N-butylpyridinium Tetrafluoroborate Research Articles

Studies on the asymmetric spatial distribution of the ionic liquid [BPy][BF4] confined in carbon nanotubes

The one-dimensional confined space within carbon nanotubes (CNTs) has a profound impact on the behavior of liquids, potentially resulting in an layering structure that differs from the bulk phase. Through a series of molecular dynamics simulations, we have observed interesting changes in the layering structure of N-butylpyridinium tetrafluoroborate ([BPy][BF4]) within different carbon nanotubes. The probability of angular distributions shows that the pyridine ring tends to be adsorbed on the inner wall of the carbon nanotube. As the diameter of the carbon nanotube increases, the layering behavior of [BPy][BF4] at the center changes alternately. Interestingly, anions and cations exhibit a significant asymmetric spatial distribution in CNT(12,12) and CNT(18,18), whereas a symmetrical distribution in CNT(16,16) and other CNTs. The asymmetric distribution is caused by the confined effects of some special carbon nanotubes on the anions and cations. The dynamical heterogeneity is also found in CNT(12,12) and CNT(18,18), which is closely related to the asymmetrical distribution of the structure properties. These novel simulation results could improve the understanding on the microstructure of the liquids including the ionic liquid in the confined space.

Molecular interaction between N-butylpyridinium tetrafluoroborate and cyclic sulfur compounds: A DFT study

Extraction of sulfur compounds from crude oil is one of the problems of industries related to crude oil. The use of ionic liquids (ILs) as a green solvent to extract these sulfur compounds, especially cyclic sulfur compounds, can be considered a potential point in this regard. A functional theory comparison was made to investigate the interaction between N-butylpyridinium tetrafluoroborate as IL and several different cyclic sulfur compounds including Thiophene, benzothiophene, dibenzothiophene, and 4,6-dibenzothiophene. The difference between the solution phase and the gas phase has been investigated. Based on the results, the proper interaction between the components of IL and the cyclic sulfur compounds, the extraction of these compounds is theoretically possible. Natural bond orbital, atoms in molecules, HOMO-LUMO overlap integral, and electron density difference were analyzed. The analysis informs on the use of ionic liquids as solvents for the removal of sulfur compounds from crude oil. The hydrogen and vander Waals bonds formed between the anion and cation of ionic liquid and the sulfur compounds have been determined. The main bonds are formed between the anion of ionic liquid and the sulfur compounds. Between the compound [C4Py][BF4] and C4H4S, the hydrogen bonds are S…H13, F29.... H38, F26…H38, has been established. The hydrogen bonds between the anion of the ionic liquid and the sulfur compound are shorter than the other hydrogen bonds formed. Due to the intermolecular bonds, the transition state with the lowest energy has been obtained. In this way, we will have a proposed mechanism for the extraction of the cyclic compounds from oil with the help of ionic liquids.

Coreactant-free strong Ru(bpy)32+ ECL at ionic liquid modified electrode and its application in sensitive detection of glucose based on resonance energy transfer

In this work, we have realized the strong anodic ECL emission of Ru(bpy)32+ at ionic liquid (N-butylpyridinium tetrafluoroborate) modified electrode without additional coreactant. Methylene blue (MB) could accept the energy of Ru(bpy)32+ ECL to construct resonance energy transfer (ECL-RET) system, leading to the decrease of ECL signal. In the presence of glucose oxidase, hydrogen peroxide generated from the oxidation process of glucose could oxidize MB and block the ECL-RET route, resulting in the recovery of ECL signal. As a consequence, the designed sensor showed outstanding performance for “signal-on” detection of glucose in the concentration range of 10 μM to 1 mM, and the detection limit was determined as 1.75 μM. Importantly, this study revealed new roles of ILs in the fabrication of coreactant-free ECL sensing, which might open up a promising route for the potential design and implement in clinical analysis.

A density functional theory study on the interactions between dibenzothiophene and tetrafluoroborate-based ionic liquids.

