Imidazolium Bromide Ionic Liquid Research Articles

Ionic liquid auxiliary exfoliation of WS2 nanosheets and the enhanced effect of hollow gold nanospheres on their photoelectrochemical sensing towards human epididymis protein 4

Ionic liquid functionalized tungsten disulfite nanosheets (IL-WS2) were prepared by using 1-vinyl-3-(3-aminopropyl)-imidazolium bromide (VAPimBr) ionic liquid as an auxiliary reagent to exfoliate WS2 bulk crystals in N-methyl pyrrolidone with ultrasonication. Hollow gold nanospheres (HGNs) were controllably synthesized by using 1,3-di(3-bromopropyl)-imidazolium bromide ionic liquid as the functional monomer. HGNs were integrated onto IL-WS2 nanosheet surface to fabricate a HGNs/IL-WS2 nanocomposite through the interaction between S and Au atoms. VAPimBr ionic liquid and HGNs can significantly enhance the photocurrent response of IL-WS2 nanosheets. Human epididymis protein 4 antibody (anti-HE4) was immobilized onto the HGNs/IL-WS2 nanocomposite modified glassy carbon electrode (GCE) surface. Followed by being treated with glutaraldehyde vapor and bovine serum albumin (BSA), a photoelectrochemical immunosensor for human epididymis protein 4 (HE4) was successfully constructed and denoted as anti-HE4/HGNs/IL-WS2/GCE. The photoelectrochemical variation upon interacting with HE4 was used for the quantitative assay. Experimental conditions including the exfoliation time, the amount of VAPimBr ionic liquid, HGNs size, ascorbic acid concentration, incubation time, incubation temperature have been optimized. Under optimal conditions, HE4 was determined by using the photoelectrochemical immunosensor in a dynamic linear range from 0.1 pg mL−1 to 10 ng mL−1 with a detection limit of 0.03 pg mL−1 (S/N = 3). HE4 in clinical serum samples were also accurately determined with satisfied results.

Structural Variation in Homopolymers Bearing Zwitterionic and Ionic Liquid Pendants for Achieving Tunable Multi-Stimuli Responsiveness and Hierarchical Nanoaggregates

A series of monomers comprising units bearing both imidazolium bromide ionic liquid (IL) and zwitterionic imidazolium alkyl carboxylate moieties with different alkyl spacer groups are designed and synthesized. RAFT polymerization of these monomers produces a new class of ionic homopolymers, named poly(zwitterionic ionic liquid)s (PZILs), which behave like poly(ionic liquid)s as well as poly(zwitterion)s depending on the solution pH. Such PZILs exhibit an isoelectric point (pI) at pH 5.7, where they exist in their zwitterionic form, making them dual responsive to both pH and temperature. Above pH 5, the aqueous transparent solution of PZIL transforms into turbid suspension due to the formation of insoluble hierarchical nanoaggregates (NAs) of various morphologies such as small spheres, large spheres, flower-like, dendrite-shaped, and dendritic fibril-like depending upon the solution pH and PZILs’ structures. The dissolution of aggregates upon heating and reaggregation upon cooling suggests existence of rev...

Preparation of organic-inorganic hybrid poly(ionic liquids) material and evaluation of the adsorption to dyes

An organic-inorganic hybrid poly(ionic liquids) material was prepared by using allyl triethoxysilane and 1-vinyl-3-octyl imidazolium bromide ionic liquids via combining free radical polymerization with sol-gel process. The prepared hybrid poly(ionic liquids) material was characterized by infrared spectroscopy and scanning electron microscopy. The adsorption properties of the prepared material to common dyes such as tartrazine, sunset yellow, amaranth and allura red were investigated. The results showed that the prepared poly(ionic liquids) material had excellent adsorption properties to sunset yellow and allura red. The adsorption capacities were 29.20 and 86.17 mg/g, respectively. When the adsorption time was 5 min, the material showed a fast adsorption rate to allura red and sunset yellow, which were 87.5% and 72.8% of the balance adsorption capacities, respectively.

