Solubility In Ethyl Acetate Research Articles

Prediction of cosolvent effect on solvation free energies and analysis of intermolecular forces of tizanidine hydrochloride in ethyl acetate + methanol / ethanol mixtures

The solubility of small molecule drug in solvents can be dramatically affected by addition of a suitable cosolvent, which makes the screening of the best-suited cosolvent an important task for the purification and preparation. The present work aims to improve the fundamental understanding of tizanidine hydrochloride (TIZ HC) solvation by cosolvent. Solubility experimental data from TIZ HCl in mixtures of ethyl acetate + alcohols were obtained at different temperatures with the method of isothermal equilibrium. In the system of ethyl acetate + methanol, the solubility data increased firstly and then decreased with an increase in ethyl acetate content, however, the strictly monotonic decreasing of solubility in ethyl acetate + ethanol mixtures was observed. The solubility correlation fitting was performed with the Jouyban-Acree model and CNIBS/R-K model. The solvent effect analysis indicates that the hydrogen bond acidity, the polarity / polarizability and the cohesive forces of the solvent have a greater influence on the solubility, which was further validated by the local quantitative molecular surface analysis results of electrostatic potential (ESP). The dissolution process of TIZ HCl in systems with different solvent compositions was analyzed in the form of preferential solvation parameters, it was found that methanol is the preferred solvent in the solvation shell of TIZ HCl in methanol-rich and ethyl acetate-rich mixtures but the ethanol is preferred in intermediate compositions and ethyl acetate-rich mixtures. Moreover, the types of intermolecular solute–solvent interactions were discussed on the basis of the structural characteristics of TIZ HCl. The solvation free energy is a key parameter describing solvent effects, which is extremely important for understanding solution chemistry. For this part, with the aid of density functional theory (DFT) and molecular dynamics (MD) simulations, it was found that the cosolvent effect is consistent with the prediction trend of solvation free energy of TIZ HCl in each systems. The effect of the cavity formed by the solvent molecules and dipole moment of solute was calculated accordingly by the solvation model based on density (SMD) for explaining the former behavior.

A comparison of the solvent liquefaction of lignin in ethanol and 1,4-butanediol

This study compares the depolymerization of soda lignin via solvent liquefaction in ethanol and 1,4-butanediol (BD). The commercial soda lignin was fractionated based on solubility in ethyl acetate and methanol providing three fractions (F1 – soluble in ethyl acetate and methanol, F2 - insoluble in ethyl acetate and soluble methanol, F3 – insoluble in either) which varied mostly based on their molecular weight ranges with the average molecular weight following the order F1 <F2 <F3. The whole lignin and its factions were subjected to solvent liquefaction in ethanol and BD at 300 °C, to test the use of a high boiling solvent (BD) to reduce the required reaction pressure. Use of neat BD resulted in a bio-oil similar to that produced via pyrolysis of lignin, and which had a higher average molecular weight and fewer remaining methoxy groups than those produced in ethanol. This may be attributable to differences in lignin solubility in the two solvents. The addition of formic acid was also examined in each solvent. Use of formic acid in combination with BD promoted crosslinking resulting in bio-oil with higher molecular weight. The use of lignin bio-oils from each solvent were compared as feedstocks for the production of bio-pitch, finding that those produced in BD provided a coking value closer to that required for many applications.

The solid-liquid equilibrium behavior of 2,7-dihydroxynaphthalene in eleven organic solvents: Thermodynamic analysis and molecular simulation understanding

2,7-Dihydroxynaphthalene (DHN), one of the most important aromatic compounds, was selected to study its differences of solubility in eleven mono organic solvents from 283.15 to 323.15 K through the gravimetric experiments and theoretical simulations. It was found that the DHN has the highest solubility in isopropanol among alcohol solvents, while in non-alcohol solvents, it has the highest solubility in ethyl acetate. Furthermore, four well-known thermodynamic equations were utilized for correlating and modeling the experimental solubility data. All the value of ARD is very small, no more than 2%, proving that these models are applicable and effective. In addition, the result of mixing thermodynamic functions underlined that the dissolution process is spontaneous and exhibits an exothermic mechanism. We also did the crystal structure stacking pattern, Hirshfeld surface, and the molecular electrostatic potential surface (MEPs) analysis to evaluate the molecular interactions of the DHN and predict the possible hydrogen bond interaction sites. Further, we did molecular dynamic (MD) simulations to illustrate and explain the diverse solubility of DHN in selected solvents from molecular perspective. Solvation free energy and radial distribution function (RDF) analysis results indicate that the molecular interactions are the decisive factors that determine the mixing process of DHN, which successfully explained the reason for the diversity in dissolution behavior. We believe that all the results in this article can provide a reference for the further purification and process development of DHN.

