Binary Mixtures Of Organic Solvents Research Articles

Experimental and Theoretical Insights into the Intermolecular Interactions in Saturated Systems of Dapsone in Conventional and Deep Eutectic Solvents.

Solubility is not only a crucial physicochemical property for laboratory practice but also provides valuable insight into the mechanism of saturated system organization, as a measure of the interplay between various intermolecular interactions. The importance of these data cannot be overstated, particularly when dealing with active pharmaceutical ingredients (APIs), such as dapsone. It is a commonly used anti-inflammatory and antimicrobial agent. However, its low solubility hampers its efficient applications. In this project, deep eutectic solvents (DESs) were used as solubilizing agents for dapsone as an alternative to traditional solvents. DESs were composed of choline chloride and one of six polyols. Additionally, water-DES mixtures were studied as a type of ternary solvents. The solubility of dapsone in these systems was determined spectrophotometrically. This study also analyzed the intermolecular interactions, not only in the studied eutectic systems, but also in a wide range of systems found in the literature, determined using the COSMO-RS framework. The intermolecular interactions were quantified as affinity values, which correspond to the Gibbs free energy of pair formation of dapsone molecules with constituents of regular solvents and choline chloride-based deep eutectic solvents. The patterns of solute-solute, solute-solvent, and solvent-solvent interactions that affect solubility were recognized using Orange data mining software (version 3.36.2). Finally, the computed affinity values were used to provide useful descriptors for machine learning purposes. The impact of intermolecular interactions on dapsone solubility in neat solvents, binary organic solvent mixtures, and deep eutectic solvents was analyzed and highlighted, underscoring the crucial role of dapsone self-association and providing valuable insights into complex solubility phenomena. Also the importance of solvent-solvent diversity was highlighted as a factor determining dapsone solubility. The Non-Linear Support Vector Regression (NuSVR) model, in conjunction with unique molecular descriptors, revealed exceptional predictive accuracy. Overall, this study underscores the potency of computed molecular characteristics and machine learning models in unraveling complex molecular interactions, thereby advancing our understanding of solubility phenomena within the scientific community.

5-Amino-2-aryl-2H-1,2,3-triazole-4-carboxamides: Unique AIEE-gens and selective Hg2+ fluorosensors

A series of fluorescent sensors based on small molecule were designed and fully characterised, demonstrating AIEE effect and revealing an outstanding ability to selectively detect Hg2+ ions.The structural and electronic properties were studied through quantum chemical calculations at (Time-Dependent) Density Functional Theory ((TD)-DFT) level. Carboxamides of 2-Aryl-1,2,3-Triazoles (CATs) showed significant differences in their photophysical properties depending on the structure of the substituent at amino function on the C5-atom in the heterocycle. When the tert-cycloalkylamino group (pyrrolidine, piperidine, azepane) was attached, the triazoles exhibited highly intensive blue fluorescence, with quantum yields (QYs) up to 95 % and lifetime up to 6.9 ns in different solvents, whereas the QYs of congeners bearing secondary alkylaminogroups (viz., NHMe, NHC6H11-cyclo) indicate low QYs (1–10 %). Nevertheless, all types of the obtained fluorophores demonstrated excellent AIEE effect and formed fluorescent nanoparticles in a binary mixtures of organic solvents and water. The introduction of the carboxamide function enhances the sensing properties of 2-aryl-1,2,3-triazoles, providing a selective fluorescence quenching reaction in the presence of Hg2+. The fluorescence intensity of the CATs declines with the addition of 1.0 eq. of Hg2+ into DMSO-water (v/v, 1:9). The other cations used did not induce any appreciable changes in fluorescence intensity. The CATs form a complex with Hg2+ with highly specific detection for Hg2+ over other competitive metal ions: the detection limits were determined to be 0.23 and 0.15 μM for the CATs 1b and 2c. The reverse effect was registered with the addition of ethylene diamine sodium salt; meanwhile, the CATs demonstrated more effective coordination with Hg2+ in comparison with cysteine. This last finding, as well as the ability to detect Hg2+, is very valuable for application within biology and medicine.

