Binary Mixed Solvents Research Articles

Preferential solvation of L-Alanine in binary mixed solvents of some alcohol in water between 293.15 K and 323.15 K

Preferential solvation of L-Alanine in binary mixed solvents of some alcohol in water between 293.15 K and 323.15 K

General Condition for Polymer Cononsolvency in Binary Mixed Solvents.

Starting from a generic model based on the thermodynamics of mixing and abstracted from the chemistry and microscopic details of solution components, three consistent and complementary computational approaches are deployed to investigate the general condition for polymer cononsolvency in binary mixed solvents at the zeroth order. The study reveals χPS - χPC + χSC as the underlying universal parameter that regulates cononsolvency, where χαβ is the immiscibility parameter between the α- and β-component. Two disparate cononsolvency regimes are identified for χPS - χPC + χSC < 0 and χPS - χPC + χSC > 2, respectively, based on the behavior of the second osmotic virial coefficient at varying solvent mixture composition x C. The predicted condition is verified using self-consistent field calculations by directly examining the polymer conformational transition as a function of x C. It is further shown that in the regime χPS - χPC + χSC < 0, the reentrant polymer conformation transition is driven by maximizing the solvent-cosolvent contact, but in the regime χPS - χPC + χSC > 2, it is driven by promoting polymer and cosolvent contact. In-between the two regimes when neither effect is dominant, a monotonic response of polymer conformation to x C is observed. Effects of the mean-field approximation on the predicted condition are evaluated by comparing the mean-field calculations with computer simulations. It shows that the fluctuation effects lead to a higher threshold value of χPS - χPC + χSC in the second regime, where local enrichment of cosolvent in polymer proximity plays a critical role.

Thermodynamic properties of β-HMX in binary mixed solvent systems and its microscopic mechanisms

Octogen (HMX) is the most powerful military explosive in current use. However, the unclear thermodynamic molecular mechanisms severely limit the development of its production process. In this paper, the solubility of β-HMX in three binary mixed solvent systems (acetone + ethanol, acetone + dichloromethane, acetone + toluene) was measured via a dynamic method at temperature ranging from 283.15 to 313.15 K under atmospheric pressure. The experimental results reveal that the solubility of β-HMX in these binary mixed solvent systems is positively correlated with acetone molar fraction and temperature, and the solvent composition has a greater impact on its solubility compared with the temperature. Moreover, the solubility of β-HMX is further correlated with the Van’t Hoff equation, modified Apelblat equation, CNIBS/R-K model, Jouyban-Acree-Van’t Hoff model, Jouyban-Acree-Apelblat model and NRTL model, and the modified Apelblat equation can give better fitting result (ARD = 8.101 × 10−3, RMSD = 1.065 × 10−5). Finally, the microscopic mechanism of the thermodynamic properties of β-HMX in binary mixed solvents is revealed by investigating the types, intensity and interaction sites of interactions based on density functional theory (DFT) and molecular dynamic (MD) simulation. The results demonstrate that both acetone molecules and ethanol molecules can form certain intermolecular interactions with β-HMX molecules, which are the main driving force of solubilization. In contrast, solvent–solvent interactions have an antagonistic effect on the solubility of β-HMX in mixed solvents. This work can further be informative for researchers in the field of energetic material for the solubility evaluations and provide a reference for the industrial production and performance enhancement of HMX in the future.

Phase Separation of Homopolymers in Binary Mixed Solvents─The Co-Nonsolvency Effect

Phase Separation of Homopolymers in Binary Mixed Solvents─The Co-Nonsolvency Effect

Measurement, correlation and thermodynamic analysis of the solubility of dicyandiamide in three binary solvents