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.

Removal of trace amount impurities in glycolytic monomer of polyethylene terephthalate by recrystallization

Chemical recycling is a promising way to achieve the closed-loop recycling for polyethylene terephthalate (PET). During this process, the post-consumer PET is depolymerized into bis(2-hydroxyethyl) terephthalate (BHET) through glycolysis and BHET can be polymerized again to produce recycled PET (rPET). However, since the applications of rPET is greatly limited to the color, recycling of PET fibers is challenged by the residual of colored impurities. In this study, a modified recrystallization process using ethyl acetate (EA) as the solvent was employed for the removal of colored impurities from the BHET. The process showed a decoloring rate of over 97.5% for the model colored impurities, performing better than the reported physical adsorption processes. Since almost no disperse dye was precipitated during the nucleation and crystal growth process due to the high solubility in EA, only a small amount of colored impurities adsorbed on the surface of crystals, leading to an excellent decolorization performance and post-consumer EA could be easily recycled through evaporation followed by condensation. Besides the model colored BHET, raw BHET obtained from the depolymerization of dark PET fibers was also purified by this modified recrystallization. By applying a composite purification strategy combining EA-based recrystallization and activated carbon adsorption, the whiteness (L*) of BHET greatly increased from around 65 to over 95 (L*=100 for pure white) and the whiteness of rPET produced from purified BHET (L*=86.21) was greatly improved compared with that from raw BHET (L*=44.01), showing the possibility of achieving the closed-loop recycling of dark PET fibers.

The Effect of Functional Groups on the Phase Behavior of Carbon Dioxide Binaries and Their Role in CCS.

In recent years we have focused our efforts on investigating various binary mixtures containing carbon dioxide to find the best candidate for CO2 capture and, therefore, for applications in the field of CCS and CCUS technologies. Continuing this project, the present study investigates the phase behavior of three binary systems containing carbon dioxide and different oxygenated compounds. Two thermodynamic models are examined for their ability to predict the phase behavior of these systems. The selected models are the well-known Peng–Robinson (PR) equation of state and the General Equation of State (GEOS), which is a generalization for all cubic equations of state with two, three, and four parameters, coupled with classical van der Waals mixing rules (two-parameter conventional mixing rule, 2PCMR). The carbon dioxide + ethyl acetate, carbon dioxide + 1,4-dioxane, and carbon dioxide + 1,2-dimethoxyethane binary systems were analyzed based on GEOS and PR equation of state models. The modeling approach is entirely predictive. Previously, it was proved that this approach was successful for members of the same homologous series. Unique sets of binary interaction parameters for each equation of state, determined for the carbon dioxide + 2-butanol binary model system, based on k12–l12 method, were used to examine the three systems. It was shown that the models predict that CO2 solubility in the three substances increases globally in the order 1,4-dioxane, 1,2-dimethoxyethane, and ethyl acetate. CO2 solubility in 1,2-dimethoxyethane, 1.4-dioxane, and ethyl acetate reduces with increasing temperature for the same pressure, and increases with lowering temperature for the same pressure, indicating a physical dissolving process of CO2 in all three substances. However, CO2 solubility for the carbon dioxide + ether systems (1,4-dioxane, 1,2-dimethoxyethane) is better at low temperatures and pressures, and decreases with increasing pressures, leading to higher critical points for the mixtures. By contrast, the solubility of ethyl acetate in carbon dioxide is less dependent on temperatures and pressures, and the mixture has lower pressures critical points. In other words, the ethers offer better solubilization at low pressures; however, the ester has better overall miscibility in terms of lower critical pressures. Among the binary systems investigated, the 1,2-dimethoxyethane is the best solvent for CO2 absorption.

