The experimental densities and ultrasonic velocities of 6-phenylthiocarbamidoaminoindole with ethanol-doubledistilled water mixture have been measured over the full range of compositions at different temperatures (303.15 K, 308.15 K, 313.15 K, 318.15 K, and 323.15 K). From these experimental data, key acoustical parameters such as adiabatic compressibility (β), intermolecular free length (Lf), acoustic impedance (z), relative association (RA) were computed. The results reveal strong evidence of solute–solvent molecular interactions, including hydrogen bonding and dipole–dipole interactions. These findings provide valuable insights into the structural behavior and interaction mechanisms in heterocyclic binary and ternary systems.
In the present work, antihypertensive drug captopril is examined in aqueous dextrose and dextrose-saline systems across a range of concentrations (0.001–0.010) mol·kg−1 at different temperatures (300.15–315.15) K to explore the nature and strength of intermolecular interactions. The main objective of this work is to elucidate the mechanisms of solute–solvent and solute–solute interactions that may influence the therapeutic efficacy and pharmacokinetic behavior of intravenous formulations of captopril. A series of physicochemical studies was employed using experimentally determined parameters: density (ρ), ultrasonic velocity (u), specific conductance (κ), and viscosity (η) to gain knowledge about the nature of these molecular interactions, and were systematically interpreted to reveal the interactional profiles and structural changes in the solution. Moreover, the results derived from UV–visible and FTIR spectral studies were also consistent with the findings of physicochemical investigations. The potential oxidative and reductive behavior of captopril in dextrose and dextrose-saline systems is highlighted through the cyclic voltammetry studies, and the DFT studies further support their thermophysical outcomes. The physicochemical behavior of captopril in aqueous dextrose and dextrose-saline systems will be useful in drug compatibility and formulation design.
This work presents new Liquid–Liquid Equilibrium (LLE) data for the extraction of thiophene from long-chain n-paraffins (n-dodecane, n-tetradecane, and n-hexadecane) using a homologous series of ionic liquids (IL), namely 1-pentyl-3-methylimidazolium hexafluorophosphate [C5mim][PF6], 1-hexyl-3-methylimidazolium hexafluorophosphate [C6mim][PF6], and 1-heptyl-3-methylimidazolium hexafluorophosphate [C7mim][PF6], at 313.15 K and atmospheric pressure. The study addresses the lack of systematic thermodynamic equilibrium data for intermediate alkyl chain lengths and provides insights into structure–property relationships governing the extractive desulfurization process. Experimental tie-line compositions were determined, and distribution coefficient ( K ) and selectivity ( S ) values were evaluated to assess extraction performance. The results indicate strong preferential partitioning of thiophene into the IL phase, where the extraction performance dependent on both the paraffin chain length and the IL structure. Distribution coefficients increase with increasing paraffin molecular weight, reflecting reduced hydrocarbon solubility in the IL phase, while the decrease in the distribution coefficient with increasing thiophene concentration is attributed to saturation of specific solute–solvent interactions (K=3.03–4.87, S=548–946). Among the investigated ILs, [C5mim][PF6] exhibited superior extraction performance, attributed to an optimal balance between polarity, viscosity, and molecular interaction strength. The experimental data were successfully correlated using the non-random two-liquid (NRTL) model, yielding an average root-mean-squared-deviation (RMSD) of 0.136. The stability of the ILs was ensured under controlled low-moisture conditions, minimizing hydrolysis of the [PF6]− anion. The generated dataset provides valuable thermodynamic information for the design of ionic liquid-based separation processes and contributes to a deeper understanding of the role of IL structure in extractive desulfurization.