Dicyandiamide (DCD) is an important chemical raw material. The solid–liquid equilibrium solubility of DCD in three kinds of binary solvent mixtures (N,N-dimethylformamide (DMF) + ethanol, DMF + acetonitrile, DMF + acetone) at T = (283.15–323.15) K was determined by gravimetric method. The thermodynamic parameters of DCD dissolution in solvents were studied. The solubility of DCD in the three groups of binary mixed solvents increases with the increase of temperature. In three binary mixed solvents, the solubility of DCD increases monotonically with the increase of DMF composition. The modified Apelblat model, van’t Hoff model, λh model, the nonrandom two-liquid (NRTL) model and the Apelblat-Jouyban-Acree model were used to correlate the solubility data. The results show that the modified Apelblat model have the best correlation with the solubility of DCD. The calculation of thermodynamic parameters during the dissolution process indicates that dissolution is exothermic and driven by both enthalpy and entropy. This work can provide reference for improving the crystallization process of DCD, as well as for improving the chemical production process using DCD as raw material.

Solubility Determination and Correlation of 1,3,5-Tribromobenzene in Five Kinds of Binary Mixed Solvents

Solubility Determination and Correlation of 1,3,5-Tribromobenzene in Five Kinds of Binary Mixed Solvents

Solubility Determination and Model Evaluation of Triethylamine Hydrochloride in Three Binary Mixed Solvents

Solubility Determination and Model Evaluation of Triethylamine Hydrochloride in Three Binary Mixed Solvents

Study on the liquid–liquid phase separation phenomenon of iohexol in a binary mixed solvent of methanol and n-butanol: Thermodynamic behavior and molecular dynamics calculation

The impact of oiling-out on the control of the crystallization purification process during iohexol crystallization is significant. Thus, the solubility of iohexol and its oiling-out behavior in a binary solvent mixture of methanol and n-butanol was investigated in this study. The solubility was determined using the equilibrium method at temperatures ranging from 273.15 K to 303.15 K under atmospheric pressure, revealing that solubility increases with temperature and methanol concentration. Four models were employed to model the solubility data, with the CNIBS/R-K model demonstrating the highest correlation. The van't Hoff equation was utilized to calculate the thermodynamic properties, the result indicating that enthalpy predominates in the dissolution process. Furthermore, ternary phase diagrams were constructed to elucidate the nucleation mechanism of iohexol, identifying nucleation sites and performing kinetic simulations from a molecular perspective. These analyses indicated that lower temperatures are favor the control of oiling-out phenomena. The nucleation of iohexol is characterized by a two-step mechanism, initiating with liquid–liquid separation, followed by nucleation and crystal growth. Solubility parameters, derived using Materials Studio, suggest enhanced interactions between iohexol and methanol, which is also corroborated by the solvation energy data from Gaussian software. This interaction explains the tendency of iohexol to oiling out in mixed solvents. Radial distribution function (RDF) analysis illustrates that methanol-iohexol interactions intensify prior to oiling-out, reach a peak during oiling-out, and diminish after nucleation due to desolvation. The occurrence of oiling-out can lead to challenges such as diminished product quality, reduced yields, and difficulties in reprocessing. Therefore, understanding the mechanism of oiling-out is fundamental to addressing these issues, rendering these insights invaluable for the study of crystallization processes and oiling out phenomena in other small organic molecules.

Ionic liquid-ethanol mixed solvent design exemplified for the decarbonization of shale gas and biogas

Shale gas and biogas, recognized as “clean” energy sources, hold the potential to replace fossil fuels, necessitating efficient decarbonization processes. This study proposes a mixed solvent, combining ionic liquid (IL) and ethanol, for a cost- and energy-effective decarbonization approach. Initially, a computer-aided molecular method optimizes the IL molecule structure, identifying 1-hydroxy-3-methyl-pyridinium trifluoroacetate ([OHMPY][CF3COO]) through solving a formulated mixed-integer nonlinear programming (MINLP) problem. The [OHMPY][CF3COO]-ethanol mixed solvent's performance is validated in shale gas and biogas decarbonization across diverse gas compositions and feed conditions. A comprehensive comparison with the traditional MDEA-based CO2 removal process is conducted, evaluating energy, economic, and environmental aspects. Results indicate that the [OHMPY][CF3COO]-ethanol decarbonization process offers 30.65%-41.48% power savings, a 3.68%-17.18% reduction in investment costs, and an 18.08%–22.45% decrease in CO2 emissions. These findings underscore the significant potential of the proposed IL-ethanol binary mixed solvent in decarbonization processes.

