Journal of Chemical & Engineering Data最新文献

Owing to the urgent environmental concerns, numerous refrigerants containing R32 or R1234yf are widely regarded as a practical approach to replace the current refrigerants in air conditioning and refrigeration equipment. To promote the commercial application of these alternative refrigerants, experimental measurements of solubility and interfacial tension for R32/POE-68 and R1234yf/POE-68 mixtures were investigated by the isochoric saturation and pendant drop methods in the temperature range from 243.15 to 363.15 K and at pressures up to 5.78 MPa. Moreover, we have further discussed the comprehensive influence of temperature and pressure on thermophysical properties by both intermolecular interstices and intermolecular interactions. Under identical thermodynamic conditions, R1234yf has a superior solubility performance in the polyol ester (POE-68) lubricant compared to R32, and their interfacial tension is more susceptible to pressure variation. Experimental data of solubility were correlated by the NRTL activity coefficient model with the maximum absolute deviations and the average absolute deviations of less than 5.83% and 3.47%, respectively. An empirical correlation has been introduced to accurately describe the interfacial tension of multicomponent mixtures, and their parameters were determined by the nonlinear optimization method. The maximum absolute deviations and the average absolute deviations of interfacial tension for R32/POE-68 and R1234yf/POE-68 mixtures are within 3.88% and 1.44%, respectively.

The mole fraction solubility of N-acetyl-l-alanine in 16 pure solvents was determined by the static gravimetric method at a temperature range of 283.15–323.15 K under a pressure of 101.2 kPa, and the solubility of N-acetyl-l-alanine was positively correlated with temperature. Whether N-acetyl-l-alanine produced a polycrystalline form in the solvent system was investigated by powder X-ray diffraction. The results showed that N-acetyl-l-alanine did not undergo crystalline transformation during solubility determination. The solubility data were fitted using the modified Apelblat, NRTL, UNIQUAC, and Margules models, and the model parameters and errors were estimated. The interactions of N-acetyl-l-alanine in solvent systems were studied using molecular electrostatic potential surfaces (MEPS). Hansen solubility parameters (HSPs) were used to evaluate the nature of the solvent and its solubility properties for N-acetyl-l-alanine. In addition, thermodynamic properties of the mixing for N-acetyl-l-alanine in solvent systems were investigated using the NRTL model, and the mixing process was found to be entropic and spontaneous. Furthermore, the difference in solubility between N-acetyl-l-alanine and l-alanine in the same solvent was analyzed, where N-acetyl-l-alanine > l-alanine, which may be due to intermolecular forces and the influence of the acetyl group.

Cryo-compressed hydrogen (CcH₂) storage is regarded as a highly promising method due to its low energy consumption and high storage density. The technological route for CcH₂ storage requires precise thermal conductivity data, as the thermal conductivity of hydrogen is a critical parameter for the design and control of temperature fields during the charging and discharging processes of CcH₂ storage systems. However, there is currently a lack of experimental thermal conductivity data for hydrogen under low-temperature and high-pressure conditions. In this work, the thermal conductivity of hydrogen was measured using the transient hot-wire method across a temperature range of 69–150 K and pressures up to 37 MPa. The experimental results show a maximum deviation of 5.09% compared to the calculated values from REFPROP 10.0. Furthermore, a residual entropy scaling (RES) model was developed, with its parameters fitted to the experimental thermal conductivity data. The calculated results from the RES model were compared with the experimental data, revealing an average absolute relative deviation (AARD) of 1.38%. To assess its generalizability, the calculated values were compared with external experimental data in the range of 80–344 K, yielding an AARD of 2.75%, which indicates a high level of reliability for the model.