Protein/ionic liquid/glassy carbon sensors following analyte focusing by ionic liquid micelle collapse for simultaneous determination of water soluble vitamins in plasma matrices

Two novel sensors based on human serum albumin (HSA)–ionic liquid (IL) and bovine serum albumin (BSA)–ionic liquid (IL) composites modified glassy carbon electrode (GCE) were produced for simultaneous determination of water soluble vitamins B2, B6 and C in human plasma following analytes focusing by IL micelles collapse (AFILMC). For selective and efficient extraction, vitamins were dissolved in 3.0molL−1 micellar solution of 1-octyl-3-methyl imidazolium bromide IL. The extracted vitamins were hydrodynamically injected by 25mbar for 20s into a running buffer of 12.5mmolL−1 phosphate at pH 6.0 followed by electrochemical detection (ECD) on protein/1-octyl-3-methyl imidazolium hexafluorophosphate IL/GC sensors. The chemical stability of proposed sensors was achieved up to 7 days without any decomposition of PF6-based IL/protein and adsorption of interfering ions. In the current work, the sensitivity enhancement factor (SEF) up to 5000-fold was achieved using the AFILMC/ECD setup compared to conventional CE/UV. Under optimal conditions, linear calibration graphs were obtained from 0.5, 0.5 and 1.0 to 1500.0µgmL−1 of vitamins B2, B6 and C, respectively. Detection limits of analytes were ranged from 180.0 to 520.0ngmL−1. The proposed AFILMC/ECD setup was successfully applied to the assay of trace level quantification of vitamins in human plasma samples and also their binding constants with HSA and BSA were determined. The concurrent use of IL micelles for the proposed separation and detection processes exhibited some advantages, such as, a reduction of use toxic solvents, an efficient extraction and a direct injection of samples with a short-single run. Furthermore, IL micelles, having variable possibility of interactions, facilitated the successful achievements of AFILMC/ECD setup for the quantification of vitamins in plasma matrices.

Preparation and evaluation of a novel hybrid monolithic column based on pentafluorobenzyl imidazolium bromide ionic liquid

To develop a novel hybrid monolithic column based on pentafluorobenzyl imidazolium bromide ionic liquid, a new ionic liquid monomer was synthesized from 1-vinylimidazole and pentafluorobenzyl bromide. By employing a facile one-step copolymerization of polyhedral-oligomeric-silsesquioxane-type (POSS) cross-linking agent and the home-made ionic liquid monomer, the hybrid monolithic columns were in situ fabricated in fused-silica capillary. The morphology of monolithic column was characterized by scanning electron microscope (SEM) and the chemical composition was confirmed by Fourier-transform infrared spectroscopy (FT-IR) and elemental analysis. Excellent mechanical stability and slight swelling propensity were exhibited which was ascribed to the rigid hybrid monolithic skeleton. Reproducibility results of run-to-run, column-to-column, batch-to-batch and day-to-day were investigated and the RSDs were less than 0.46%, 1.84%, 3.96% and 3.17%, respectively. The mixed-mode retention mechanism with hydrophobic interaction, π–π stacking, ion-exchange, electrostatic interaction and dipole–dipole interaction was explored systematically using analytes with different structure types. Satisfied separation capability and column efficiency were achieved for the analysis of small molecular compounds such as alkylbenzenes, polycyclic aromatic hydrocarbons, nucleosides and halogenated compounds.

Eco-friendly ionic liquid assisted capillary electrophoresis and α-acid glycoprotein-assisted liquid chromatography for simultaneous determination of anticancer drugs in human fluids.

