1-butyl-3-methylimidazolium-chloride and 1-butyl-3-methylimidazolium-tetrafluoroborate

The study of the toxicity, biocompatibility, and environmental sustainability of room-temperature ionic liquids (ILs) is still in its infancy. Understanding the impact of ILs on living organisms, especially from the aquatic ecosystem, is urgent, since large amounts of these substances are starting to be employed as solvents in industrial chemical processes, and on the other side, evidence of toxic effects of ILs on microorganisms and single cells have been observed. To date, the toxicity of ILs has been investigated by means of macroscopic assays aimed at characterizing the effective concentrations (like the EC

Topics: Cell Line, Tumor; Cell Membrane; Elastic Modulus; Epithelial Cells; Humans; Imidazoles; Ionic Liquids; Microscopy, Atomic Force; Molecular Structure

A non-linear model has been developed to estimate the water content of 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium methylsulfate, and 1,3-dimethylimidazolium methylsulfate ionic liquids using their respective refractive index values. The experimental values measured to design the neural network (NN) model were registered at 298.15K. These were determined at different relative humidity values which ranged from 11.1% to 84.3%. The estimated results were compared with experimental measurements of water content obtained by the Karl Fischer technique, and the differences between the real and estimated values were less than 0.06% in the internal validation process. In addition, an external validation test was developed using bibliographical references. In this case, the mean prediction error was less than 5.4%. In light of these results, the NN model shows an acceptable goodness of fit, sufficient robustness, and a more than adequate predictive capacity to estimate the water content of the ILs through the analysis of their refractive index.

Topics: Humidity; Imidazoles; Ionic Liquids; Neural Networks, Computer; Predictive Value of Tests; Refractometry; Temperature; Water

Direct electrochemistry of cytochrome c (cyt-c) entrapped in agarose hydrogel on gold electrode (Au), edge plane pyrolytic graphite electrode (EPPGE) and glassy carbon electrode (GC) in two room temperature ionic liquids was investigated. The effects of the addition of N,N-dimethylformamide (DMF) in the agarose-cyt-c film, water concentration in ionic liquids and exterior metal ions on the electrochemical behavior of cyt-c were monitored, and electrocatalytic properties of cyt-c were also done. Results showed that a good quasi-reversible redox behavior of cyt-c could be found after adding DMF in agarose-cyt-c film, and peak shape would not change after continuously scanning for 50 cycles. In addition, a certain amount of water in hydrophilic ionic liquids is necessary to maintain electrochemical activities of cyt-c, electrochemical performance of cyt-c is the best when the water content is 5.2% and 5.8% for 1-butyl-3-methylimidazolium bromide ([Bmim][Br]) and 1-butyl-3-methylimidazolium tetrafluoroborate([Bmim][BF(4)]) respectively. However, electrochemical activities of cyt-c are inhibited by exterior metal ions. Interestingly, cyt-c entrapped in agarose hydrogel on EPPGE and GC could catalyze the electroreduction of trichloroacetic acid (TCA) and tert-butyl hydroperoxide (t-BuOOH) in [Bmim][BF(4)], but could not in [Bmim][Br]. Reasons for above-mentioned differences of electrochemical properties of cyt-c in different ionic liquids were preliminarily discussed.

Topics: Animals; Biosensing Techniques; Cytochromes c; Electric Impedance; Electrochemical Techniques; Gold; Graphite; Horses; Hydrogel, Polyethylene Glycol Dimethacrylate; Imidazoles; Ionic Liquids; Sepharose

Thenanofiltration of aqueous solutions of the ionic liquids (ILs) 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF(4)), and 1-butyl-3-methylimidazolium bromide ([Bmim]Br) with a polyamide nanofiltration membrane was investigated. The practical transport coefficients, including hydrodynamic permeability (L(p)), reflection (sigma) and solute permeability (omega) were calculated in terms of a non-equilibrium thermodynamics approach. It was found that L(p) and sigma diminished as the concentration of the IL solutions increased. These characteristics are similar to those observed in inorganic electrolyte-water systems. In addition, it was shown that the rejection and volume flux for both ionic liquid solutions rose with feed pressure, while it decreased with feed concentration. The maximum rejection efficiencies for [Bmim]Br and [Bmim]BF(4) are 67 % and 60 %, respectively, on our experimental scale. All the data suggests that a highly efficient process for IL separation could be developed when the operating conditions are optimized further.

Topics: Filtration; Imidazoles; Ionic Liquids; Nanostructures; Nylons; Solutions; Thermodynamics; Water

The aggregation behavior of long-chain ionic liquids 1-alkyl-3-methylimidazolium bromide (C(n)mimBr) in another ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF(4)), was studied for the first time. Surface tension measurements revealed that aggregates are formed by C(n)mimBr, and freeze fracture transmission electron microscopy (FF-TEM) observations suggested the aggregates are spheres with a size much larger than traditional micelles. The sizes of the aggregates were further confirmed by dynamic light scattering (DLS) measurements.

