Binary Mixed Solvents Research Articles

Solubility and thermodynamics properties of FOX-7 in binary (N-methyl pyrrolidone + acetone, ethanol, water) mixed solvents

ABSTRACT The solubility of 1,1-diamino-2,2-dinitroethylene (FOX-7) was measured by using a laser monitoring system in binary (N-methyl pyrrolidone + acetone, ethanol, water) mixed solvents with temperatures changing from 293.15 K to 333.15 K under 0.1 MPa. The experimental solubility data for FOX-7 were correlated and fitted to thermodynamic models such as van’t Hoff model, modified Apelblat model, and Yaws model. The results show that the solubility of FOX-7 increases with increasing temperature and N-methyl pyrrolidone ratio. Three models can be used to correlate the solubility data commendably. However, the Yaws model fits best for the solvent system selected in this work. At last, the standard dissolution enthalpy, standard dissolution entropy, and standard Gibbs free energy of FOX-7 can be calculated. It was found that the dissolution of FOX-7 in all test solvents was endothermic and non-spontaneous.

Determination and correlation of solubility of efinaconazole in fifteen mono solvents and three binary mixed solvents at various temperatures

In this study, the solubility data of the solid–liquid equilibrium of efinaconazole in acetone, acetonitrile, 1-butanol, diethylene glycol monoethyl ether (DEGME), dichloromethane, dimethylformamide (DMF), ethanol, ethyl acetate, methanol, 1-propanol, 2-propanol, propylene glycol, polyethylene glycol 400 (PEG 400), tetrahydrofuran, water, and three binary mixed solvents (DEGME + water, ethanol + water, and PEG 400 + water) were measured at five different temperatures (288.15–308.15 K) using the shake-flask technique. The solubility of efinaconazole in the fifteen mono solvents was highest in dichloromethane, followed by tetrahydrofuran, DMF, and acetone, and lowest in water. In the binary mixtures, the solubility of efinaconazole increased with an increase in the DEGME, ethanol, and PEG 400 mass fraction at a defined temperature, respectively. According to the Kamlet-Taft linear solvation energy relationship model analysis, the self-cohesiveness of the solvent indicating solvent–solvent interaction was the main factor affecting the solubility of efinaconazole, which resulted in decreased solubility. Nine models, including the van’t Hoff, modified Apelblat, Buchowski-Ksiazczak λh, simplified CNIBS/R-K, Jouyban-Acree, Jouyban-Acree-van’t Hoff, Jouyban-Acree-modified Apelblat, Sun, and Ma models, were used to regress the experimental solubility data of efinaconazole in fifteen mono solvents and the three binary mixtures. In addition, the dissolution thermodynamic properties of efinaconazole were estimated using a modified van’t Hoff analysis. The experimental solubility data and correlated models of efinaconazole in fifteen mono solvents and the three binary mixed solvents could be useful for the crystallization, purification, and development of liquid dosage forms such as topical solutions during drug development.

Solubility determination and dissolution thermodynamic properties of dodecanedioic acid in binary-mixed solvents from T = (288.15–328.15) K

In this paper, the solubility and dissolution thermodynamic properties of dodecanedioic acid (DDDA) in four binary-mixed solvents (ethyl acetate + ethanol, ethyl acetate + acetic acid, and ethyl acetate + acetone) were investigated. The gravimetric method was employed to determine the mole fraction solubility of DDDA in different solvent ratios from 288.15 K to 328.15 K under the atmosphere. In the binary solvents of ethyl acetate + ethanol and ethyl acetate + acetic acid, when the composition was varied the solubility change was not monotonous, and the phenomenon of co-solvency occured. Furthermore, four models were employed to fit the solubility data, among which the modified Apelblat equation and CNIBS/R-K model had better fitting results. Finally, the dissolution thermodynamic properties of DDDA were analyzed based on the modified Van’t Hoff equation.