Determination of Polycyclic Aromatic Hydrocarbons in Agricultural Products

The procedure for the determination of polycyclic aromatic hydrocarbons (PAH) in agricultural products on the example of five crops (rapeseed, sunflower, flax, corn, soybeans) by gas chromatography mass spectrometry (GC-MS) was developed. It was showed the advantage of using binary mixtures of organic solvents "hexanedichloromethane" for PAH extraction. The time of Soxhlet extraction is from 6 to 8 hours at optimized conditions. The fractionation and purification of extracts by column chromatography on deactivated alumina was optimized. The article presents the optimization of sample injection in the programmed temperature vaporization (PTV) mode, parameters of gas chromatographic separation and mass spectrometric detection in determining 16 priority PAH in agricultural products. The recoveries, correctness and accuracy of the proposed method were checked by “spikes” with concentrations 0.5, 1.0, 2.5, 5.0 μg kg-1. The linearity of the method was determined by calibration curves obtained for three measurements of calibration solutions with concentrations of 0.5-100 ng mL-1. The effectiveness of the proposed combination of sample preparation and analysis by PTV-GC-MS was studied for linearity, accuracy, matrix effects and reproducibility. The method was validated by linearity, accuracy, matrix effect and reproducibility.

Organic solvent mixture separation during reverse osmosis and nanofiltration by a perfluorodioxole copolymer membrane

Highly selective separation of one organic solvent from its mixture with another organic solvent by reverse osmosis will be very useful. Using a 1.67 μm thick film of a particular variety of a glassy amorphous copolymer, perfluoro-2,2-dimethyl-1,3-dioxole copolymerized with tetrafluoroethylene, (PDD-TFE), supported on an e-PTFE support, organic solvent reverse osmosis (OSRO) separations of a number of types of binary organic solvent mixtures were studied. A few studies employed a 0.6 μm thick film of the same copolymer variety designated CMS-7. The feed pressures were varied between 1000 and 5000 kPa; most of the data involved 2500–3500 kPa. Different types of solvent mixtures were studied (similar classes mentioned together): ethanol-NMP, ethanol-dimethylsulfoxide (DMSO); methanol-DMSO, methanol-NMP; toluene-methanol, toluene-N-Methyl-2-pyrrolidone (NMP), toluene-dimethylformamide (DMF); heptane-dodecane; heptane-ethanol. In quite a few cases, a pure solvent was obtained as permeate; the permeate flux could be as much as 3.5 L/m2-hr depending on the feed composition and pressure. Since this behavior is unusual in reverse osmosis, mixture sorption studies were implemented. Mixture sorption data of various mixtures in the copolymer show exclusive sorption by the species showing up as the pure permeate under certain conditions. These and other observed OSRO permeation rate and sorption behavior in the perfluoro-copolymers explain the basis for such extraordinary selectivity for quite a few systems.To illustrate OSRO-facilitated solvent-exchange in organic solvent nanofiltration, studies were carried out also to retain the dye Oil Blue N using the following binary solvent mixtures: toluene-NMP; methanol-NMP. These and other potential applications of highly selective OSRO have been discussed.

Heterogeneous Biocatalytic Processes of the Low-Temperature Synthesis of Esters: Selection of Organic Solvent

Processes of the low-temperature enzymatic synthesis of esters in nonaqueous media of organic solvents with participation of heterogeneous biocatalysts synthesized by the adsorption immobilization of a recombinant lipase from Thermomyces lanuginosus (Pichia pastoris producer) on macroporous carbon aerogel were investigated. The esterification reaction was conducted using individual organic solvents of different polarity, such as nonpolar ones (lоgP > 2.5) – hexadecane, hexane and toluene, and polar solvents (lоgP < 1) – diethyl ether, tert-butanol and acetone, as well as their binary mixtures of different composition, for example, a mixture of hexane with diethyl ether having the composition 1 : (1/5÷3, vol. fr.). The effect of the solvent and co-solvent nature on the properties of synthesized biocatalysts, namely the enzymatic activity and operational stability, was studied in the batch esterification of heptanoic acid (C7:0) by alcohols, particularly the polar substrates – ethanol and n-butanol, or nonpolar alcohols – n-octanol and n-hexadecanol. Activity of the synthesized biocatalysts was found to depend to a great extent on polarity of both the solvents used in the reaction and the alcohol substrates. The maximum activity of 400 EA·g–1 was observed in a medium of nonpolar and nonviscous hexane (lоgP = 2.9), whereas the minimum activity of 4 EA·g–1 – in acetone (lоgP = 0.4); esterification of heptanoic acid in the presence of tert-butanol (lоgP = 0.6) virtually did not proceed. The activity of biocatalysts was shown to depend nonmonotonically on the lоgP value of individual solvent. In the binary mixtures of organic solvents, such as hexane/diethyl ether, biocatalytic activity linearly increased with an increase in lоgPmixture; in addition, biocatalysts exhibited the maximum operational stability.