Topics: Borates; Imidazoles; Ionic Liquids; Microscopy, Electron, Transmission; Models, Chemical; Surface Properties; Surface Tension

Ionic liquids (ILs) are low-melting organic salts that are being researched intensively as possible environmentally friendly replacements for volatile organic solvents. Despite their nonmeasurable vapor pressure, some quantities of ILs soon will be present in effluent discharges because solubility of ILs in water is small, but far from negligible. Therefore, it is important to understand how ILs will influence aquatic ecosystems. In the present study, the toxic effects of imidazolium-based ILs (1-butyl-3-methylimidazolium cation associated with bromide [BMIM] [Br] and tetrafluoroborate [BMIM] [BF4]) to the freshwater green alga Selenastrum capricornutum were investigated. Two approaches were followed to quantify toxicity of these compounds: Analyses of photosynthetic activity and cell proliferation. The obtained data showed that the relative declines of growth rates generally were more pronounced than those of photosynthetic activity. The ecotoxicity of a range of common organic solvents also was examined. It was revealed that both imidazolium-based ILs studied were some orders of magnitude more toxic than methanol, isopropanol, and dimethylformamide. In addition, with respect to IL incorporating perfluorinated anion, EC50 values (concentrations which lead to a 50% reduction of the exposed organisms relative to control) of the previously prepared stock solution were significantly lower compared to those of the freshly made one. This might be due to hydrolytic effects of [BMIM][BF4] leading to fluoride formation, which was confirmed by ion chromatography analysis. This indicates that, after ILs are discharged into the aqueous system, they can become more toxic than expected by laboratory data with fresh ILs.

Topics: Biosensing Techniques; Borates; Cell Proliferation; Chlorophyta; Dose-Response Relationship, Drug; Ecosystem; Imidazoles; Ionic Liquids; Photosynthesis; Reproducibility of Results; Sensitivity and Specificity; Time Factors; Toxicity Tests

In this paper, the application of 1-n-butyl -3-methylimidazolium-based ionic liquids aqueous solutions as solvents in the microwave-assisted extraction (MAE) technique was first developed for the extraction of trans-resveratrol from Rhizma Polygoni Cuspidati. 1-butyl-3-methylimidazolium bromide ([bmim]Br) solution was selected as solvent; the conditions of MAE including the size of sample, liquid/solid ratio, extraction temperature and time were optimized by means of an orthogonal design L(9)(3(4)). Under optimized conditions, the extraction yield value of trans-resveratrol was 92.8% in a one-step extraction. The recovery was in the range 93.7-103.2% with relative standard deviation lower than 3.0% by the proposed procedure. The method was applied to extract trans-resveratrol from several different region samples. On the basis of extraction solvent and time, the proposed extraction technique was a green, rapid and alternative technique to extract and analyze trans-resveratrol in Rhizma Polygoni Cuspidati samples.

Topics: Borates; Chemical Fractionation; Chromatography, High Pressure Liquid; Fallopia japonica; Imidazoles; Microwaves; Resveratrol; Solvents; Stilbenes

The solubility of H(2)S in a series of 1-butyl-3-methylimidazolium ([bmim](+)) based ionic liquids (ILs) with different anions, chloride, tetrafluoroborate ([BF(4)](-)), hexafluorophosphate ([PF(6)](-)), triflate ([TfO](-)), and bis(trifluoromethyl)sulfonylimide ([Tf(2)N]-), and in a series of [Tf(2)N] ILs with different cations, i.e., N-alkyl-N'-methylimidazolium, 2-methyl-N-methyl-N'-alkyimidazolium, N-alkylpyridinium, N-butyl-N-methylpyrrolidinium, and N-alkyl-N,N-dimethyl-N-(2-hydroxyethyl)ammonium has been determined using medium-pressure NMR spectroscopy. The observed solubilities are significantly higher than those reported for many other gases in ILs, suggesting the occurrence of specific interactions between H2S and the examined ILs. Quantum chemical calculations have been used to investigate at a molecular level the interaction between H2S and the [bmim](+)-based ILs.

Topics: Anions; Borates; Hydrogen Sulfide; Imidazoles; Magnetic Resonance Spectroscopy; Models, Molecular; Quantum Theory; Solubility; Thermodynamics

Molecular dynamics simulations of the liquid/vacuum surfaces of the room temperature ionic liquids [bmim][PF(6)], [bmim][BF(4)] and [bmim][Cl] have been carried out at various temperatures. The surfaces are structured with a top monolayer containing oriented cations and anions. The butyl side chains tend to face the vacuum and the methyl side chains the liquid. However, as the butyl chains are not densely packed, both anions and rings are visible from the vacuum phase. The effects of temperature and the anion on the degree of cation orientation is small, but the potential drop from the vacuum to the interior of the liquid is greater for liquids with smaller anions. We compare the simulation results with a range of experimental observations and suggest that neutron reflection from samples with protiated butyl groups would be a sensitive probe of the structure.

Topics: Borates; Computer Simulation; Imidazoles; Ions; Solutions; Surface Tension; Temperature