Bmim Research Articles

Synthesis of Propargylic Alcohols by base promoted Alkynylation of Ketones with Ethynylbenzene using Ionic Liquid [(bmim) PF6

A mild and efficient addition of ethynylbenzene with ketones using KOH in ionic liquid 1-butyl-3-methylimidazolium hexaflurophosphate [(bmim) PF6] gives propargylic alcohols in high yields.

Ternary (liquid + liquid) equilibria of the azeotrope (ethyl acetate + 2-propanol) with different ionic liquids at T = 298.15 K

Experimental (liquid + liquid) equilibria involving ionic liquids {1,3-dimethylimidazolium methyl sulfate (MMIM MeSO 4)}, {2-propanol + ethyl acetate + 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM PF 6)} and {2-propanol + ethyl acetate + 1-hexyl-3-methylimidazolium hexafluorophosphate (HMIM PF 6)} were carried out to separate the azeotropic mixture ethyl acetate and 2-propanol. Selectivity and distribution ratio values, derived from the tie-lines data, were presented in order to analyze the best separation solvent in a liquid extraction process. Experimental (liquid + liquid) equilibria data were compared with the correlated values obtained by means of the NRTL, Othmer–Tobias and Hand equations. These equations were verified to accurately correlate the experimental data.

Experimental Liquid−Liquid Equilibria of 1-Alkyl-3-methylimidazolium Hexafluorophosphate with 1-Alcohols

Liquid−liquid equilibria were measured for nine binary systems containing 1-alkyl-3-methylimidazolium hexafluorophosphates with alcohols in the following temperature ranges: BMIM PF6 with 1-propanol or 1-butanol or 1-pentanol and HMIM PF6 with 1-butanol or 1-pentanol from (278.15 to 343.15) K; HMIM PF6 with 1-propanol from (278.15 to 328.15) K; and OMIM PF6 with 1-propanol or 1-butanol or 1-pentanol from (278.15 to 307.15) K, (278.15 to 323.15) K, and (278.15 to 333.15) K, respectively. The equation results were satisfactorily correlated by the NRTL and UNIQUAC models.

Micellization of PS‐PMMA Diblock Copolymers in an Ionic Liquid

AbstractThree polystyrene‐block‐poly(methyl methacrylate) (PS‐PMMA) block copolymers with varying molecular content have been shown to form micelles when dissolved in the ionic liquid 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMIM PF6). The micellar structure was studied via cryogenic transmission electron microscopy and dynamic light scattering, and a morphological transition from spherical to cylindrical micelles was observed upon reduction of the PMMA volume fraction. The possibility of frozen micellar morphology was considered, due to the solution preparation method and high glass transition temperature (Tg) of the PS blocks that form the micellar cores. By comparison of the behavior of a 100 kDa PMMA homopolymer dissolved in both BMIM PF6 and a known good solvent, acetone, it was determined that BMIM PF6 behaves as a good solvent for PMMA. It was also observed that extended exposure to the electron beam during cryogenic transmission electron microscopy could damage the copolymer micelles and result in a reversal of contrast.magnified image

Thermodynamic Properties of Ionic Liquids in Organic Solvents from (293.15 to 303.15) K

Densities, speeds of sound, and refractive indices of the binary mixtures of BMIM PF6 (1-butyl-3-methyl imidazolium hexafluorophosphate), HMIM PF6 (1-hexyl-3-methylimidazolium hexafluorophosphate), OMIM PF6 (1-methyl-3-octylimidazolium hexafluorophosphate), and MMIM CH3SO4 (1,3-dimethylimidazolium methyl sulfate) with 2-butanone, ethylacetate, and 2-propanol were determined from (293.15 to 303.15) K. Excess molar volumes, changes of refractive index on mixing, and deviations in isentropic compressibility were calculated for the above systems. The liquid−liquid equilibrium data of the binary mixtures ionic liquid + 2-propanol were carried out, and they were compared with the correlated values obtained by means of the NRTL and UNIQUAC equations.

Psychosocial correlates of dietary intake among overweight and obese men.

To investigate the relationship between theoretically based psychosocial constructs and dietary components among overweight men. Participants were 441 men (BMI M = 34.2). Psychosocial constructs included self-efficacy, decisional balance, social support, and behavior change strategies. Dietary components were fat, fiber, and fruit and vegetable intake. All significant findings were in the expected direction. Multiple regression models indicated that the psychosocial factors accounted for the most variance in vegetable intake (R(2)=.13) and the least variance in fat (R(2)=.05). Theoretically based psychosocial constructs were related to overweight men's dietary intake and have potential for use in tailored behavior-change interventions.

