Binary Aqueous Solvent Mixtures Research Articles

Experimental and Theoretical Screening for Green Solvents Improving Sulfamethizole Solubility.

Solubility enhancement of poorly soluble active pharmaceutical ingredients is of crucial importance for drug development and processing. Extensive experimental screening is limited due to the vast number of potential solvent combinations. Hence, theoretical models can offer valuable hints for guiding experiments aimed at providing solubility data. In this paper, we explore the possibility of applying quantum-chemistry-derived molecular descriptors, adequate for development of an ensemble of neural networks model (ENNM), for solubility computations of sulfamethizole (SMT) in neat and aqueous binary solvent mixtures. The machine learning procedure utilized information encoded in σ-potential profiles computed using the COSMO-RS approach. The resulting nonlinear model is accurate in backcomputing SMT solubility and allowed for extensive screening of green solvents. Since the experimental characteristics of SMT solubility are limited, the data pool was extended by new solubility measurements in water, five neat organic solvents (acetonitrile, N,N-dimethylformamide, dimethyl sulfoxide, 1,4-dioxane, and methanol), and their aqueous binary mixtures at 298.15, 303.15, 308.15, and 313.15 K. Experimentally determined order of decreasing SMT solubility in neat solvents is the following: N,N-dimethylformamide > dimethyl sulfoxide > methanol > acetonitrile > 1,4dioxane >> water, in all studied temperatures. Similar trends are observed for aqueous binary mixtures. Since N,N-dimethylformamide is not considered as a green solvent, the more acceptable replacers were searched for using the developed model. This step led to the conclusion that 4-formylmorpholine is a real alternative to N,N-dimethylformamide, fulfilling all requirements of both high dissolution potential and environmental friendliness.

The Solubility Profile of 3,4,5-Trimethoxybenzaldehyde in Aqueous Binary Solvent Mixtures at Several Temperatures

The Solubility Profile of 3,4,5-Trimethoxybenzaldehyde in Aqueous Binary Solvent Mixtures at Several Temperatures

Solid-liquid equilibrium solubility measurement, model evaluation and Hansen solubility parameter of 2,4,5-trimethoxybenzaldehyde in four aqueous binary solvent mixtures

The solid–liquid equilibrium solubility of 2,4,5-trimethoxybenzaldehyde (ANH) in four kinds of aqueous binary solvent mixtures (including water + acetone, water + acetonitrile, water + N, N-dimethylformamide and water + tetrahydrofuran) was determined with a temperature ranging from 278.15 K to 323.15 K under approximately 0.1 MPa. The solubility of ANH increases with the increase of temperature and the composition of good-solvent in all the tested binary solvent mixtures. The solubility of ANH is temperature-sensitive in the binary solvent mixture of water + THF system and solvent-sensitive in the binary solvent mixture of water + DMF. The Hansen solubility parameter for ANH and the selected solvents was employed to analyze the probabilities of miscibility between solute and solvents. Four thermodynamic models (i.e., the modified Jouyban-Acree model, the Sun model, the NRTL model, and the Wilson model) were selected to correlate the experimental data. The NRTL model fitted best among all the thermodynamic models with RAD and RMSD values are less than 0.0186 (water + acetone) and 0.000950 (water + THF), respectively. The solubility data are of guiding significance to the crystallization process of ANH.

Solid-liquid phase equilibrium of clozapine in aqueous binary solvent mixtures

The solid-liquid phase equilibrium solubility of clozapine in six of aqueous binary solvent mixtures (i.e., water + methanol, water + ethanol, water + n-propanol, water + acetone, water + N, N-dimethylformamide, and water + tetrahydrofuran) was determined from 278.15 K to 323.15 K at approximately 101.3 kPa with a gravimetric method. The solubility increases with the increase of temperature and the composition of good-solvent in all the selected binary solvent mixture systems. Polarity is an essential factor affecting the solubility of clozapine in mixed solvents. Hansen solubility parameters were used to analyse the solubility behaviour. Four thermodynamic models, including the CNIBS/R-K model, the modified Jouyban-Acree model, the NRTL model, and the Wilson model were chosen to fit the experimental solubility data. Relative average deviation, and root mean square deviation were employed to evaluate the fitting degree of each thermodynamic model. NRTL model fits best with the maximum RAD and RMSD value of 0.0177 (water + methanol) and 0.000847 (water + THF), respectively. Solubility data are the basis for calculation of supersolubility and induction time of the crystallization process. The basic solubility data play an important role in the process optimization of clozapine crystallization.

