Journal of Solution Chemistry最新文献

To fully understand the metallogenic regularity and the geochemical equilibrium rules of brine migration and transformation among potassium, barium and strontium in gas field water, the isothermal dissolution equilibrium method was used to study the phase equilibria of quaternary system KCl + BaCl₂ + SrCl₂ + H₂O and its two ternary systems BaCl₂ + SrCl₂ + H₂O and KCl + BaCl₂ + H₂O at 323 K. The equilibrium liquid phase compositions of each system was measured, the corresponding equilibrium solid phases were identified by chemical analysis and X-ray powder diffraction, and the equilibrium phase diagrams were drawn. No double salts or solid solutions were found in the ternary systems BaCl₂ + SrCl₂ + H₂O and KCl + BaCl₂ + H₂O at 323 K and the phase diagrams both contain one invariant point, two isothermal solubility curves and two crystallization regions. The hydrate forms in the quaternary system KCl + BaCl₂ + SrCl₂ + H₂O at 323 K are the same as those of its subsystems. The quaternary phase diagram contains one invariant point, three isothermal solubility curves and three crystallization regions, where the equilibrium solid phases are KCl, BaCl₂·2H₂O and SCl₂·6H₂O. These results provide basic thermodynamic data for the design of a comprehensive utilization process of potassium, barium and strontium resources in gas field water.

Densities ((rho)) and viscosities ((eta)) of the binary mixtures of 2-ethyl-1-hexanol (2-EH) with ethylenediamine, 1,2-dichloroethane (DCE) and monoethanolamine (MEA) were measured at T = (298.15–318.15) K under atmospheric pressure over the entire composition range ((x_{{1}} = 0 - 1.0)). For these binary mixtures ultrasonic speeds ((u)) and refractive indices ((n_{{text{D}}})) were also measured at 298.15 K. With these experimental data the excess molar volumes ((V_{{text{m}}}^{{text{E}}})), viscosity deviations ((Delta eta)), excess molar refractions ((R_{{text{m}}}^{{text{E}}})), excess isentropic compressibility ((kappa_{{text{S}}}^{{text{E}}})) and other derived properties were determined at various experimental temperatures. Such thermophysical properties were discussed in terms of molecular interactions and structural effects well corroborated with IR spectra of the mixtures. Excess molar volumes ((V_{{text{m}}}^{{text{E}}})) of the binary mixtures were used to derive partial molar volumes ((overline{V}_{{text{m,1}}}^{{0}}) and (overline{V}_{{{text{m,}},{kern 1pt} {2}}}^{{0}})) and excess partial molar volumes ((overline{V}_{{text{m,1}}}^{{text{0,E}}}) and (overline{V}_{{text{m,2}}}^{{text{0,E}}})) at infinite dilution to reveal the volume changes of the binary mixtures. Prigogine-Flory-Paterson theory (PFP), Peng-Robinson Equation of States (PR-EOS) and Bloomfield-Dewan (BF-D) model were used to predict excess molar volumes ((V_{{text{m}}}^{{text{E}}})) and viscosities ((eta)) of the mixtures. Ultrasonic speeds ((u)) of the binary mixtures predicted using empirical or semi-empirical theories like free length theory, Impedance dependence relation, Ideal mixture relation, Junjie’s relation, collision factor theory and Nomoto’s relation, etc. Computational studies have also been performed to establish the degree and nature of solvent–solvent interactions theoretically.

At temperatures ranging from 293.15 to 343.15 K and atmospheric pressure, the densities, refractive indices, dynamic viscosities, surface tensions, and sound speeds for [Cnmpyr][[NTf₂] (n = 3,4,6,8), [Cnmpyr][[N(CN)₂] (n = 3,4), [Cnmim][[N(CN)₂] (n = 2,4) and [Bnzmim][[N(CN)₂] were measured and discussed. As expected, all properties decrease as the temperature rises, with dynamic viscosity being the property most affected by the temperature change. Using linear correlation as a function of temperature, the density, speed of sound, surface tension, and refractive index are calculated, whereas the dynamic viscosity is correlated using the well-known Vogel–Fulcher–Tamman (VFT) equation. Using the experimental density data, the corresponding coefficients of thermal expansion were calculated. Furthermore, the Laplace–Newton equation was utilized to determine the isentropic compressibility. Results unveiled that the type of anions has the higher influence on the physical properties of the studied ionic liquids, while the elongation of the alkyl chain is less significant.

Palladium-107 is one of the selected radionuclides in the safety assessment of geological disposal of radioactive waste. Although isosaccharinic acid (ISA) forms strong complexes with many elements and enhances element solubility, the thermodynamic evaluation of the complex of Pd with ISA has not been conducted. In this study, the solubility of Pd(OH)₂ at pH 8.5–12.5 in the presence of ISA was investigated under inert gas (N₂) atmosphere. Furthermore, the coordination state of aqueous Pd and ISA was investigated by X-ray absorption and Fourier transform infrared spectroscopy, respectively. According to experimental results, the number of OH ligands in the mixed complex depends on pH. The thermodynamic model and conditional equilibrium constants of the Pd-ISA complex were estimated by slope analyses of solubility experiments at different pH levels and ionic strengths based on the specific ion interaction theory. Hence, the impact of complexation with ISA on Pd(II) solubility under disposal conditions could be quantified using the proposed thermodynamic models in this study.

