Binary Solvent Mixtures Of Ethanol Research Articles

Solubility measurement and thermodynamic model correlation of propyl gallate in pure and binary solvents from T = (293.15 to 333.15) K

The solid−liquid equilibrium data of propyl gallate in nine pure solvents and binary solvent mixtures of ethanol + n-propanol were measured over the temperature range from (293.15 to 333.15) K by using a gravimetric method under atmospheric pressure. The experimental result proved that the rising temperature led to increased solubility of the propyl gallate in all selected solvents. For pure solvents, the solubility of propyl gallate increased according to the following order: ethanol < isobutanol < ethyl acetate < methanol < n-butanol < methyl acetate < isopropanol < n-propanol < acetone. For ethanol + n-propanol mixture solvents, the solubility of propyl gallate decreased with the increase of ethanol mass fraction. The experimental solubility in each selected solvent were correlated with a series of equations, including the modified Apelblat equation, Van't Hoff equation, λh equation, NRTL equation and Wilson equation. Computational results showed that all five selected models well fitted the experimental data. Hansen solubility parameters (HSP) were also applied to explain the solubility behavior of propyl gallate. In addition, the Van't Hoff equation was used to estimate the dissolution enthalpy (∆H°sol), dissolution entropy (∆S°sol) and Gibbs energy (ΔG°sol) of propyl gallate in selected solvents.

Thermodynamic and population balance models for solvent-mediated phase transformation of lansoprazole

In this work, two new polymorphs (monohydrate and ethanol solvate) of lansoprazole were first discovered and fully characterized. The transformation between two polymorphs of lansoprazole was investigated both experimentally and theoretically. The ternary phase diagram of the two polymorphic forms of lansoprazole in the binary solvent mixtures of ethanol and water at 15 °C, 25 °C and 35 °C was determined and the thermodynamic model was established. Raman spectroscopy was used to in situ monitor the solvent-mediated transformation from monohydrate to ethanol solvate of lansoprazole, while the solution concentration was measured by UV spectroscopy. The population balance models were established to analyze and compare the dissolution, nucleation and crystal growth process during polymorphic transformation. By combining the experimental and simulation results, the rate-controlling step, the changing profiles of the suspension density and the solid compositions of both polymorphs were investigated and discussed. Furthermore, the effect of temperature on the transformation process was also analyzed.

Stability of lysozyme incorporated into electrospun fibrous mats for wound healing

In this study, we investigated the feasibility of incorporating protein drugs into electrospun fibrous mats (EFMs) for wound healing using lysozyme as a model drug. Lysozyme nanoparticles (Lyso- NPs) were first obtained by electrospray. Lysozyme solutions were prepared with a binary solvent mixture of ethanol (EtOH)-water (H2O) at varied volume ratios. Subsequently, Lyso-NPs were suspended in poly(lactic-co-glycolic acid) (PLGA) solutions using trifluoroethanol (TFE) as a solvent. Lyso-NPs loaded EFMs were obtained by electrospinning of the aforementioned suspensions, and the bioactivity of lysozyme in the EFMs was investigated using fluorescence-based assay kit. The electrosprayed Lyso-NPs were spherical with barely altered bioactivity as compared to the untreated raw material when using EtOH- H2O (30:70, v/v) as the solvent. After the subsequent electrospinning process, more than 90% of the bioactivity of lysozyme was retained compared to the raw material. The cytotoxicity of the produced EFMs was evaluated by thiazolyl blue tetrazolium bromide (MTT) study and the proliferation and distribution of mouse fibroblast cells (L929) growing on EFMs were investigated using 4,6-diamidino-2-phenylindol dihydrochloride (DAPI) for nucleic acid staining. Nearly negligible cytotoxicity of all the EFMs was observed according to the MTT study. Furthermore, it was observed that the L929 cells grew well on the Lyso-EFMs, especially those with the modification of polyethylene glycol (PEG) that was added to improve the hydrophilicity of EFMs. This study demonstrated that the electrospray/electrospinning processes are suitable for loading biomacromolecules to produce functionalized wound dressings to promote wound healing.