Solubility and peculiar thermodynamical behaviour of 2-aminobenzoic acid in aqueous binary solvent mixtures at 288.15 to 308.15 K

The equilibrium saturated solubility of 2-aminobenzoic acid (2-AA) in water and aqueous dimethylformamide (DMF), acetonitrile (ACN), dimethylsulfoxide (DMSO) are determined using ‘formol titrimetric’ method at five temperatures under atmospheric pressure and normal pH of the solutions. The solubility are analyzed to investigate the temperature effect and a comparative study to justify the effect of solvent on solubility and solvation thermodynamics of 2-AA. The saturated solubility data are used to resolve the transfer Gibbs energies ΔGt0(i), and entropies ΔSt0(i), of 2-AA in the present experimental binary solution. The chemical contributions for solvent-solvent and solute-solvent interactions via free energies (ΔGt, ch0(i)) and entropies (ΤΔSt, ch0(i)) of transfer of 2-AA are evaluated by eliminating the cavity and dipole-dipole interactions effects from the total transfer energies. Finally the solubility, physicochemical and other thermodynamical properties of 2-AA in aqueous-organic solvent mixtures are described to clarify the chemical stability of 2-AA. The results are found in this study are very essential for biochemistry, pharmaceutical sciences, industrial design and for further theoretical studies.

Investigation on Preferential Solvation, Transfer Properties and Solvent Effect of Sulfachloropyridazine in Aqueous Co-solvent Solutions of Some Alcohols

The effect of solvent on the solubility of sulfachloropyridazine was studied by making a correlation between the solubility values and solvent’s descriptors for solvent–solute and solvent–solvent interactions with the help of linear solvation energy relationships concept. From analysis of the molecular structure of sulfachloropyridazine, the variation of solubility was well explained in terms of the change in hydrogen bond basicity of mixtures when the mole fraction of methanol (or ethanol or isopropanol) increased in all aqueous binary solvent mixtures. The preferential solvation analysis of sulfachloropyridazine in the three aqueous co-solvent solutions of isopropanol, ethanol and methanol was carried out from solubility values through the method of inverse Kirkwood–Buff integrals. In water-rich compositions of the aqueous co-solvent solutions, the δx1,3 values are negative, indicating that the sulfachloropyridazine was solvated preferentially by the solvent water. In intermediate and alcohol-rich compositions, sulfachloropyridazine was preferentially solvated by the isopropanol, ethanol or methanol. The magnitude of preferential solvation of sulfachloropyridazine is greater in isopropanol solutions than in the other two co-solvent solutions. Analysis results of the KAT-LSER and IKBI methods indicate that the solute mainly acts as a Lewis acid through its –NH2 and > NH functionalities. In addition, the enthalpy, Gibbs energy and entropy of transfer were obtained, which demonstrated that the solubilization ability was more favorable in intermediate composition of the alcohols.

Effect of choline chloride-oxalic acid based deep eutectic solvent on the ultrasonic assisted extraction of polyphenols from Aegle marmelos

In spite of their superior dissolution capacity for bioactive compounds, reduced environmental impact and low toxicity, the high viscosity of DES may affect the extraction capacity and efficiency, for which, necessary modification may be necessary. However, such changes can lead to a drastic reduction in the extraction yield because of the highly sensitive nature of the supramolecular structure of DES. To investigate the effect of molar ratio, water addition and temperature, ultrasound-assisted extraction of phenolic compounds from Aegle marmelos was performed with a series of DESs based on choline chloride and oxalic acid (DES: oxaline) with different molar ratio and water addition levels. HPLC-DAD was applied to quantify individual phenolic compounds. To understand the structural and physical characteristics under different processing conditions, FTIR, density and rheology analysis of oxaline were performed. Binary aqueous solvent mixtures were used as the reference. According to the experimental results, oxaline11 with 25% water and 80 °C was the best combination for extracting polyphenols from bael. The optimized condition enabled better cavitiational process by lowering viscosity and forming a stronger H-bonding between the DES and components, enhancing the extraction yield and capacity by >60% compared to conventional solvents. The results of this study highlight the potential application of deep eutectic solvent as an alternative to conventional organic solvents in food, cosmetic and pharmaceutical applications.

