Fast proton conductor under anhydrous condition synthesized from 12-phosphotungstic acid and ionic liquid

In this study, we synthesized a molecular hybrid conductor electrolyte using PWA ([H₃PW₁₂O₄₀·nH₂O]) and [1-butyl-3-methylimidazole][bis-(fluoromethanesulfonyl) amide] ([BMIM][TFSI]) ionic liquid. The [BMIM][TFSI] ionic liquid can interact with the strongly acidic PWA. The hybrids were hydrophilic, and included some water molecules in the structure of the hybrids. The water molecules remained up to 80 °C, contributing to improve conductivity under an anhydrous N₂ atmosphere. The conductivity of PWA-[BMIM][TFSI] hybrid under anhydrous conditions increased from 10⁻⁴ S/cm to 0.04 S/cm at 60 °C. The conductivity of the hybrids at each temperature was higher than that of pure PWA and [BMIM][TFSI] under anhydrous condition. It can be due to the protonic carriers.     

Ionic Liquids and Salts from Ibuprofen as Promising Innovative Formulations of an Old Drug

Herein we report the synthesis of novel ionic liquids (ILs) and organic salts by combining ibuprofen as anion with ammonium, imidazolium, or pyridinium cations. The methodology consists of an acid–base reaction of neutral ibuprofen with cation hydroxides, which were previously prepared by anion exchange from the corresponding halide salts with Amberlyst A-26(OH). In comparison with the parent drug, these organic salts display higher solubility in water and biological fluids and a smaller degree of polymorphism, which in some cases was completely eliminated. With the exception of [C₁₆Pyr][Ibu] and [N_1,1,2,2OH1][Ibu], the prepared salts did not affect the viability of normal human dermal fibroblasts or ovarian carcinoma (A2780) cells. Therefore, these ibuprofen-based ionic liquids may be very promising lead candidates for the development of effective formulations of this drug.     

Ionic Liquid Catalyzed 4,6-Disubstituted-3-Cyano-2-Pyridone Synthesis Under Solvent-Free Conditions

Abstract  

A green protocol for the synthesis of 4,6-disubstituted-3-cyano-2-pyridones from cyanoacetamides and 1,3-dicarbonyl compounds or chalcones using guanidine based ionic liquid as catalyst has been developed. In solvent-free conditions at 30 °C, [TMG][Lac] (1,1,3,3-tetramethylguanidine lactate) was found to have the highest catalytic activity among the ionic liquids including [TMG][Ac] (1,1,3,3-tetramethylguanidine acetate), [TMG][Pr] (1,1,3,3-tetramethylguanidine propionate), [TMG][n-Bu] (1,1,3,3-tetramethylguanidine n-butyrate) and [TMG][TFA] (1,1,3,3-tetramethylguanidine trifluoroacetate). The catalyst was recovered and recycled several times without significant loss of catalytic activity.     

Novel ionic liquids as reaction medium for ATRP of acrylonitrile in the absence of any ligand

Atom transfer radical polymerization (ATRP) of acrylonitrile (AN) with ethyl 2-bromoisobutyrate (EBiB) as the initiator was firstly approached in the absence of any ligand in three novel ionic liquids, 1-methylimidazolium acetate ([mim][AT]), 1-methylimidazolium valerate ([mim][VT]) and 1-methylimidazolium caproate ([mim][CT]), respectively. All the polymerizations in the ionic liquids proceeded in a well-controlled manner. The polymerization in [mim][AT] not only showed the best control of molecular weight and its distribution but also provided a rather rapid reaction rate with the molar ratio of [AN]:[FeBr₂]:[EBiB] at 200:2:1. The resulting polyacrylonitrile was successfully used as the macroinitiator to proceed the chain extension polymerization in [mim][AT]. After simple purification, all the ionic liquids and FeBr₂ could be recycled and reused and had no effect on the living nature of polymerization.     

