Journal of Solution Chemistry最新文献

The mixtures CH₃(CH₂)_u-1COO(CH₂)_v-1CH₃ (u = 5–13, v = 1,2; u = 1,2,3; v = 3,4; u = 1,2,4, v = 5) + n-alkane have been investigated on the basis of excess molar functions, enthalpy ((H_{{text{m}}}^{{text{E}}})), volume ((V_{{text{m}}}^{{text{E}}})), isobaric heat capacity ((C_{{p{text{m}}}}^{{text{E}}})), and isochoric internal energy ((U_{{V{text{m}}}}^{{text{E}}})), and viscosity data, and by means of different models (Flory, Grunberg-Nissan and Bloomfield-Dewan). Solutions are characterized by weak orientational effects. Large structural effects are encountered in a number of systems, such as those containing pentane. The variation with the ester size of the difference between the standard enthalpy of vaporization at 298.15 K of an ester and that of the homomorphic alkane along an homologous series formed by methyl or ethyl n-alkanoates reveals the existence of structural changes in longer n-alkanoates, which lead to stronger interactions between them. A similar result is obtained from values of cohesive energy density. The variation of (V_{{text{m}}}^{{text{E}}}) values of the corresponding heptane mixtures supports this statement. The observed decrease of (H_{{text{m}}}^{{text{E}}}) for systems with a given n-alkane (heptane, e.g.) seems to be more related to the COO group is more sterically hindered than to interactional effects. The (U_{{V{text{m}}}}^{{text{E}}}) (n) function (n is the number of C atoms in the n-alkane) shows a minimum for systems with esters characterized by (u (ge) 4, v = 1); (u (ge) 7, v = 2), or (u (ge) 1, v = 4,5). A similar dependence of (U_{{V{text{m}}}}^{{text{E}}}) (n) was encountered for n-alkane mixtures involving cyclic molecules (cyclohexane, benzene). This result suggests that certain n-alkanoates, in an alkane medium, can form quasi-cyclic structures. Viscosity data are well described by means of free volume effects only. For systems with butyl ethanoate or methyl decanoate, the variation of (Delta eta)(n) (deviation of dynamic viscosity) is consistent with that of (U_{{V{text{m}}}}^{{text{E}}})(n), which supports the existence of the mentioned cyclic structures in these esters. The Flory model provides poor results on (H_{{text{m}}}^{{text{E}}}) for systems characterized by large structural effects. Results are improved when the model is applied to (U_{{V{text{m}}}}^{{text{E}}}) data.

In recent decades, researchers have increasingly explored alternative fuels to improve emission characteristics without compromising diesel engine performance. Among these, water-in-diesel emulsion (W/D) has gained attention due to its potential to reduce emissions, while enhancing engine efficiency. This review critically examines the effectiveness of W/D emulsions in diesel engines, focusing on their impact on both emission reduction and performance characteristics. Various factors crucial to the commercial viability of W/D are assessed, including stability, viscosity, density, and calorific value. While W/D emulsions generally enhance brake thermal efficiency (BTE) and combustion efficiency, some studies report an increase in brake-specific fuel consumption (BSFC) due to the lower calorific value of the emulsion. Additionally, the use of W/D consistently leads to reductions in nitrogen oxides (NO_x), and particulate matter (PM). However, reported findings vary due to differences in experimental conditions, water content, surfactant types, and emulsion stability. The phenomenon of micro-explosion, which improves atomization and combustion, is also discussed as a key factor influencing W/D performance. This review highlights the need for further research to address inconsistencies in reported results, particularly in optimizing surfactant selection for stability and performance. Future studies should also focus on long-term engine durability, real-world engine testing, and economic feasibility assessments to ensure the commercial adoption of W/D emulsions in diesel engines.