Relation between solubility and microextraction recovery data of lamotrigine for prediction of partitioning properties

The aim of this investigation was to study the solubility behavior of lamotrigine (LTG) as a model for basic drugs in the components of solvent systems used for a binary solvent dispersive liquid- liquid microextraction (BS-DLLME). In this system, chloroform (CLF) and dichloromethane (DCM) were used as the binary extracting agents and acetonitrile (ACN) and acetone (ACTN) were used as disperser solvents. Solubility of LTG were measured in the binary mixed solvents of ACN + water, ACTN + water and dry and water saturated mixtures of DCM + CLF at 298.2 K. Furthermore, two solvent mixtures including CLF, DCM, ACN and CLF, DCM, ACTN in various percentages were used to investigate the best solvents composition for extraction of LTG from aqueous samples. The solubility and recovery results were mathematically correlated by the Jouyban-Acree model and the accuracies of this model were evaluated by computing MRD%. The overall MRD% of 7.6% obtained for solubility data and 2.1% for recovery data show the capability of the Jouyban-Acree model for numerical representation of solubility and recovery profiles. Finally, it was tried to find a relation between solubility and recovery data to predict the partitioning of a drug between different liquids and exploring the appropriate solvent system for extraction from aqueous samples via DLLME procedure.

Solubilities of 2,4-Dinitroanisole in Pure Organic and Mixed Organic Solvents at Temperatures between 283.15 and 313.15 K

The solubility of 2,4-dinitroanisole (DNAN) was measured in nine commonly used pure organic solvents, including ethanol, acetone, ethyl acetate, n-propanol, i-propanol, butyl alcohol, cyclohexanone, toluene, and cyclohexane, and four binary mixed solvents between 283.15 K and 313.15 K at atmosphere pressure by the gravimetric method. The solubility of DNAN showed a temperature dependence in all test solvents. The order of the solubility of DNAN was acetone ≈ cyclohexanone > ethyl acetate > n-propanol + acetone ≈ ethanol + acetone ≈ toluene > ethanol > n-propanol > water + acetone > n-butanol + acetone > n-butanol ≈ i-propanol > cyclohexane. The experimental mole fraction solubility data were correlated with the modified Apelblat equation, Yaws equation, and van’t Hoff equation. The correlation showed good agreement with the experimental results, and the largest value of the root-mean-square deviation was 11.88 × 10–4. All of the obtained results would benefit the purification and crystallization of DNAN, which would extend its applications in the field of explosives.

Solubility determination and analysis of methimazole in different solvent systems at T = 278.15–323.15 K

Methimazole is a commonly used drugs for treatment ofhyperthyroidism. Researching the solubility property of methimazole in multifarious solvent systems can be used for optimizing the purification process of methimazole in industry. In this study, the solubility properties of methimazole in twelve pure solvents (methanol, ethanol, 1-propanol, isopropanol, 1-butanol, isobutanol, 1,4-dioxane, methyl acetate, acetonitrile, ethyl acetate, tetrahydrofuran, acetone) and four binary mixed solvents (methanol + ethyl acetate, methanol + acetonitrile, methanol + isopropanol, methanol + methyl acetate) were tested within 278.15 K to 323.15 K under 101.325 kPa. The results show that methimazole has the highest solubility in methanol and the smallest solubility in ethyl acetate. In addition, solubility is positively correlated with temperature in pure solvents and mixed solvents. The XRD spectrum results show that the crystal form of methimazole before and after dissolving in twelve pure solvents do not change. The DSC test shows that the melting point of methimazole is 417.27 K, and it is also proved that methimazole do not decompose before reaching the melting point. Herein, the Modified Apelblat model and Buchowski-Ksiazaczak λh model were used to fit the solubility data of methimazole in pure solvents. Jouyban-Acree model, CNIBS/R-K model and SUN model were used to fit the solubility data of methimazole in binary mixed solvents. The results show that Modified Apelblat model and CNIBS/R–K model have the best correlation with the solubility of methimazole. Analysis using the KAT-LSER model reveals that the influence of the interaction between part of the solvent and solute molecule on solubility. The results show that the impact of dipolarity/polarizability is dominant.