In this study, isopiestic measurements were performed for the system {yNaCl + (1 – y) NaH₂PO₄}(aq) over an ionic strength range of I_m = (1.28744–6.84034) mol·kg^–1, with NaCl ionic strength fractions of y = (0.0; 0.24436; 0.463541; 0.65899; 0.83776) at T = (298.15 ± 0.01) K. NaCl(aq) was used as the reference solution. The osmotic coefficients of NaH₂PO₄(aq) up to m = 6.84034 mol·kg^–1 were determined from 13 isopiestic measurements. These data were used together with literature values to estimate the parameters for the Extended Pitzer and Clegg–Pitzer–Brimblecombe models. In addition, 52 values for the osmotic coefficient for the ternary system were determined and used to derive mixing parameters for the Extended Pitzer, Clegg–Pitzer–Brimblecombe, and Scatchard models. All three models provide accurate estimates of the osmotic coefficients. In addition, the obtained parameters were tested to compare the mean ionic activity coefficients of NaCl in {yNaCl + (1 – y) NaH₂PO₄} (aq) up to an ionic strength of 1 mol·kg^–1, with literature data from electromotive force measurements for validation. The differences between the experimental and calculated values were within △γ_± = ±7 × 10^–3. Finally, the applicability of the Zdanovskii rule was also investigated.

This study investigated the phase equilibrium behavior of binary (CO₂ + oleic acid) and ternary (CO₂ + oleic acid + 2-MeTHF-3-one) systems at temperatures ranging from 313.00 to 343.00 K and pressures from 5.24 to 24.00 MPa. The experimental analysis enabled the identification of biphasic and triphasic regions, highlighting the influence of the oleic acid-to-2-MeTHF-3-one mole ratio on the nature of the phases formed. The addition of the cosolvent 2-MeTHF-3-one enhanced solubilization among the system components, reducing the transition pressure and promoting medium homogenization. In contrast, higher concentrations of oleic acid intensified the formation of vapor–liquid–liquid (VLL) regions. Thermodynamic modeling using the PR–WS equation of state, globally fitted for temperature, exhibited satisfactory predictive performance, with low MAD and RMSD values, confirming its suitability for representing complex multiphase systems. These findings provide fundamental thermodynamic data for the design of supercritical processes, supporting future developments in sustainable applications such as the enzymatic synthesis of sugar-based surfactants and other bioactive compounds.

Aprotic N-heterocyclic anion (AHA) ionic liquids (ILs) are promising solvents for carbon capture due to their high CO₂ capacities at low partial pressures and tunability. However, water, a common contaminant, significantly affects the thermophysical properties of ILs. We investigate the effects of varying water loadings on the density, viscosity, and ionic conductivity of four AHA ILs: 4-nitropyrazolide [4-NO₂Pyra]⁻, 3-(trifluoromethyl)pyrazolide [3-CF₃Pyra]⁻, 2-cyanopyrrolide [2-CNPyr]⁻, and 4-bromopyrazolide [4-BrPyra]⁻, each paired with triethyl(octyl)phosphonium cation, [P₂₂₂₈]⁺. Density and viscosity were measured from 293.13 to 333.13 K. All AHA ILs exhibited ideal volumetric mixing, with mixture densities lying between those of the pure components. At higher water loadings (>17 wt %), viscosities of AHA IL + water mixtures were less than one-fifth the values of the pure ILs. We found that pairing the bulkier trihexyl(tetradecyl)phosphonioum [P₆₆₆₁₄]⁺ cation with [2-CNPyr]⁻ resulted in a greater decrease in viscosity relative to the neat IL compared to the [P₂₂₂₈]⁺ cation. Finally, ionic conductivities at 298.15 K peaked near water mole fractions of 0.98–0.99 (up to 1.967 S/m for [P₂₂₂₈][2-CNPyr]), and the Walden Plot indicates that as water content increases, the ions ([P₂₂₂₈]⁺ and AHA) become more dissociated.