Modified COSMO-UNIFAC model for ionic liquid–CO2 systems and molecular dynamic simulation

A new predictive molecular thermodynamic model (i.e., modified COSMO-SAC-UNIFAC) was first proposed and extended to predict the solubility of CO₂ in pure and mixed ionic liquids (ILs) at the temperatures down to 263.2 K. It is interesting to discover that with equimolar amounts, the solubility of CO₂ in such 1:1 IL pairs, that is, [A₁][B₁] + [A₂][B₂] and [A₁][B₂] + [A₂][B₁], was consistent at the same temperature and pressure in the case of exchanging their respective cations and anions. The molecular dynamic (MD) simulation for CO₂ + mixed ILs was performed to deeply analyze and explain this intriguing phenomenon. Not only the CO₂ gas drying experiment with the ILs ([C2mim][OAc], [C2mim][dca], and [C2mim][OAc] + [C2mim][dca]) as absorbents but also the corresponding process simulation and optimization were made to stress the effectiveness and applicability of the new thermodynamic model. Thus, this work ranges from molecular level to systematic scale.     

Raman Microscopic Study of Japanese Beech (Fagus crenata) As Treated with the Ionic Liquid, 1-Ethyl-3-Methylimidazolium Chloride

The chemical changes in various morphological regions of Japanese beech (Fagus crenata) upon treatment with the ionic liquid 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]), which preferentially dissolves cellulose, have been investigated by Raman microscopy. The reactivity of polysaccharides and lignin with [C2mim][Cl] differed depending on the types of wood tissues. Chemical components in parenchyma cells showed higher resistance to degradation upon [C2mim][Cl] treatment than wood fiber and vessel. In addition, the lignin structure was partially degraded or modified by [C2mim][Cl] treatment, and its binding mode was complicated; nevertheless, lignin was stable in [C2mim][Cl].     

Simple, efficient and recyclable palladium catalytic system for Heck reaction in functionalized ionic liquid network

In functionalized ionic liquid network of [BMIM][TPPMS] and [BMIM][OAc], PdCl₂(CH₃CN)₂ efficiently catalyzed the Heck reaction of bromobenzene to ethyl cinnamate with yield of 60% and without the activity loss even after 11 recycling uses. The beneficial influences of this ionic liquid network on activity and stability were explained in terms of synergic ligand effects of [BMIM][TPPMS] and [BMIM][OAc], no accumulation of sodium or ammonium bromides by using [BMIM][OAc] as base, and the positive effect of [BMIM]Br by avoiding the formation of palladium black. The generality of this ionic liquid system to the different substrates also gave the pleasing results.     

Performance and pressure drop of CO2 absorption into task-specific and halide-free ionic liquids in a microchannel

The gas–liquid two-phase flow pattern, absorption rate and pressure drop of CO₂ absorbed into the aqueous solution of the task-specific ionic liquids (1-aminopropyl-3-methylimidazole tetrafluoroborate [Apmim][BF₄] and 1-hydroxyethyl-3-methylimidazole tetrafluoroborate [OHemim][BF₄]) and halide-free ionic liquid 1-butyl-3-methylimidazolium methylsulfate [Bmim][CH₃SO₄] were investigated in a microreactor. The absorption mechanism of the three ionic liquids was analyzed employing the ¹³C NMR spectroscopy. The [Apmim][BF₄] was found to have the best ability of CO₂ capture compared with the other two ionic liquids, as chemical absorption occurred between [Apmim][BF₄] and CO₂, while only physical absorption took place between [OHemim][BF₄]/[Bmim][CH₃SO₄] and CO₂. The sequence of CO₂ absorption rate in three ionic liquids aqueous solutions is: [Apmim][BF₄] > [Bmim][CH₃SO₄] > [OHemim][BF₄]. Furthermore, the effects of gas–liquid flow rate and ionic liquids concentration on CO₂ absorption rate and pressure drop were studied, the pressure drop models based on various flow patterns were proposed.     

Physical and electrochemical properties of 1-(2-hydroxyethyl)-3-methyl imidazolium and N-(2-hydroxyethyl)-N-methyl morpholinium ionic liquids