The interactions between dibenzothiophene (DBT) and N-butyl-N-methylimidazolium tetrafluoroborate ([BMIM][BF4]), N-butyl-N-methylmorpholinium tetrafluoroborate ([Bmmorpholinium][BF4]), N-butyl-N-methylpiperdinium tetrafluoroborate ([BMPiper][BF4]), N-butyl-N-methylpyrrolidinium tetrafluoroborate ([BMPyrro][BF4]), and N-butylpyridinium tetrafluoroborate ([BPY][BF4]) were investigated using density functional theory approach. Geometric, electron, and topological properties were analyzed using natural bond orbital, atoms in molecules theory, and noncovalent interaction methods in order to understand intermolecular interactions between DBT and ionic liquids. The result shows that hydrogen bond and van der Waals interactions are widespread in all the ionic liquids-DBT systems. Ion-π interactions between DBT and cation or anion are also observed, while π+-π interactions are only found in the [BMIM][BF4]-DBT and [BPY][BF4]-DBT systems. The order of interaction energy is [BPY][BF4]-DBT > [BMIM][BF4]-DBT >> [BMPiper][BF4]-DBT > [BMPyrro][BF4]-DBT > [BMmorpholinum][BF4]-DBT. The energies between DBT and the two ionic liquids containing aromatic cations are significantly higher.

Phase diagram of ionic liquid aqueous two-phase systems with N-butylpyridinium tetrafluoroborate, ammonium Citrate/Sodium acetate, and water from 308.15 K to 328.15 K

In this study, the phase diagrams and liquid–liquid equilibrium data for two-phase systems of N-butylpyridinium tetrafluoroborate ([BPy]BF4)+ammonium citrate ((NH4)3C6H5O7) have been experimentally determined at 308.15K, 313.15K, 318.15K and 328.15K. Sodium acetate (CH3COONa)+water had also been determined at 308.15K, 318.15K and 328.15K. The binodal data were fit to the Merchuk equation and to two empirical equations with several parameters. Good agreement was obtained among these models.

Laser Flash Photolysis Mechanism of Anthraquinone-2-Sodium Sulfonate in Pyridine Ionic Liquid/Water Mixed System

The photochemical reaction process of anthraquinone-2-sodium sulfonate (AQS) in the mixture of water (H2O) and N-butylpyridinium tetrafluoroborate ([BPy][BF4]) was studied using the laser flash photolysis technique. Experimental results show that the excited triplet of AQS (3AQS*) could react rapidly with H2O and the transient absorption spectra greatly changed by increasing the volume fraction of the ionic liquid (VIL) in [BPy][BF4]/H2O mixtures. The absorbance at 510 nm increased gradually with increasing VIL when 0<VIL<0.1. By contrast, the absorbance decreased gradually when VIL>0.1. Otherwise, the absorbance of the band near 380 nm steadily increased. The apparent kinetic parameters of transient species B and 3AQS* are obtained approximately. 3AQS* abstracting hydrogen from [BPy]+ was also explored. It was deduced that the 350–420 nm band was the superposition of the peaks of 3AQS* and AQSH·. The two reactions of 3AQS* with [BPy][BF4] and H2O are a pair of competitive reactions. We also concluded that the entire reaction processes slow down in the case of high [BPy][BF4] concentrations.

Effect of Temperature on the Liquid–Liquid Equilibrium of the Ternary Aqueous System Containing N-Butylpyridinium Tetrafluoroborate and Sodium Dihydrogen Phosphate

New experimental data of the binodal and tie lines for the ionic liquid N-butylpyridinium tetrafluoroborate \(+\) sodium dihydrogen phosphate \(+\) water system were measured at T \(=\) 293.15 K, 298.15 K, 308.15 K, and 318.15 K. An empirical equation was used to correlate the binodal data, whereas a two-parameter model (the Setschenow-type equation) was employed for the tie-line data. The correlation coefficients showed that the experimental data were well fitted to both of the empirical equations. The temperature variation effect on the binodal curves and tie lines was also discussed, which indicates that a lower temperature corresponds to higher salting-out abilities.