The gravimetric method was employed to determine the solubility of diclofenac (DIC) in twelve organic solvents (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, isobutanol, acetonitrile, ethyl acetate, isopropyl acetate, toluene, n-hexane, cyclohexane) from 288.15 to 328.15 K. In every solvent examined, the measurements demonstrated that the solubility increased with rising temperature. According to Hirshfeld surface analysis, H⋯H and C⋯H contacts are the predominant contributors to the crystal lattice. In addition, the solubility data were fitted to the Apelblat model, λh model, van’t Hoff model, and Pakkhesal model. The average relative deviation is 2.05
Monomethylgermanium (MMGe), the dominant organogermanium species in aquatic systems, exists predominantly as the neutral mononuclear species (CH3)Ge(OH)3 under environmentally relevant conditions. MMGe displays conservative behavior in freshwater and marine environments, an observation consistent with high chemical stability, yet its fundamental acid–base properties remain poorly characterized. To address this gap, we investigated the protolytic properties of (CH3)Ge(OH)3 at 298.2(2) K across a range of ionic strengths (0.1–1.0 mol·L−1) and five supporting electrolytes (LiCl, NaCl, KCl, CsCl, TMACl) by glass-electrode potentiometry. The first deprotonation constant (pKa = –log K1) of (CH3)Ge(OH)3 was consistently determined across experimental conditions with values ranging from 11.07(4) to 11.22(3), except in 1 mol·L−1 TMACl, where an anomalously high value (11.62(5)) was attributed to specific ion effects. 1H and 13C NMR titrations in 1 mol·L−1 KCl confirmed a single protonation equilibrium with pKa = 11.22(1), in excellent agreement with the potentiometric results. No evidence was found for the formation of a doubly deprotonated species under the investigated p[H] range (< 13). These findings contribute fundamental thermodynamic data for MMGe and enhance our understanding of its chemical behavior in natural waters.
The oil–gas field brine of Nanyishan in Qinghai province is a liquid mineral resource of significant exploitation and utilization value. In addition to abundant sodium, potassium, magnesium, and calcium, it contains a certain concentration of trace elements such as strontium and bromine. In-depth studies on its physicochemical properties are crucial for realizing comprehensive resource development and utilization. Focusing on the compositional characteristics of this brine, this study employed isothermal dissolution equilibrium method to investigate the phase equilibria of quinary system NaBr − MgBr2 − CaBr2 − SrBr2 − H2O and its quaternary subsystem MgBr2 − CaBr2 − SrBr2 − H2O at 298.15 K. Experimental determinations of liquid phase compositions and solid phase precipitation form were conducted, enabling the construction of equilibrium phase diagrams. Based on the Pitzer thermodynamic model, theoretical calculations of solubility data at 298.15 K were performed using existing model parameters. The results showed that simulated phase diagrams exhibited a good consistency with experimental ones, validating the model’s accuracy. The findings of this study not only provide a foundation for further research on multitemperature phase equilibria and thermodynamic properties of complex brine systems containing magnesium, calcium, strontium, and bromine, but also offer fundamental thermodynamic data to guide the comprehensive development and utilization of similar brine resources.
Furfuryl alcohol is a significant fine chemical; however, its industrial separation from aqueous by-products remains a challenge. To address the lack of thermodynamic data, this study reports liquid–liquid equilibrium data for ternary systems containing water, furfuryl alcohol, and extractants (benzyl alcohol or 1-hexanol) at 303.2, 313.2, and 323.2 K. The extraction efficiency was evaluated by the distribution coefficient (D) and selectivity coefficient (S), with the highest D value reaching 7.28 and the highest S value reaching 103.42, indicating that both solvents exhibit excellent potential for separating furfuryl alcohol from water. Furthermore, the experimental data were correlated using NRTL and UNIQUAC models. The root mean square deviation values were less than 0.64 and 0.55
To address the critical issue that SiO2 aerogels are prone to agglomeration and exhibit poor dispersibility in aqueous fire-extinguishing agent systems, sodium dodecylbenzene sulfonate (SDBS), a low-cost and environmentally friendly dispersant, is employed in this study. To ensure efficient dispersion, SDBS is used at a concentration exceeding its critical micelle concentration (CMC). Accordingly, it is essential to investigate the dispersion effect and underlying mechanism under this condition, and further clarify the effective concentration range. The findings reveal that optimal dispersion performance is achieved when the stirring duration is set at 30 min, with an SDBS-to-aerogel mass ratio of 1.5:1. Under these conditions, the modified aerogel suspension exhibits an absolute Zeta potential value exceeding 30 mV, while maintaining a stable viscosity below 1 Pa·s. Analysis suggests that SDBS primarily regulates the dispersion process through electrostatic repulsion effects, hydrogen bond formation, and steric hindrance mechanisms. Furthermore, it is proposed that SDBS micelles undergo self-assembly to form a three-layered structure, comprising the aerogel core, a micellar shell, and an irregular surface-active molecular entanglement layer.