The Preferential Solvation of Methyl Red in Various Binary Aqueous Solutions: Solvatochromism, Preferential Solvation Parameters, Microheterogeneity of Solvents and Polarity Scale.

The solvatochromic characteristics of methyl red were examined in several aqueous solutions from pure water, with methanol, ethanol, propanol, acetonitrile, and dioxane. In order to explain the preferred solvation of the probe azo dye in the binary mixed solvents, the solvent exchange model of Bosch and Roses was used to evaluate the association between the empirical solvent polarity scale (ET) values of MR and solvent composition. Non-linear solvatochromism of methyl red was noted in all aqueous mixtures containing methanol, ethanol, propanol, acetonitrile, and dioxane. In addition to calculating the local mole fraction of each solvent composition in the cybotactic area of the probe, the impact of the solvating shell composition on the preferential solvation of the solute dye was examined in terms of both solvent-solvent and solute-solvent interactions. The local mole fraction of each solvent composition in the cybotactic region of the probe was also calculated. The results indicated that the MR solvation shell was thoroughly saturated with the solvent complex S12 in the following order: dioxane > ethanol > methanol > acetonitrile > propanol. Data from the binary systems were analyzed with KAT parameters using a multi-model; in aqueous methanol and ethanol solutions, the hydrogen acidity was more responsible for the spectral shift, whereas in aqueous acetonitrile and dioxane solutions, the basicity has a greater influence.

Solid-liquid equilibrium solubility, modeling, Hansen solubility parameter and thermodynamic analysis of 2-Mercaptobenzimidazole in eleven mono-solvents and three binary solvents at different temperatures

The solubility of drugs is an important physicochemical data for its development and design. In this work, the solubility of 2-mercaptobenzimidazole (2-MBI) in eleven mono-solvent solvents (2-propoxyethanol, isopropyl acetate, butyl acetate, 2-methoxyethanol, 2-butanol, ethyl formate, 2-ethoxyethanol, isobutanol, 4-methyl-2-pentanone, 2-butoxyethanol and ethylene glycol) and three binary solvents (2-methoxyethanol + ethyl formate, 2-methoxyethanol + isopropyl acetate, 2-ethoxyethanol+ ethyl formate) was measured by a gravimetric analysis method at the temperatures from 283.15 to 323.15 K. The solubility of 2-MBI in the studied solvents increased with the increasing temperature. The measured solubility data of 2-MBI was described mathematically and back-calculated by CNIBS/R-K model, Margules model, UNIQUAC model, Jouyban-Acree-van't Hoff model and NRTL model. Hansen solubility parameters was calculated to assess the qualitative trend of 2-MBI in all selected mono and binary mixed solvents, analysis results indicating that the solubilization behavior of 2-MBI was intricate and can not only be assessed by one factor. In this study, the apparent thermodynamic parameters including ∆solHo, ∆solSo, ∆solGo, ξH and ξTS were investigated, positive values of ∆solHo indicating that the corresponding dissolution process of 2-MBI in all selected solvents was endothermic. In conclusion, these experimental and thermodynamic analysis can enrich the database and give support for design and optimize the crystallization process of 2-MBI.

Solubility Determination, Modeling, and Thermodynamic Analysis of 3-Aminophenol in Ten Monosolvents and Three Binary Mixed Solvents

Solubility Determination, Modeling, and Thermodynamic Analysis of 3-Aminophenol in Ten Monosolvents and Three Binary Mixed Solvents

The non-ideality in binary aqueous systems contributed to the different abilities of solvent entities incorporated in the solvation shell of methylene blue