Interactions between pyrene and pyridinium ionic liquids studied by ultraviolet–visible spectroscopy

Pyrene has been used as a probe molecule to investigate the interactions in the mixture of the ionic liquid N-butylpyridinium tetrafluoroborate ([BPy][BF4]) and acetonitrile (MeCN) by ultraviolet–visible (UV–vis) spectroscopy. The results show that an obvious red-shift of characteristic absorption spectra of pyrene was observed with the adding of [BPy][BF4] to its acetonitrile solution. The position of absorption peaks was only relative to the fraction of [BPy][BF4] and almost did not change with the concentration of pyrene. When measurements were carried out in other ionic liquids, similar results were obtained. However, the hyperchromic effect was observed in [BPy][BF4] and the hypochromic effect was observed in [BPy][NTf2] (N-butylpyridinium bis((trifluoromethyl)sulfonyl)imide) for the maximum absorption peak near 335nm. The local microstructure transformation of [BPy][BF4]/MeCN mixed solutions could be indicated by results for the electrical conductivity and viscosity. It was concluded that the red-shift was induced not only by the polarity change of the solution but also by the local microstructure and the solvent–solute interaction.

Thermodynamic properties and microstructures of the mixture of N-butylpyridinium tetrafluoroborate with acetonitrile studied by molecular dynamics simulation

The binary system of the ionic liquid (IL) N-butylpyridinium tetrafluoroborate ([BPy][BF4]) and acetonitrile (MeCN) was investigated by molecular dynamics simulation method. The thermodynamic properties of the mixture were obtained by simulation including density, self-diffusion coefficients, viscosity, and vaporization enthalpy. This study focused on the relationship between the microscopic structure and the proportion of [BPy][BF4] in the mixed system. Radial distribution functions (RDFs) for different components were also compared. Results showed that the first peak of the nonpolar regions of [BPy][BF4] increased with increasing mole fraction xi of IL, whereas that of polar regions decreased. The coordination number as a function of distance was calculated by integrating RDFs to the first shell. Results indicated that a wide distribution of possible configurations in ion pairs formed by anions and cations of the IL in mixtures. Spatial distribution functions (SDFs) indicated that the anions [BF4]− were mainly distributed around the pyridine ring of the cation [BPy]+ and the methyl of MeCN. Moreover, the excess molar volume was negative and showed a minimum at xi=0.3, consistent with the change law of SDFs.

Photochemical Reaction Kinetics of Duroquinone in a Mixture of Ionic Liquid [BPy][BF<sub>4</sub>] and Acetonitrile

Photochemical reactions of duroquinone (DQ) in solutions consisting of mixtures of the ionic liquid N-butylpyridinium tetrafluoroborate ([BPy][BF4]) and acetonitrile (MeCN) were studied using the 355 nm laser flash photolysis technique. Increasing the ratio of [BPy][BF4] had no obvious impact on the absorption peak of the triplet excited state of DQ ((3)Da), which followed monoexponential kinetics in the N-2-saturated solution. However, increasing the ratio of [BPy] [BF4] did affect the photoinduced electron transfer process from triethylamine to (3)DQ in the mixture by decreasing the reaction rate and the quantum yield of the transient radical. The results highlight the ability to tune the efficiency and the rate of the photoinduced electron transfer by changing the proportion of [BPy][BF4] in the mixture.

Liquid–liquid equilibria of ionic liquid N-butylpyridinium tetrafluoroborate and disodium hydrogen phosphate/sodium chloride/sodium sulfate/ammonium sulfate aqueous two-phase systems at T = 298.15 K: Experiment and correlation

Liquid–liquid equilibrium data for N-butylpyridinium tetrafluoroborate ([BPy]BF4)+Salt(disodium hydrogen phosphate, sodium chloride, sodium sulfate, and ammonium sulfate)+H2O systems have been determined experimentally at T=298.15K. The binodal curves are fitted to an empirical nonlinear expression developed by Merchuk, and the tie lines were described by the Othmer–Tobias, Bancroft, and two-parameter equations. Factors affecting the binodal curves such as salts are also studied. It was found that the salting-out behavior indicates that Na2HPO4>Na2SO4>(NH4)2SO4>NaCl, which may be related to the Gibbs free energy of hydration of the ions (ΔGhyd). Furthermore, the tie-line was also discussed to evaluate the phase separation abilities of the investigated systems. These data are exposed to be useful for the development and design of the extraction process using ILs.