Various ionic liquids (ILs) were prepared via metathesis reaction from two kinds of 1-(2-hydroxyethyl)-3-methyl imidazolium ([HEMIm]⁺) and N-(2-hydroxyethyl)-N-methyl morphorinium ([HEMMor]⁺) cations and three kinds of tetrafluoroborate ([BF₄]⁻), bis(trifluoromethanesulfonyl)imide ([TFSI]⁻) and hexafluorophosphate ([PF₆]⁻) anions. All the [HEMIm]⁺ derivatives were in a liquid state at room temperature. In particular, [HEMIm][BF₄] and [HEMIm][TFSI] showed no possible melting point from −150 °C to 200 °C by DSC analysis, and their high thermal stability until 380-400 °C was verified by TGA analysis. Also, their stable electrochemical property (electrochemical window of more than 6.0 V) and high ionic conductivity (0.002-0.004 S cm⁻¹) further confirm that the suggested ILs are potential electrolytes for use in electrochemical devices. Simultaneously, the [HEMMor]⁺ derivatives have practical value in electrolyte applications because of their easy synthesis procedures, cheap morpholinium cation sources and possibilities of high Li⁺ mobility by oxygen group in the morpholinium cation. However, [HEMMor]⁺ derivatives showing high viscosity usually had lower ionic conductivities than [HEMIm]⁺ derivatives.     

Purification of ionic liquids by supercritical CO2 monitored by infrared spectroscopy

Transmission infrared and Attenuated Total Reflection (ATR) in situ infrared spectroscopies were combined for the time-resolved monitoring of both liquid and supercritical phases during extraction of water and other impurities from ionic liquids with supercritical carbon dioxide (scCO₂). Cleaning and drying by scCO₂ at 100 bar and 40 °C proved to be efficient for all ionic liquids tested, including 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF₄]), 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF₆]), and 1-butyl-3-methylimidazolium trifluoromethansulfonate ([bmim][TfO] or [bmim] triflate). Despite the moderate solubility of water in scCO₂ compared to other classical solvents, the amount of water decreased continuously during the drying. The extraction could be followed by simple transmission IR spectroscopy of the supercritical phase. During the extraction, organic impurities and water were removed rapidly from the ionic liquid phase as scCO₂ improved the transport properties in the ionic liquids.     

Preparation of well-defined dendrimer encapsulated ruthenium nanoparticles and their application as catalyst and enhancement of activity when utilised as SCILL catalysts in the hydrogenation of citral

Silica supported dendrimer encapsulated ruthenium nanoparticles were prepared and evaluated as catalysts in the hydrogenation of citral. The dendrimer encapsulated nanoparticles were prepared using the generation 4 (G4), generation 5 (G5) and generation 6 (G6) hydroxyl-terminated poly(amidoamine) (PAMAM-OH) dendrimers as templating agents with different Ru metal:dendrimer ratios. The effects of ionic liquids as catalyst coatings on the catalytic activity were investigated for the ionic liquids [BMIM][NTf₂], [OMIM][NTf₂], [BMIM][BF₄], [BMIM][PF₆], [EMIM][OcS] and [EMIM][EtS]. An enhancement in catalytic activity was observed when utilising [BMIM][NTf₂] as an ionic liquid coating with selectivity towards citronellal.     

Enhanced stability of <Emphasis Type="Italic">Candida antarctica</Emphasis> lipase B in ionic liquids

The activity and stability of lipase from Candida antarctica were investigated in the kinetic resolution of (R,S)-1-phenylethanol with vinyl acetate using ionic liquids (ILs) as reaction media. Among ILs tested, the highest activity of lipase was observed in [Edmim][Tf₂N]. In hydrophobic ILs such as [Edmim][Tf₂N], [Emim][Tf₂N] and [Pmim] [PF₆], lipase could retain its activity after 5 times reuse, while the activity of lipase in hydrophilic ILs and organic solvents was drastically decreased. The activities of lipase in [Edmim][Tf₂N], [Emim][Tf₂N] and [Pmim][PF₆] were also well maintained after 1 day incubation at 80 °C. The lipase suspended in [Edmim][Tf₂N] could be successfully reused 6 times without loss of activity.     

Promoting the sulfuric acid catalyzed isobutane alkylation by quaternary ammonium ionic liquids

Seven typical quaternary ammonium ionic liquids, amino acid ionic liquids, and imidazolium ionic liquids were synthesized, characterized, and investigated as co-catalyst for the sulfuric acid catalyzed isobutane alkylation. The results show that the introduction of [OPSIm][HSO₄] or [Pr₃NPS][HSO₄] both leads to a better catalytic performance and higher quality of alkylate products. The molecular dynamic simulation indicates that the [OPSIm][HSO₄] can promote the dissolution of isobutane molecules at interface, further improving the ratio of isobutane to olefin from 1.02 to 1.18. Differently, the [Pr₃NPS][HSO₄] can significantly increase the interface width from 0.66 to 0.97 nm and reduce the interface tension from 28.49 to 14.62 mN/m, thereby enhancing the reaction area and improving the ion transfer. The [Pro][HSO₄] and [Gly][HSO₄] result in a worse quality of alkylate products due to no positive effect on the interfacial properties such as interfacial solubility of isobutane.     