Solubility measurement and thermodynamic properties of sulfamonomethoxine in pure solvents and sulfamonomethoxine hydrate in acetone + water binary solvent at different temperature

The experimental solubility of sulfamonomethoxine in six different pure solvents (methanol, ethanol, 1-propanol, l-butanol, ethyl acetate and acetone) and sulfamonomethoxine hydrate in acetone + water mixture solvents were measured from 294.55 K to 362.15 K by a laser dynamic method under atmospheric pressure. Experimental results indicated that the solubility data of sulfamonomethoxine increased with temperature increasing in pure solvents and the solubility followed this order: acetone > methanol > ethanol > ethyl acetate > 1-propanol > 1-butanol, but solubility in ethyl acetate was not affected significantly by temperature. In acetone + water mixture solvent, the solubility of sulfamonomethoxine hydrate increased with temperature and the acetone concentration. Thermodynamic equations were applied to correlate solubility data of sulfamonomethoxine and sulfamonomethoxine hydrate including the modified Apelblat equation, λh equation, Wilson equation, NRTL equation, Van’t Hoff-Jouyban Acree equation and modified Apel-Jouyban-Acree equation. Furthermore, thermodynamic properties ΔGd, ΔHd and ΔSd of sulfamonomethoxine and sulfamonomethoxine hydrate in dissolution process were obtained and discussed with the modified Van’t Hoff equation and Gibbs equation.

Recovery and determination of cholesterol-lowering compounds from Olea europaea seeds employing pressurized liquid extraction and gas chromatography-mass spectrometry

Our previous work demonstrated the presence of compounds with hypocholesterolemic capacity in olive seeds. These compounds were extracted using CO2-expanded ethyl acetate and identified as tyrosol, hydroxytyrosol, and β-sitosterol using GC–MS. This work describes the extraction of these compounds from different olive seeds using pressurized ethyl acetate. Their solubility in ethyl acetate at temperatures ranging from 40–200 °C was theoretically predicted by Hansen solubility parameters. The content of these compounds was estimated by GC–MS, as well as, the reduction of the micellar cholesterol solubility (RMCS) capacity of extracts enabling to establish the optimum extraction temperature at 100 °C. A GC–MS method was developed and validated in terms of its analytical characteristics for a sensitive determination and quantification of tyrosol, hydroxytyrosol, and β-sitosterol in different olive seeds. Within varieties, Manzanilla seeds presented the highest concentration of tyrosol, hydroxytyrosol, and the lowest concentration of β-sitosterol, as well as the highest RMCS capacity.

Measurement, correlation and modelling of high-pressure phase equilibrium of PLGA solutions in CO2

Poly (lactic-co-glycolic acid) (PLGA) is a copolymer used as drug carrier in controlled release systems as microparticles or scaffolds. Foamed structures are industrially obtained by injecting gas at temperatures above the melting point of the polymer that may promote PLGA degradation. High temperatures are avoidable in this foaming process if a polymer dissolution is used. Ethyl acetate and ethyl lactate are suitable solvents for the PLGA since the polymer is easily solubilised, is environmentally friendly and highly recommendable for medical purposes. CO2 is proposed as antisolvent because is environmentally benign, non-flammable and non-toxic. The knowledge of the solubility of these solvents in CO2 is essential to find the most appropriate working conditions for the foaming process. In this work, the solubility of ethyl acetate and ethyl lactate in CO2 in the presence of different initial concentrations of PLGA has been studied at 298.15 K and at pressures up to 150 bar using a high-pressure variable volume view cell.

Solubility determination and thermodynamic functions of 2-chlorophenothiazine in nine organic solvents from T = 283.15 K to T = 318.15 K and mixing properties of solutions

Solubility of 2-chlorophenothiazine in nine organic solvents including methanol, ethanol, isopropanol, n-propanol, ethyl acetate, acetone, acetonitrile, 1-butanol and 2-butanone was determined experimentally by the isothermal saturation method over a temperature range from T=283.15K to T=318.15K under 101.1kPa. Within the studied temperature range, the mole fraction solubility of 2-chlorophenothiazine in these solvents increased with a rise of temperature. Except for the solvent of acetonitrile, they follow the order of 2-butanone>(acetone, ethyl acetate)>methanol>ethanol>n-propanol>isopropanol>1-butanol. The solubility in ethyl acetate and acetonitrile had the strongest positive dependency on temperature. The determined solubility of 2-chlorophenothiazine in the solvents studied was correlated by using the modified Apelblat equation, Buchowski–Ksiazaczak λh equation, Wilson model and NRTL model. The maximum values of root-mean-square deviation (RMSD) and relative average deviation (RAD) were 2.77×10−4 and 0.59%, respectively. In general, the four thermodynamic models were all satisfactory for describing the solubility of 2-chlorophenothiazine, and the Wilson model can correlate the experimental solubility best based on the result of Akaike Information Criterion analysis. Furthermore, the mixing properties including the mixing Gibbs energy, mixing enthalpy, mixing entropy, activity coefficient at infinitesimal concentration (γ1∞) and reduced excess enthalpy (H1E,∞) were computed. The findings will be very useful in optimizing the purification process of 2-chlorophenothiazine.

