1-butyl-3-methylimidazolium-hexafluorophosphate and 1-butyl-3-methylimidazolium-tetrafluoroborate

The joint toxicities of [BMIM]BF

Topics: Acetylcholinesterase; Borates; Cholinesterase Inhibitors; Drug Synergism; Imidazoles; Inhibitory Concentration 50; Ionic Liquids; Kinetics; Models, Chemical; Toxicity Tests

Lipases catalyze the hydrolysis and synthesis of triglycerides and their reactions are widely used in industry. The use of ionic liquids has been explored in order to improve their catalytic properties. However, the effect of these compounds on kinetic parameters of lipases has been poorly understood. A study of the kinetic parameters of Lip1, the most thermostable lipase from the supernatant of the strain ID17, a thermophilic bacterium isolated from Deception Island, Antarctica, and a member of the genus Geobacillus is presented. Kinetic parameters of Lip1 were modulated by the use of ionic liquids BmimPF6 and BmimBF4. The maximum reaction rate of Lip1 was improved in the presence of both salts. The highest effect was observed when BmimPF6 was added in the reaction mix, resulting in a higher hydrolytic activity and in a modulation of the catalytic efficiency of the enzyme. However, the catalytic efficiency did not change in the presence of BmimBF4. The increase of the reaction rates of Lip1 promoted by these ionic liquids could be related to possible changes in the Lip1 structure. This effect was measured by quenching of tryptophan fluorescence of the enzyme, when it was incubated with each liquid salt. In conclusion, the hydrolytic activity of Lip1 is modulated by the ionic liquids BmimBF4 and BmimPF6, improving the reaction rate and the catalytic efficiency of this enzyme when BmimPF6 was used. This effect is probably due to changes in the structure of Lip1 induced by the presence of these ionic liquids, stimulating its catalytic activity.

Topics: Antarctic Regions; Geobacillus; Imidazoles; Ionic Liquids; Kinetics; Lipase; Protein Structure, Secondary

A rapid, sensitive and efficient analytical method based on the use of ionic liquids for determination of non-steroidal anti-inflammatory drugs (NSAIDs) in water samples was developed. High-performance liquid chromatography equipped with a diode array and fluorescence detector was used for quantification of ketoprofen, ibuprofen and diclofenac in tap and river water samples. This new method relies on the use of two ionic liquids with multiple functionalities: one functions as an extraction solvent (1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), and the other changes the polarity in the aqueous medium (1-butyl-3-methylimidazolium tetrafluoroborate, ([BMIM][BF4]). Factors such as the type and volume of the ILs and dispersive solvent, sample volume, and centrifugation time were investigated and optimized. The optimized method exhibited good precision, with relative standard deviation values between 2% and 3%, for the three NSAIDs. Limits of detection achieved for all of the analytes were between 17 and 95 ng mL(-1), and the recoveries ranged from 89% to 103%. Furthermore, the enrichment factors ranged from 49 to 57. The proposed method was successfully applied to the analysis of NSAIDs in tap and river water samples.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Chromatography, High Pressure Liquid; Diclofenac; Fluorescence; Ibuprofen; Imidazoles; Ionic Liquids; Ketoprofen; Liquid Phase Microextraction; Water Pollutants, Chemical

A series of imidazolium and pyridinium ionic liquids with different anions (Cl(-), Br(-), BF₄(-), PF₆(-)) has been evaluated for their adsorption activity on silica gel. Quantification of the ionic liquids has been performed by the use of RP-HPLC with organic-aqueous eluents containing an acidic buffer and a chaotropic salt. Pseudo-second order kinetic models were applied to the experimental data in order to investigate the kinetics of the adsorption process. The experimental data showed good fitting with this model, confirmed by considerably high correlation coefficients. The adsorption kinetic parameters were determined and analyzed. The relative error between the calculated and experimental amount of ionic liquid adsorbed at equilibrium was within 7%. The effect of various factors such as initial ionic liquid concentration, temperature, kind of solvent, kind of ionic liquid anion and cation on adsorption efficiency were all examined in a lab-scale study. Consequently, silica gel showed better adsorptive characteristics for imidazolium-based ionic liquids with chaotropic anions from aqueous solutions in comparison to pyridinium ionic liquids. The adsorption was found to decrease with the addition of organic solvents (methanol, acetonitrile) but it was not sensitive to the change of temperature in the range of 5-40 °C.

