Solvatochromic Parameters and Preferential Solvation Behavior for Binary Mixtures of 1,3-Dialkylimidazolium Ionic Liquids with Water

Binary mixtures of 1,3-dialkylimidazolium based ionic liquids (ILs) and water were selected as solvent systems to investigate the solute-solvent and solvent-solvent interactions on the preferential solvation of solvatochromic indicators at 25℃. Empirical solvatochromic parameters, dipolarity/polarizability (π^*), hydrogen-bond donor acidity (α), hydrogen-bond acceptor basicity (β), and Reichardt's polarity parameters (E_T^N) were measured from the ultraviolet-visible spectral shifts of 4-nitroaniline, 4-nitroanisole, and Reichardt's dye. The solvent properties of the IL-water mixtures were found to be influenced by IL type and IL mole fraction (x_IL). All these studied systems showed the non-ideal behavior. The maximum deviation to ideality for the solvatochromic parameters can be obtained in the xIL range from 0.1 to 0.3. For most of the binary mixtures, the π^* values showed the synergistic effects instead of the E_T^N, α and β values. The observed synergy extent was dependent on the studied systems, such as the dye indicator and IL type. A preferential solvation model was utilized to gather information on the molecular interactions in the mixtures. The dye indicator was preferentially solvated on the following trend: IL >IL-water complex >water.     

Determination of Solubility Parameters of Ionic Liquids and Ionic Liquid/Solvent Mixtures from Intrinsic Viscosity

The total and partial solubility parameters (dispersion, polar and hydrogen‐bonding solubility parameters) of ten ionic liquids were determined. Intrinsic viscosity approaches were used that encompassed a one‐dimensional method (1D‐Method), and two different three‐dimensional methods (3D‐Method1 and 3D‐Method2). The effect of solvent type, the dimethylacetamide (DMA) fraction in the ionic liquid, and dissolution temperature on solubility parameters were also investigated. For all types of effect, both the 1D‐Method and 3D‐Method2 present the same trend in the total solubility parameter. The partial solubility parameters are influenced by the cation and anion of the ionic liquid. Considering the effect on partial solubility parameters of the solvent type in the ionic liquid, it was observed that in both 3D methods, the dispersion and polar parameters of a 1‐ethyl‐3‐methylimidazolium acetate/solvent (60:40 vol %) mixture tend to increase as the total solubility parameter of the solvent increases.     

Temperature-Dependent Surface Enrichment Effects in Binary Mixtures of Fluorinated and Non-Fluorinated Ionic Liquids

Using angle-resolved X-ray photoelectron spectroscopy (ARXPS), we investigate the topmost nanometers of various binary ionic liquid (IL) mixtures at different temperatures in the liquid state. The mixtures consist of ILs with the same [PF₆]⁻ anion but two different cations, namely 3-methyl-1-(3,3,4,4,4-pentafluorobutyl)imidazolium hexafluorophosphate, [PFBMIm][PF₆], and 1-butyl-3-methylimidazolium hexafluorophosphate, [C₄C₁Im][PF₆], with 10, 25, 50 and 75 mol % content of [PFBMIm][PF₆]. We observe a preferential enrichment of the fluorinated chain in the topmost layer, relative to the bulk composition, which is most pronounced for the lowest content of [PFBMIm][PF₆]. Upon cooling the mixtures stepwise from 95 °C until surface charging effects in XPS indicate solidification, we observe a pronounced increase in surface enrichment of the fluorinated chain with decreasing temperature in the liquid state. In contrast to the mixtures with lower [PFBMIm][PF₆] contents, cooling the 75 mol % mixture additionally shows an abrupt decrease of the fluorinated chain signal before complete solidification occurs, which is assigned to partial precipitation effects.     

Excess Molar Volume and Viscosity of Isobutyric Acid + Water Binary Mixtures Near and Far Away from the Critical Temperature

The excess molar volume V^E, shear viscosity deviation Δη and excess Gibbs energy of activation ΔG^∗E of viscous flow have been investigated by using density (ρ) and shear viscosity (η) measurements for isobutyric acid + water (IBA+W) mixtures over the entire range of mole fractions at five different temperatures, both near and close to the critical temperature (2.055K ≤ (T−T_c)≤ 13.055K). The results were also fitted with the Redlich–Kister equation. This system exhibited very large negative values of V^E and very large positive values of Δη due to increased hydrogen bonding interactions and correlation length between unlike molecules in the critical region and to very large differences between the molar volumes of the pure components at low temperatures. The activation parameters ΔH^∗ and ΔS^∗ have been also calculated and show that the critical region has an important effect on the volumetric properties.     