Commentary on the “Solubility of l-histidine in different aqueous binary solvent mixtures from 283.15 K to 318.15 K with experimental measurement and thermodynamic modelling”

Abstract Errors are discovered regarding the published equation coefficients of Liu and co-workers [J. Chem. Thermodynamics 105 (2017) 1–14] for mathematically describing the solubility behaviour of l -histidine in aqueous solvent mixtures using the modified Apelblat equation and modified Jouyban-Acree model. The calculated values using the published equation coefficients for the two models are not the mole fraction solubility as stated in the published paper.

Theoretical and Experimental Study of the Thermodynamic Solubility of Pioglitazone HCl in Ethanol, N-Methyl Pyrrolidone or Propylene Glycol + Water Mixtures at Various Temperatures

The solubilities of pioglitazone HCl (99 data points) in binary solvent mixtures of ethanol, N-methyl pyrrolidone (NMP) or propylene glycol (PG) + water are reported at three temperatures ranging from 298.2 to 308.2 K. Three different cosolvency models, those of Yalkowsky, Jouyban–Acree and combined version of the Jouyban–Acree model with the van’t Hoff approach, have been used for correlating the reported data, and the corresponding overall mean relative deviations (OMRDs) are 88.9, 19.1 and 14.8%, respectively. Also, three previously trained versions of the Jouyban–Acree model have been used for predicting the solubilities of pioglitazone HCl in the aqueous binary solvent mixtures of ethanol, NMP and PG which the prediction OMRDs are 38.9, 93.0 and 50.0%, respectively.

Solubility of L-histidine in different aqueous binary solvent mixtures from 283.15 K to 318.15 K with experimental measurement and thermodynamic modelling

In this study, the solubility of L-histidine in three different binary solvents, including (water+acetone), (water+ethanol) and (water+2-propanol), was measured over temperatures from 283.15K to 318.15K by employing a gravimetric method at atmospheric pressure. It was found that the solubility of L-histidine in the binary mixed solvents increases with the increasing temperature at a given solvent composition, whereas it decreases with the rise of mole fraction of organic solvents. The experimental results were well correlated by the modified Apelblat equation, CNIBS/R-K model, combined version of the Jouyban-Acree model and NRTL model, respectively. This shows that these models can correlate the solubility in three binary mixed solvents accurately. Furthermore, the mixing thermodynamic properties of L-histidine in different binary solvent mixtures were also calculated based on the NRTL model. The result indicates that the mixing process of L-histidine is endothermic and spontaneous.

Measurement and correlation of deferiprone solubility: Investigation of solubility parameter and application of van't Hoff equation and Jouyban–Acree model

The available solubility of deferiprone (DFP) in mono and mixed solvent systems is limited. The aim of this work is to find solvation of DFP with respect to the composition of the solvent mixture. Solubility of DFP in water, ethanol (EtOH) and N-methyl-2-pyrrolidone (NMP) was experimentally determined at 293.2, 298.2, 303.2, 308.2 and 313.2K. Its solubility in aqueous binary mixtures of EtOH and NMP was also investigated. Solubility of DFP in aqueous binary solvent mixtures of ethylene glycol (EG), propylene glycol (PG) and polyethylene glycol 400 (PEG 400) and non-aqueous binary solvent mixtures of EG+EtOH, EG+NMP, EG+PG and EG+PEG 400 is investigated and solubility profile shape of each system is explained in terms of solubility parameter. Total solubility parameter of DFP is calculated by Fedor's group contribution method and compared to solubility parameter of various solvent mixtures in order to estimate maximum solubility in specific co-solvent ratio.Based on the generated experimental solubility data, trained versions of the van't Hoff and Jouyban–Acree models were used to simulate DFP solubility in the binary mixture compositions. The applicability of the thermodynamic model to predict the solubility of DFP was studied. The experimental data was used to provide accurate estimations of solubility in the investigated solvent systems using van't Hoff and Jouyban–Acree equations.