In the current work, two eco-friendly analytical methods based on capillary electrophoresis (CE) and reversed phase liquid chromatography (RPLC) were developed for simultaneous determination of the most commonly used anticancer drugs for Hodgkin's disease: methotrexate (MTX), vinblastine, chlorambucil and dacarbazine. A background electrolyte (BGE) of 12.5 mmol/L phosphate buffer at pH 7.4 and 0.1 µmol/L 1-butyl-3-methyl imidazolium bromide (BMImBr) ionic liquid (IL) was used for CE measurements at 250 nm detection wavelength, 20 kV applied voltage and 25 °C. The rinsing protocol was significantly improved to reduce the adsorption of IL on the interior surface of capillary. Moreover, RPLC method was developed on α-1-acid glycoprotein (AGP) column. Mobile phase was 10 mmol/L phosphate buffer at pH 6.0 (100% v/v) and flow rate at 0.1 mL/min. As AGP is a chiral column, it was successfully separated l-MTX from its enantiomer impurity d-MTX. Good linearity of quantitative analysis was achieved with coefficients of determinations (r(2) ) >0.995. The stability of drugs measurements was investigated with adequate recoveries up to 24 h storage time under ambient temperature. The limits of detection were <50 and 90 ng/mL by CE and RPLC, respectively. The using of short-chain IL as an additive in BGE achieved 600-fold sensitivity enhancement compared with conventional Capillary Zone Electrophoresis (CZE). Therefore, for the first time, the proposed methods were successfully applied to determine simultaneously the analytes in human plasma and urine samples at clinically relevant concentrations with fast and simple pretreatments. Developed IL-assisted CE and RPLC methods were also applied to measure MTX levels in patients' samples over time.

Comparative antioxidant status in freshwater fish Carassius auratus exposed to eight imidazolium bromide ionic liquids: A combined experimental and theoretical study

Imidazolium bromide ionic liquids such as 1-alkyl-3-methylimidazolium bromides ([AMIm]Br) and 1-alkyl-2,3-dimethylimidazolium bromides ([AMMIm]Br) are common-use organic salts. However, data on comparative toxicological effects of these ILs are lacking for fish. In this study, a combined experimental and theoretical approach was applied to compare and analyze the effects of these ILs on biochemical biomarkers in liver of Carassius auratus treated with different concentrations (2 and 20mg/L) for 3 and 16d. Changes in the activities of superoxide dismutase, catalase, glutathione peroxidase, and in the levels of reduced glutathione and malondialdehyde were detected, indicating that these ILs exhibit potential biotoxicity. The integrated biomarker response (IBR) index suggested that 1-hexyl-3-methylimidazolium bromide ([HMIm]Br), 1-octyl-3-methylimidazolium bromide ([OMIm]Br), 1-hexyl-2,3-dimethylimidazolium bromide ([HMMIm]Br), and 1-octyl-2,3-dimethylimidazolium bromide ([OMMIm]Br) showed the highest biotoxicity under different concentrations or exposure time, while 1-ethyl-3-methylimidazolium bromide ([EMIm]Br) always showed the least stressful power towards the test organism. Quantum chemical calculations (electronic parameters, frontier molecular orbitals, and Wiberg bond order) were also conducted to interpret the experimental results. Notably, some descriptors were correlated with the toxicity order. In addition, theoretical calculations provided some valuable information on metabolic pathways of these ILs, which may help to get better understanding on their environmental behavior and fate. In general, the toxicological determination and analysis of these ILs were performed with a combined experimental and theoretical method, which may contribute to the future ecotoxicological studies.

Atomistic simulations of the solid-liquid transition of 1-ethyl-3-methyl imidazolium bromide ionic liquid

Achieving melting point around room temperature is important for applications of ionic liquids. In this work, molecular dynamics simulations are carried out to investigate the solid-liquid transition of ionic liquid 1-ethyl-3-methyl imidazolium bromide ([emim]Br) by direct heating, hysteresis, void-nucleation, sandwich, and microcanonical ensemble approaches. Variations of the non-bonded energy, density, diffusion coefficient, and translational order parameter of [emim]Br are analyzed as a function of temperature, and a coexisting solid-liquid system is achieved in the microcanonical ensemble method. The melting points obtained from the first three methods are 547 ± 8 K, 429 ± 8 K, and 370 ± 6 K; while for the sandwich method, the melting points are 403 ± 4 K when merging along the x-axis by anisotropic isothermal-isobaric (NPT) ensemble, 393 ± 4 K when along the y-axis by anisotropic NPT ensemble, and 375 ± 4 K when along the y-axis by isotropic NPT ensemble. For microcanonical ensemble method, when the slabs are merging along different directions (x-axis, y-axis, and z-axis), the melting points are 364 ± 3 K, 365 ± 3 K, and 367 ± 3 K, respectively, the melting points we get by different methods are approximately 55.4%, 21.9%, 5.1%, 14.5%, 11.6%, 6.5%, 3.4%, 3.7%, and 4.3% higher than the experimental value of 352 K. The advantages and disadvantages of each method are discussed. The void-nucleation and microcanonical ensemble methods are most favorable for predicting the solid-liquid transition.

