Journal of Chemical & Engineering Data最新文献

9,9-Dimethylfluorene is a core intermediate underpinning the development of modern organic electroluminescent (OLED) display technology. Its unique molecular structure and physicochemical properties make it a key basic raw material for the synthesis of OLED materials. These materials are widely applied in mainstream display devices such as smartphones and televisions. Therefore, the dissolution behavior of 9,9-dimethylfluorene in individual solvents holds certain research value. The solubility of 9,9-dimethylfluorene was measured using a static gravimetric method. The measurements were conducted in 15 individual solvents, which encompass ethanol, n-butanol, methanol, iso-propanol, iso-butanol, iso-pentanol, acetone, n-pentanol, acetonitrile, 2-butanone, n-propanol, methyl acetate, sec-butanol, propyl acetate, and ethyl acetate. The solubility increased with temperature in all 15 solvents. At 298.15 K, it was the lowest in methanol (0.009091 mol/mol) and the highest in 2-butanone (0.2575 mol/mol). A comprehensive analysis of cohesive energy density, hydrogen bonding, polarity, and Hansen solubility parameters was conducted. Dispersion forces were revealed to be the key factors governing the dissolution behavior of the substance. Additionally, among the four model fittings, the Apelblat model exhibited the highest degree of fitting. Molecular simulations were employed to systematically elucidate the internal interactions within 9,9-dimethylfluorene. The simulations included the analysis of molecular electrostatic potential (MEP) surfaces and the calculation of interaction energies.

The solubility of 3,5-dihydroxybenzoic acid (3,5-DHBA) in nine pure organic solvents and in one binary mixture (ethanol + acetonitrile) was measured gravimetrically at ambient pressure over the temperature range of 298.15–333.15 K. The mole fraction solubility increased with rising temperature in all systems studied. In pure solvents, solubility followed this order: isopropanol > ethanol > n-propanol > n-butanol > isobutanol > ethyl acetate > n-propyl acetate > isopropyl acetate > acetonitrile. In the ethanol + acetonitrile mixture, solubility increased continuously with higher ethanol mass fraction.Experimental data were correlated using three semiempirical equations (van’t Hoff, modified Apelblat, and λh) and three activity coefficient models (NRTL, Wilson, and UNIQUAC). The modified Apelblat equation yielded the best correlation, with average relative deviations (ARD) below 0.60% across all systems. Dissolution in pure solvents was analyzed using the “like-dissolves-like” principle and Hansen solubility parameters. Solvent effects were quantitatively assessed via the KAT-LSER model, where multiple linear regression showed that solubility was mainly governed by π* (41.83%) and δ_H (30.69%), with lesser contributions from β (21.80%) and α (5.68%). These solubility data provide a valuable reference for designing and optimizing industrial crystallization processes for 3,5-DHBA.

The Qaidam Basin of China abounds in salt lake resources containing lithium, potassium, and boron. Lithium precipitation mother liquor is generated during lithium carbonate production. To investigate solution thermodynamic properties of lithium salts and support its utilization, the thermodynamic activity coefficients and phase equilibria of the LiCl–KCl–CH₃OH–H₂O mixed solvent system at 298.2 K are studied. The mean activity coefficients of KCl in the KCl−CH₃OH−H₂O and the LiCl−KCl−CH₃OH−H₂O mixed solvent system are measured using cell potentials and the Nernst equation. Via multiple linear regression and nonlinear programming fitting, the Pitzer single-salt parameters of LiCl (β⁽⁰⁾, β⁽¹⁾, and C^Φ) and ion interaction parameters (θ_K,Li and ψ_K,Li,Cl) at 298.2 K are obtained, and then mean activity coefficients of LiCl, osmotic coefficients, water activities, and excess Gibbs free energies via the Pitzer model are calculated accordingly. Moreover, the mixed solvent system’s phase equilibria via isothermal dissolution equilibrium are also determined. Solubility data modeling with these parameters agrees well with experimental results, validating the model’s efficacy in predicting lithium–potassium salt phase behavior in methanol-containing mixed solvents.