Behavior of fullerene C70 in binary organic solvent mixtures as studied using UV-Vis spectra and dynamic light scattering

In this paper, the formation of colloidal species of fullerene C70 in organic solvents was studied. The examining of the UV-visible spectra was accompanied by particle size analysis using dynamic light scattering, DLS. Stock solutions of C70 in non-polar toluene and n-hexane were diluted with polar solvents acetonitrile and methanol. The appearance of colloidal species with a size within the range of ≈50–500 nm is accompanied by alterations of the absorption spectra. In the toluene–acetonitrile and toluene–methanol binary mixed solvents at 25 oC, the absorption spectra of C70 (5×10–6 M) tend to retain the features of the spectrum in neat aromatic solvent even if the C70 molecules are gathered into colloidal aggregates. Earlier such phenomenon was observed for C60 in benzene–acetonitrile and toluene–methanol solvent systems. This gives support to the idea of rather stable primary solvate shells formed by aromatic molecules around the fullerene molecules. The behavior of C70 in toluene mixtures with methanol was compared with the earlier reported results from this laboratory for the C60 fullerene in the same solvent system. The study of n-hexane–methanol mixtures was performed at elevated temperature because of limited miscibility of these solvents at 25 oC. Accordingly, the C70–toluene–methanol system was also examined at 40 oC. A small but distinctly noticeable difference was revealed. Whereas in the case of the last-named system, the absorption spectrum typical for molecular form of C70 is still observable when colloidal species are already present in the solution, the turning-point between molecules and colloids as determined by both UV-visible spectra and DLS coincides for the n-hexane–methanol binary mixed solvent. Hence, the solvation shells formed by the aliphatic solvent around C70 are less stable as compared with those formed by toluene. Finally, the absorption spectra of C70 in the mixed solvents toluene–n-hexane were analyzed. These data give some support to the assumption of preferable solvation of the C70 molecules by the aromatic co-solvent.

Dissolution of Asphaltene in Binary Mixtures of Organic Solvents and Model Maltenes: Unambiguous Evidence for Asphaltene Preferential Solvation and Relevance to Assessing the Efficiency of Additives for Asphaltene Stabilization

Asphaltenes (Asps) are operationally defined as the toluene-soluble but n-pentane- or n-heptane-insoluble fractions, e.g., of crude oils. Therefore, there is intense interest in determining the concentration of n-heptane required to precipitate Asps from their solutions in particular media (solvents, solvent mixtures, and maltenes). Here, we report on the dependence of Asp dissolution in binary mixtures of n-heptane (solvent 1, S1)/organic solvent (solvent 2, S2) over the entire mole fraction range of S2, χS2, and in few selected maltene models (n-heptane + S2 + benzothiazole + n-octyl-1-napthoate). The S2 employed were benzonitrile, cyclohexanone, ethyl benzoate, 1-methylnaphthalene, tetrahydropyran, and toluene. For all S2 and model maltenes, the dependence of wt % dissolved Asp (determined by mass and UV/vis absorbance) on χS2 was nonlinear. We attribute this nonlinear, i.e., nonideal dissolution behavior to “preferential solvation” of the Asp by a component(s) of the medium (binary solvent mixtures an...