Molar conductances for sodium chloride have been measured in the solvent system mannitol-water covering the solvent composition range from pure water to saturated aqueous mannitol at temperature from 293.15 to 313.15 K at 5 K intervals. According to the Fuoss–Justice conductance equation, limiting molar conductance (Lambda^{infty }), association constants (K_text{A}), and the Walden products were obtained and their variations were in conformity with the thermodynamics study of solvent effect. The Eyring’s activation enthalpy of charge transport (Delta H^{dag }) was derived and the results have stipulated that this kinetic procedure depends only on the solvent properties. Ion association thermodynamic quantities, Gibbs energy ((Delta G^{ circ })), enthalpy ((Delta H^{ circ })), and entropy ((Delta S^{ circ })) were also calculated and their interpretation were further supported by other methods. Besides, by appropriate splitting of Gibbs’ energy of association into electrostatic and non-electrostatic contributions.

The structure, hydrogen bonding, and hydrogen transfer of 1-butyl-3-methylimidazolium hydroxide ([Bmim]OH) aggregations, including dimer and trimer of carbene(α) and covalent(β) conformation, have been investigated using density functional theory B3LYP together with D3 dispersion correction. The geometrical parameters, Gibbs free energy of formation in gas and solution phases were calculated for aggregates of the complex [Bmim]OH conformation. The strengths and binding energies of different types of H-bonds were predicted by quantum theory of atoms-in-molecules descriptors. The results show that O–H···C hydrogen bonds were formed between most hydroxyl protons and the carbon atom of the carbene ring (C2) in [Bmim]OH aggregations. Furthermore, we examine the proton transfer in dimer and trimer conformation of [Bmim]OH, the reaction pathway for proton transfer from hydroxyl of β-conformer to carbene ring was investigated, and the proton transfer process is energetically favorable.

The negative logarithm of the acid dissociation constant values (pK_a1 and pK_a2) of 4,4′-trimethylenedipiperidine (TMDP) was determined by a pH metric titration at 298 K. The experimentally determined pK_a values were compared with the predicted pK_a values by chem-bioinformatics software like ACD/Labs and ChemAxon. This experiment gave an excellent opportunity to deepen engagement with the Henderson–Hasselbalch equation, acid/base dissociation constant (K_a/K_b), and half equivalence point.

Graphical Abstract

Knowing about the dissolution kinetics and solubility is necessary for controlling crystallization separation process of lysozyme. In this study, the impact of four ionic liquids (ILs), namely, 1-butyl-3-methylimidazolium tetrafluoroborate [C₄mim]BF₄, 1-butyl-3-methylimidazole chloride [C₄mim]Cl, 1-butyl-3-methylimidazole bromide [C₄mim]Br, and 1,3-dimethylimidazolium iodide [dmim]I, on the dissolution rate of lysozyme was determined in an aqueous solution at 20 ℃, pH 5.01, under 101.3 kPa. The results revealed that the dissolution rate of lysozyme increased with increasing concentrations of [C₄mim]BF₄ and [C₄mim]Cl, while it remained stable with increasing concentrations of [C₄mim]Br. In contrast, the dissolution rate gradually decreased with increasing concentrations of [dmim]I. This suggests that the interaction between lysozyme molecules is influenced by the ILs, leading to variations in the dissolution rates. Additionally, the effect of anions and cations on the equilibrium solubility was analyzed. The results indicated that the order of anionic and cationic effects on equilibrium solubility is as follows: BF⁴⁻ < Cl⁻ < Br⁻ = [C₄mim]⁺  < [dmim]⁺  < I⁻. Furthermore, dissolution kinetic models were established, which could be used to predict the dissolution behavior of large molecules like lysozyme in ILs aqueous solution. These findings have significant implications for the design of crystallization process and optimization of parameters during lysozyme recovery.

The hygrometric method is used to determine new thermodynamic data on water activity and saturated aqueous solution of the water/d-sucrose/ammonium dihydrogen phosphate (ADP) system in a wide range of NH₄H₂PO₄ molality, ranging from 0.1 to 3 mol⋅kg⁻¹, and for various d-sucrose contents from 0 to 4 mol⋅kg⁻¹. Powder X-ray diffraction (XRD) and attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy were used to characterize the solid state. The Pitzer–Simonson–Clegg model (PSC) is used to fit the experimental data of osmotic coefficient obtained from water activities data. The predicted saturated aqueous solutions, with the PSC model, are in good agreement with experimental data. For the concentration inferior to 1 mol⋅kg⁻¹, the negative deviation from ideality was shown with increasing the ADP concentrations. The estimated values of the activity coefficient of d-sucrose, activity coefficient of ADP, and the Gibbs energy of transfer of ADP from water to mixture (water/d-sucrose) show that both ADP and d-sucrose exert significant salting-out effects on the aqueous solution.