The physicochemical properties of N,N-dimethylacetamide + methyl acrylate/ethyl acrylate/n-butyl acrylate binary mixtures are used to investigate the prevailing molecular interactions therein. The speeds of sound and viscosities of N,N-dimethylacetamide + methyl acrylate/ethyl acrylate/n-butyl acrylate binary mixtures are measured at 15 mol fractions at temperatures from 288.15 K to 318.15 K and at pressure, p = 100 kPa. Using the measured data, the excess isentropic compressibilities, excess speeds of sound, excess molar isentropic compressions and deviations in viscosity are calculated. The partial and excess partial molar isentropic compressions of the constituents at all mole fractions and at infinite dilution are computed. These properties are understood in terms of prevailing intermolecular interactions in these mixtures. The excess isentropic compressibility, excess molar isentropic compression, deviation in viscosity and excess partial molar isentropic compression exhibit negative values, and excess ultrasonic speeds exhibit positive values. These results specify the existence of dipole–dipole interactions among amide and alkyl acrylates molecules, and these interactions decrease with increase in size of the alkyl group of acrylate molecules in the order: methyl acrylate > ethyl acrylate > n-butyl acrylate. Further, the scaled particle theory is applied to theoretically estimate u values, and outcomes are compared with experimental data. Also, various empirical relations and models are applied to evaluate the viscosities, and the outcomes are equated to the experimental values.

The article discusses the results of a study of the effect of aqueous solution composition on the polymerization process of elemental phosphorus under the influence of accelerated electrons. Placing elemental phosphorus in water and aqueous solutions eliminates direct contact with air, thus making the process safer. In turn, adding various substances to the solution, one can control the speed and efficiency of the process. The solutions used were distilled water, degassed water, and water solutions of acetonitrile (0.01 mol·L^–1), and sodium hypophosphite (1.8⋅10^–5 mol·L^–1). It is shown that the use of aqueous solutions of acetonitrile and sodium hypophosphite allows increasing the conversion of phosphorus by 7% compared to the use of water. It is noted that these substances also increase the polymerization rate at low absorbed dose values (800–1000 kGy).

This study measured thermophysical parameters such as density (ρ), speed of sound (u), and viscosity (η) for binary liquid systems containing morpholine and butylamines (mono-, di-, and tri-butylamine) at three temperatures (303.15 K, 308.15 K, and 313.15 K) under atmospheric pressure. On the basis of the experimental findings, thermodynamic properties such as excess molar volume (({V}_{m}^text{E})), excess molar isentropic compressibility (({k}_{s,m}^text{E})), and deviation in viscosity ((Delta eta)) were calculated. These were then fitted to a Redlich–Kister (R–K) polynomial. For all binary systems, ∆η is positive, whereas ({V}_{m}^text{E}) and ({k}_{s}^text{E}) are negative. The findings for the binary liquid systems under research suggest the existence of new H-bonding and packing efficiency interactions between dissimilar components. Moreover, how temperature impacts molecular interactions between molecules using thermodynamic results is discussed.

The solubility of α -ketoglutaric acid in water, ethyl acetate, n-butyl acetate, and the mixed solutions of these three solvents and pyruvic acid, namely water and pyruvic acid, ethyl acetate and pyruvic acid, and n-butyl acetate and pyruvic acid, was determined by the static method under normal pressure ranging from 278.15 to 293.15 K. The experimental results show that the solubility of α-ketoglutaric acid in these solvents is positively correlated with the temperature. The order of solubility in pure solvents at 284.15 K is as follows: water (12.75 × 10^–2) > ethyl acetate (4.182 × 10^–2) > n-butyl acetate (3.367 × 10^–2). Moreover, an increase in the pyruvic acid mole fraction (y_b) decreases the solubility of α-ketoglutaric acid in the three mixed solvent systems. Solubility data in pure solvents and mixed solutions are fitted with Apelblat equation, Yaws equation, van’t Hoff model, and (CNIBS)/Redlich–Kister equation, and the fitting performances are good. Furthermore, the apparent thermodynamic parameters (Delta_{text{sol}} H_{text m}^{^circ }) (Delta_{text{sol}} G_{text m}^{^circ }) and (Delta_{text{sol}} S_{text m}^{^circ }) have been calculated using the Van’t Hoff equation. Both (Delta_{text{sol}} H_{text m}^{^circ }) and (Delta_{text{sol}} G_{text m}^{^circ }) are positive values, indicating that the dissolution of α-ketoglutaric acid in these systems is an endothermic process. The solvent–solvent interactions in the mixed solvent systems are investigated by using the Materials Studio to calculate the molecular electrostatic potential through the DMol³ module and the radial distribution function through the Forcite module, and the order of the interaction strengths is consistent with that of solubility size.

This study investigated the solubility of isophthalic acid in binary mixtures of 1-propanol/2-propanol and water, across temperatures from 298.2 to 313.2 K. The solubility was determined using a laser-based robotic system. The resulting solubility data were analyzed through various mathematical models, including the van’t Hoff, Jouyban–Acree, Jouyban–Acree–van’t Hoff, mixture response surface, and modified Wilson models. The experimental data on isophthalic acid dissolution included several thermodynamic properties such as ΔG°, ΔH°, ΔS°, and TΔS°. These properties provided important insights into the energetic aspects of the dissolution process and were calculated using the van’t Hoff equation.