The solvatochromic properties of methylene blue (MB) were investigated in neat water, methanol, ethanol, propanol, dioxane and their corresponding aqueous mixtures. The correlation of the empirical solvent polarity scale (ET) values of MB with solvent composition was analysed using the solvent exchange model of Bosch and Roses to explain the preferential solvation of the probe thiazine dye in the binary mixed solvents. Non-linear solvatochromism of MB was observed in aqueous mixtures of methanol, ethanol, propanol and dioxane. The influence of the composition of the solvating shell in preferential solvation of the solute dye was investigated in terms of both solvent?solvent and solute?solvent interactions, and the local mole fraction of each solvent composition in the cybotactic region of the probe was also calculated. Effective mole fraction variation can provide important physicochemical insights into the microscopic and molecular interactions between MB species and solvent components. The results showed that the MB solvation shell was thoroughly saturated with the solvent complex S12 for dioxane more than ethanol and propanol mixtures, and opposite trends for methanol mixtures, whereas the solvent complex S12 could not incorporate into the MB solvation shell. Data from the binary systems were analysed with KAT parameters using a dual model of basicity and polarity. The results showed that the polarity was better suited for spectral shift in aqueous methanol and ethanol solutions, while the basicity was better for aqueous propanol and dioxane solutions.

Determination of Gibberellin A3 solubility in different solvents based on mathematical models, solvent effect and thermodynamic analysis

For gibberellin A3, one of the important phytohormones, solubility parameters and characterisation are the basis of data for its isolation and purification. In this work, the solubility of GA3 was determined in twelve pure solvents (ethanol, isopropanol, 1-butanol, n-hexane, n-heptane, trichloromethane, ethyl acetate, acetone, xylene, tetrahydrofuran, dimethylsulfoxide and acetonitrile) and three binary mixed solvents (trichloromethane + ethanol, acetonitrile + ethanol and n-hexane + ethanol) at temperatures ranging from 278.15 K to 323.15 K. The experimental results showed that the solubility of GA3 in various solvents was positively correlated with the temperature, with better solubility in ethanol. The measured data were fitted with the modified Apelblat model, the Buchowski-Ksiazaczak λh model, the CNIBS/R-K model and the Jouyban-Acree model. Then, the solvent effect was analyzed using the KAT-LSER model, which showed that the dipole polarisation rate of the solvent had the greatest effect on the solubility of GA3. In addition, the dissolution thermodynamic properties of GA3 were studied with the van't-Hoff equation, concluding that the dissolution of GA3 was an entropy-driven heat absorption process. The data obtained from this research will contribute to improve the purity of GA3 in the recrystallisation process, and ensure its efficacy and stability, thereby playing a certain guiding role in the industrial production of GA3.

Solubility, correlation, Hansen solubility parameter and thermodynamic analysis of 2,4-dinitroanisole in three binary mixed solvents

Melt cast explosive is the most widely used type of military explosives. Then 2,4-dinitroanisole (DNAN) is a liquid phase carrier of melt cast explosives, and it is the most promising substitute for TNT. In this study, the solubility of DNAN in three binary mixed solvents (MeOH + water, EtOH + water, i-PrOH + water) at the temperature range of 298.15 ∼ 333.15 K at atmospheric pressure (0.1 MPa) was measured by laser dynamic method. The experimental results show that the solubility of DNAN increase with increasing temperature and the fraction of the organic solvents. In order to expand the applicability of solubility, Apelblat equation, van't Hoff equation, λh equation and modified Jouyban-Acree model were used to correlate the solubility, and satisfactory results were obtained. The Apelblat equation have best correlation with the solubility data of DNAN. The solubility parameters of DNAN and binary mixed solvents were calculated through Hansen solubility parameter and Materials Studio. The solubility of DNAN in three binary mixed solvents show a regular pattern of i-PrOH + H2O > EtOH + H2O > MeOH + H2O. The above pattern is consistent with the solubility parameters prediction results and prove that the solubility data is true and effective. In addition, according to the experimental data, the standard solubility enthalpy ΔHdis° degree, standard entropy ΔSdis° degree, standard Gibbs free energy ΔGdis°, the enthalpy %ξH and the entropy %ξS were calculated and discussed.

