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The solubility isotherms of the ternary systems Li⁺(K⁺), NH₄⁺//CO₃^2–-H₂O are determined at 278.15, 288.15, and 298.15 K using the isothermal dissolution method, and the pH of the equilibrium liquid phase is monitored. The saturated binary Li₂CO₃ solution shows a pH up to 11.7, while K₂CO₃ solutions exceeded 14. The addition of (NH₄)₂CO₃ markedly reduces the alkalinity, with the pH ranging from 10.0 to 9.2 and 12.5 to 9.2 for Li- and K-based systems, respectively. Due to the presence of the ionization equilibria NH₄⁺-NH₃·H₂O and CO₃^2–-HCO₃^–, both systems are pseudoternary, derived from a more complex Li⁺(K⁺), NH₄⁺//CO₃^2–, HCO₃^–-NH₃·H₂O equilibrium system. Solubility measurements at 298.15 K reveal that the Li₂CO₃-(NH₄)₂CO₃–H₂O system exhibits two invariant points and three crystallization regions: Li₂CO₃, Li₂CO₃·3(NH₄)₂CO₃, and (NH₄)₂CO₃·H₂O. The K-based system shows one invariant point and two regions: K₂CO₃·3H₂O and (NH₄)₂CO₃. Lowering the temperature eliminates the Li₂CO₃·3(NH₄)₂CO₃ crystallization regions, retaining only the Li₂CO₃ and (NH₄)₂CO₃·H₂O regions in the Li-based system. In contrast, in the K-based system, the crystallization region of K₂CO₃ and the composition of the invariant point remain nearly unchanged with decreasing temperature, while the (NH₄)₂CO₃ crystallization region expands significantly. These results provide theoretical guidance for ammonium carbonate-based ammonia-alkali cyclic carbonation processes in treating sulfate or halide systems.

The solubility of 3-methoxycinnamic acid was determined in nine pure solvents (methanol to ethyl acetate) and ethanol–ethyl acetate binary mixtures (293.15–333.15 K). Results demonstrate positive temperature dependence in all systems, with maximum solubility in binary solvent at ethanol volume fraction of 0.3, while benzene exhibited the lowest solubility. Solid–liquid equilibrium (SLE) data were correlated using five thermodynamic models (modified Apelblat, Van’t Hoff, Wilson, NRTL, UNIQUAC). The modified Apelblat equation showed superior accuracy for both solvent systems. KAT-LSER analysis revealed solvent hydrogen-bond acidity (α), basicity (β), and cohesive energy density (CED) (δ_H) as dominant molecular descriptors. Thermodynamic parameters (ΔG_mix < 0) confirmed spontaneous dissolution, with enthalpy–entropy compensation revealed by Gibbs energy deconvolution. The obtained solubility and thermodynamic data may be useful for the design and optimization of crystallization processes of 3-methoxycinnamic acid.

We propose two new group-contribution models for the ideal gas heat capacity c_p^ig(T), one for the critical temperature T_c, and the normal boiling point T_b. For all properties the model is based on a decomposition into base and second-order groups, which are simultaneously parametrized to experimental data. For the critical temperature and normal boiling point, each group is assigned one or two parameters based on data availability. For the critical temperature, 1454 substances were used for optimization, resulting in a mean absolute relative deviation (MARD) from experimental data of 2.46%. For the normal boiling point 5591 substances were used for optimization with a MARD of 2.26%. For the ideal gas heat capacity we propose two new group-contribution models based on the Aly-Lee equation and a reparameterization of the Joback and Reid model. The models are parametrized for the temperature range 50–3000 K for 1009 substances, where the MARD to the experimental data for the best model is 1.73%. In addition, we individually parametrize 1162 substances with a deviation to the experimental data of 0.54%. As Supporting Information, we provide Python code to estimate the critical temperature, the normal boiling point, and the ideal gas heat capacity based on the proposed models.

Phase equilibrium data of clathrate hydrates are essential for evaluating their potential in gas storage and separation. In this study, we determined three-phase (hydrate–gas–liquid) equilibrium points for the systems (N4446Cl or N4446Br) + H₂O + (CH₄, CO₂, or N₂) at pressures of up to 10 MPa. N4446Cl, previously reported to stabilize the hexagonal structure-I (HS-I) phase, formed hydrates with all three gases even at aqueous compositions lower than those reported earlier. The P–T slope analyses suggest gas uptake potentials for CH₄ and CO₂ comparable with N4446Cl hydrates and N4446Br hydrates. The slope analysis suggests that N4446Br likely forms a phase similar to the HS-I structure under CH₄ and CO₂ but shows reduced capacity for N₂. These results expand the known guest species capable of stabilizing HS-I hydrates and highlight the distinct gas-specific behavior of bromide and chloride salts. The phase equilibrium data reported here provide a basis for designing HS-I hydrate-based gas storage and separation applications, including the capture of CO₂ from lean mixtures.