Ionothermally synthesized sandwich-type phosphotungstate

A new sandwich-type phosphotungstate compound, H3(Emim)7[Ni4(Mim)2(PW9O34)2]·4H2O, was successfully synthesized. We used the ionothermal method with 1-ethyl-3-methyl imidazolium bromide ([Emim]Br) ionic liquids (ILs) to synthesize the compound. We characterized the material using X-ray diffraction, elemental analysis, infrared spectroscopy, thermogravimetric analyses, electrochemistry and photocatalysis. The crystal state of the sandwich-type phosphotungstate was: Monoclinic; space group C2/c; a = 35.584(7) ; b = 14.513(3) ; c = 24.423(5) ; α = 90.000°; β= 101.38(3)°; γ= 90.000°; V = 12365(4) 3; and Z = 4. The polyoxoanion of the sandwich-type phosphotungstate is two methylimidazole molecules and a modified sandwich-type hybrid tungstophosphate [Ni4(Mim)2(PW9O34)2]10-. In the packing arrangement, the adjacent hybrid polyoxoanions of the compound are connected through C-H-O hydrogen bonds between the dissociative [Emim]+ cations and the surface oxygen atoms of the polyoxoanions. This structure forms a three-dimensional open-framework.

Synthesis of dimethyl carbonate from ethylene carbonate and methanol using immobilized ionic liquid on amorphous silica

Ionic liquid immobilized on mesoporous amorphous silica was prepared from the coupling of 1-(triethoxysilylpropyl)-3- n-alkyl-imidazolium halides with tetraethyl orthosilicate (TEOS) through template-free condensation under strong acidic conditions. The immobilized 1- n-butyl-3-methyl imidazolium bromide ionic liquid on amorphous silica (BMImBr-AS) was characterized by EA, N 2 adsorption, FT-IR, 13C NMR and 29Si NMR. The immobilized amount of IL was 1.27 mmol/g-SiO 2 and surface area was 652 m 2/g with bimodal distribution of pores. The average pore diameter was 3.3 and 24.6 nm, respectively. The silica-supported ionic liquids were proved to be an effective heterogeneous catalyst for the synthesis of dimethyl carbonate (DMC) from transesterification of ethylene carbonate (EC) with methanol. High temperature, high carbon dioxide pressure, and longer reaction time were favorable for the reactivity of BMImBr-AS. The catalyst can be reused for the reaction up to three consecutive runs with a slight decrease of its catalytic activity.

Ionothermal synthesis of gallophosphate molecular sieves in 1-alkyl-3-methyl imidazolium bromide ionic liquids

Gallophosphate (GaPO 4) molecular sieves were ionothermally prepared in 1-alkyl-3-methyl imidazolium bromide ionic liquids (ILs) with alkyl chain length varying from 2 to 6 carbons for the first time. Three kinds of GaPO 4 materials such as GaPO 4-a, cloverite (denoted as CLO below) and GaPO 4-LTA were obtained, and their structures and morphologies were characterized by powder and single crystal XRD, SEM and multi-nuclear NMR. In the case of 1-ethyl-3-methyl imidazolium bromide ionic liquid, large single crystals of GaPO 4-LTA with well-defined octahedral morphology was obtained in both sealed (ca. 400 μm in size) and open vessels (ca. 300 μm in size). Ionothermal synthesis is an effective method for the preparation of large single crystal of molecular sieves. With the alkyl chain length of the ionic liquids increasing from 2 carbons to 6 carbons, the size of GaPO 4-LTA decreased sharply. The organic template cations in the as-synthesized GaPO 4-LTA crystals may have two different kinds of conformational structures. Fluorine plays a role of co-template along with organic cations of ILs in the synthesis of GaPO 4-LTA and CLO, while only GaPO 4-a was obtained in the absence of fluorine. The reaction temperature can also affect the structure of the final structure. In the reaction medium of 1-ethyl-3-methyl imidazolium bromide IL, GaPO 4-LTA was obtained at 180 °C, while CLO was obtained at 150 °C.