A Novel Prostate-Specific Membrane-Antigen (PSMA) Targeted Micelle-Encapsulating Wogonin Inhibits Prostate Cancer Cell Proliferation via Inducing Intrinsic Apoptotic Pathway

Prostate cancer (PCa) is a malignant tumor for which there are no effective treatment strategies. In this study, we developed a targeted strategy for prostate-specific membrane-antigen (PSMA)-positive PCa in vitro based on 2-(3-((S)-5-amino-1-carboxypentyl)ureido) pentanedioic acid (ACUPA) modified polyethylene glycol (PEG)-Cholesterol micelles containing wogonin (WOG), which was named ACUPA-M-WOG. ACUPA-M-WOG was conventionally prepared using a self-assembling method, which produced stable particle size and ζ potential. Moreover, ACUPA-M-WOG showed good drug encapsulating capacity and drug release profiles. Fluorescence activated cell sorting (FACS) results suggested that ACUPA modified PEG-Cholesterol micelles could effectively enhance the drug uptake on PSMA(+) PCa cells, and the cytotoxicity of ACUPA-M-WOG was stronger than other controls according to in vitro cellular proliferation and apoptosis assays, separately through methyl thiazolyl tetrazolium (MTT) and Annexin V/Propidium Iodide (PI) staining. Finally, the molecular mechanisms of ACUPA-M-WOG’s effects on human PSMA(+) PCa were investigated, and were mainly the intrinsic or extrinsic apoptosis signaling pathways. The Western blot results suggested that ACUPA-M-WOG could enhance the WOG-induced apoptosis, which was mainly via the intrinsic signaling pathway rather than the extrinsic signaling pathway. In conclusion, ACUPA-M-WOG was successfully developed for WOG-selective delivery to PSMA(+) PCa cells and had stronger inhibition than free drugs, which might make it an effective strategy for PSMA(+) PCa.     

Antitumor Activity of Ionic Liquids Based on Ampicillin

Significant antiproliferative effects against various tumor cell lines were observed with novel ampicillin salts as ionic liquids. The combination of anionic ampicillin with appropriate ammonium, imidazolium, phosphonium, and pyridinium cations yielded active pharmaceutical ingredient ionic liquids (API‐ILs) that show potent antiproliferative activities against five different human cancer cell lines: T47D (breast), PC3 (prostate), HepG2 (liver), MG63 (osteosarcoma), and RKO (colon). Some API‐ILs showed IC₅₀ values between 5 and 42 nM , activities that stand in dramatic contrast to the negligible cytotoxic activity level shown by the ampicillin sodium salt. Moreover, very low cytotoxicity against two primary cell lines—skin (SF) and gingival fibroblasts (GF)—indicates that the majority of these API‐ILs are nontoxic to normal human cell lines. The most promising combination of antitumor activity and low toxicity toward healthy cells was observed for the 1‐hydroxyethyl‐3‐methylimidazolium–ampicillin pair ([C₂OHMIM][Amp]), making this the most suitable lead API‐IL for future studies.     

Screening of ionic liquids as entrainers for the separation of 1-propanol + water and 2-propanol + water mixtures using COSMO-RS model

The COSMO-RS model was used to screen potential ionic liquids for the separation of aqueous azeotropic mixtures 1-propanol?+?water and 2-propanol?+?water. A combination of 22 cations (involving imidazolium, pyridinium, pyrrolidinium, quinolinium, and ammonium) and 36 anions were investigated. The anions chloride [Cl] and dihydrogen phosphate [H₂O₄P] were found to strongly influence the vapor liquid equilibrium behavior, whereas the ammonium-based cations diethanol ammonium [(Et)₂AMM]⁺ and tetra methyl ammonium [M₄AMM]⁺ were the most promising cations. In addition, the study of mixing enthalpy and excess Gibbs free energy confirmed that the molecular interaction of ionic liquids with water was found to be much larger than that with alcohols 1-propanol and 2-propanol, indicating the presence of a strong hydrogen bonding between the ionic liquids and water. Further, the addition of ionic liquids to the alcohol–water mixture reduces the activity coefficient of water and increases the relative volatility of the mixture, facilitating easier separation. Ionic liquids [(Et)₂AMM][Cl], [(Et)₂AMM][H₂O₄P], [M₄AMM][Cl], and [M₄AMM][H₂O₄P] are expected to be effective entrainers for the separation of the industrially important 1-propanol?+?water and 2-propanol?+?water systems.     