Solubility Determination and Modeling and Dissolution Thermodynamic Properties of Raspberry Ketone in Binary Solvent Mixtures of Ethanol and Water

The solubility and dissolution thermodynamic properties of raspberry ketone in a set of binary solvent mixtures (ethanol + water) with different compositions were experimentally determined by static gravimetrical method in the temperature range of 283.15–313.15 K at 0.10 MPa. The solubility of raspberry ketone in this series of ethanol/water binary solvent mixtures was found to increase with a rise in temperature and the rising mole fraction of ethanol in binary solvent mixtures. The van’t Hoff, modified Apelblat and 3D Jouyban–Acree–van’t Hoff equations were increasingly applied to correlate the solubility in ethanol/water binary solvent mixtures. The former two models could reach better fitting results with the solubility data, while the 3D model can be comprehensively used to estimate the solubility data in all the ratios of ethanol and water in binary solvent mixtures at random temperature. Furthermore, the changes of dissolution thermodynamic properties of raspberry ketone in experimental ethanol/water solvent mixtures were obtained by van’t Hoff equation. For all the above experiments, these dissolution processes of raspberry ketone in experimental ethanol/water binary solvent mixtures were estimated to be endothermic and enthalpy-driven.

Optimization of the tape casting slurries for high-quality zirconia substrates

A cheap and environmental friendly non-aqueous tape casting process for preparing high density ZrO2 ceramic substrates was explored. A binary solvent mixture of ethanol and ethyl acetate -based formula was developed by using castor oil, polyvinyl butyral and dibutyl phthalate as the dispersant, binder and plasticizer, respectively. The influence of dispersant content, binder content and solid loading on the rheological properties of ZrO2 slurries was firstly investigated. It was found that the optimized formulation for dispersant, binder and solid loading was 1wt%, 4wt% and 60wt%, respectively. The flat, flexible and uniform green tapes with a thickness of 200–280µm and high-quality including high bulk density, uniform pore distribution and low porosity were obtained. After drying and debinding, the green sheets were sintered at 1480℃ for 1h, where ZrO2 ceramics with a relative density of 98% and a dielectric constant being 32 can be achieved. The sintered samples could satisfy the use requirement of the fingerprint identification cover plate.

Solubility of amiodarone hydrochloride in aqueous co-solvent mixtures revisited: IBKI preferential solvation analysis

The preferential solvation parameters (δx1,3) of amiodarone hydrochloride (AMDH) in three binary solvent mixtures of ethanol (1)+water (2), N-methyl pyrrolidone (NMP) (1)+water (2) and propylene glycol (1)+water (2) were derived from their available solubility data by using the inverse Kirkwood–Buff integrals method. The values of δx1,3 varied non-linearly with the co-solvent (1) proportion in all the aqueous mixtures. For the system of ethanol+water, the values of δx1,3 were negative in water-rich mixtures and co-solvent-rich mixtures, but positive in intermediate compositions. However, for the propylene glycol (1)+water (2) mixtures with composition 0.167<x1<1 and NMP (1)+water (2) mixtures with composition 0.20<x1<1, the δx1,3 values were positive indicating that AMDH is preferentially solvated by co-solvent. The positive δx1,3 values could be explained on the basis of the higher acidic behavior of AMDH molecules interacting with the hydrogen acceptor groups present in co-solvent.

Preferential solvation of rosmarinic acid in binary solvent mixtures of ethanol + water and methanol + water according to the inverse Kirkwood–Buff integrals method

The preferential solvation parameters (δx1,3) of rosmarinic acid in binary solvent mixtures of ethanol+water and methanol+water were derived from their thermodynamic properties by means of the inverse Kirkwood–Buff integrals method. δx1,3 was negative in water-rich mixtures but positive in solvent compositions from 0.20 or 0.24 to 1 in mole fraction of methanol or ethanol, respectively. It was conjecturable that in water-rich mixtures, the hydrophobic hydration around the nonpolar aromatic groups of rosmarinic acid played a relevant role in the solvation. The higher solvation by methanol or ethanol in mixtures of similar co-solvent compositions could be mainly due to polarity effects. The preference of rosmarinic acid in intermediate compositions and in methanol-rich or ethanol-rich mixtures could be explained in terms of the higher acidic behavior of rosmarinic acid molecules interacting with the hydrogen acceptor groups in methanol or ethanol. The calculations were required in the pharmaceutical and chemical industries to save time and money in the optimization of the solubilization and/or crystallization process designs.

