a challenging task. Herein, imidazolium-based ionic polymers with hydroxyl/carboxyl groups and high ionic density were facilely prepared by a one-pot quaternization reaction. Catalytic evaluation demonstrated that the presence of HBDs (hydroxyl or carboxyl) could enhance the catalytic activities of ionic polymers significantly toward the CO₂ cycloaddition reaction. Among the prepared catalysts, carboxyl-functionalized ionic polymer (PIMBr-COOH) displayed the highest catalytic activity (94% yield) in the benchmark cycloaddition reaction of CO₂ and epichlorohydrin, which was higher than hydroxyl-functionalized ionic polymer (PIMBr-OH, 76% yield), and far exceeded ionic polymer without HBDs groups (PIMBr, 54% yield). Furthermore, PIMBr-COOH demonstrated good recyclability and wide substrate tolerance. Under ambient CO₂ pressure, a number of epoxides were smoothly cycloadded into cyclic carbonates. Additionally, density functional theory (DFT) calculation verified the formation of strong hydrogen bonds between epoxide and the HBDs of ionic polymers. Furthermore, a possible mechanism was proposed based on the synergistic effect between carboxyl and Br⁻ functionalities. Thus, a facile, one-pot synthetic strategy for the construction of bifunctional ionic polymers was developed for CO₂ fixation. Full article

Anion exchange membrane fuel cells (AEMFCs) are considered superior to their counterpart proton exchange fuel cells due to their many advantages. Both fuel cells use membranes as polymer electrolytes to improve fuel-cell properties and power output. This work evaluates a series of imidazolium-quaternized poly(2,6-dimethyl-1,4-phenylene oxide) (ImPPO) functionalized zeolitic imidazole framework-8 (ZIF-8) (ImPPO/ZIF-8) as anion exchange membrane (AEM) electrolytes in a direct methanol alkaline fuel cell. FTIR and ¹H NMR were used to confirm the successful membrane fabrication. SEM and TGA were used to study the morphological and thermal stability properties of the ImPPO/ZIF-8 membranes. The AEMs obtained in this work had contact angles ranging from 55.27–106.73°, water uptake from 9–83%, ion exchange capacity (IEC) from 1.93–3.15 mmol/g, and ion conductivity (IC) from 1.02–2.43 mS/cm. The best-performing membrane, ImPPO/3%ZIF-8, showed a water uptake of up to 35% at 80 °C, a swelling ratio of 15.1% after 72 h, IEC of 4.06 mmol/g, and IC of 1.96 mS/cm. A power density of 158.10 mW/cm² was obtained. This makes ZIF-8 a good prospect as a filler for enhancing membrane properties. Full article

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. Full article

Imidazoline is a five-membered heterocycle derived by the partial reduction of one double bond of the imidazole ring. This work prepared new anion exchange membranes (AEMs) based on imidazoline quaternized polystyrene copolymers bearing N-b-hydroxyethyl oleyl imidazolinium pendent groups to evaluate the application potential for anion exchange membrane fuel cells (AEMFCs). For comparison, an imidazole quaternized polystyrene copolymer was also synthesized. The polymer chemical structure was confirmed by FTIR, NMR, and TGA. In addition, the essential properties of membranes, including ion exchange capacity (IEC), water uptake, and hydroxide conductivity, were measured. The alkaline stabilities of imidazolium-based and imidazolinium-based AEMs were compared by means of the changes in the TGA thermograms, FTIR spectra, and hydroxide conductivity during the alkaline treatment in 1 M KOH at 60 °C for 144 h. The results showed that the imidazolinium-based AEMs exhibited relatively lower hydroxide conductivity (5.77 mS/cm at 70 °C) but much better alkaline stability compared with the imidazolium-based AEM. The imidazolinium-based AEM (PSVBImn-50) retained 92% of its hydroxide conductivity after the alkaline treatment. Besides, the fuel cell performance of the imidazolium-based and imidazolinium-based AEMs was examined by single-cell tests. Full article

Dicationic ionic liquids present a novel class of ionic liquids composed of dication and two monoanions; the latter have shown an increasing interest in recent years and are used in many applications. Compared to conventional ionic liquids, the physicochemical properties of dicationic ionic liquids can be set by modifying the languor and the type of chains linking the cationic heads as well as the type of cation. In this work, we present the synthesis of three dicationic ionic liquids based on imidazolium with two steps; the first of which is a quaternization reaction leading to the formation of dicationic ionic liquids with the iodide ion. The characterization of these organic salts was carried out by magnetic resonance spectroscopy, allowing a better identification of the products obtained. Full article

A focused array of green imidazolium ionic liquids (ILs) encompassing benzothiazole ring and amide linkage were designed and synthesized using quaternization and metathesis protocols. The synthesized ILs have been fully characterized by usual spectroscopic methods and screened for their anticancer activities against human cancer cell lines originating from breast and colon cancers. Collectively, our biological data demonstrate that the newly synthesized series has variable anticancer activities in the examined cancer types. The synthesized ILs 8, 10 and 21–29 comprising the methyl and methyl sulfonyl benzothiazole ring emerged as the most potent compounds with promising antiproliferative activities relative to their benzothiazole ring counterparts. Furthermore, the mechanism underlying the observed anticancer activity was investigated. The most active compound 22 appears to exert its anticancer effect through apoptosis dependent pathway in breast cancer cells. Interestingly, compound 22 has also shown good in silico absorption (81.75%) along with high gastro-intestinal absorption as per ADME predictions. Full article

In this study, imidazolium brushes tethered by –NH₂-containing ligands were grafted onto the surface of a 2D material, MXene, using precipitation polymerization followed by quaternization. Functionalized MXene was embedded into chitosan matrix to prepare a hybrid alkaline anion exchange membrane. Due to high interfacial compatibility, functionalized MXene was homogeneously dispersed in chitosan matrix, generating continuous ion conduction channels and then greatly enhancing OH⁻ conduction property (up to 172%). The ability and mechanism of OH⁻ conduction in the membrane were elaborated based on systematic tests. The mechanical-thermal stability and swelling resistance of the membrane were evidently augmented. Therefore, it is a promising anion exchange membrane for alkaline fuel cell application. Full article