In this study, the solubility data of N-Boc-N′-nitro-l-arginine was measured in 12 pure solvent systems (water, methanol, ethanol, 1-propanol, isopropanol, 1-butanol, isobutanol, sec-butanol, 1-pentanol, acetonitrile, DMF, and ethyl acetate) and a binary methanol + water system by the static gravimetric method over the temperature range of T = 283.15–323.15 K and P = 101.2 kPa. The results showed that the solubility consistently increased with rising temperature and was mainly affected by the solvent polarity E_T(30), hydrogen bonding, and cohesive energy density. The experimental data were correlated by the van’t Hoff model, modified Apelblat model, Yaws model, and Apelblat–Jouyban–Acree model. The RAD and RMSD values showed that both the modified Apelblat and Yaws models provided better agreement with the experimental data and exhibited superior fitting performance.

Fmoc-l-tyrosine, an important derivative of l-tyrosine, has significant medicinal applications. Its solubility in 12 monosolvents (including alcohols, esters, acetone, and acetonitrile) was determined from 293.15 to 333.15 K using the static gravimetric method. Experimental data showed that temperature-dependent solubility increases in all solvents. At 308.15 K, the solubility order (mol/mol) was as follows: acetone (0.07795) > isopropanol > sec-butanol > n-butanol > methyl acetate > n-pentanol > ethyl acetate > isobutanol > propyl acetate > butyl acetate > dimethyl carbonate > acetonitrile (0.003820). Four thermodynamic models (Apelblat, Margules, NRTL, UNIQUAC) were correlated, with the Apelblat model exhibiting the highest accuracy (ARD 1.744%, RMSD 0.473 × 10^–3). Solvent effect analysis indicated that hydrogen bonding (correlation coefficient of 0.8730) is the dominant factor, surpassing polarity (E_T(30)) and cohesive energy density. Hansen solubility parameters (HSPs) revealed that solvent polarity influences solubility, with lower R_a(v) values (e.g., acetone at 6.76 MPa^0.5) corresponding to higher solubility. Molecular electrostatic potential surface (MEPS) and Hirshfeld surface (HS) analyses identified hydrogen bond interaction sites, while IGMH quantification confirmed the prevalence of hydrogen bonding. This study provides comprehensive solubility data for the purification process design of Fmoc-l-tyrosine.

Vapor–liquid equilibrium (VLE) is crucial for the design of waste photoresists and solvent recycling processes. Isobaric VLE data for the butyl acetate + ethyl lactate binary system were experimentally determined using a modified Othmer still at pressures of 101.3, 80.0, 60.0, and 40.0 kPa. The thermodynamic consistency of experimental VLE data was rigorously validated using Fredenslund’s test and Van Ness’s point-to-point test. The data were then correlated to the Wilson, NRTL, and UNIQUAC models. The results demonstrate that the three local composition models provide an excellent fit to the experimental data, significantly outperforming the predictive UNIFAC model. The thermodynamic consistency of the regressed binary interaction parameters was further confirmed through a graphical analysis of the Gibbs energy of mixing. These findings are essential for the accurate design and simulation of distillation processes and facilitate the development of sustainable solvent recovery technologies for the semiconductor industry.

To separate the azeotropic system of 2-methyl-2-butanol and water, the liquid–liquid equilibrium (LLE) data of water + 2-methyl-2-butanol + solvents (methyl tert-butyl ether (MTBE), isopropyl ether, isooctyl alcohol, methyl acetate, mesityl oxide, and 4-methyl-2-pentanol (MIBC)) were measured at 308.2 K under 101.3 kPa. All systems conform to Treybal’s type II ternary phase behavior, with water + solvents and water + 2-methyl-2-butanol being partially miscible binary mixtures, while 2-methyl-2-butanol + solvents are miscible binary mixture. The distribution coefficient (D) and selectivity coefficient (S) were employed to evaluate solvent performance for extracting 2-methyl-2-butanol from water. Intermolecular interactions between 2-methyl-2-butanol and both solvents and water were investigated by using the DMol3 module. The nonrandom two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) models were applied to correlate LLE data, obtaining binary interaction parameters with root-mean-square deviations (RMSDs) < 0.60%. The consistency of regression parameters for both models was validated using the GUI-MATLAB tool.