Solubility of Etoricoxib in Aqueous Solutions of 1,4-Butanediol, 1,4-Dioxane, N,N-Dimethylacetamide, N,N-Dimethylformamide, Dimethyl Sulfoxide, and Ethanol at 298.2 K

Models for predicting the solubility of drugs in monosolvents and their mixtures have a practical importance in design and development of new products in pharmaceutical industries. Thus, present investigation pertains to the utility of a correlative model for solubility prediction of etoricoxib (ETR). The molar solubilities of ETR in a number of monosolvents and various mass fractions of their binary aqueous solvent mixtures were determined using the shake-flask method at 298.2 K. Densities of ETR saturated solutions in the monosolvents and their binary solvent mixtures were measured and then correlated using a well-established method proposed by Jouyban and Acree. Overall mean percentage deviations (OMPDs) between experimental and predicted values were 3.4 % for the molar solubilities and 0.1 % for the densities of the saturated solutions.

UV–Vis spectroscopic study and DFT calculation on the solvent effect of trimethoprim in neat solvents and aqueous mixtures

The solvatochromic behavior of trimethoprim (TMP) was analyzed using UV–Vis spectroscopy and DFT methods in neat and binary aqueous solvent mixtures. The effects of solvent dipolarity/polarizability and solvent–solute hydrogen bonding interactions on the absorption maxima were evaluated by means of the linear solvation energy relationship concept of Kamlet and Taft. This analysis indicated that both interactions play an important role in the position of the absorption maxima in neat solvents. The simulated absorption spectra of TMP and TMP:(solvent)n complexes in ACN and H2O using TD-DFT methods were in agreement with the experimental ones. Binary aqueous mixtures containing as co-solvents DMSO, ACN and EtOH were studied. Preferential solvation was detected as a nonideal behavior of the wavenumber curve respective to the analytical mole fraction of co-solvent in all binary systems. TMP molecules were preferentially solvated by the organic solvent over the whole composition range. Index of preferential solvation, as well as the influence of solvent parameters were calculated as a function of solvent composition.

Reactivity trends of hydroxide ion attack on high spin Fe(II) complexes including bromosalicylidene amino acid ligands in some mixed aqueous solvents: Gibb’s Free Energy of Transfer and initial-transition state analysis

The kinetics of hydroxide ion attack on bis(bromosalicylidene alanate)iron (II) (bsali), bis(bromosalicylidene phenylalanate)iron(II) (bsphali), bis(bromosalicylidene aspartate)iron(II) (bsasi), (bromosalicylidene histidinate)iron(II) (bshi), bis(bromosalicylidene arginate)iron(II) (bsari) have been reported in different binary aqueous solvent mixtures at 298K. The observed reactivity trends are discussed in terms of the hydrophilic and hydrophobic forms of the complexes investigated, as well as the transfer chemical potentials of hydroxide ion and the complex. Both the solvent–solute and solvent–solvent interactions have been considered. The hydrophobic character of the complexes studied was manifested by decreasing in reactivity. Solvent effect on reactivity trends of the investigated complexes has been analyzed into initial and transition state components by using the transfer chemical potentials of the reactants and the kinetic data of the studied compounds. The decrease in the observed rate constant values (kobs) of the base hydrolysis of the investigated complexes with increasing of solvent % is dominated by the initial state (IS).