Volumetric Study of Binary Solvent Mixtures Constituted by Amphiphilic Ionic Liquids at Room Temperature (1-Alkyl-3-Methylimidazolium Bromide) and Water

At room temperature, the 1-decyl-3-methylimidazolium bromide (DMImBr) is a long alkyl chain imidazolium ionic liquid miscible with water and forming a gel zone between 5 and 40% w/w H₂O. We measured the density of the liquid mixtures of water and DMImBr. We determined the apparent molar volume of the molten salt for dilute solutions. For the concentrated solutions the partial molar volume of each component was evaluated by a perturbation method. These results are shown to be substantially different from those obtained with a short chain bromide ionic liquid, 1-butyl-3-methylimidazolium bromide (BMImBr). The amphiphilic ionic liquid (DMImBr) has been shown to form micelles and its critical micelle concentration (cmc) has been determined. Below the cmc, the Debye–Hückel limiting law for 1:1 electrolytes describes very accurately the behavior of low concentrations of the DMImBr salt in water. Above the cmc, the partial molar volume of the micellized monomer was approximately equal to the molar volume of the pure fused salt. The partial molar volume of water in these mixtures was similar to that of pure water. The concentrated solutions behave like mixtures of interpenetrated phases.     

Density and Viscosity of the Binary Mixtures Formed by p-Xylene with Methanol,n-Propanol and n-Butanol+

Abstract

Density and viscosity measurements on the binary mixtures of methanol+p-xylene, n-propanol+p-xylene and n-butanol+p-xylene at 303.15, 313.15 and 323.15K are reported The representation of the data by common mixing rules is also studied.     

两种疏水型膦类离子液体的密度、动力粘度及电导率

Two air and water stable hydrophobic phosphonium ionic liquids (ILs), tributyl-hexylphosphonium tetrafluoroborate ([P4446][BF4]) and tributyl-hexylphosphonium bis (trifluoromethylsulfonyl) imide ([P4446][NTf2]), were prepared by the traditional method. Their basic physico-chemical properties of density, dynamic viscosity, and electrical conductivity were measured in the temperature range of 283.15-353.15 K. The effect of the temperature and structure of the anion on the thermodynamic properties were discussed. The properties are compared with the cation structures changing of the phosphonium type ILs. The most important thermodynamic properties for their practical application, such as molecular volume, standard molar entropy, and lattice energy, were calculated from their density using empirical equations. The calculated values were compared with those of imdazolium and pyridinium type ILs. Molar electrical conductivity was determined from density and electrical conductivity. The applicability of the Vogel-Fulcher-Tamman (VFT) and Arrhenius equations to the fitting of the dynamic viscosity and electrical conductivity was validated. The activation of the electrical conductivity and dynamic viscosity were obtained from the final VFT equation. According to the Walden rule, the density, dynamic viscosity, and electrical conductivity were described by the Walden equation. The results are very important for academic studies as well as industrial applications of these ILs.     

新型3-吗啉-3-四取代氧化吲哚的合成

以3-卤氧化吲哚和吗啉（或硫代吗啉）为起始原料,碳酸钠为催化剂,于60 ℃发生3-叔胺基化反应,合成了10个新型的3-吗啉四取代氧化吲哚 (3aa~3bh),收率86%~94%,其结构经¹H NMR, ¹³C NMR和HR-MS（ESI-TOF）表征。     

Dew Points of Binary Nitrogen + Water Mixtures

Abstract

Experimental measurements of dew point for binary nitrogen + water were carried out between 5.010⁵Pa and 100.210⁵ Pa and temperatures from 263.0 K to 283.7 K. The experimental method is based on the generation of wet gases by water condensation in two temperature-controlled condensers with continuous gas flow at specified pressures.     

Thermal Analysis of Binary Mixtures of Imidazolium,Pyridinium, Pyrrolidinium,and Piperidinium Ionic Liquids

Ionic liquids (ILs) are being widely studied due to their unique properties, which make them potential candidates for conventional solvents. To study whether binary mixtures of pure ionic liquids provide a viable alternative to pure ionic liquids for different applications, in this work, the thermal analysis and molar heat capacities of five equimolar binary mixtures of ionic liquids based on imidazolium, pyridinium, pyrrolidinium, and piperidinium cations with dicyanamide, trifluoromethanesulfonate, and bis(trifluoromethylsulfonyl)imide anions have been performed. Furthermore, two pure ionic liquids based on piperidinium cation have been thermally characterized and the heat capacity of one of them has been measured. The determination and evaluation of both the transition temperatures and the molar heat capacities was carried out using differential scanning calorimetry (DSC). It was observed that the thermal behavior of the mixtures was completely different than the thermal behavior of the pure ionic liquids present, while the molar heat capacities of the binary mixtures were very similar to the value of the average of molar heat capacities of the two pure ionic liquids.     