Densities and viscosities for ionic liquids mixtures containing [eOHmim][BF4], [bmim][BF4] and [bpy][BF4

Densities and viscosities of binary ionic liquids mixtures, 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate ([eOHmim][BF4])+1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), 1-(2-hydroxyethyl)-3-methylimidazolium tetrafluoroborate ([eOHmim][BF4])+N-butylpyridinium tetrafluoroborate ([bpy][BF4]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4])+N-butylpyridinium tetrafluoroborate ([bpy][BF4]) were measured over the entire mole fraction from T=(298.15 to 343.15)K. The excess molar volumes were calculated and correlated by Redlich–Kiser polynomial expansions. The viscosities for pure ionic liquids were analyzed by means of the Vogel–Tammann–Fulcher equation and ideal mixing rules were applied for the ILs mixtures.

Formic acid oxidation reaction on a PdxNiy bimetallic nanoparticle catalyst prepared by a thermal decomposition process using ionic liquids as the solvent

The nano-catalysts of PdxNiy bimetallic nanoparticles (NPs, the nominal atomic ratios of Pd to Ni are 2:1, 3:2 and 1:1) supported on multi-walled carbon nanotubes (MWCNTs) (denoted as PdxNiy/MWCNTs) have been synthesized by a thermal decomposition process using room temperature ionic liquids (RTILs) of N-butylpyridinium tetrafluoroborate (BPyBF4) as the solvent. X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) were employed to characterize the morphology of the samples, revealing that the prepared PdxNiy NPs were quite uniformly dispersed on the surface of MWCNTs with an average particle size of ∼8.0 nm. Formic acid oxidation reaction (FAOR) was investigated on the as-prepared catalysts by using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), demonstrating that the peak current on the Pd3Ni2/MWCNTs catalyst was about three times higher than that on the Pd/MWCNTs. The lower electrode potential and easier hydrogen evolution, based on the results obtained from chronopotentiometry and CV, respectively, were thought as the main reasons for the excellent electrocatalysis of the Pd3Ni2/MWCNTs toward formic acid oxidation reaction (FAOR) when compared to other samples.

Determination of Physicochemical Properties of Pyridinium-Based Ionic Liquid Binary Mixtures with a Common Component through Neural Networks

A nonlinear model based on neural networks has been proposed to estimate the refractive index, density, and viscosity of two ionic liquid (IL) binary mixtures with a common component (N-butylpyridinium tetrafluoroborate ([bpy][BF4]) and 4-methyl-N-butylpyridinium bis(trifluoromethylsulfonyl)imide ([4mbpy][Tf2N]), and [bpy][BF4] and N-butylpyridinium bis(trifluoromethylsulfonyl)imide ([bpy][Tf2N])) using their composition (molar fractions) and temperature, which ranged from 273.15 to 353.15 K. The results of the mathematical model were studied through mean prediction errors (MPEs). For the estimation of refractive index, density, and viscosity, the MPEs were 0.02%, 0.11%, and 3.24%, respectively, with a correlation coefficient greater than 0.99 in all cases. In light of these results, the model designed is very accurate and more than capable to assist in the estimation of physicochemical properties of binary mixtures formed by ILs.

The nature of interactions between N-butylpyridinium tetrafluoroborate and thiophenic compounds: A theoretical investigation

Abstract In an effort to understand the nature of the interactions between pyridinium-based ionic liquids and thiophenic compounds, the electronic and topological properties of the interactions between N -butylpyridinium tetrafluoroborate ([BPY] + [BF 4 ] − ) and thiophene (TS), benzothiophene (BT), dibenzothiophene (DBT) have been investigated by density functional theory. The most stable structure of the [BPY] + [BF 4 ] − ion-pair indicated that hydrogen bonding interactions between fluorine atoms on [BF 4 ] − anions and C2–H2 on the pyridinium ring play an important role in the formation of the ion-pair. The NBO and AIM analyses indicate the occurrence of π–π stacking interactions. The electron density at bond critical points and Wiberg bond indices are correlated with the interacting distances of H···F interactions, so electron density and Wiberg bond index can demonstrate the interacting strength of H···F hydrogen bonds. The interaction energies suggest that DBT adsorbs prior to the other compounds on N -butylpyridinium tetrafluoroborate ionic liquid.

