Journal of Solution Chemistry最新文献

The density and viscosity of the pseudo-binary mixtures of eutectic solvent (ES) composed of choline chloride and ethylene glycol ([ChCl/EG]) with dimethylsulfoxide (DMSO) were measured. In order to understand the effect of the mole ratio of ChCl:EG, two ChCl/EG ESs with the mole ratio of 1:3 and 1:4 (abbreviated as [ChCl/EG]_(1:3) and [ChCl/EG]_(1:4) in this work) were prepared. The measurements were carried out by digital vibrating U-tube density meter and Ubbelohde capillary viscometer from 303.15 to 323.15 K at atmospheric pressure (98.5 kPa). The Jouyban–Acree model was applied to correlate the experimental density and viscosity data of DMSO/[ChCl/EG]_(1:3) and DMSO/[ChCl/EG]_(1:4) mixtures. In addition, based on the experimental data, the derived properties of the mixtures, such as excess molar volume and viscosity deviation, were calculated. The comparison and analysis of excess molar volume and viscosity deviation for DMSO/[ChCl/EG]_(1:2) reported in literature and the results obtained in this work were carried out.

The binary system of [Bmim][OAc] (1-butyl-3-methylimidazolium acetate) with NMP (N-methylpyrrolidone) is a potential effective cellulose solvent, and its physicochemical properties and solute–solvent interaction are important to design and understand its application. The physicochemical properties can infer the solute–solvent interaction of a system, especially for an infinite dilution; so, in this work, over the molality range 0.0–2.1 mol·kg⁻¹ and temperature range 288.15–318.15 K, the density and absolute viscosity for the dilute solution of [Bmim][OAc] in NMP were measured and correlated. The apparent molar volume and the relative viscosity were calculated and correlated by Redlich–Rosenfeld–Meyer equation (including parameters (V_{Phi}^0), A_v, B_v) and Jones–Dole equation (including parameters D, F), respectively. Then, the structure behavior of [Bmim][OAc] on solution and the [Bmim][OAc]–NMP interaction were discussed based on the parameters (V_{Phi}^0), A_v, B_v, D, F, and the volume ratio r, limiting apparent molar expansibility (E_{Phi}^0) and the solvation number n_s. The results show that [Bmim][OAc] acts as a structure-maker for the solution, the [Bmim][OAc]–NMP interaction is weaker than the interactions of cation–anion and NMP–NMP, and such effect becomes more and more obvious with increasing temperature. Finally, based on the interactions and the widely accepted solvation hypothesis, the possible better temperature to dissolve cellulose was discussed for the potential cellulose solvent.

The Pitzer–Debye–Hückel equation (PDH) is widely used as the long-range term in electrolyte local composition models to describe the non-ideality of electrolyte solutions in the low concentration range. However, the PDH equation’s derivation typically involves disregarding the third term of the radial distribution function, which leaves uncertainties regarding its impact on asymmetric systems, especially those with high asymmetry. This paper addresses this issue by introducing a trinomial radial distribution function and re-deriving the PDH equation, aiming to evaluate the efficacy of the modified equation in describing various asymmetric electrolyte systems at low concentrations (0–1 mol·kg⁻¹). Initially, the osmotic coefficients of 19 single asymmetric electrolyte systems were fitted using the modified PDH equation (M-PDH). The results demonstrated that the accuracy of the M-PDH equation was significantly higher compared to the original PDH equation, yielding standard deviations (SD) of 0.1812 and 0.4238, respectively. Furthermore, an analysis and recommendation for the distance parameter b were provided. Finally, a comparative analysis was conducted to assess the contributions of the third term of the radial distribution function in contrast to the first two terms to the osmotic coefficients. Overall, this study enhances our understanding of how asymmetry affects the PDH equation in describing the thermodynamic properties of electrolyte systems.

In the production of cyclohexene by benzene hydrogenation, the by-product cyclohexane forms an azeotrope with cyclohexene. For the extraction and distillation of the binary azeotrope (cyclohexene + cyclohexane), the selectivity and relative volatility of 24 different entrainers were compared and the intermolecular interaction forces and interaction energies were analyzed by the DMol3 module of Materials Studio (MS). N, N-dimethylformamide (DMF) was identified as the entrainer, and vapour–liquid equilibrium (VLE) data were measured at atmospheric pressure for the binary system {cyclohexane + cyclohexene} with a temperature range of 354 K to 356 K, the binary system {cyclohexane + DMF} with a temperature range of 354 K to 390 K, and the binary system {cyclohexene + DMF} with a temperature range of 357 K to 421 K. In addition, the thermodynamic consistency of the experimental data was checked using the Wisniak and Van Ness method. The Wilson, NRTL, and UNIQUAC models were used to regress and fit the experimental data to optimize the binary interaction parameters, and the root mean square (RMSD) and average absolute deviation (AAD) values of all models were below 0.01%, indicating that the experimental data provide a basis for the simulation and optimization of the extractive distillation process.