Hydrophobicity, reactivity trends of base catalyzed hydrolysis of some novel high spin Fe(II) Schiff base amino acid chelates in some binary aqueous solvent mixtures: Initial-transition state analysis

Rate constants for the base hydrolysis of bis(naphthylidene alanate)iron (II) (nali), bis(naphthylidene phenylalanate)iron(II) (nphali), bis(naphthylidene aspartate)iron(II) (nasi), (naphthylidene histidinate)iron(II) (nhi), bis(naphthylidene arginate)iron(II) (nari) have been reported in different binary aqueous solvent mixtures at 298K. The observed reactivity trends are discussed in terms of the hydrophilic and hydrophobic forms of the complexes investigated, as well as the transfer chemical potentials of the hydroxide ion and the complex. Both the solvent–solute and solvent–solvent interactions have been considered. The hydrophobic character of the complexes studied was manifested by a decrease in reactivity. Solvent effect on reactivity trends of the investigated complexes have been analyzed into initial and transition state components. This can be achieved by using the transfer chemical potentials of the reactants and the kinetic data of the studied compounds. The decrease in the observed rate constant values (kobs) of the base hydrolysis of the investigated complexes with increase of solvent% is dominated by the initial state (IS).

Micellization of Some Bile Salts in Binary Aqueous Solvent Mixtures

AbstractThe micellization behavior of bile salts—sodium cholate and sodium deoxycholate was studied in aqueous methanol, ethanol and ethylene glycol mixtures (10–20 % v/v) over a temperature range (300–320 K) by surface tension and conductivity methods. Critical micelle concentration, extent of counter ion binding (α), interfacial property (Amin, ζmax, π‐CMC, ) and thermodynamic parameters (, , ) for the micellization process are reported and discussed.

Facile Evaluation of Thermodynamic Parameters for Reverse Thermochromism of Indolinobenzospiropyran-6-carboxylates in Aqueous Binary Solvents

E-mail: keum@korea.ac.kr Received March 7, 2012, Accepted May 16, 2012The position of the thermodynamic equilibrium for reverse thermochromic spiropyran 6-carboxylates (SP-COOHs) was easily determined in aqueous binary mixtures, such as water-methanol, water-acetonitrile andwater-dimethyl sulfoxide. The existence of more than one type of interconvertible species of the ring-openedform of SP-COOH in aqueous binary solvents enables us to evaluate the molar extinction coefficients of thering-opened species of SP-COOH and to obtain the thermodynamic parameters. Key Words : Reverse thermochromism, Aqueous binary solvent mixtures, Prototropic equilibrium, E

Correlation of the Rates of Solvolyses of 4-Methylthiophene-2-carbonyl Chloride Using the Extended Grunwald-Winstein Equation

methanol binary mixtures. Comparison of the specific rates of solvolyses of 1 with those for p-methoxybenzoyl chloride (2) in terms of linear free energy relationships (LFER) are helpful in mechanistic considerations, as is also treatment in terms of the extended Grunwald-Winstein equation. It is proposed that the solvolyses of 1 in binary aqueous solvent mixtures proceed through an SN1 and/or ionization (I) pathway rather than through an associative SN2 and/or addition-elimination (A-E) pathway.

Luminescence study on the solvation of Cm(III) in binary aqueous solvent mixtures

AbstractThe preferential solvation of Cm(III) in binary aqueous mixtures of MeOH,tBuOH, DMSO, MeCN and acetone is studied at varied solvent composition. Solvation is investigated by time-resolved laser fluorescence spectroscopy and emission spectra and fluorescence lifetime data are obtained. At high mole fractions of organic solvent, preferential solvation of Cm(III) increases in the order: Me2CO <tBuOH ≈ MeOH < MeCN < H2O < DMSO. Thermodynamic data are derived from the spectroscopic results showing small positive standard Gibbs energies for the transfer of Cm(III) into the various solvent mixtures except for DMSO mixtures where negative values are found. The spectroscopically obtained enthalpies of transfer are fitted to a solvation model using the model parameters Δ Δ Hº12and (αn+βN)º, rendering valuable information on the interaction of Cm(III) with the solvent molecules. Cm(III)-solvent interaction increases in the order:tBuOH < MeCN < MeOH < DMSO.

Mathematical Representation of Fluorescence Intensity of Probes in Aqueous Binary Solvent Mixtures

Fluorescence intensities of propranolol and atenolol in binary solvent mixtures at various temperatures are measured and mathematical models are proposed to represent the fluorescence intensity data. The results showed that the proposed models are able to correlate/predict the data with reasonable error. The fluorescence intensity of pyridoxal HCl in binary solvents at 25 °C is also determined and represented by the proposed model as an additional test probe.