Topics: Acetonitriles; Adsorption; Halogens; Imidazoles; Ionic Liquids; Kinetics; Methanol; Silica Gel; Solid Phase Extraction; Thermodynamics

Field Cycling Nuclear Magnetic Resonance (FC NMR) relaxation studies are reported for three ionic liquids: 1-ethyl-3- methylimidazolium thiocyanate (EMIM-SCN, 220-258 K), 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF4, 243-318 K), and 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6, 258-323 K). The dispersion of (1)H spin-lattice relaxation rate R1(ω) is measured in the frequency range of 10 kHz-20 MHz, and the studies are complemented by (19)F spin-lattice relaxation measurements on BMIM-PF6 in the corresponding frequency range. From the (1)H relaxation results self-diffusion coefficients for the cation in EMIM-SCN, BMIM-BF4, and BMIM-PF6 are determined. This is done by performing an analysis considering all relevant intra- and intermolecular relaxation contributions to the (1)H spin-lattice relaxation as well as by benefiting from the universal low-frequency dispersion law characteristic of Fickian diffusion which yields, at low frequencies, a linear dependence of R1 on square root of frequency. From the (19)F relaxation both anion and cation diffusion coefficients are determined for BMIM-PF6. The diffusion coefficients obtained from FC NMR relaxometry are in good agreement with results reported from pulsed- field-gradient NMR. This shows that NMR relaxometry can be considered as an alternative route of determining diffusion coefficients of both cations and anions in ionic liquids.

Topics: Diffusion; Imidazoles; Ionic Liquids; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Thermodynamics

Two imidazolium-based ionic liquids (ILs), hydrophilic 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) and hydrophobic 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), have been chosen as solvents for investigating bioelectroanalysis of four heme proteins. Heme proteins including hemoglobin, myoglobin, catalase and horseradish peroxidase immobilized in DNA can form stable and electrochemically active films on glassy carbon electrode. The morphology studies of films were demonstrated by atomic force microscopy. The direct electrochemistry of heme proteins were performed in ILs, and a pair of well-defined and nearly reversible redox peaks were observed. The electron transfer rate and reversibility of heme proteins in [bmim][BF4]/water were better than those in [bmim][PF6]. Through comparing several electrochemical parameters such as formal potentials and electron transfer rate constant of proteins in ILs, this paper tried to explain the differences of electrochemical properties of proteins as a function of viscosity, solubility characteristics, etc. of ILs. The possibility to specifically vary the properties of ILs by the selection of suitable cations and anions make them ideal candidates for wide applications in cell biological processes.

Topics: Animals; Cattle; DNA; Electrochemical Techniques; Hemeproteins; Horses; Imidazoles; Immobilized Proteins; Ionic Liquids; Oxidation-Reduction

Homogeneous ionic liquid microextraction (HILME) was developed for the extraction of schizandrin, schisantherin A and deoxyschizandrin from Schisandra chinensis and Schisandra sphenanthera. 1-Butyl-3-methylimidazolium tetrafluoroborate ([C(4)MIM][BF(4)]) aqueous solution was used as extraction solvent, and ammonium hexafluorophosphate ([NH(4)][PF(6)]) was used as ion-pairing agent. 1-Butyl-3-methylimidazolium hexafluorophosphate ([C(4)MIM][PF(6)]), which is barely soluble in water, was formed in situ, and was used as sample solution. High-performance liquid chromatography (HPLC) was employed for separation and determination of the analytes. The calibration curve showed good linear relationship (r>0.9998). The recoveries were between 69.71% and 88.33% with RSDs lower than 4.86%. External standard method was adopted in the proposed method, and internal standard method was applied for the evaluation of the proposed method. The two methods were compared and the results indicated that the proposed method was acceptable and simple. The HILME is free of volatile organic solvents, and represents lower expenditures of sample, extraction time and solvent, compared with ultrasonic and Soxhlet extraction. There was no obvious difference in the extraction yields of active constitutions obtained by the three extraction methods.