Viscosity Calculation for Binary Mixtures of Organic Solvents Based on Modified Eyring-Modified Two-Suffix-Margules (MTSM) Model

Recently, the Eyring-modified two-suffix-margules (MTSM) model for calculating viscosities of ionic liquid mixtures was proposed by Atashrouz et al. (Atashrouz, S.; Zarghampour, M.; Abdolrahimi, S.; Pazuki, G.; Nasernejad, B. J. Chem. Eng. Data 2014, 59, 3691–3704). In this work, a simple modification of the Eyring-MTSM model was presented and applied to the viscosity calculation of binary mixtures of organic solvents. The accuracy of the modified model was assessed by comparing experimental viscosities at atmospheric pressure for 182 binary mixtures, and the overall average relative deviation (ARD) between the calculated results and literatures is 0.61%. In addition, the relationship between the parameters in the model and the boiling point of mixtures was established. Experimental viscosities containing 478 binary mixtures were used to evaluate the reliability of the relations, and good agreement was obtained between experimental and calculated values with ARD of 1.62%. Furthermore, the modified Eyring-...

Effect of Binary Organic Solvent Mixtures on Lipase-Catalyzed Regioselective Acylation of 6-Azauridine with Various Structural Vinyl Esters

Effect of Binary Organic Solvent Mixtures on Lipase-Catalyzed Regioselective Acylation of 6-Azauridine with Various Structural Vinyl Esters

IUPAC-NIST Solubility Data Series. 98. Solubility of Polycyclic Aromatic Hydrocarbons in Pure and Organic Solvent Mixtures: Revised and Updated. Part 1. Binary Solvent Mixtures

This work updates Vols. 54, 58, and 59 in the IUPAC Solubility Data Series and presents solubility data for polycyclic aromatic hydrocarbon solutes dissolved in binary organic solvent mixtures. Published solubility data for anthracene, naphthalene, phenanthrene, phenothiazine, and pyrene that appeared in the primary literature between 1995 to the end of 2011 are compiled and critically evaluated. Experimental solubility data for 360 different solute-binary solvent systems are included in the volume. Solubility data published prior to 1995 were contained in three earlier volumes (Vols. 54, 58, and 59) and are not repeated in this volume.

Toluidine Red Nanoparticles and Their Application in Electrophoretic Display

Toluidine red pigment nanoparticles were prepared by anti-solvent precipitation and were modified by different surfactants aimed to use as the electrophoretic particles. Experimental conditions have been discussed in this paper including the effect of different surfactants, the concentration of surfactants, the reaction temperature and the agitation rate. Binary mixtures of organic solvents have been selected as suspending medium to improve the dispersion stability of the prepared particles. The produced nanoparticles have been characterized by scanning electron microscopy, laser diffractometer and electrophoretic display measuring system. The results indicated that the prepared particles modified by alkyl hydroxy oximido acid are in the average size of 80 nm with a spherical shape within narrow particle size distribution. The optimum content of AHOA, reaction temperature agitation rate are 3.75 g/L, 20 degrees C and 900 rpm, respectively. The prepared nanoparticles exhibit superior electrophoretic properties. Finally, the sedimentation of prepared particles dispersed into binary mixtures of tetrachloroethylene (C2Cl4) and cyclohexane is 4.76% for 2 months.

On the microscopic structure of liquid water

The radial distribution function of liquid water, as obtained by the computer simulations of several classical models of water, is re-examined herein and shown to display two intriguing features. These consist of a compact ‘three-peaks structure’ over three molecular diameters, which is followed by an apparent loss of the packing correlations beyond Å. This is in contrast to simple liquids for which the correlations decay continuously with distance. This structure is reproduced for many widely used classical force field models of water and by scattering experiments as well. It is also preserved in aqueous binary mixtures of organic solvents, even up to equimolar mixture in some cases. The analysis of the structure factor highlights the role played by the competition between the packing effect and the hydrogen bonding interactions. This analysis, in terms of competition of two length scales, is also supported by a simple core-soft model, which reproduces the structural features outlined above.

J-aggregation of N-sulfobutyl oxacarbocyanine in binary mixtures of organic solvents

N-sulfobutyl oxacarbocyanine in binary mixtures of dimethyl sulfoxide (DMSO) as a polar solvent (0.15–2 vol.%) and four less polar solvents, such as dioxane, toluene, trichloroethylene and tetrahydrofuran forms J-aggregates. Along with J-aggregates cyanine dyes form H-aggregates in the mixture of DMSO with trichloroethylene. In the mixture of DMSO with dioxane J-aggregates are formed from the monomers and the reaction proceeds with time. The relative yield of J-aggregates and the maximum rate of formation depend on the DMSO content and both are equal to zero at 5% of DMSO. J-aggregates are characterized by resonance fluorescence. For DMSO/trichloroethylene initially an H-aggregate is formed which is transformed via the monomer into a J-aggregate. The results obtained are rationalized in terms of the solvophobic effect.