Solubility determination and thermodynamic characterization of orotic acid in twelve pure solvents and four binary mixed solvents

This research reports the solubility and thermodynamic characterization of orotic acid (OA) when it reaches solid–liquid equilibrium in twelve pure solvents and four binary solvents. Solubility determinations were determined by HPLC in the temperature range of T = 278.15–323.15 K (DMSO at 293.15–323.15 K). The results exhibit that in pure solvents, the solubility order of OA is DMSO > DMF > THF > methanol > water > n-propanol > isopropanol > n-butanol > ethanol > acetone > methyl acetate > ethyl acetate. The solubility order in four binary solvents is DMF + ethyl acetate > THF + ethyl acetate > methanol + ethyl acetate > n-propanol + ethyl acetate. According to the solubility data, it can be found that the solubility of OA in the selected pure solvents is positively correlated with temperature. As the temperature gradually rises to 323.15 K, the mole fraction solubility of OA also reaches the maximum. In binary solvents, in addition to the influence of temperature, the increase in the mole fraction of DMF, THF, methanol and n-propanol also promote the dissolution of OA. The properties of the solute and the solvent were combined, the KAT-LSER model was used to investigate the solvation effect of OA in the dissolution process. According to the results, the solubility of OA mainly depends on the ability to accept the hydrogen bond of investigated solvents, and the proportion of the total solvent effect of it is 21.99%. Through the fitting analysis of five thermodynamic models (λh model, modified Apelblat model, CNIBS/R-K model, Jouyban-Acree model and SUN model), the maximum RAD and RMSD are 0.3082 and 0.2272, respectively, indicating that the experimental data is highly correlated with five models.

Solubility and thermodynamic properties of an energetic intermediate in four binary solvents (water + n-butanol, n-pentanol, isobutanol and isoamyl alcohol)

The solubility of 4-nitropyrazole (4-NP) in four different binary solvents (i.e., water + n-butanol, water + n-pentanol, water + isobutanol, and water + isoamyl alcohol) was firstly determined by a gravimetric method within a temperature range of 288.15 K to 328.15 K at atmospheric pressure (P = 0.1 MPa). The experimental results indicated that the solubility of 4-NP in selected binary solvents increases with the increasing temperature and decreases with the rising water mass-fraction ranging. Besides, the (solid + liquid) equilibrium values in the studied solvents were correlated based on the modified Apelblat equation, Jouyban-Acree model, CNIBS/R-K model, and Wilson model. Moreover, all of the 324 experimental values were used to correlate the parameters of the Wilson model, and the correlated results were superior to the other three models by comparing the average 104RMSD and R2. The average root-mean-square deviation (104RMSD) values were 1.87, 31.83, 6.04, and 1.18, respectively. In addition, Hansen solubility parameters were employed to provide a reasonable illustration for the solubility order of 4-NP in the 4 binary mixed solvents, and the order of 4-NP solubility in each binary solvent mixture was the result of the combined effects of hydrogen bonding, dispersion, and polarity. Furthermore, the Wilson model was applied to calculate the thermodynamic properties of 4-NP including mixing enthalpy, mixing entropy, and mixing free Gibbs energy in the studied binary solvent mixtures at a given temperature. It is easy to understand that dissolution is an exothermic process from the results. Solid-liquid surface tension (γ) and surface entropy factor (f) of 4-NP were estimated by using the experimental solubility data, and the results showed that γ and f increase with the increasing mass-fraction of water content in the binary mixed solvent and decrease with the increasing temperature. The experimental solubility values, model parameters, and thermodynamic properties of 4-NP in different mixed solvents will provide the necessary support for its preparation, crystallization process, and further theoretical studies.

Solubility of 2-Amino-5-chloro-3-methylbenzoic Acid in Ten Pure Solvents and Three Groups of Binary Mixed Solvents at T = 278.15–323.15 K

In this paper, the solubility of 2-amino-5-chloro-3-methylbenzoic acid under 0.1 MPa atmospheric pressure and temperature T = 278.15–323.15 K was determined by gravimetric analysis. Considering the...