The present study has effectively investigated and evaluated the potential impacts of alcohols and hydrotropes (HyTs) on the phase separation behavior of triton X-100 (TX-100) and indigo carmine (IC) mixture by means of classical cloud point model. Indigo carmine has broader applications in the textile, food and cosmetic industries. The combined system containing all necessary components was studied at a fixed concentration of TX-100 (92.7 mmol·kg⁻¹), IC (0.05 mmol·kg⁻¹), and variable concentrations of alcohols and hydrotropes. Methanol (MeOH), ethanol (EtOH), 1-propanol (1-PrOH), and 1-butanol (1-BuOH) were used as alcohols as well as sodium benzoate (NaBenz) and sodium salicylate (NaSal) were utilized as HyTs in the studied system. The results revealed that hydrophilicity behavior of TX-100 significantly affected the clouding progression of TX-100 + IC mixture, and clouding process was found to be quite sensitive in the presence of alcohols and HyTs. The TX-100 + IC mixture experienced the reduction in the CP values with rising the alcohols and HyTs contents, where the magnitudes of CP followed the order: ({text{CP}}_{text{Aq}.text{ NaSal}}>{text{CP}}_{text{Aq}.text{ NaBenz}}>{text{CP}}_{text{Aq}.text{ EtOH}}>{text{CP}}_{text{Aq}. 1-text{PrOH}}) (approx {text{CP}}_{text{Aq}.text{ MeOH}}>{text{CP}}_{text{Aq}. 1-text{BuOH}}). The various energy parameters were observed to be solely dependent on the concentrations of IC dye, alcohols as well as HyTs in the micellar phase. In all circumstances, free energy change (({Delta G}_{c}^text{o})) values were positive, stating the nonspontaneity nature of phase changes, whereas this nonspontaneity turned to the direction of spontaneous process (reduced + ({Delta G}_{c}^text{o}) values) at the higher contents of alcohols and HyTs. The positive magnitudes of both ({Delta H}_{c}^text{o}) and ({Delta S}_{c}^text{o}) refer to the presence of hydrophobic interacting forces among the respective components, while the negative ({Delta H}_{c}^text{o}) and ({Delta S}_{c}^text{o}) values appeared from the consequences of electrostatic interactions of components. Evaluation of enthalpy-entropy compensation parameters showed the good analogy to the solutions of biological and small solute molecules. The significant findings of this investigation might be highly useful and beneficial for the purpose of drug storage, new drug development, drug transport, and better pharmaceutical formulations.

Graphical Abstract

This paper studied the thermodynamic properties of the 1-octene hydration reaction and screened cosolvents to enhance water–oil mutual solubility, thereby increasing the reaction rate. Using COSMOtherm, the solubilization effects of five cosolvents (acetonitrile, isophorone, 1,4-dioxane, methanol, and acetone) were simulated. The liquid–liquid equilibrium (LLE) of 1-octene+water+1,4-dioxane and 1-octene+water+isophorone systems was simulated at 308.15–348.15 K under 101.3 kPa, followed by experimental validation. Results showed that higher temperatures improved solubilization, confirming COSMOtherm’s accuracy. The NRTL and UNIQUAC models were used to correlate LLE experimental data, demonstrating excellent fitting for both systems. High correlation between regression and experimental results confirmed the accuracy of the data, with both models effectively describing the systems.

Solubility of 1H-1,2,4-triazole in water, methanol, ethanol, n-propanol, and also in water + methanol/ ethanol/ n-propanol binary mixtures have been experimentally measured using a gravimetric method at temperatures (293.15 to 313.15) K. Solubility values were correlated with temperature by the Apelblat equation. The combined nearly ideal binary solvent (NIBS)-Redlich–Kister equation is used to fit experimental solubility data in different solvents at constant temperature. Thermodynamic functions including (Delta H_{text{soln}}^text{o}), (Delta G_{text{soln}}^text{o}), and (Delta S_{text{soln}}^text{o}) of 1H-1,2,4-triazole in different solvents were obtained from the modified van’t Hoff equation. The densities of the saturated solutions were also measured using bicapillary pycknometer in pure and binary solvent mixtures at temperatures mentioned above.