Lipid Bilayer-Assisted Release of an Enediyne Antibiotic from Neocarzinostatin Chromoprotein

The nine-membered enediyne class has drawn extensive interest because of extremely high antitumor potency and intricate interactions with its carrier protein. While the drug-induced DNA cleavage reactions have been mostly elucidated, the critical release-transport process of the labile enediyne molecule in cellular environment remained obscure. Using neocarzinostatin chromoprotein as a model, we demonstrated a lipid bilayer-assisted release mechanism. The in vitro enediyne release rate under aqueous conditions was found to be too slow to account for its efficient DNA cleavage action. Via the presence of lipid bilayers, chaotropic agents, or organic solvents, we found the release was substantially enhanced. The increased rate was linearly dependent on the lipid bilayer concentration and the dielectric value of the binary organic solvent mixtures. While lipid bilayers provided a low surrounding dielectricity to assist in drug release, there were no major conformational changes in the apo and holo forms of the carrier protein. In addition, the lifespan of the released enediyne chromophore was markedly extended through partitioning of the chromophore in the hydrophobic bilayer phase, and the lipid bilayer-stabilized enediyne chromophore significantly enhanced DNA cleavage in vitro. Collectively, we depicted how a lipid bilayer membrane efficiently enhanced dissociation of the enediyne chromophore through a hydrophobic sensing release mechanism and then acted as a protector of the released enediyne molecule until its delivery to the target DNA. The proposed membrane-assisted antibiotic release-transport model might signify a new dimension to our understanding of the modus operandi of the antitumor enediyne drugs.

Highly regioselective enzymatic synthesis of 5′-O-stearate of 1-β-D-arabinofuranosylcytosine in binary organic solvent mixtures

In this paper, highly regioselective enzymatic acylations of 1-beta-D-arabinofuranosylcytosine (ara-C) with vinyl stearate (VS) in binary organic solvents were explored for the preparation of 5'-O-stearate of ara-C with potential antitumor activity. Twelve kinds of hydrolases were tested for the regioselective acylation reaction and the immobilized Candida antarctica lipase B (Novozym 435) showed the highest regioselectivity (>99.9%) towards the 5'-OH of ara-C. A comparative study showed that the lipase had much higher catalytic activity in the binary mixture of hexane and pyridine than in other tested co-solvent systems. To better understand lipase-mediated acylation conducted in the best binary organic solvent system, the effects of hydrophobic solvent content, molar ratio of VS to ara-C, initial water activity, and reaction temperature on the acylation reaction were studied. It was found that the most suitable hexane content, VS-ara-C molar ratio, initial water activity, and reaction temperature were shown to be 25% (v/v), 20:1, 0.07, and 50 degrees C, respectively. Under these reaction conditions, the initial reaction rate, the maximum substrate conversion, and regioselectivity were as high as 86.0 mmol.L(-1)h(-1), 96.6%, and >99.9%, respectively. The product of Novozym 435-catalyzed acylation was characterized by Carbon-13((13)C) NMR and confirmed to be 5'-O-stearate of ara-C.

Free and immobilized Aspergillus niger epoxide hydrolase-catalyzed hydrolytic kinetic resolution of racemic p-chlorostyrene oxide in a neat organic solvent medium

An enantio- and regioselective hydrolytic kinetic resolution (HKR) of racemic p-chlorostyrene oxide ( rac- pCSO) was achieved by epoxide hydrolase (EH) from recombinant Aspergillus niger in a selected neat organic solvent medium. The solid free EH was reused four times in repeated-batch reactors; however, the relative activity as well as the enantiomeric ratio ( E-value) of this EH decreased from 100 to 20% and from 68 to 23, respectively. In order to overcome the diffusion hindrance, due to the accumulation of the hydrophilic diol in the enzyme micro-environment, and thereby to improve the operational stability of EH after recycling, strategies consisting of the immobilization of EH and the use of a binary organic solvent as the reaction medium were successfully applied. Although the highest protein immobilization yield (82%) and retention of EH activity (142%) in heptane were obtained upon the immobilization of EH on Accurel EP, the E-value and the operational stability of the resulted EH immobilizate after recycling were reduced as compared to the free EH. In contrast, the nonporous DEAE-cellulose improved the operational stability of EH by more than twofold. On the other hand, both the HKR efficiency and the operational stability of A. niger EH were found to be modest to excellent in various binary organic solvent mixtures of heptane and dioxane, depending on their ratio resulting in different Log P.