Topics: Chromatography, High Pressure Liquid; Cyclooctanes; Dioxoles; Fruit; Imidazoles; Ionic Liquids; Lignans; Polycyclic Compounds; Schisandra

Density functional calculations have been performed to explore the interactions of thiophene and two ionic liquids of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]⁺[PF₆]⁻) and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]⁺[BF₄]⁻). The electronic properties and topological properties of [BMIM]⁺[PF₆]⁻-thiophene and [BMIM]⁺[BF₄]⁻-thiophene were analyzed. The calculated results reveal that the dominant interactions of C2--H2⋯F hydrogen bonds in [BMIM]⁺[PF₆]⁻ or [BMIM]⁺[BF₄]⁻ were not destroyed by the thiophene interactions with [BMIM]⁺[PF₆]⁻ and [BMIM]⁺[BF₄]⁻. The C--H ([BMIM]⁺⋯π (thiophene) hydrogen bonds and H(thiophene)⋯F([PF₆]⁻ or [BF₄]⁻ hydrogen bonds play crucial roles in the adsorption of thiophene on [BMIM]⁺[PF₆]⁻ and [BMIM]⁺[BF₄]⁻.

Topics: Electrons; Hydrogen Bonding; Imidazoles; Ionic Liquids; Thiophenes

Ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim](+)[PF(6)](-)) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim](+)[BF(4)](-)) were found to promote an unusual Wagner-Meerwein rearrangement of steroidal 16α,17α-epoxides leading to unnatural 13-epi-18-nor-16-one derivatives as the main products. These compounds were isolated in good to excellent yields. 16α-Hydroxy-Δ(13)-18-norsteroids, the results of the usual rearrangement, were obtained as minor components of the reaction mixtures. The ionic liquid [bmim](+)[PF(6)](-) was shown to induce C-ring aromatization of 16α,17α-epoxyestranes due to the formation of HF, the hydrolysis product of [PF(6)](-). Increasing amounts of HF and [PO(2)F(2)](-) were detected by (19)F and (31)P NMR when the ionic liquid was reused. The structures of the steroidal products, 16-oxo-18-nor-13α-steroid derivatives, 16α-hydroxy-Δ(13)-18-norsteroids, and C-aromatic compounds were determined by two-dimensional NMR techniques and high-resolution mass spectrometry (HRMS). The ionic liquids were recirculated efficiently.

Topics: Androstanols; Estranes; Imidazoles; Ionic Liquids; Molecular Structure; Stereoisomerism

The present paper reports the results of a systematic rheological study of the dynamic moduli of 1-butyl 3-methylimidazolium tetrafluoroborate ([Bmim][BF(4)]), 1-butyl 3-methylimidazolium hexafluorophosphate ([Bmim][PF(6)]), and 1-ethyl 3-methylimidazolium ethylsulfate ([Emim][EtSO(4)]) in the vicinity of their respective glass transition temperatures. The results show an anomalous aging in that the dynamic and the low shear rate viscosities decrease with time at temperatures near to, but above, the glass transition temperature, and this is described. The samples that are aged into equilibrium obey the time-temperature superposition principle, and the shift factors and the viscosities follow classic super-Arrhenius behaviors with intermediate fragility values as the glass transition is approached. Similar experiments using a high-purity [Bmim][BF(4)] show that using a higher purity of the ionic liquid, while changing absolute values of the properties, does not eliminate the anomalous aging response. The data are also analyzed in a fashion similar to that used for polymer melts, and we find that these ionic liquids do not follow, for example, the Cox-Merz relationship between the steady shear viscosity and the dynamic viscosity.

Topics: Glass; Imidazoles; Ionic Liquids; Molecular Structure; Rheology; Stereoisomerism; Temperature

Feruloylated monoacyl- and diacyl-glycerols (FMAGs and FDAGs) are lipophilic antioxidants and potential UV absorbers. FMAGs and FDAGs were synthesized by a novel chemoenzymatic method: firstly, ferulic acid was esterified with glycerol to synthesize glyceryl ferulate, using p-toluenesulfonic acid as chemical catalyst in 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF(4)); secondly, glyceryl ferulate was esterified with oleic acid to synthesize FMAGs and FDAGs, using Novozym 435 as biocatalyst in 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]PF(6)). The conversion of ferulic acid and yield of glyceryl ferulate in the first reaction were both 98%. The yields of FMAGs and FDAGs in the second reaction reached 34 +/- 2% and 66 +/- 3%, respectively.