Solute–solvent interactions in imidazolium camphorsulfonate ionic liquids

We directly observe the interaction between 1-butyl-3-methylimidazolium (bmim) or 1-butyl-2,3-dimethylimidazolium (bm(2)im) and the solute, ethyl acrylate (EA), which is the popular dienophile in the Diels-Alder reaction and an H-bonding acceptor, by using specially designed electrospray mass spectrometry. In imidazolium ionic liquids, cation-anion interactions are controlled by selecting the appropriate anion, and the naked C(2)-H of imidazolium, which loosely interacts with its counterion, can readily interact with an H-bonding acceptable solute. The ion-counterion (solvent-solvent) interaction affects the ion-solute (solvent-solute) interaction. This relation is one of the key criteria for selecting the cation-anion combination in tailoring ILs.

Study on the phase behaviour and thermodynamic properties of ionic liquids containing imidazolium cation with ethanol at several temperatures

Experimental densities, speeds of sound and refractive indices of the binary mixtures of ethanol with MMIM MeSO 4 (1,3-dimethylimidazolium methyl sulfate), BMIM MeSO 4 (1-butyl-3-methylimidazolium methyl sulfate), BMIM PF 6 (1-butyl-3-methylimidazolium hexafluorophosphate), HMIM PF 6 (1-hexyl-3-methylimidazolium hexafluorophosphate) and OMIM PF 6 (1-methyl-3-octylimidazolium hexafluorophosphate) were determined from T = (293.15 to 303.15) K. Excess molar volumes, changes of refractive index on mixing and deviations in isentropic compressibility for the above systems were calculated. The (liquid + liquid) equilibrium (LLE) data of (IL + ethanol) were carried out experimentally and the NRTL and UNIQUAC correlative equation was applied to these mixtures.

High-pressure phase behavior of carbon dioxide in ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide

Phase equilibrium data of carbon dioxide in the ionic liquid 1-butyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf2N]) are presented at high pressures up to about 30 MPa and at temperatures between 298.15 K and 343.15 K. The solubilities at a given temperature were determined by measuring the bubble point pressure of the ionic liquid solution with carbon dioxide dissolved using the high-pressure equilibrium apparatus equipped with a variable-volume view cell. Solubility results are reported for carbon dioxide concentrations ranging from 0.21 up to 0.80 mole fraction. Carbon dioxide gave very high solubilities in the ionic liquid at lower pressures, while the equilibrium pressure increased very steeply at higher concentrations of carbon dioxide. The solubility of carbon dioxide in the ionic liquid decreased with an increase in temperature.

Recyclable Selective Palladium‐Catalyzed Synthesis of Five‐, Six‐ or Seven‐Membered Ring Lactones and Lactams by Cyclocarbonylation in Ionic Liquids

AbstractThe ionic liquids, BMIM PF6 or BMIM NTf2, are used successfully for the palladium‐catalyzed cyclocarbonylation of 2‐allylphenols and anilines, 2‐vinylphenols, and 2‐aminostyrenes. The reaction proceeds cleanly and efficiently to afford high yields of lactones or lactams with good or excellent selectivity for one isomer. The ionic liquid containing the palladium catalyst, and ligand, is recyclable in all cases.

Study of Aromatic Nucleophilic Substitution with Amines on Nitrothiophenes in Room-Temperature Ionic Liquids: Are the Different Effects on the Behavior of para-Like and ortho-Like Isomers on Going from Conventional Solvents to Room-Temperature Ionic Liquids Related to Solvation Effects?

The kinetics of the nucleophilic aromatic substitution of some 2-L-5-nitrothiophenes (para-like isomers) with three different amines (pyrrolidine, piperidine, and morpholine) were studied in three room-temperature ionic liquids ([bmim][BF4], [bmim][PF6], and [bm(2)im][BF4], where bmim = 1-butyl-3-methylimidazolium and bm(2)im = 1-butyl-2,3-dimethylimidazolium). To calculate thermodynamic parameters, a useful instrument to gain information concerning reagent-solvent interactions, the reaction was carried out over the temperature range 293-313 K. The reaction occurs faster in ionic liquids than in conventional solvents (methanol, benzene), a dependence of rate constants on amine concentration similar to that observed in methanol, suggesting a parallel behavior. The above reaction also was studied with 2-bromo-3-nitrothiophene, an ortho-like derivative able to give peculiar intramolecular interactions in the transition state, which are strongly affected by the reaction medium.

Recycling Chiral Organocatalyst (4S)‐Phenoxy‐(S)‐proline for Direct Asymmetric Aldol Reaction in Ionic Liquid (bmim)PF6

AbstractRoom temperature ionic liquid (bmim)PF6 was evaluated for recycling an organocatalyst (4S)‐phenoxy‐(S)‐proline for direct asymmetric aldol reactions. The desired aldol products were obtained with good yields up to 93.2% and enantioselectivities up to 88.5%, and isolation of the products by simple extraction allowed recycling the ionic liquid containing the immobilized catalyst in subsequent reactions without significant decrease of yields and enantioselectivities.