Reveal the molecular mechanism of cosolvency behaviors of proline in alcohol + acetone binary mixed solvent

Cosolvency is a thermodynamic phenomenon of great research significance. But the current theoretical research is still not comprehensive. In this paper, L-proline, (R)-β-proline and (S)-β-proline were used as model materials to reveal the mechanism of cosolvency interaction at the molecular level. By means of spectral analysis and molecular simulation, the effects of aggregates, coordination numbers and interactions on cosolvency were systematically studied. The results show that with the change of solvent composition, the aggregation form and coordination number of solute change, which leads to the change of the interaction between solute and solvent, and finally leads to the cosolvency phenomenon.

Photoinduced organocatalytic lignin C–C bond cleavage in mixed binary solvents

Lignin presents a renewable alternative of fossil feedstock to produce value-added aromatic chemicals. Oxidative cleavage of C−C bonds in lignin is of great importance, but obtaining aromatic monomers in high selectivity under mild conditions is challenging. Herein, we report a novel strategy of photoinduced oxidative C–C cleavage of lignin β–O–4 derivatives using photoredox organocatalysts, among which Mes-10-phenyl-Acr+-BF4– exhibited high yields of aromatic aldehydes and phenyl formate. Besides, mixed binary organic solvents were demonstrated to promote bond cleavage and inhibit over-oxidation side reactions. The absorbance, excitation, and interaction with the lignin model of the photocatalyst in different solvents were investigated by UV-Vis, PL, and CV tests. Furthermore, through mechanism studies, a C-centered radical intermediate was captured, providing evidence for the direct Cα−Cβ bond cleavage mechanism during the reaction. This work presents a new photocatalytic strategy and provides deep insights into the bond cleavage mechanism for lignin valorization.

Solubility Determination and Analysis of Phenol Red in Monosolvent and Binary Mixed Solvent at T = 278.15–323.15 K

Solubility Determination and Analysis of Phenol Red in Monosolvent and Binary Mixed Solvent at <i>T</i> = 278.15–323.15 K

Dissolution thermodynamics and polymorphic transformation behaviors of glutathione

Glutathione (GSH) is a bioactive oligopeptide which was widely used in sports, pharmaceutical and food industry. This paper compared the properties of two crystalline forms of GSH (Form α and Form β) in thermodynamics and explored the transformation of corresponding polymorph. The solubility data of GSH were determined by using the dynamic method in binary mixed solvents (methanol + water, ethanol + water, isopropanol + water, ethylene glycol + water) at temperatures ranging from 278.15 to 313.15 K. The solubilities of the two forms both increased with the increasing of mole fraction of water and temperature. The modified Apelblat equation, the CNIBS/R-K model and the Jouyban-Acree model were used to correlate the experimental solubility. The mixing thermodynamic properties of GSH in the binary mixed solvents were calculated by Van’t Hoff equation. Form β was supposed to be the stable crystalline form based on the thermodynamics analysis, which corresponded to the solvent-mediated transformation from Form α to Form β.

Solubility and Thermodynamic Modeling of 5-Nitrofurazone in Pure Solvents and Binary Solvent Mixtures

In this work, the solubility of 5-nitrofurazone (Form α) in 10 pure solvents (water, methanol, ethanol, acetonitrile, ethyl acetate, n-propanol, isopropanol, acetone, formamide, N,N-dimethylformamide) and two binary mixed solvents (N,N-dimethylformamide + water, N,N-dimethylformamide + acetonitrile) were measured by ultraviolet–visible spectrophotometry from 278.15 to 313.15 K. The experimental results showed that the solubility of 5-nitrofurazone (Form α) in all pure solvents and binary mixed solvents was positively correlated with temperature. Additionally, the modified Apelblat equation, the λh equation, and the nonrandom two-liquid (NRTL) model were used to correlate the experimental solubility results. The results showed that all of these models could correlate the experimental data well, and the modified Apelblat equation provided the best fitting results. Finally, the mixing and dissolution thermodynamic properties of 5-nitrofurazone (Form α) in 10 pure solvents and two binary solvents, including enthalpy, entropy, and Gibbs energy, were calculated by experimental results and the NRTL model.