Cloud point (CP) of aqueous solution of metformin hydrochloride (MNH) and triton X-100 (TX-100) was examined in presence of several alcohols (MeOH, EtOH, 1-PrOH, 2-PrOH, and 1-BuOH). The main focal point of this study was to evaluate the cloud development for the combination of TX-100 and MNH, as well as to indicate the mode of how various alcohols influence both the physicochemical parameters and interaction forces of that mixture. The cloud point (CP) measurement technique was chosen because of its broad applicability in both the medical and industrial sectors. As alcohol contents increased, higher CP values of TX-100 and MNH mixture were observed except in aq. 1-BuOH (CP is decreased). In the aqueous alcoholic medium (above 3000 mmol·kg⁻¹), the phase separation of TX-100 (92.7 mmol·kg⁻¹) and MNH (2 mmol·kg⁻¹) mixture showed the subsequent trend: CP (H₂O + 2-PrOH) ˃ CP (H₂O + MeOH) > CP (H₂O + EtOH) ˃ CP (H₂O + 1-PrOH). It was observed that the depth to which alcohol molecules penetrate micelles is influenced by the length of the alcohol chain. Longer hydrophobic alcohol molecules have the ability to impair more ethylene oxide–water (EO-water) interactions by penetrating deeper into the micelle’s palisade layer. As a result, there is more occurrence of dehydration, which promotes the production of micellar particles as well as lowers the cloud point substantially. The calculated ({Delta G}_{c}^{0}) values of the TX-100 + MNH mixture in alcohols media are appeared as positive in every scenario examined, proving that the clouding procedure is not spontaneous. The positive ({Delta G}_{c}^{0}) results might be attributed to the surfactant’s surface layer in forming H-bond via the water molecules. A decrease in the positive ({Delta G}_{c}^{0}) values is evidenced by a rise in alcohol concentrations. Consequently, there is less non-spontaneity at higher alcohol concentrations. The (+{Delta H}_{c}^{0}) (endothermic) and (+{Delta S}_{c}^{0}) magnitudes are detected in aq. MeOH, EtOH, and 2-PrOH solutions. However, ({Delta H}_{c}^{0}) and ({Delta S}_{c}^{0}) magnitudes are found as positive (endothermic) and negative (exothermic) at lower and higher contents of 1-PrOH solution while the opposite trend in the ({Delta H}_{c}^{0}) and ({Delta S}_{c}^{0}) was detected in aq. 1-BuOH solution.

Graphical Abstract

Possible interactions among TX-100 and metformin hydrochloride in aqueous 1-BuOH media

Levulinic acid (LA), a carboxylic acid with a keto-acid structure, has recently been gaining increasing attention as a promising biorefinery platform chemical due to its potential to be feasible and sustainable. This work focuses on using trioctylamine (TOA) to separate LA from an aqueous solution by liquid–liquid extraction. For that, binodal curves and tie lines were determined at T = (293.15, 313.15, and 333.15) K under atmospheric pressure. The slope of the determined tie lines demonstrates that higher extraction efficiencies are possible with higher acid concentrations. Furthermore, infrared spectroscopy (FT-IR) was applied to better understand the behavior of phase diagrams. This study detected the acid-extractant complex formation between (LA) and (TOA). Finally, the experimental data were successfully correlated with the NRTL model at all the measured temperatures. The obtained parameters were applied using a decanter model.

In this work, the absorption of sulfur dioxide (SO₂) was investigated using the 1,3-propanediol (PDO) + dimethyl sulfoxide (DMSO) system, and the gas−liquid equilibrium (GLE) data were analyzed over a temperature range of 298.15–318.15 K (with a temperature gradient of 5 K) at a pressure of 123.15 kPa. By fitting the gas–liquid equilibrium data, it is observed that the process of absorption SO₂ conforms to Henry’s Law. The change in specific entropy, enthalpy, and Gibbs free energies of the SO₂ absorption process was as well calculated. In addition, the capture and regeneration properties of the PDO + DMSO system were investigated under atmospheric pressure, and the results of regeneration experiments demonstrated that 97.3% of SO₂ could be desorbed by heating and bubbling with N₂. Furthermore, there was no notable reduction in absorption capacity of the absorbent solvents after multiple cycles. Finally, the FTIR spectra and computational information were noted to analyze the interaction between SO₂ and the system. As a result, an intermolecular hydrogen bonding association between PDO, DMSO, and SO₂ can be inferred.