Determination of the solubility of 6-Chloro-7-azapurine in twelve single solvents and four binary mixed solvent systems at t = (278.15–323.15) K

The work of this article is to measure the solubility of 6-Chloro-7-azapurine in twelve single solvents (methanol, ethanol, isopropanol, n-propanol, n-butanol, tetrahydrofuran, acetone, ethyl acetate, acetonitrile, n-hexane, n-heptane, toluene) and four binary mixed solvent systems (Tetrahydrofuran + ethyl acetate) (Tetrahydrofuran + isopropanol) (Tetrahydrofuran + acetonitrile) (Tetrahydrofuran + methanol) at different temperatures (283.15–303.15 K) under atmospheric pressure. According to the solubility curve, we can see that solubility depends on temperature and solvent composition. The solubility increases with increasing temperature. It has better solubility in alcohols and THF, while alkanes are less effective as solvents. Several mathematical calculation models, such as modified Apelblat, Buchowski–Ksiazaczak λh, simplified CNIBS/R-K, Jouyban-Acree-van't Hoff, Jouyban-Acree-modified Apelblat, Sun and Ma, and KAT-LSER models were used for analysis Experimental solution. The experimental solubility data and calculation model of 6-Chloro-7-azapurine are of great significance for future synthesis process selection and formulation research.

A spherical FOX-7 crystal: Preparation, characterization, solubility and thermodynamic study

ABSTRACT The solubility of 1,1-diamino-2,2-dinitroethylene (FOX-7) in four binary mixed solvents (Dimethyl sulfoxide + Acetonitrile, Cyclohexanone, 1,2-Dichloroethane, 2-Propanol) was determined by using a laser dynamic method at temperatures from 293.15 to 333.15 K under 0.1 MPa. The measured results showed that the experimental solubility of FOX-7 increased with increasing temperature and Dimethyl sulfoxide content in the studied mixture solvents. Solubility data were well correlated by the modified Apelblat model, Yaws model and van’t Hoff model, and the modified Apelblat model has the lowest root-mean-square deviation and can be used as the optimal model for data fitting. In addition, the thermodynamic parameters of the dissolution process, the surface tension, and surface entropy factor of FOX-7 were calculated based on the experimental data, which provided basic data for the optimization of crystallization process and industrial amplification of FOX-7. The cooling crystallization experiments were carried out in the investigated mixed solvents. The crystal morphology of FOX-7 obtained in the Dimethyl sulfoxide + Cyclohexanone mixed solvent (x DMSO = 0.3266) was regular, spherical, uniform in particle size, and have better thermal stability. Cyclohexanone could be the excellent non-solvent in the sphericalization of FOX-7.

Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction and Capillary Electrophoretic Determination of Tramadol in Human Plasma

Background: Tramadol, (±)-trans-2-[(dimethylamino) methyl]-1-(3-methoxyphenyl) cyclohexanol, is a synthetic centrally acting analgesic used in the treatment of moderate to chronic pain. Tramadol, like other narcotic drugs, is used for the treatment of pain and may also be abused. Its overdose can cause adverse effects such as dizziness, vomiting, and nausea. The aim of this paper is to develop a sample preparation method for the determination of tramadol in human plasma samples, followed by CE analysis. Methods: Ultrasound assisted-dispersive liquid-liquid microextraction using binary mixed extractant solvent (chloroform and ethyl acetate) was used for the extraction of one hundred microliters of tramadol spiked human plasma samples and in real human plasma samples obtained from the patients with abuse of tramadol. After evaporation of the extractant solvent, the residue was reconstituted in 100 μL deionized water and subsequently analyzed by CE-UV. Results: The developed method has remarkable characteristics, including simplicity, good repeatability and appreciable accuracy. Under the best extraction conditions, a low limit of detection at 7.0 μg per liter level with good linearity in the range of 0.02-10 μg mL-1 was obtained. Conclusion: UA-DLLME, using a binary mixed extraction solvent, was established for the determination of tramadol in human plasma samples via the CE method with UV-detection. In addition, the analysis of tramadol in some plasma samples of patients with abuse of tramadol indicated that the method has acceptable performance for the determination of tramadol in plasma samples, which indicates that the method is suitable for clinical applications.

