Journal of Solution Chemistry最新文献

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.

The solubility data of spectinomycin dihydrochloride pentahydrate (SDP) in three binary solvents were determined over a temperature range of 278.15–318.15 K by the gravimetric method. Among the selected binary solvents, the solubility of SDP increased with the rise in temperature and initial methanol composition of binary solvents, and the general order of solubility of SDP under the same conditions was: (methanol + ethanol) > (methanol + n-propanol) > (methanol + i-propanol). Subsequently, solubility–temperature models including van’t Hoff equation, λh equation, Yaws equation, and Apelblat equation; solubility–solvent composition models including general single model; solubility–temperature and solvent composition models including NRTL equation and modified Jouyban–Acree model were used to correlate the solubility data. Regarding the application of the NRTL equation in binary solvent systems, the influence of solvent composition on model parameters was first taken into account by introducing a solvent composition correction factor, thereby exhibiting an enhancement in fitting accuracy. To gain deeper insights into the dissolving behavior of SDP, molecular electrostatic potential surface, Hirshfeld surface analysis and the KAT-LSER model were applied to analyze the molecular interactions between SDP molecules and the solvent effects. Meanwhile, entire solubility data in three binary solvent systems at 298.15 K were associated as a function of solvent properties on the basis of KAT-LSER model. The results revealed that SDP primarily acts as hydrogen bond acceptors in solution, and polar interactions between SDP and solvent molecules can play a crucial role in promoting the dissolution of SDP.

The investigation carried out in this study focused on exploring the hydrogen bonding structure of liquid solutions of methyl lactate and 1-alkanols include 1-butanol, 1-pentanol, 1-hexanol, and 1-heptanol. To analyze the interactions between the molecules, the researcher utilized the cubic-plus-association (CPA) model, which takes into account both the physical and association interactions. The maximum deviation observed in the density of the liquid solutions of methyl lactate with 1-heptanol was 0.28%, indicating the effectiveness of the CPA model in accurately modeling the density. Additionally, the researchers calculated the excess molar volumes and deviation in viscosity for the studied liquid mixtures. The analysis of these measurements revealed that the solutions of methyl lactate with 1-alkanols exhibited positive excess molar volumes across the entire concentration range. On the other hand, negative viscosity deviations were observed for the mentioned alkanols. These findings suggest that there are weak intermolecular associations within the liquid solutions, with weaker bond strength observed in higher alkanols.

An aqueous two-phase system (ATPS) composed of PEG35000, Na₂CO₃, K₂CO₃, and their mixtures at 298 K was studied. The liquid–liquid equilibrium (LLE) of these systems, including binodal curves, tie-lines, tie-line length, and slope of the tie-line, were obtained. Additionally, for the first time, salt mixtures with different initial mass ratios of 1:3, 1:1, and 3:1 were used to prepare the aqueous two-phase systems. The effect of electrolyte and salting-out power for these systems was examined and compared. Consistent with the literature, it was found that the salting-out power of Na⁺ is higher than that of the K⁺ cation. Furthermore, in Na₂CO₃ and K₂CO₃ mixtures, increasing the amount of sodium ions resulted in stronger salting-out power. The LLE data was correlated with the Othmer-Tobias, Bancroft, and Setschenow models, and good agreement was found with all three models.

This review article provides an overview of the fundamental background and application of aqueous two-phase systems (ATPSs) in protein and enzyme extraction. The types of ATPSs, including polymer/salt, polymer/polymer, alcohol/salt, surfactant-based, and ionic liquid-based ATPSs, are discussed, along with the unconventional ATPSs. Factors affecting partitioning in ATPSs, such as molecular weight and polymer concentration, pH, temperature, hydrophobicity, and affinity, are also examined. The article then focuses on the application of ATPSs in protein and enzyme extraction, including continuous processing and scaling-up. The future prospects, challenges, and limitations of ATPSs in this field are discussed, along with the challenges associated with their use in industry. The results section highlights the potential of citrate green salts as an alternative to sulfate and phosphate salts in salt-based ATPSs and the need for more research on using ionic liquids as an additive in ATPS types for protein and enzyme extraction. Overall, this review suggests combining cheap and environmentally friendly materials in ATPSs can be a practical solution for using ATPSs in the industry.