Acute Toxicity Profile of 1-Butyl-3-Methylimidazolium Chloride

Acute Toxicity Profile of 1-Butyl-3-Methylimidazolium Chloride

Computer Simulation Study of the Mixtures of Room Temperature Ionic Liquid [bmim][BF<sub>4</sub>] and Water

针对室温离子液体[bmim][BF4]和水的混合物,用分子动力学模拟研究了溶液的微观组成与浓度的关系.模拟结果表明:该混合物中各组分间的径向分布函数随[bmim][BF4]摩尔分数的增加呈有规律的变化;在此基础上计算了溶液的局部组成以及组分间的缔合因子,进一步考察了各组分间的相互作用情况;另外基于Kirkwood-Buff理论估算了混合物的偏摩尔体积、等温压缩因子以及活度系数对浓度的偏导数,对于理解离子液体与水之间的交互作用具有一定的参考意义.

Use of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate in countercurrent chromatography.

Room temperature ionic liquids (RTIL) are molten salts that are liquids at room temperature. Their liquid state makes them possible candidates as solvents in countercurrent chromatography (CCC), which uses solvents as both the mobile and stationary phases. The study focuses on 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM PF(6)), an easy to synthesize and purify RTIL whose melting point is -8 degrees C. It is shown that BMIM PF(6) behaves like a solvent of significant polarity (comparable with that of ethanol). The ternary phase diagram water-acetonitrile-BMIM PF(6) is given, because it was necessary to add acetonitrile to reduce the ionic liquid viscosity. The 40:20:40% w/ w water-acetonitrile-BMIM PF(6) biphasic liquid system was found to be appropriate as a biphasic liquid system for CCC. Different aromatic solutes, including bases, acids, and neutral compounds, were injected into the CCC column to estimate their distribution constants between the ionic liquid-rich phase and the aqueous phase. The resulting K(il/w) constants were compared with the corresponding literature octanol-water partition coefficients, K(o/w). The important drawbacks in the use of RTIL in CCC are clearly pointed out: high viscosity producing pressure build-up, UV absorbance limiting the use of the convenient UV detector, and non-volatility precluding the use of the evaporative light-scattering detector for continuous detection.

Assessment of the suitability of imidazolium ionic liquids as reaction medium for base-catalysed reactions Case of Knoevenagel and Claisen–Schmidt reactions

Abstract For the Knoevenagel condensation of benzaldehyde and malononitrile in 1-butyl-3-methylimidazolium hexafluorophosphate [(bmim)PF6] to which alkali metal hydroxide in ethanol had been previously added, the product is formed with high selectivity and the ionic liquid could be reused for at least five runs without the need of additional base. Low to moderate mass balances were observed in the first runs until the ionic liquid becomes saturated and the mass balances become almost complete. For the Claisen–Schmidt condensation of acetophenone with benzaldehyde, besides the expected conjugated ketone formed with high selectivity, minor amounts of ethyl benzoate are also formed. Reuse of the ionic liquid require additional amounts of base. Acid–base titration shows that most of the base (up to 80%) may disappear by reaction with the ionic liquid in the absence of any reagent. Therefore, addition of extra amounts of base is necessary in order to achieve high substrate conversion in subsequent runs and the reactions become not catalytic. This raises the point that imidazolium ionic liquids are only suitable for a small range of base catalysed reactions, and that imidazolium liquids substituted at the 2-position will be more suited as medium for based-catalysed reactions.

Structure, crystal polymorphim and rotational isomerism in prototype ionic liquid-[bmim]Cl as studied by near infrared Raman spectroscopy

Structure, crystal polymorphim and rotational isomerism in prototype ionic liquid-[bmim]Cl as studied by near infrared Raman spectroscopy

Coexistence of two distinct structures in ionic liquids: rotational isomerism of the butyl-methylmidazolium ([bmim]+) cation

Coexistence of two distinct structures in ionic liquids: rotational isomerism of the butyl-methylmidazolium ([bmim]+) cation

Dehydration of fructose into 5-hydroxymethylfurfural in the presence of ionic liquids

The acid-catalyzed dehydration of fructose was performed in a microbatch reactor at 80 °C using two commercially available ionic liquids, a hydrophilic one, 1-butyl 3-methyl imidazolium tetrafluoroborate (BMIM +BF 4 −), and a hydrophobic one, 1-butyl 3-methyl imidazolium hexafluorophosphate (BMIM +PF 6 −). When the reaction is carried out in 1-butyl 3-methyl imidazolium tetrafluoroborate as solvent and Amberlyst-15 as catalyst, a yield up to 50% in 5-hydroxymethylfurfural (HMF) is obtained within around 3 h. When the reaction is carried out now in 1-butyl 3-methyl imidazolium tetrafluoroborate and in 1-butyl 3-methyl imidazolium hexafluorophosphate as solvents and Amberlyst-15 as catalyst, DMSO is used as a co-solvent, in order, in particular, to solubilize fructose in the hydrophobic ionic liquid. Under these conditions, both ionic liquids allow the reaction to work more rapidly than in DMSO alone and with yields in HMF close to 80% within 24 h.

The First Corey—Chaykovsky Epoxidation and Cyclopropanation in Ionic Liquids.

AbstractFor Abstract see ChemInform Abstract in Full Text.