Solubility determination, model evaluation, Hansen solubility parameter, molecular simulation and thermodynamic properties of benflumetol in four binary solvent mixtures from 278.15 K to 323.15 K

By means of the laser dynamic method, the saturation solubility of benflumetol (BFL) in four binary mixtures ((ethyl acetate (EAC), n-propyl acetate (NPAC), n-butyl acetate (NBAC) and n-amyl acetate (NAAC)) + methanol (MtOH)) was achieved at temperatures from 278.15 K to 323.15 K and ambient pressure (p = 0.1 MPa). The solubility values (mole fraction) of BFL in above four binary mixed solvents increased as temperature elevated and obeyed the decreasing tendency with the decrease of the mass fraction of the positive solvent (EAC, NPAC, NBAC and NAAC) at a certain temperature. The Hansen solubility parameter provided a reasonable interpretation for the BFL solubility in 4 binary solvent mixtures. Then, the analysis of intermolecular interactions of solute and binary mixed solvents utilizing RDF obtained utilizing MD simulation show that the order of solute-solvent interactions and solvent-solvent interactions are both closely related to the order of the saturation solubility of BFL in binary mixed solvents researched. The saturation solubility of BFL gained through experiments was fitted by the use of five models namely modified Apelblat, λh, Jouyban-Acree, Ma and Sun. Correlation resulted that the modified Apelblat model and λh model gave much lower relative average deviations than the other models for the 4 binary mixed solvents researched. Finally, the derived apparent thermodynamic parameters (ΔsolG°, ΔsolH°, ΔsolS° ζH, ζTS) resulted in terms of the Van't Hoff equation show an entropy-driven, endothermic and spontaneous process of dissolution of BFL in chosen mixed solvents, and the main contribution of ΔsolG° comes from the positive ΔsolH°.

Measurement, correlation of solubility and thermodynamic properties analysis of 2,4,6-trinitroresorcinol hydrate in pure and binary solvents

The solubility of 2,4,6-trinitroresorcinol hydrate (TNR∙2/3H2O) in the pure solvents (methanol, ethanol, isopropanol and water) and the binary mixed solvents (methanol-water, ethanol-water and isopropanol-water) was measured by the laser dynamic method from 298.15 K to 323.15 K under the atmospheric pressure. The TNR∙2/3H2O do not change before and after the solubility measurement in the selected solvents. The solubility increases with the increase of the temperature, and methanol is more suitable for the cooling crystallization of TNR∙2/3H2O. In the pure solvents, the solubility order at the same temperature is: methanol > ethanol > isopropanol > water, which may be affected by the properties (such as hydrogen bond, polarity, dielectric constant, cohesive energy density etc.) of the alcohol solvents, self-association of water molecules, the hydrophobic wing of the TNR∙2/3H2O and so on. In the mixed solvents, the solubility has different sensitivity to the content of organic components (x2) in the solvent. The possible reason is that: the interaction between solvent and solvent plays an important role (the formation of azeotropic mixtures of alcohols and water, the interaction between water and alcohol solvents, the properties of the solvents etc.). The solubility data of TNR∙2/3H2O were compared with that of 2,4,6-trinitrophenol (TNP) that have been reported. It can be found that the solubility of TNP is always greater than that of TNR∙2/3H2O with the same solvent and temperature, and x2 = 0.63–0.69 (ethanol-water) and x2 ≈ 0.73 (isopropanol-water) are more suitable as the solvents for solution crystallization to separate TNR∙2/3H2O from the mixture of TNP and TNR∙2/3H2O. The experimental mole fraction solubility data (xexp) of TNR∙2/3H2O were correlated by the modified Apelblat, Van't Hoff, CNIBS R-K, and Jouyban-Acree-modified Apelblat model. All of these models give satisfactory results, and the Van't Hoff model has better correlation and helps to expand the solubility data of TNR∙2/3H2O. The thermodynamic properties during the dissolution process were analyzed based on the Van't Hoff. And the dissolution of TNR∙2/3H2O in the solvents used is considered to be an “endothermic, non-spontaneous and entropy-driven” process and the enthalpy is the main contributor to the Gibbs free energy in the process of dissolution.