Physical Characterization of an Aromatic Extraction Solvent Formed by [bpy][BF4] and [4bmpy][Tf2N] Mixed Ionic Liquids

The binary mixture of N-butylpyridinium tetrafluoroborate ([bpy][BF4]) and 4-methyl-N-butylpyridinium bis(trifluoromethylsulfonyl)imide ([4bmpy][Tf2N]) ionic liquids (ILs) has recently been proposed as an environmentally friendly solvent in the liquid–liquid extraction of toluene from heptane. In addition to the extractive properties, a solvent must possess adequate physical properties to be used in an industrial process. In this paper, we have measured refractive indices, densities, and dynamic viscosities of {[bpy][BF4] + [4bmpy][Tf2N]} IL mixtures over the whole range of compositions at temperatures from 293.15 K to 353.15 K. A comparative analysis between physical properties of binary IL mixtures and those of sulfolane has been made. The accuracy of the group contribution method proposed by Ye and Shreeve in predicting experimental densities of a binary pyridinium-based IL mixture composed of four different ions has been evaluated. The Bingham and the Grunberg–Nissan mixing rules have also been used t...

Electron transfer in N-butylpyridinium tetrafluoroborate ionic liquid by pulse radiolysis

The radiolysis behavior of neat pyridinium ionic liquids (ILs) and their aqueous solutions was investigated using nanosecond pulse radiolysis techniques. Radiolysis of the ionic liquids, such as N-butylpyridinium tetrafluoroborate (BuPyBF4), resulted in the formation of solvated electrons and organic radicals. Solvated electrons reacted with the pyridinium moiety to produce a pyridinyl radical, which can transfer electrons to various acceptors. The electron-transfer rate constants of the solvent-derived butylpyridinyl radicals in BuPyBF4 and in several compounds (for example, duroquinone, 4,4′-pyridine, benzophenone, and 1,1′-dimethyl-4,4′-bypyridinium dichloride) (k of the order 108 L/(mol s) were lower than those measured in water and in i-PrOH but were significantly higher than the diffusion-controlled rate constants estimated based on viscosity. The electron-transfer rate constants in neat BuPyBF4 were one order of magnitude faster than the diffusion-controlled values. This finding suggests that Bu-PyBF4 acts not only as solvent but also as active solute, such as in solvent-mediated reactions. These reactions result in electrons reaching their final destinations via intervening pyridinium groups without requiring the diffusion of a specific radical.

Densities and thermal conductivities of N-alkylpyridinium tetrafluoroborates at high pressure

Densities and thermal conductivities are reported for a series of N-alkylpyridinium tetrafluoroborate compounds with butyl (N-butylpyridinium tetrafluoroborate), hexyl (N-hexylpyridinium tetrafluoroborate) and octyl (N-octylpyridinium tetrafluoroborate) groups. The densities were measured with a vibrating tube densimeter over the temperature range 293–353K at pressures ≤20.0MPa. The transient short hot wire method was used to measure thermal conductivity over the temperature range 294–335K at pressures ≤20MPa. It was found that the effect of alkyl chain length on thermal conductivities in N-alkylpyridinium tetrafluoroborates is the same degree as 1-alkyl-3-methylimidazolium tetrafluoroborates. The experimental values at 293K and 0.1MPa were consistent with the predicted values proposed by Fröba et al.

Solubility Parameters for Nine Ionic Liquids

Solubility parameters are useful for estimating solubilities of solutes in ionic liquids when no solubility data are available. Solubility parameters are reported for nine ionic liquids; they were obtained from solubility data for a variety of solutes. The ionic liquids are 1-butyl,3-methylimidazolium hydrogen sulfate, 1-ethyl,3-methylimidazolium acetate, 1-methyl,3-trimethylsylilimidazolium chloride, 4-methyl,n-butylpyridinium tetrafluoroborate, ethylammonium nitrate, 1-ethyl,3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-methyl,3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl,3-methylimidazolium bis(trifluoromethylsulfonyl)imide, and 1-ethyl,3-methylimidazolium ethylsulfate.

Ionic Vapor: What Does It Consist Of?

A comprehensive description of room-temperature ionic liquids (RTILs) requires characterization of their properties around normal boiling and critical. Using a thoroughly parametrized force field, we report atomistic simulations of the vapor phase of N-butylpyridinium tetrafluoroborate and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulphonyl)amide, existing in equilibrium with the liquid phase. We show that in contrast to traditional gases comprised of one type of molecules, the saturated vapor of RTILs consists of a broad range of structures, involving both neutral and charged species. While typically the ionic pair is the most stable vapor structure, the species distribution depends on RTIL chemical composition and is sensitive to temperature and pressure.