Cooperative and synergistic solvent effects in SET‐LRP of MA

AbstractSET‐LRP requires a combination of ligand and solvent that mediates the disproportionation of Cu(I)X into Cu(0) activator, and Cu(II) deactivator. The solvent also modulates the kinetics of the reaction. More polar solvents, including mixtures of water and organic solvents enhance the rate of polymerization in accord with the Dimroth‐Reichardt parameter. Here, it is demonstrated that a similar effect is observed in binary mixtures of organic solvents, wherein the addition of a more polar solvent to a less polar solvent provides a linear increase in the apparent rate constant of propagation, k. However, this linear relationship does not hold for the entire range of volume fraction for binary mixtures when ethylene carbonate (EC) or MeOH are one of the two components. Results herein, suggest that the kinetics of SET‐LRP in these solvent mixtures is cooperatively and synergistically determined by polarity, degree of disproportionation, and also by another parameter related to the ability of the solvent to stabilize colloidal Cu(0) and determine its particle size. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5591–5605, 2009

New efficient reaction media for SET‐LRP produced from binary mixtures of organic solvents and H2O

AbstractSET‐LRP is mediated by a combination of solvent and ligand that promotes disproportionation of Cu(I)X into Cu(0) and Cu(II)X2. Therefore, the diversity of solvents suitable for SET‐LRP is limited. SET‐LRP of MA in a library of solvents with different equilibrium constants for disproportionation of Cu(I)X such as DMSO, DMF, DMAC, EC, PC, EtOH, MeOH, methoxyethanol, NMP, acetone and in their binary mixtures with H2O was examined. H2O exhibits the highest equilibrium constant for disproportionation of Cu(I)X. The apparent rate constant of the polymerization exhibits a linear increase with the addition of H2O. This is consistent with higher equilibrium constants for disproportionation generated by addition of H2O to organic solvents. Furthermore, with the exception of alcohols and carbonates, the rate constant of polymerization in binary mixtures could be correlated with the Dimroth‐Reichardt solvent polarity parameter. This is consistent with the single‐electron transfer mechanism proposed for SET‐LRP that involves a polar transition state. These experiments demonstrate that the use of binary mixtures of solvents with H2O provides a new, simple and efficient method for the elaboration of a large diversity of reaction media that are suitable for SET‐LRP even when one of the two solvents does not mediate disproportionation of Cu(I)X. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5577–5590, 2009

Levitated single-droplet drying: Case study with itraconazole dried in binary organic solvent mixtures

The objective of this case study of the single-droplet drying of two itraconazole/polymer formulations was to determine how the solvent system influences drying rate and dried particle morphology. A clear dual functionality of the two solutes could be identified. The polymeric component (PVP or HPMC) determined drying rate, whereas the drug determined end particle morphology. This could be related to solubilities of the two components in the binary solvent mixtures used. The formulation of a surface skin early on in drying only occurred with HPMC and strongly influenced drying rate but not dried particle morphology.

Solvatochromic Study on Binary Solvent Mixtures with Ionic Liquids

Solvent effects on 2,6-dichloro-4-(2,4,6-triphenyl-pyridinium-1-yl)phenolate [ET (33) dye] and 7- diethylamino-3,4-benzophenoxazine-2-one (Nile Red) in binary mixtures of organic solvents (acetone, acetonitrile, propylene carbonate, methanol and ethane-1,2-diol) with 1,3-dialkyl imidazoliumbased ionic liquids were studied by UV-visible spectroscopy. Highly nonlinear behaviour of mixtures of alcohols and ionic liquids was found. A preferential solvation model was applied to the data obtained on solvatochromic shifts over the entire mixing range. It is fitting the data well for alcohol mixtures and for other solvent mixtures with different ionic liquids.