Solubility and thermodynamic properties of FOX-7 in four binary mixed solvents from T = 298.15 to 333.15 K

The solubility of 1,1-diamino-2,2-dinitroethylene (FOX-7) in four binary mixed solvents (Dimethyl sulfoxide+Acetonitrile, Cyclohexanone, 1,2-Dichloroethane, Ethyl acetate) was measured by a laser dynamic method over the temperature range from 298.15 K to 333.15 K under 0.1 MPa. Experimental results showed that the solubility increases monotonously as the temperature increases at a given solvent composition or increases with the increasing of mole fraction of good solvent (Dimethyl sulfoxide) in binary mixed solvents, whereas there exists a maximum solubility value in Dimethyl sulfoxide+ Cyclohexanone system. Solubility data were well correlated by the Apelblat equation, van't Hoff equation, general single model (GSM) and modified Jouyban-Acree model, and the Apelblat equation achieved the best fitting results. Moreover, the thermodynamic properties of FOX-7 dissolution process in the investigated mixed solvents, including standard dissolution enthalpy, standard dissolution entropy and standard Gibbs free energy, were calculated by the van't Hoff and the Gibbs equations. The results demonstrate that the dissolution of FOX-7 is a non-spontaneous and endothermic process. The solubility data, correlation models, and thermodynamics properties presented in this study would provide essential support for the further research of crystallization and spheroidization of FOX-7.

A Conductometric Study of Complexation Reactions between Kryptofix5 with Al3+, Fe3+, Cu2+, and Ca2+ Metal Cations in Acetonitrile–Ethanol Binary Solvent Solutions

In the current study, the results of the conductometric work of the complexation reaction of Kryptofix5 (Scheme 1) with Al3+, Cu2+, Ca2+, and Fe3+ cations are studied in acetonitrile–ethanol (AN–EtOH) binary non-aqueous solvents. In all cases, the achieved results reveal that the stoichiometry of the complexes formed between the ligand and Al3+, Cu2+, Ca2+, and Fe3+ metal cations is 1 : 1 [ML] complex. GENPLOT (the computer program) calculates the stability constants of complexes of (Kryptofix5 · M)n+. The selectivity order of Kryptofix5 ligand for the studied metal cations in pure AN and AN–EtOH (AN = 50 mol % ) binary mixed solvent at 15°C is found to be Ca2+ > Fe3+ > Cu2+ > Al3+ and Cu2+ > Fe3+ > Ca2+ > Al3+, respectively. As a result, the selectivity order of the ligand for the metal cations shows independence from the nature and composition of the mixed binary solvent. By using the Van’t Hoff plots, the thermodynamic parameters ( $$\Delta H_{{\text{c}}}^{^\circ }$$ , $$\Delta S_{{\text{c}}}^{^\circ }$$ ) value for 1 : 1 complexes are calculated from the temperature due to the stability constants of the complexes. The achieved findings reveal that the thermodynamics of the complexation reaction is affected by the nature and composition of the mixed solvents, and the complexation processes entropy and enthalpy are stabilized in most cases.

Conductance Study of Aerosol-OT in Binary Mixed Solvents of Short-Chain Alcohol–Water Systems at Various Temperatures

The conductivity of the anionic surfactant sodium bis(2-ethylhexyl) sulfosuccinate (AOT) is measured in binary mixed solvent media containing 0.000, 0.080, 0.252, and 0.440 mass fractions of methan...