Isobaric vapor liquid equilibrium (VLE) data for the acrylonitrile-isopropyl alcohol binary system were measured at 10.0, 50.0, and 100.0 kPa. It showed that the system forms a minimum-boiling azeotrope at each of the three studied pressures with different compositions and boiling temperatures. The experimental data were correlated with the NRTL, Wilson, and UNIQUAC activity coefficient models, and their binary interaction parameters were obtained correspondingly. Thermodynamic consistency was verified using both the Fredenslund method and Redlich–Kister area test. According to the maximum absolute deviation, root-mean-square deviation, and average absolute deviation, all three models provided satisfactory correlations with the experimental data. In view of the differences in the azeotropic composition and VLE behavior of acrylonitrile-isopropyl alcohol at 10.0 and 100.0 kPa, pressure-swing distillation could be used to separate the components. This work provided a crucial thermodynamic basis for the design and optimization of distillation processes for separating the acrylonitrile and isopropanol mixtures.

Progesterone is a hydrophobic steroid hormone that plays a crucial role in human health. Its limited aqueous solubility presents a significant challenge for both pharmaceutical applications and academic research, showing the importance of accurately predicting its solubility behavior in different solvents. This study assesses the performance of the modern quasi-chemical equation of state known as COSMO-SAC-Phi (CSP), in comparison with its underlying COSMO-SAC (CS) activity coefficient model when modeling solid–liquid equilibrium of progesterone in 14 different solvents. Pure compound parameters employed in CSP calculations were obtained from the vapor pressure and liquid volume data of each pure compound. No binary parameters were adjusted. The results were compared with experimental solid–liquid equilibrium data collected from the literature. As a reference, the classical UNIFAC (Do) group contribution method was also used. The CSP model generally provided more accurate predictions of phase equilibrium, captured solubility trends among similar solvents, and reproduced the correct deviations from ideality for most systems, whereas the CS model was often less accurate in these aspects. An intermediate performance was observed for UNIFAC (Do). The mean absolute deviation in log₁₀ units from experimental solubility data highlights the advantage of the equation-of-state approach, yielding an average value of 0.26 for CSP compared to 0.60 for the underlying activity model and 0.37 for UNIFAC (Do). Nevertheless, CS should be sufficiently accurate for the preliminary screening of new solvent alternatives.

Over 90% of natural gas hydrates (NGHs) on Earth occur in fine-grained clayey-silty sediments, which also serve as ideal sites for hydrate-based CO₂ geological sequestration. However, hydrate phase equilibria in such sediments remain poorly understood, hindering advancements of NGH exploitation and carbon sequestration technologies. Here, we conducted a series of experiments to investigate the phase behavior of methane hydrates in representative clayey-silty sediments (montmorillonite and silt) with varying clay and water contents and measured the hydrate dissociation conditions via a stepwise heating method. The results demonstrate that the hydrate dissociation temperature depression increases exponentially with rising clay content and decreasing water content. This leads to a more pronounced dissociation temperature shift in silty clays (clay content >50 wt %) than in clayey silts (clay content <50 wt %). Specifically, at a water content of 20 wt %, the hydrate dissociation temperature depression in silty clays (80 wt % montmorillonite and 20 wt % silt) is as high as 1.5 K on average relative to bulk hydrates, whereas that in clayey silts (20 wt % montmorillonite and 80 wt % silt) remains below 0.3 K. Furthermore, compared to clayey silts, the hydrate dissociation temperature depression in silty clays exhibits a stronger dependence on water content. These findings highlight the pivotal role of clay and water content in regulating hydrate stability within geological systems.