Using organic solvents in lithium-ion battery electrolytes presents environmental issues due to their volatility and toxicity. This work explores lithium perchlorate in deep eutectic solvents (DESs) as eco-friendly alternatives for organic electrolytes in batteries and electrochemical devices. We studied ternary mixtures of lithium perchlorate with DESs (using choline chloride (ChCl) as the hydrogen bond acceptor and ethylene glycol (EG) in a 1:2 molar ratio, malonic acid (MA) in a 1:1 molar ratio, lactic acid (LA) in a 1:2 molar ratio, or propionic acid (PA) in a 1:2 molar ratio as hydrogen bond donors) and propylene carbonate. Experimental measurements of density, speed of sound, and viscosity were conducted at temperatures from 288.15 to 318.15 K. These data facilitated the calculation of thermophysical properties such as the viscosity B-coefficient, partial molar volumes of transfer (Δ_trV_φ⁰), standard partial molar volume (V_φ⁰), apparent molar volume (V_φ), partial molar isentropic compressibility (κ_φ⁰), and apparent molar isentropic compressibility (κ_φ). Additionally, density functional theory (DFT) calculations were performed using Gaussian09. The experimental data showed that the interactions between lithium perchlorate and ChCl/lactic acid were stronger than those with other studied DESs.

To understand the interrelationships within the multi-ion coexisting sulfate system during the solid–liquid transformation of polyhalite in the Bieletan area, phase equilibria of ternary systems M, Ca²⁺//SO₄^2–-H₂O (M = Na⁺, K⁺, Mg²⁺) at 288.2 K were studied by the isothermal dissolution equilibrium method. The solubility and density of the equilibrium liquid phases of the system were measured experimentally, and the composition of the equilibrium solid phase at the ternary invariant point was determined by X-ray powder diffractometry. It is found that the ternary system K⁺, Ca²⁺//SO₄^2–-H₂O at 288.2 K forms the double salt syngenite (K₂SO₄·CaSO₄·H₂O), while the systems Na⁺, Ca²⁺//SO₄^2–-H₂O and Mg²⁺, Ca²⁺//SO₄^2–-H₂O at 288.2 K only form with the formation of CaSO₄·2H₂O and Na₂SO₄·10H₂O (MgSO₄·7H₂O). Multitemperature comparison of the M, Ca²⁺//SO₄^2–-H₂O (M = Na⁺, K⁺, Mg²⁺) systems shows that the phase diagrams of Mg²⁺, Ca²⁺//SO₄^2–-H₂O are consistent at the selected temperature, only containing CaSO₄·2H₂O and MgSO₄·nH₂O (n = 1, 6, 7). While K⁺, Ca²⁺//SO₄^2–-H₂O and Na⁺, Ca²⁺//SO₄^2–-H₂O change from 288.2 and 298.2 to 348.2 K, the phase diagram forms double salt(s) K₂SO₄·5CaSO₄·H₂O (Na₂SO₄·5CaSO₄·3H₂O and Na₂SO₄·CaSO₄).

l-Norvaline has antifungal activity and is also used as a key intermediate in antihypertensive drugs. The solubility of l-norvaline in 12 monosolvents was determined by the static weighing method in the temperature range of 298.15–323.15 K and atmospheric pressure of 101.2 kPa. The solubility and temperature were positively correlated. Two models (the modified Apelblat model and the Yaws model) were used to correlate the solubility data, with the Yaws model providing the best fit. X-ray powder diffraction analysis was used to characterize the crystalline form of l-norvaline before and after dissolution equilibrium, and the solubility of l-norvaline in 12 single solvents was evaluated by quantum chemical analysis and Hansen solubility parameters (HSPs). The solvation behavior was mainly influenced by the solvent polarity (E_T(30)). The relationship between the solubilities of different solutes in the same solvent was then discussed by comparing the solubilization behavior of l-norvaline and l-valine in the single solvent species. These experimental analyses are useful for the purification, crystallization, and industrial application of l-norvaline. Therefore, it is necessary to study the solvation behavior of l-norvaline in different single solvents to provide sufficient data to support the design of its crystallization process.

The surging demand for lithium-ion batteries (LIBs) in electric vehicles and energy storage drives the need for the efficient recovery of high-performance electrolyte additives, such as 1,2-dichloroethylene carbonate (DCEC), fluoroethylene carbonate (FEC), and ethylene carbonate (EC). Their high boiling points and thermal instability, including the risk of polymerization, pose challenges to recycling. This study reports experimental vapor–liquid equilibrium (VLE) data for DCEC + FEC, DCEC + EC, and FEC + EC binary systems at 0.4 kPa, measured using a recirculating still to enable low-temperature separation. The data, comprising the temperature, liquid-phase (x), and vapor-phase (y) compositions, were correlated with the NRTL, Wilson, and UNIQUAC models, with the NRTL showing a superior fit. Excess Gibbs energy (G^E/RT) analysis indicated positive deviations for DCEC + FEC and negative deviations for DCEC + EC and FEC + EC, reflecting a system-specific nonideality. The thermodynamic consistency was verified using Van Ness and Wisniak’s L-W tests, confirming the data reliability. These novel VLE data and models fill a critical literature gap, providing essential thermodynamic insights for designing energy-efficient vacuum distillation processes to recover carbonate-based LIB additives and enhance the sustainability of battery manufacturing and recycling.