Preparation of Porous Silicone Resin Sheet with Phase Inversion in Parallel with Non Solvent Induced Phase Separation and Application to Hollow Particle Formation

We have tried to prepare the porous silicone resin sheet with the phase inversion method in parallel with the non solvent induced phase separation method. In the experiment, ethyl acetate and water were adopted as a good solvent and a poor solvent for silicone resin, respectively and ethyl alcohol as an amphiphilic solvent was used to increase the solubility of ethyl acetate in water and decrease the interfacial tension by mass transfer from water to ethyl acetate. The concentration of silicone resin in ethyl acetate and the oil soluble surfactant species were changed. Increasing the concentration of silicone resin could depress coalescence between the water droplets in the (W/O) dispersion and increase the porosity and pore number density of silicone resin sheet. Span 80 among the oil soluble surfactant species made the porosity and pore number density larger. The effect of physical proparties of liquids concerned on the porosity and pore number density was discussed on the basis of dispersing behavior of liquid droplets in the liquid-liquid dispersion. The hollow silicone resin particles could be prepared by applying the preparation method presented here.

Recovery of acetic acid from dilute aqueous solutions using catalytic dehydrative esterification with ethanol

We have developed a direct esterification of aqueous acetic acid with ethanol (molar ratio=1:1) catalyzed by polystyrene-supported or homogeneous sulfonic acids toward the recovery of acetic acid from wastewater in chemical plants. The equilibrium yield was significantly increased by the addition of toluene, which had a high ability to extract ethyl acetate from the aqueous phase. It was shown that low-loading and alkylated polystyrene-supported sulfonic acid efficiently accelerated the reaction. These results suggest that the construction of hydrophobic reaction environments in water was critical in improving the chemical yield. Addition of inorganic salts was also effective for the reaction under not only biphasic conditions (toluene–water) but also toluene-free conditions, because the mutual solubility of ethyl acetate and water was suppressed by the salting-out effect. Among the tested salts, CaCl2 was found to be the most suitable for this reaction system.

Determination and Correlation of Solubility Data and Dissolution Thermodynamic Data of l-Lactide in Different Pure Solvents

The solubility of l-lactide in pure ethanol, ethyl acetate, acetone, isopropanol, methanol, and methylbenzene from (278.15 to 338.15) K was determined by dynamic method with a laser monitoring technique. It was found that l-lactide is sparingly soluble in ethanol, isopropanol, methanol, and methylbenzene while it has high solubility in ethyl acetate and acetone. The solubility data of l-lactide in different solvents increase with the increasing of temperature. The measured solubility data of l-lactide were correlated by using the modified Apelblat, Wilson, nonrandom two-liquid (NRTL), and universal quasichemical (UNIQUAC) models, respectively. It was found that NRTL equations give the best correlation results for most solvents except for ethanol. The dissolution enthalpy, entropy of l-lactide, and the free Gibbs energy change of l-lactide in these solvents were obtained by using the van’t Hoff equation. From solubility data, melting point, fusion enthalpy, and entropy of l-lactide and d-lactide, it was pr...

Solubility of ethyl acetate in diluted aqueous solutions of fructose

ABSTRACTEthyl acetate solubility data were experimentally determined in diluted solutions containing fructose. Concentrations results for the organic solute in water–fructose solution at temperatures between 278.2 and 293.2 K are new. However, it was possible to compare and discuss the solubility behaviour by regarding fructose concentrations and temperature effects. The results confirmed that the solubility of ethyl acetate decreases as the fructose concentration increases. Also, some changes could be observed in the solubility of the acetate when there were variations of temperature. Ethyl acetate demonstrated the same behaviour in solutions of fructose as is observed in pure water; the solubility decreased with the increasing temperature. Copyright © 2012 John Wiley &amp; Sons, Ltd.

Solubility of drugs in ethyl acetate-ethanol mixtures at various temperatures

A generally trained version of the Jouyban-Acree model is presented employing 51 solubility data sets of 19 drugs in ethyl acetate + ethanol mixtures at various temperatures. Using this model, the solubilities of a drug in ethyl acetate and ethanol are required to predict the solubility in ethyl acetate + ethanol mixtures. The overall percentage deviation (%D) for the correlated data was 10.9%.