Ionothermal Synthesis of Magnesium‐Containing Aluminophosphate Molecular Sieves and their Catalytic Performance

MAPO-11 molecular sieves (see figure) were successfully synthesized by using the ionothermal method in 1-butyl 3-methyl imidazolium bromide ionic liquid. Catalysts based on this material supported by platinum were applied in the hydroisomerization of n-dodecane and exhibited excellent catalytic performance.

Synthesis and characterization of hybrid molecular material prepared by ionic liquid and silicotungstic acid

Abstract A white colour IL-SiWA hybrid molecular material has been synthesized using 1-butyl 3-methyl imidazolium bromide ionic liquid and silicotungstic acid. The material is found to dissolve in polar organic solvent such as DMSO, but not in water. It is characterized by CHN analysis, FTIR, XRD, UV–vis DRS, TGA and SEM. The FTIR spectra indicate the formation of a hybrid compound showing fingerprint vibrational bands of both Keggin ions of silicotungstic acid and imidazolium ions. There is a strong evidence of interaction between the Keggin anions and imidazolium cations from the UV–vis DR spectra and the splitting of imidazolium C–H bands in the IR spectrum of the IL-SiWA. The near IR shows loss of crystallization water from heteropoly acid when it reacts with ionic liquid forming the hybrid molecular material.

Characterization of hybrid molecular material prepared by 1-butyl 3-methyl imidazolium bromide and phosphotungstic acid

A hybrid molecular material has been synthesized using 1-butyl 3-methyl imidazolium bromide ionic liquid and phosphotungstic acid. The material formed is a white colour solid which dissolves in dimethyl sulfoxide (DMSO) but not in water. It is characterised by CHN analysis, FTIR, UV–Vis DRS and 31P MAS NMR. The FTIR spectra indicate the formation of a hybrid molecular compound showing fingerprint vibrational bands of both Keggin and imidazolium ions.

1-Alkyl-3-methyl Imidazolium Bromide Ionic Liquids in the Ionothermal Synthesis of Aluminium Phosphate Molecular Sieves

The systematic increase in alkyl chain length from 2 to 5 carbons in 1-alkyl-3-methyl imidazolium bromide ionic liquids is investigated in the ionothermal synthesis of aluminophosphate (AlPO) zeolite materials in sealed autoclaves. The effect of alkyl chain branching and the use of an imidazolium dication ionic liquid are also investigated. On addition of HF to the reaction mixture, a small amount of 1,3-dimethylimidazolium cation is formed in all cases (except when the alkyl chain length is 2), which acts as the structure directing agent (SDA) in the formation of AlPO molecular sieves with the CHA framework (SIZ-10). For 1-ethyl-3-methyl imidazolium bromide ionic liquids, the cation is incorporated intact into the SIZ-4 structure. The resulting materials are characterized by single-crystal X-ray diffraction and 13C MAS NMR.

Microwave Assisted Dealkylation of Alkyl Aryl Ethers in Ionic Liquids.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Microwave Assisted Dealkylation of Alkyl Aryl Ethers in Ionic Liquids

Alkyl aryl ethers undergo selective dealkylation in 1-butyl pyridinium bromide and 1-butyl-3-methyl imidazolium bromide ionic liquids under microwave irradiation to give the corresponding phenols in high yields. The ionic liquids serve the dual purpose of solvent as well as reagent and allow easy isolation of products.