Journal of Chemical & Engineering Data最新文献

Phase equilibria and diagrams can provide essential theoretical data for the enrichment and extraction of elements in the development and utilization of brines. For the composition of boron- and calcium-rich brines, the solid–liquid equilibria of the ternary system Li⁺, Ca²⁺// Borate–H₂O at 298.2, 323.2, and 348.2 K were studied. In this work, calcium borate CaB₆O₁₀·5H₂O was synthesized by a hydrothermal method for phase equilibria experiments, the structure and phase analyses of CaB₆O₁₀·5H₂O were performed by X-ray diffractometer (XRD), scanning electron microscope (SEM), and Fourier transform infrared (FTIR) spectrometer, and the purity of CaB₆O₁₀·5H₂O was determined by chemical analysis. Meanwhile, the solubility of CaB₆O₁₀·5H₂O at 273.2–348.2 K was determined, which showed that it increases first and then decreases with the rise in temperature. The solubility, density, refractive index, and pH of the system Li⁺, Ca²⁺// Borate–H₂O at 298.2, 323.2, and 348.2 K were measured, and the corresponding phase diagrams and physicochemical properties versus composition diagrams were constructed. The system Li⁺, Ca²⁺// Borate–H₂O is a simple system at 298.2, 323.2, and 348.2 K; two crystalline regions correspond to CaB₆O₁₀·5H₂O and Li₂B₄O₇·3H₂O (CaB₆O₁₀·5H₂O > Li₂B₄O₇·3H₂O) and with the increase in temperature, the crystallization region of CaB₆O₁₀·5H₂O increases.

Deep eutectic solvents (DESs) are new green solvents, and quaternary ammonium salt acid DESs have been widely used in the field of analytical separation in recent years due to their low cost and environmental friendliness. In this work, the density, viscosity, and electrical conductivity of binary mixtures containing three quaternary ammonium salt–(dl)-lactic acid DESs with H₂O were determined. The average molar volume, excess molar volume, and viscosity deviation of the DESs’ aqueous solutions trends were computed. The viscous flow activation energy of DESs’ aqueous solutions was derived using the Arrhenius equation. The DESs’ physical properties are significantly influenced by their structure, temperature, and water content. The excess molar volume and viscosity deviation are negative over the entire concentration range, indicating a strong interaction between DESs and water. The variation of viscosity and electrical conductivity of the binary system with temperature conforms to the Vogel–Fulcher–Tammann (VFT) equation and shows an opposite trend, i.e., viscosity decreases and electrical conductivity increases with increasing temperature. The VFT equation can be conveniently applied to the aqueous solutions of DESs.

Methanol is the world’s recognized renewable, environmentally friendly, efficient low-carbon biofuel and can be widely used in various fields. Based on the new high temperature and pressure flow calorimeter developed in this work, the isobaric heat capacity of fluids can be measured at temperatures T = 298–573 K and pressures up to 15 MPa. The heat loss of the flow calorimeter was calibrated by n-heptane at various temperatures. The isobaric specific heat capacity c_p of methanol was measured for temperatures T ranging from 298 to 573 K and pressures p ranging from 0.1 to 15 MPa in both liquid and vapor phases. The experimental data were compared and agreed well with the Helmholtz equation of state (EoS), indicating the average absolute deviation (AAD) of 0.32% and 0.80% for liquid and vapor phases, respectively. A new correlation of heat capacity with temperature and pressure was proposed and used to fit the experimental data of methanol both in liquid and vapor phases, which showed better performance than other models. Based on the new model, our data were able to compare with the available published experimental data, and most data agreed well with our correlation.

A systematic experimental study of the isoplethic sections for the quaternary system H₂O–H₃PO₄–TBP–MIBK was carried out at 298.2 K under atmospheric pressure in order to evaluate the synergic effect of tributyl phosphate (TBP) and methyl isobutyl ketone (MIBK) as a mixed solvent for orthophosphoric acid (H₃PO₄) extraction. Liquid–liquid equilibria diagrams were fully established for the following TBP/MIBK mass-percent ratios: 0/100, 30/70, 50/50, 80/20, and 100/0. The reliability of the LLE measurements was confirmed by the Othmer-Tobias and Hand equations. The results show that the quaternary system is type II and that the demixing area expands with an increasing TBP content. Moreover, the mixed solvent enhances MIBK selectivity for acid concentrations below 50 wt %, while the 80/20 weight ratio shows the optimal selectivity for acid concentrations below 25 wt %. Furthermore, these experimental results were compared to the values predicted by the NRTL model. It can be seen that the interaction parameters of the NRTL model used provide good results with a root-mean-square deviation (RMSD) of 0.0135.