Accurate prediction of CO_2 solubility in physical solvents is crucial for advancing carbon capture technologies. However, although existing machine learning and deep learning models offer high accuracy, their “black-box" nature limits their application in engineering practice and scientific discovery. To address the contradiction between accuracy and interpretability, this paper applies Kolmogorov–Arnold Networks (KAN) to CO_2 solubility prediction for the first time, establishing a systematic framework that spans from performance validation to model simplification. First, in terms of the full feature set, KAN performs noticeably better than 10 mainstream methods. Subsequently, to mitigate the impact of feature redundancy on model generalization, seven feature selection methods are systematically evaluated, and Lasso regression is ultimately adopted to determine a 4-dimensional optimal feature subset. The KAN constructed based on this subset achieves a coefficient of determination (R^2) of 0.999115. Compared to the second-best method (XGB), R^2 is improved by 1.17 R^2 of 0.941937), and achieves an 8.18-fold inference speedup over the original KAN model. This work provides interpretable theoretical guidance for solvent selection and optimization in CO_2 capture processes, contributing to the advancement of carbon capture technologies.
The speciation of binary Nickel(II) complexes with pyridinecarboxylic acids—Nicotinic Acid (HNic), Picolinic Acid (HPic), and Dipicolinic Acid (H2Dipic)—as well as their ternary complexes with various amino acids (Glycine, Asparagine, Lysine, Serine, and Aspartic Acid) was investigated in aqueous solution. The study was conducted using potentiometric measurements (emf(H)) at 25 °C and an ionic strength of 1.0 mol·dm–3 NaCl. The stability constants were determined by analyzing the potentiometric data with the LETAGROP software. For the binary systems, the formation of [Ni(Nic)]+, [Ni(Pic)n] (n = 1, 2, 3), and Ni(Dipic)n (n = 1, 2) species was established. In the ternary systems, the results indicate the formation of several mixed-ligand species, including protonated complexes such as [Ni(Pic)(HL)]+ and hydrolyzed species like [Ni(Pic)(L)(OH)]− at higher pH values. The coordination behavior of the amino acids was found to be predominantly bidentate, with the side chains of bulky amino acids showing minimal involvement in metal coordination due to steric hindrance. Species distribution diagrams were generated to illustrate the prevalence of these complexes across a wide pH range (2.0–10.0), providing a comprehensive view of the chemical equilibria in these bioinorganic-relevant systems.
Kinetics of oxidation of Curcumin and analogues of Curcumin by V(V) has been studied under pseudo-first order and second order conditions in acid media using aqueous ethanol as solvent in the temperature range 303–333 K. It is observed that the increase in both [acid] and [V(V)] increased the oxidation reaction rate indicated it is second order reaction. The effect [Curcumin] was variable: at higher concentrations (from 2.5 × 10−5 to 2 × 10−4 mol.dm−3) the reaction rate decreased with increasing [Curcumin] where at lower concentrations (from 2 × 10−6 to 2.5 × 10−5 mol.dm−3) the rate increased with increasing [Curcumin] wherein it gave fractional order, this observation indicated steric hindrance at higher concentrations from curcumin. Moreover, increase the temperature showed increase in the rate where on the other hand, decrease ethanol
Errors have been identified in the published equation coefficients reported by Zhang et al. [J Solution Chem (2025). https://doi.org/10.1007/s10953-025-01525-5], which were originally employed to mathematically characterize the solubility of ammonium sulfate in aqueous solutions of caprolactam via three distinct thermodynamic models, i.e. the modified Apelblat equation, the lambda h equation and the Van't Hoff-Yaws model. Notably, the values calculated using these published coefficients for the models do not correspond to the mole fraction solubility values as claimed in the aforementioned study.
Deep eutectic solvents (DESs) have been widely explored in recent decades as a new generation of green solvents. When using active pharmaceutic ingredients (APIs) to construct DESs, therapeutic DESs (THEDES) were obtained. A series of THEDESs based on fatty acid (FA) have been developed and shown excellent bio-activities, which displayed great potential applications in fields like wound healing, transdermal drug delivery etc. Physical properties, like density, and viscosity etc., are of great importance in practical implementation scenarios, thus, deep insights on the thermodynamic properties are highly desirable. In this work, physical properties, i.e. refractive index, surface tension, density, and viscosity, for a series of matrine and FA DESs were precisely measured. The influence of temperature, HBD composition and alkyl chain length on these properties were further discussed. It has been suggested by the results herein that all explored physical properties displayed a decline tendency with temperature, which may be ascribed to the decrease of H-bonding interaction with temperature. Besides, for each DES, increasing the HBD composition resulted in a decrease of all measured physical properties due to the decrease of molar weight of DES. As to the change of physical properties with alkyl chain length, the conclusions were much complex. The refractive index enhanced with alkyl chain length, while density and surface tension showed obvious decline with alkyl chain length. Moreover, variance of alkyl chain length caused only slight increase of viscosity that may be resulted from the increase of molar weight of DES.