Topics: Antioxidants; Benzenesulfonates; Coumaric Acids; Enzymes, Immobilized; Fungal Proteins; Imidazoles; Ionic Liquids; Lipase; Monoglycerides; Oleic Acid; Radiation-Protective Agents

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

A comparative study of peak shape, elution behavior, elution strength and resolution of seven beta-blockers (acebutolol, alprenolol, labetalol, metoprolol, nadolol, pindolol and propranolol) chromatographed with aqueous-organic mobile phases containing additives such as the ionic liquid (IL) 1-butyl-3-methylimidazolium (BMIM BF(4)) or triethylamine (TEA) is performed using a conventional reversed-phase Kromasil C(18) column and isocratic elution. The efficiencies and asymmetry factors achieved for the group of beta-blockers in the Kromasil C(18) column improve when the cationic modifiers are added to the aqueous-organic mobile phase as competing additives for the silanol active sites. BMIM BF(4) is a significantly better additive compared to TEA. The improvement is more notably for the asymmetry factor, BMIM BF(4) allowing to obtain higher plate numbers than TEA at the same concentration. The effects of both modifiers on elution strength and retention factors are, however, different. TEA decreases the solute retention factors when BMIM BF(4) does not change them significantly. Using other additives taken in the IL family such as 1-butyl-3-methylimidazolium hexafluorophosphate and 1-octyl-3-methylimidazolium tetrafluoroborate (OMIM BF(4)), it is shown that the silanol screening effect is always observed, due to the IL cation, when it is possible to increase or to decrease the solute retention factors playing with the hydrophobic nature or chaotropic character of its anion.

Topics: Adrenergic beta-Antagonists; Borates; Chromatography, High Pressure Liquid; Ethylamines; Imidazoles; Ions

The influence of the two most commonly used ionic liquids (1-butyl-3-methyl imidazolium tetrafluoroborate, [BMIM][BF(4)], 1-butyl-3-methyl imidazolium hexafluorophosphate, [BMIM][PF(6)]) and three selected organic solvents (dimethylsulfoxide, ethanol, methanol) on the growth of Escherichia coli, Pichia pastoris and Bacillus cereus was investigated. [BMIM][BF(4)] was toxic at 1% (v/v) on all three microorganisms. The minimal inhibitory concentration (MIC) of [BMIM][BF(4)] on E. coli growth was between 0.7 and 1% (v/v). In contrast, [BMIM][PF(6)] was less toxic for P. pastoris and B. cereus, whereas E. coli was not able to tolerate [BMIM][PF(6)] (MIC value: 0.3-0.7% v/v). Growth of P. pastoris was unaffected by [BMIM][PF(6)] at 10% (v/v). Similar results were found for dimethylsulfoxide. Thus, ionic liquids (ILs) can have substantial inhibitory effects on the growth of microorganisms, which should be taken into account for environmental reasons as well as for the use of ILs as co-solvents in biotransformations.

Topics: Bacillus cereus; Borates; Cell Proliferation; Dose-Response Relationship, Drug; Escherichia coli; Imidazoles; Ions; Organic Chemicals; Pichia; Solutions; Solvents; Species Specificity

Room-temperature ionic liquids (RTILs) are useful in many chemical applications. Recent publications have attempted to determine the polarity of RTILs using empirical solvent polarity scales. The results have indicated that most RTILs have similar polarities. Nevertheless, RTILs are capable of behaving quite differently when used as solvents in organic synthesis, matrixes in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry, liquid-liquid extraction, and as stationary phases in gas chromatography. The work presented in this study uses a linear free energy approach to characterize 17 RTILs on the basis of their distinct multiple solvation interactions with probe solute molecules. This model provides data that can be used to help identify the interactions and properties that are important for specific chemical applications.

Topics: Alkanes; Borates; Chromatography, Gas; Imidazoles; Ions; Linear Energy Transfer; Quaternary Ammonium Compounds; Regression Analysis; Solutions; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Temperature

[reaction:see text] Candida antarctica lipase was shown to catalyze alcoholysis, ammoniolysis, and perhydrolysis reactions using the ionic liquids 1-butyl-3-methylimidazolium tetrafluoroborate or hexafluorophosphate as reaction media. Reaction rates were generally comparable with, or better than, those observed in organic media.

Topics: Borates; Catalysis; Imidazoles; Lipase; Solutions