CO₂-loaded and unloaded densities of N-methyldiethanolamine (MDEA) + piperazine (PZ) + tetramethylene sulfone (SFL) aqueous mixtures were measured concurrently with CO₂ solubility from 303.15 to 363.15 at 20 K steps and pressures of about 1200 kPa using a developed, sophisticated isochoric pressure drop method. Moreover, the CO₂ solubility was measured at 313.15, 328.15, and 343.15 K using a conventional isochoric saturation system to check the reliability and consistency of the solubility data from low pressure to 3000 kPa. Increasing the PZ concentration improved the MDEA absorption capacity in aqueous and mixed aqueous sulfolane solutions in the low-loading region. Furthermore, solution densities decreased by increasing the temperature at all loadings while increasing by increasing the CO₂ loading at each isotherm. CO₂-loaded and unloaded/fresh solution densities were correlated using a modified Setchenow equation. The average percent relative deviation (AARD %) of correlated densities from the experimental data was 0.21%, indicating the completely good correlative accuracy of the Setchenow model. Furthermore, a combination of the Deshmakh–Mather (DM) activity coefficient model and Peng–Robinson (PR) equation of state for electrolytic liquid and vapor phases, respectively, was used to correlate the vapor–liquid equilibrium data for the CO₂ + H₂O + MDEA + PZ + SFL system. The DM–PR model showed a good correlative accuracy with AARD % = 10.2 and was used to assess the accuracy and reliability of reported data for aqueous MDEA/PZ/SFL solutions.

The saturation shake-flask technique was employed herein to determine the equilibrium solubility of tolfenamic acid in 12 monosolvents, including ethylene glycol, 1-pentanol, 1-hexanol, 1-heptanol, ethyl formate, ethyl acetate, 1,4-dioxane, acetonitrile, cyclohexane, dimethyl sulfoxide, N,N-dimethylformamide, and pentyl acetate. The effects of the solvent properties on the solubility were studied using the linear solvation energy relationship. Correlation of the magnitudes of equilibrium solubility was conducted by means of several semiempirical equations and activity coefficient models such as Wilson, Apelblat, λh, and NRTL. The mixing solution properties and activity coefficient together with partial molar excess enthalpy at infinite dilution were also estimated using the Wilson equation. Additionally, the electrostatic characteristics of the basicity and acidity of the tolfenamic acid molecule were explained using a quantitative study of the molecular surface. To further explore tolfenamic acid’s miscibility in the chosen solvents, Gaussian 09 was used. The strong interaction between tolfenamic acid and solvents resulted in higher solubility.

The solubility of methyl l-leucinate hydrochloride in 12 pure solvents (methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, dimethyl carbonate, n-butanol, n-pentanol, acetonitrile, acetone, 2-butanone, n-hexane, and 1,4-dioxane) was determined by a gravimetric method under atmospheric pressure (101.2 kPa) and temperature ranging from 283.15 to 323.15 K. Furthermore, the solvent thermodynamic functions were derived by van’t Hoff model. The values of Δ_solG°, Δ_solH°, and Δ_solS° are positive in selected 12 solvents, indicating that the dissolution process of methyl l-leucinate hydrochloride is endothermic and driven by entropy. In addition, the contributions of multiple physicochemical properties of solvents to the solubility of methyl l-leucinate hydrochloride were evaluated. The solvents had a strong tendency to form a hydrogen bond with methyl l-leucinate hydrochloride. The solid phase of methyl l-leucinate hydrochloride in the investigated solvent systems was characterized by powder X-ray diffraction test. The increasing temperature exhibits a positive effect on the methyl l-leucinate hydrochloride solubility in pure solvents. The dissolution behavior was affected by the combined effects of four factors consisting of solvent polarity, formation of hydrogen bonds, solvent–solvent intermolecular interactions (represented by cohesive energy density), and molecular structures of solvents and the solute. Additionally, the Yaws model and the modified Apelblat model were utilized to fit the data of solubility, and the values of ARD as well as RMSD were calculated to evaluate the relative applicability of the two solubility models. The results show that the modified Apelblat model could give a better correlation result for the solubility data than the Yaws model. The results could facilitate the crystallization operation of methyl l-leucinate hydrochloride for purification and separation.

In this paper, we have performed all-atom molecular dynamics simulations to understand the structure, dynamics, and thermodynamic behavior of Na⁺ ions in water-mixed ionic liquids. We have considered seven different combinations of water-mixed ionic liquids having common cation 1-ethyl-3-methylimidazolium [EMIM⁺] along with seven different anions such as acetate [ACT]⁻, formate [FRM]⁻, trifluoromethyl-sulfonate [TFS]⁻, benzoate [BEZ]⁻, nitrate [NO₃]⁻, hexafluorophosphate [PF₆]⁻, and tetrafluoroborate [BF₄]⁻. Two different water mole fractions (x) are considered: 0.55 to 0.71. Various structural and dynamic properties are investigated such as radial distribution functions, ion self-diffusion coefficients, and ionic conductivity. We understand that hydrophilic anions interact more with water, which would lead to enhanced mobility of the Na⁺ ions in the neat IL [EMIM]⁺ [TFS]⁻ that presents higher ionic conductivity values; on the other hand, water-mixed IL presents higher conductivity values for the [EMIM]⁺ [BF₄]⁻ and [EMIM]⁺[NO₃]⁻. The self-diffusion coefficient values of Na⁺ ions present higher values in [EMIM]⁺ [BF₄] and [EMIM]⁺ [NO₃]⁻ in water-mixed ILs compared to other ionic liquid–water combinations. Overall, the results presented in this manuscript will help in understanding the molecular-level behavior of imidazolium-based electrolytes for battery applications.