A Conductometric study of complexation reaction between dibenzyl-14-crown-4, with ZrO2+ in some binary mixed nonaqueous solvents

In Some binary methanol mixtures, (MeOH), 1,2 dichloroethane (DCE), acetonitrile (AN), and tetrahydrofuran (THF), with dimethylformamide (DMF) at different temperatures using the conductometric process, the reaction of macrocyclic ligand to complexation, dibenzyl-14-crown-4 (DB14C4) with ZrO2+ cation was examined. The conductance data show that in all solvent systems, the stoichiometry of the complex formed between (DB14C4) and ZrO2+ cation is 1:1 (M:L). The stability order of (DB 14C4.ZrO)2+complex in pure non-aqueous solvents was found to be: [AN], [DCE], [MeOH], [THF], [DMF]. A non-linear behaviour was observed improvements in log Kf of (DB14C4.ZrO)2+ complex or Binary mixed solvent composition, It Was clarified as to the Interactions with solvents and even solvents in terms of the hetero-selective solving of the ecosystem affected by complexation response. The obtained results show that the stability of (DB14C4.ZrO)2+ complex is sensitive to the composition of the mixed solvent. The values of thermodynamic parameters ΔH°cand ΔS°c) for the formation of (DB14C4.ZrO)2+complex using van’t Hoff maps, the stability constant was obtained from temperature dependence. The results show that in most cases, the (DB 14C4.ZrO)2+complex is enthalpy destabilized but entropy balanced and the values and signs of thermodynamic parameters are often These are decided by nature and composition of the mixed solvents.

Reinvestigation of the photophysics of 3-aminobenzoic acid in neat and mixed binary solvents.

The present study elucidates the reinvestigation of the photophysical behavior of 3-aminobenzoic acid (3ABA) in solvents of different polarities using the steady-state spectroscopic techniques. Kamlet-Taft and Catalan solvatochromic models have been used to analyze the solvatochromic changes in neat solvents. The hydrogen bond donating ability of the solvent was found to be the main parameter affecting the spectral behavior of 3ABA. The solvatochromic characteristics of 3ABA have also been examined in binary solvent mixtures viz. acetonitrile (ACN)-methanol (MeOH) and benzene (BEN)-MeOH using the concept of preferential solvation. The preferential solvation of 3ABA shows unusual behavior for BEN-MeOH binary mixture and described unnoticed sigmoidal behavior in the ground state and synergistic impact in the excited state. Besides, the 3ABA was studied theoretically by quantum chemical calculations using (HF) Hartree-Fock and (DFT/B3LYP) density functional theories and its electronic absorption bands have been assigned by time-dependent density functional theory (TD-DFT). The effect of solvents on 3ABA was considered using a IEF-PCM-TDDFT (integral equation formalism of the polarizable continuum model- TDDFT) method. Thus, the theoretical results were found to be closer to the experimental results.

Solubility determination, model evaluation, Hansen solubility parameter and thermodynamic properties of benorilate in six pure solvents and two binary solvent mixtures

The equilibrium solubility and thermodynamic properties of benorilate in six pure solvents (methyl acetate, n-propyl acetate, n-butyl acetate, n-pentyl acetate, DMAC and DMSO) and two binary solvents (DMAC + n-pentyl acetate, DMSO + n-pentyl acetate) were reported. Solubility determinations were performed through the laser monitoring method at T = (278.15–323.15) K and p = 0.1 MPa, except DMSO at (293.15–323.15) K. The measurement results illustrated that the solubility of benorilate in all the six mono-solvents and two binary solvents shows a positive relation with temperature variation. And with the mass fraction of positive solvents (DMAC, DMSO) in the binary mixed solvents increasing, the solubility of benorilate also rises. And then, the Hansen solubility parameter (HSP) of benorilate as well as solvents selected were summarized to analyse the probabilities of miscibility between solute and solvents. The results indicate that the HSP could explain the solubility trend well, and the miscibility of benorilate with selected solvents is caused by a combination of factors. In addition, all recorded solubility of benorilate in pure solvents were regressed by λh, modified Apleblat, Two-Suffix Margules, NRTL and UNIQUAC models, while solubility of benorilate in two binary solvents were regressed by λh, modified Apleblat, Three-Suffix Margules, NRTL and UNIQUAC models. By calculating the deviation between the experimental data and the regression data, it shows that the modified Apelblat model and λh model can provide more accurate correlation results for the solubility of benorilate in all the solvents studied. Furthermore, the apparent thermodynamic properties of benorilate in all solvents were calculated and investigated by the Van't Hoff equation. The results demonstrate that the dissolution process of benorilate is an endothermic, non-spontaneous process driven by entropy.