Enhancement of Solubility and Mass Transfer Coefficient Through Hydrotropy

This paper presents a comprehensive study on the effect of hydrotropes on the solubil- ity and mass transfer coefficient of ethyl acetate in water. The solubility and mass transfer studies were performed using hydrotropes such as tri-sodium citrate, urea, sodium benzoate, and sodium salicylate under a wide range of concentrations (0 to 3.0 mol/L) and system temperatures (303 to 333 K). The performance of the hydrotropes was measured in terms of the Setschenow constant (Ks). It was found that the solubility of ethyl acetate increases with increase in hydrotrope con- centration and also with system temperature. A Minimum Hydrotrope Concentration (MHC) in the aqueous phase was found required to initiate significant solubilization of ethyl acetate. Con- sequent to the increase in solubilization of ethyl acetate, the mass transfer coefficient was also found to increase with increase in hydrotrope concentration. All hydrotropes used in this work showed an enhancement in the solubility and mass transfer coefficient to different degrees. The maximum enhancement factor, which is the ratio of the value in presence and absence of a hy- drotrope, has been determined for both solubility and mass transfer coefficient. These character- istics would be much useful in increasing the rate of output of the desired product made from ethyl acetate. In addition, the separation of ethyl acetate from any liquid mixture which is found to be difficult can be carried out effectively using this technique.

Solubility of Atractylenolide III in Hexane, Ethyl Acetate, Diethyl Ether, and Ethanol from (283.2 to 323.2) K

The solubility of atractylenolide III in hexane, ethyl acetate, diethyl ether, and ethanol solutions was measured over the temperature range of (283.2 to 323.2) K. The solubility of atractylenolide III in hexane is the smallest, and the solubility in ethyl acetate is the largest. The solubility data were correlated with the Apelblat equation.

Oral Small Peptides Render HDL Antiinflammatory in Mice and Monkeys and Reduce Atherosclerosis in ApoE Null Mice

A peptide containing only 4 amino acid residues (KRES) that is too small to form an amphipathic helix, reduced lipoprotein lipid hydroperoxides (LOOH), increased paraoxonase activity, increased plasma HDL-cholesterol levels, rendered HDL antiinflammatory, and reduced atherosclerosis in apoE null mice. KRES was orally effective when synthesized from either L or D-amino acids suggesting that peptide-protein interactions were not required. Remarkably, changing the order of 2 amino acids (from KRES to KERS) resulted in the loss of all biologic activity. Solubility in ethyl acetate and interaction with lipids, as determined by differential scanning calorimetry, indicated significant differences between KRES and KERS. Negative stain electron microscopy showed that KRES formed organized peptide-lipid structures whereas KERS did not. Another tetrapeptide FREL shared many of the physical-chemical properties of KRES and was biologically active in mice and monkeys when synthesized from either L- or D-amino acids. After oral administration KRES and FREL were found associated with HDL whereas KERS was not. We conclude that the ability of peptides to interact with lipids, remove LOOH and activate antioxidant enzymes associated with HDL determines their antiinflammatory and antiatherogenic properties regardless of their ability to form amphipathic helixes.

Extraction of compactin (ML-236B): equilibrium distribution in water–ethyl acetate system

Equilibrium partitioning of compactin in water–ethyl acetate system was measured at 298 K. The extraction pH showed strong influence on the partitioning ratio: the partitioning ratio decreased with pH. The dissociation constant and distribution coefficients of compactin were determined by treating equilibrium data with numerical approach. Distribution coefficient of compactin in water–ethyl acetate system was treated as a variable and a function of compactin concentration in aqueous solution. The estimated values of dissociation constant and distribution coefficient were compared with the values of water–toluene system. The mutual solubility of ethyl acetate and water was also measured at the same temperature when compactin concentration was varied. The investigation found that increasing compactin concentration increased mutual solubility of water in organic phase as well as of ethyl acetate in aqueous phase. The increasing mutual solubility caused the change of solute composition in aqueous solution and affect equilibrium distribution of compactin.

Solubility of Nitro and Bromo Derivatives of Octaphenyltetraazaporphine

The equilibrium solubility in benzene, tetrachloromethane, and ethyl acetate of octaphenyltetraazaporphine containing electron-acceptor (NO2) and electron-donor (Br) substituents in the phenyl rings was determined. In these solvents, p-substitution in aromatic rings with bromine considerably (by an order of magnitude and more) increases the solubility of porphyrins, whereas p-substitution with the NO2 group does not noticeably affect the solubility of the macrocycle in nonpolar solvents but increases the solubility in ethyl acetate by a factor of more than 200.