Binary Mixtures of Aprotic and Protic Ionic Liquids Demonstrate Synergistic Polarity Effect: An Unusual Observation

In this communication, we demonstrate the solute–solvent and solvent–solvent interactions in the binary mixtures of two aprotic ionic liquids, namely 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, with the protic ionic liquid 1-methylimidazolium acetate. The synergistic effects as expressed by the solvatochromic parameter are noted. This observation is in contrast to the mixing of protic ionic liquids 1-methylpyrrolidium acetate and 4-methylmorpholine acetate with 1-methylimidazolium acetate, respectively. It appears that the synergistic effects in the binary mixtures of aprotic and protic ionic liquids are caused by the formation of hydrogen bonds, since cations are dominant H-bond donors while anions are dominant H-bond acceptors. Preferential solvation models are used to describe the solute–solvent interactions in the binary ionic liquid mixtures.     

Self‐Assembly of Imidazolium‐Based Surfactants in Magnetic Room‐Temperature Ionic Liquids: Binary Mixtures

The phase behaviour of binary mixtures of ionic surfactants (1‐alkyl‐3‐imidazolium chloride, C_nmimCl with n=14, 16 and 18) and imidazolium‐based ionic liquids (1‐alkyl‐3‐methylimidazolium tetrachloroferrate, C_nmimFeCl₄, with n=2 and 4) over a broad temperature range and the complete range of compositions is described. By using many complementary methods including differential scanning calorimetry (DSC), polarised microscopy, small‐angle neutron and X‐ray scattering (SANS/SAXS), and surface tension, the ability of this model system to support self‐assembly is described quantitatively and this behaviour is compared with common water systems. The existence of micelles swollen by the solvent can be deduced from SANS experiments and represent a possible model for aggregates, which has barely been considered for ionic‐liquid systems until now, and can be ascribed to the rather low solvophobicity of the surfactants. Our investigation shows that, in general, C_nmimCl is a rather weak amphiphile in these ionic liquids. The amphiphilic strength increases systematically with the length of the alkyl chain, as seen from the phase behaviour, the critical micelle concentration, and also the level of definition of the aggregates formed.     

Density and Viscosity of Methanol + Trichloroethylene,n-Propanol + Trichloroethylene and n-Butanol + Trichloroethylene Mixtures

Abstract

Density and Viscosity measurements on the binary mixtures of methanol + trichloro-ethylene, n-propanol + trichloroethylene, and n-butanol + trichloroethylene binary mixtures at 303.15, 313.15 and 323.15K are reported. The representation of the data by simple mixing rules is also studied.     

新型胍盐离子液体剪切粘度性质的预测

[guanidinium]^＋[Tf₂N]^－是一类可应用于锂离子电池电解液的新型胍盐离子液体. 针对该类九种胍盐离子液体, 基于全原子分子力场, 采用非平衡分子动力学(周期性微扰方法)对其剪切粘度进行了计算和预测. 讨论了模拟尺寸、稳态速度场以及力场参数对模拟结果的影响. 计算结果很好的体现出剪切粘度系数随着温度以及分子尺寸大小的变化趋势. 利用周期性微扰线性外推的方法计算得到的粘度系数与实验值吻合良好, 在353 K下的最大偏差在12%以内.     

Physico-Chemical Characterization of Binary and Ternary Mixtures of Imidazolium Based Cation and Common Anion Ionic Liquids with Lactams

Journal of Solution Chemistry - Excess molar volumes, $$V_{{}}^{{\text{E}}}$$ , excess isentropic compressibilities, $$\kappa_{{\text{S}}}^{{\text{E}}}$$ of binary 1-butyl-2,3-dimethylimidazolium...     

Microwave and Ionic Liquids: Inverse Temperature Dependence of Viscosity in Aqueous Medium of Grafted Copolymers

We elaborated a route to the thermosensitive polyelectrolyte system composed of 1‐methyl‐3‐vinylimidazolium salt with β‐cyclodextrin complexed counterions and mono‐(meth)acrylic functionalized poly(N‐isopropylacrylamide) as grafted side chains via a three‐step synthetic procedure. The aqueous solution of the polyelectrolyte displays partially inverse thermoresponsive behavior; it exhibits enhancement of shear viscosity up to body temperature. Furthermore, based on classically prepared poly(NIPAAm) bearing terminal amino groups, corresponding (meth‐) acrylamide‐type of macromonomers were easily obtained under microwave conditions.

     

Excess Molar Polarization in Binary Mixtures of Polar Liquids

Abstract

Excess Molar Polarizations (ΔP _W.Q., ΔP _D.D.) have been evaluated in the binary mixture of associated + associated and associated + nonassociated polar liquids using Winkelmann-Quitzsch and Davis-Douheret equations. It is observed that Winkelmann-Quitzsch equation ΔP _W.Q. is the more appropriate one for interpretation of dynamic characteristics of the molecular association in a liquid mixture.     

First Binary Mixture Ionic Liquids Containing EMIMBr and IM

A new series of binary mixture ionic liquids comprising 1-ethyl-3-methylimidozalium bromide(EMIMBr) and imidazole(IM) have been synthesized.The melting prints of the ionic liquids vary with te different content of IM while they still keey satisfactory conductivity and viscosity.According to the analysis of its phase diagram,the cutectic point is about 16.5℃ with the mass percentage of IM 29%.