The preconcentration of uranium VI (U(VI)) at trace levels in some real water and wastewater samples and its determination by spectrophotometry using a homogeneous solvent-based microextraction method, specifically in-situ solvent formation microextraction, were investigated. This microextraction method uses a unique task-specific ionic liquid (IL) as the specific complexing agent and/or extracting phase. A pyrrolidinium-based IL modified with (E)-5-(bromomethyl)-2-(pyridin-2-yldiazenyl) phenol as a task-specific IL (E)-1-(3-hydroxy-4-(pyridin-2-yldiazenyl) benzyl)-1-methylpyrrolidinium bromide (TSIL/Br) was successfully synthesized and characterized by ¹HNMR and FTIR analyses. TSIL/Br chelated with U(VI) ions in the aqueous phase to form a hydrophilic [U(VI)-TSIL/Br₂] complex with high efficiency. It was then converted to a hydrophobic [U(VI)-TSIL/(NTf₂)₂] complex through a counter-ion agent, such as bis(trifluoromethanesulfonyl)imide ((text{NTF}_2^-)) for separation from the aqueous solution phase. This process eliminates the need for a separate complexing agent, because TSIL/Br acts simultaneously as both a complexing agent and an extracting solvent. In brief, the conditions of the microextraction process must be optimized for the analysis of real water samples. Under the optimum conditions, a preconcentration factor, detection limit, quantification limit, linear dynamic range, and relative standard deviation of 218, 1.62 ng·mL⁻¹, 5.42 ng·mL⁻¹, 20.0–450.0 ng·mL⁻¹, and 2.47% (n = 10, 20 ng·mL⁻¹) were obtained, respectively. Finally, to assess the method’s ability, it was successfully employed to determine the U(VI) ion content in various real water, wastewater and reference material samples.

In this work, the physiochemical properties of the drug, isoproterenol hydrochloride, were analyzed in the presence of β-cyclodextrin in an aqueous medium to gain a better understanding of the prevailing interactions among solute–solvent systems with the help of viscosity and conductivity studies. From viscosity measurements, the viscosity (B)-coefficient along with its transfer parameter was calculated using the Jones–Dole equation. In addition to this, the activation parameters such as (Delta {mu }_{1}^{text{o}{#}}), (Delta {mu }_{2}^{text{o}{#}}), (Delta {S}_{2}^{text{o}{#}}), and ({Delta H}_{2}^{text{o}{#}}) were evaluated and discussed to gain a better understanding of the mechanism of viscous flow in terms of transition state theory. Along with this, conductivity studies were performed to investigate the thermodynamics of the ternary system in terms of changes in Gibbs free energy. Also, the delayed critical aggregate concentration of the ternary system supports favourable interaction between the studied drug and β-cyclodextrin molecules.

The development of highly sensitive and visual analytical methods for monitoring pH change has always attracted great attention due to significant roles in various fields including food, environmental and biological systems. In this paper, a dual-response sensor for pH detection, [1,2']biindenylidene-3,1',3'-trione L, was synthesized from substrate indane-1,3-dione, and its structure was confirmed by ¹H NMR, ¹³C NMR, ESI–MS and single crystals. Interestingly, sensor L exhibits solvatochromic properties and visualized color changes at different poplar solutions, and it can show significant changes in fluorescence intensity, UV–Vis absorbance and color at moderate acidic (pH = 3.52–5.03) and strong basic conditions (pH = 13.09–13.27) based on intramolecular proton transfer (IPT) mechanism. These results indicate that L can act as a double functional probe for the analysis and visual detection of pH change under moderate acidic and strong basic conditions in a quite narrow pH range. In addition, L can also selectively identify solvent CH₂Cl₂ by inducing larger blue-shift in wavelength and increase in fluorescence intensity, which means that it may be used as an indicator for monitoring trace amount of CH₂Cl₂. The potent applicantions for sensor L were also investigated and that it could conveniently be made into a series of strips for pH detection was indicated.