Compared with salt lake brine, deep brine features high temperature and high calcium content, which alters potassium’s phase equilibria behavior. Accordingly, the phase equilibria of the quaternary system K⁺, Mg²⁺, Ca²⁺//Cl^–-H₂O at 323.2 and 348.2 K were investigated using the isothermal dissolution method. The phase diagrams at both temperatures consist of four quaternary invariant points, nine univariate curves, and six crystallization regions. Three double salts chlorocalcite (KCl·CaCl₂), carnallite (KCl·MgCl₂·6H₂O), and tachyhydrite (2MgCl₂·CaCl₂·12H₂O) were identified. In this system, potassium crystallizes as KCl, KCl·MgCl₂·6H₂O, and KCl·CaCl₂, with KCl having the largest crystallization region, followed by KCl·MgCl₂·6H₂O and then KCl·CaCl₂. A multitemperature comparison (298.2 to 348.2 K) of K⁺, Mg²⁺, Ca²⁺//Cl^–-H₂O reveals that at 298.2 K, potassium crystallizes only as KCl and KCl·MgCl₂·6H₂O, and the crystallization phase region of KCl has the largest region, which is favorable for the separation and extraction of potassium. When at 323.2 and 348.2 K, in addition to KCl and KCl·MgCl₂·6H₂O, the double-salt KCl·CaCl₂ also forms, and the crystallization region of KCl·CaCl₂ increases with increasing temperature, which may affect the stability of potassium extraction raw materials such as KCl and KCl·MgCl₂·6H₂O.

Deep eutectic solvents (DESs) have emerged as promising alternatives to conventional solvents due to their tunable properties and potential environmental benefits. While most studies focus on ionic DESs, nonionic DESs remain less explored. In this work, four nonionic deep eutectic solvents (DESs) are prepared using diethylene glycol dimethyl ether or isoquinoline as hydrogen-bond acceptors (HBA) and cyclohexanecarboxylic acid, nonanoic acid, or 1-naphthylamine as hydrogen-bond donors (HBD) at specific molar ratios. Their fundamental thermophysical properties, including density, viscosity, surface tension, electrical conductivity, and melting point, are systematically measured over the temperature range of 303.15–343.15 K. The temperature dependence of all measured properties is quantitatively analyzed using appropriate empirical or Arrhenius-type correlations. The results provide insights into the influence of molecular composition on nonionic DES behavior, expanding the experimental database and highlighting their potential as low-viscosity, tunable, and versatile solvents for chemical engineering applications.

The densities and dynamic viscosities of pure components, binary solutions and ternary solutions of 2-amino-2-methyl-1-propanol (AMP), 2-ethylaminoethanol (EAE) and water were systematically measured at (293.15–323.15) K. Based on experimental findings, calculations were made for the excess molar volume, thermal expansion coefficient, dynamic viscosity deviation, and solution viscous activation energy to assess intermolecular interactions. The negative excess molar volumes of binary and ternary aqueous solutions indicate significant hydrogen bonding interaction and a filling effect within the solutions. The negative excess molar volumes of binary and ternary aqueous solutions indicate significant hydrogen bonding interactions and a filling effect within the solutions. For the AMP–EAE system, the hydrogen bonding interaction and filling effect are weakened due to the similar volume and steric hindrance effect.

This study systematically investigated the synthesis, thermophysical properties, and electronic characteristics of three novel trimethylsiloxy (TMS)-functionalized amino silane coupling agents: 3-aminopropyltris(trimethylsiloxy)silane (AP-trisTMS), 3-[1,3,3,3-tetramethyl-1-[(trimethylsilyl)oxy]-1-disiloxanyl]-1-propanamine (AP-diTMS), and 1,1,1,3,5,5,5-heptamethyl-3-N-2-(aminoethyl)-3-aminopropyltrisiloxane (AEAP-diTMS). By precise design of the molecules through partial replacement of alkoxy groups with TMS, the hydrogen bonding ability, hydrophobicity, and thermal stability of these compounds were adjusted. Based on experimental results such as density, viscosity, and vapor pressure, combined with density functional theory calculations of electronic properties (the analysis of electrostatic potential energy of molecular surfaces, frontier molecular orbitals, simplified density gradient functional analysis, and localized orbital locator scatter plots), the molecular characteristics are comprehensively discussed. This research not only deepens our understanding of these compounds but also highlights their potential as high-performance materials.