Synthesis of Fluorinated Imidazole[4,5f][1,10]phenanthroline Derivatives as Potential Inhibitors of Liver Cancer Cell Proliferation by Inducing Apoptosis via DNA Damage

Phenanthroline derivatives containing fluorinated imidazole ring are effective anti-neoplastic agents. Herein, a series of four fluorinated imidazole[4,5f][1,10]phenanthroline derivatives were synthesized and investigated as potential inhibitors to fight against the growth of liver cancer cells. The in vitro antitumor activity of targeted compounds have been evaluated by using MTT assay, and results showed that compound 4 (2-(2,3-difluorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) exhibited excellent inhibitory effect against the growth of various tumor cells, particularly for HepG2 cells, with IC₅₀ value of approximately 0.29 μM. This result has been further confirmed by colony formation assay, showing that compound 4 suppressed the proliferation of HepG2 cells. Moreover, cell apoptosis (AO/PI dual staining and flow cytometry) analyses as well as comet assay showed that compound 4 may induce apoptosis of HepG2 cells through triggering DNA damage. Furthermore, the in vivo anti-tumor activity were evaluated on zebrafish bearing HepG2 cells showed that compound 4 can observably block the growth of liver cancer cells. All in together, these compounds, particularly compound 4 , may be developed as a potential agent to treat liver cancer in the future.     

Effect of immobilization of titanocene catalyst in aralkyl imidazolium chloroaluminate media on performance of biphasic ethylene polymerization and polyethylene properties

1-(2-Phenylethyl)-3-methylimidazolium and 1-benzyl-3-methylimidazolium chloroaluminates, [Ph-C₂mim][AlCl₄] and [Bzlmim][AlCl₄], were applied as media of the Cp₂TiCl₂ catalyst for biphasic ethylene polymerization. The studied aralkyl ionic liquids ensure greater stability of the catalyst at higher temperatures and more regular morphology of the produced polyethylene than analogous 1-n-alkyl-3-methylimidazolium chloroaluminates. The alkylaluminium compound participates in the termination reaction of the polymer chain. The catalyst is stable and enables recycling of the ionic liquid phase in the consecutive polymerization reactions. The [Ph-C₂mim][AlCl₄] ionic liquid and AlEt₂Cl alkylaluminium compound turned out to be the most suitable for the biphasic process. The influence of the kind of ionic liquid, alkylaluminium compound (AlEt₂Cl and AlEtCl₂), activator/catalyst molar ratio, reaction temperature, reaction time and catalyst recycling on the polymerization performance as well as polyethylene properties such as molecular weight (M _w ), polydispersity, melting temperature, crystallinity degree, bulk density and particle size is presented.     

CO2 absorption properties of Brønsted acid-base ionic liquid composed of N,N-dimethylformamide and bis(trifluoromethanesulfonyl)amide

The solubilities of CO₂ and the liquid densities in a Brønsted acid-base ionic liquid, [DMFH][Tf₂N], composed of N,N-dimethylformamide (DMF) and bis(trifluoromethanesulfonyl)amide (HTf₂N) have been investigated at high pressures and at different temperatures. The results were compared with those in DMF and a typical 1-butyl-3-methylimidazolium analogue with the same anion, [BMIM][Tf₂N]. The mole fraction scaled solubilities of CO₂ in the three liquids showed a slight increase in the following order, DMF < [DMFH][Tf₂N] < [BMIM][Tf₂N], whereas more remarkable difference was observed in the volume scaled concentrations of CO₂, [BMIM][Tf₂N] < [DMFH][Tf₂N] « DMF, mainly due to the bulkiness of liquid entities.