This study proposes a novel method for estimating the surface tension (ST) of binary and ternary liquid mixtures based on the Eyring’s theory. Initially, four weighted average models based on mole and mass fractions were evaluated using ideal solution systems. The results confirmed that the Eyring-based weighted average models successfully reproduces experimental ST values. For non-ideal systems, we developed the “Wilson-SurTen model” by incorporating the Wilson model as an excess Gibbs energy model to describe excess ST based on the Eyring’s theory. Model parameters were regressed using the experimental ST data of various binary systems, including both non-aqueous and aqueous systems. The proposed model demonstrated superior correlation performance, particularly in aqueous systems where conventional models often fail. Furthermore, STs for ternary systems were predicted only using binary parameters determined from the constituent binary systems, without additional ternary interaction parameters. The results indicate that the Wilson-SurTen model significantly improves estimation accuracy, particularly for non-ideal aqueous systems. Furthermore, the mass fraction-based approach consistently outperformed the mole fraction-based one in terms of predictive capability.
In this work, nEB-PEI1800 (n = 0.22, 0.29, 0.35), a property tunable polymer for CO2 capture, is reported by partially modifying poly (ethylene imine) (PEI1800) with 1,2-epoxybutane (EB). The density and viscosity of CO2-free and loaded aqueous nEB-PEI1800 solution are measured at the temperatures of (293.15 to 333.15) K and 0.1 MPa. The aqueous solutions with various weight fractions of w = (5, 10, 15, 20 and 30
This study investigates an aqueous two-phase system (ATPS) composed of TX-100, Na2CO3, K2CO3, and their salt mixtures at 298 K. Binodal curves, tie-lines, tie-line lengths (TLL), and slopes (TLS) were determined as key equilibrium parameters. The effects of salt mixtures and their salting-out capacities were systematically compared, revealing that sodium cations (Na+) exhibit stronger salting-out power than potassium (K+), consistent with prior literature whether evaluated as individual salts or mixed systems. The obtained binodal and liquid–liquid equilibrium data were further correlated using the Othmer-Tobias, Bancroft, and Setschenow models. Notably, the Bancroft and Setschenow equations demonstrated excellent agreement with the results, while the Othmer-Tobias model showed deviations. These findings provide insights into phase behavior and ion-specific effects in ATPS, with potential applications in separation processes and biomolecule purification.
Research into green solvents is pivotal for advancing sustainable practices in pharmaceutical and chemical industries. Green chemistry focuses on minimizing the adverse impacts of chemical substances and processes on both human health and the environment through the implementation of proactive and sustainable prevention strategies. Within this framework, binary solvent mixtures have emerged as particularly promising due to their tunable properties and broad applicability. The present review focuses the potential of binary solvent mixtures as green solvents in synthesis procedures, discussing on their fundamental behavior, physicochemical properties, and applications. Furthermore, this work highlights representative applications in synthetic processes and discusses their advantages, limitations, and future prospects, thereby providing a comprehensive framework for their rational design and implementation in sustainable chemistry.
A polemic is given regarding the volumetric properties that Talabattula and coworkers reported in their published paper. The tabulated apparent molal volumes, ( V_φ) , were found to be inconsistent with the experimental densities reported in the paper for both thiamine and biotin dissolved in aqueous-lactobionic acid mixtures.
In this study, the spectroscopic, electronic, and biological properties of the imidazole derivative N-methoxy-N-methyl-1H-imidazole-1-carboxamide (NMNMIC) were investigated using a combined experimental and theoretical approach. FT–IR, 1H- and 13C-NMR, and UV–Vis spectra were recorded experimentally and were reproduced theoretically using density functional theory (DFT). DFT calculations revealed that the NMNMIC ligand exhibits an electronically stable structure in both the gas phase and solvent environments. However, solvent-induced molecular polarization was found to enhance the ligand’s ability to participate in intermolecular interactions. Charge distribution analyses, together with molecular electrostatic potential (MEP), electron localization function (ELF), and localized orbital locator (LOL) maps, identified the imidazole nitrogen and carboxamide oxygen atoms as the most chemically active regions of the molecule. These electronic features were consistent with the binding modes and interaction patterns obtained from molecular docking studies, indicating favorable ligand–protein interactions. In addition, the in vitro antidiabetic and antioxidant activity results supported the computational findings. Overall, the results demonstrate that NMNMIC is electronically stable yet functionally interaction-prone in solution, highlighting this imidazole-based carboxamide derivative as a promising candidate for further pharmaceutical research.