Solubility and dissolution thermodynamic properties of 2-Cyano-4′-methylbiphenyl in binary solvent mixtures

The solubility of 2-Cyano-4′-methylbiphenyl (OTBN) in binary solvent mixtures of ethanol+(ethyl acetate, acetonitrile and acetone) was measured at temperature ranging from 268.05K to 303.05K by using a gravimetric method under atmospheric pressure. The results showed that the solubility of OTBN monotonously decreases with increasing mole fraction of ethanol at given temperature except for the solubility of OTBN in binary solvent mixture of ethanol+acetonitrile around x20=0.1375mol under 268.05K and 272.97K. In the temperature range investigated, the solubility data of OTBN increases with the increasing of temperature in the studied binary solvent mixtures. Furthermore, the experimental solubility data was fitted using the modified Apelblat equation, the CNIBS/R-K model and the Jouyban–Acree model successfully. In addition, the molar dissolution thermodynamic properties of OTBN were calculated and analyzed based on the NRTL model and the experimental solubility data.

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.

Thermal Diffraction of Binary Fluids With Metal Nanoparticles

A laser propagating through a metal nanocolloid exhibits a far-field fringe pattern that is the signature of its optical and thermally induced response. Here, we directly exploit the sensitive far-field features to measure the thermo-optic coefficients of binary-solvent mixtures of ethanol and water. This study extends our fundamental understanding of the thermal self-diffraction toward future optical characterization of the nanocolloid fluid motion.

Measurement and Correlation of Solubility of γ-Aminobutyric Acid in Different Binary Solvents

The solubility of γ-aminobutyric acid (GABA) in binary solvent mixtures of ethanol + methanol, 1-propanol + methanol and 2-propanol + methanol was measured over the temperature ranging from(283.15 to 323.15 K with the gravimetric method. It is found that the solubility of GABA increases with increasing temperature, whereas it decreases with the increase of the GABA free-base mole fraction of ethanol, 1-propanol, or 2-propanol. The solubility data have been correlated with the modified Apelblat equation, the CNIBS/R-K equation, two modified versions of Jouyban-Acree models (the Van’t-JA equation and the Apel-JA equation) and NRTL model, respectively. The results show that the CNIBS/R-K equation gives the best correlation results in these three binary mixed solvents. Also, the mixing thermodynamic properties of enthalpy, entropy, and Gibbs energy change of GABA in these solvent mixtures have also been calculated and discussed.

Correlation of solubility and prediction of the mixing properties of rosmarinic acid in different pure solvents and in binary solvent mixtures of ethanol + water and methanol + water from (293.2 to 318.2) K

The solubility of rosmarinic acid was measured in water, ethanol, methanol, and in the binary solvent mixtures (ethanol+water) and (methanol+water), with different molar fraction values for ethanol and methanol, from (Xsolv=0.10 to 0.90), over a temperature range of (T=293.15, 298.15, 303.15, 308.2, 313.15 and 318.15) K. With increasing temperature and molar fraction of ethanol and methanol, the solubility of rosmarinic acid increased from 0.26 to 0.46 and from 0.28 to 0.49 respectively. The experimental solubility values were well correlated by the modified Apelblat equation. From the measured solubility data, the thermodynamic properties enthalpy of dissolution (ΔsolHRA) and entropy of dissolution (ΔsolSRA) of rosmarinic acid, during the dissolution process in water, ethanol, methanol, and binary solvent mixtures (ethanol+water) and (methanol+water), could be calculated based on these fits. The results indicate that the dissolution process is endothermic.

Solubility of Cefpiramide Sodium in Binary Ethanol + Water and 2-Propanol + Water Solvent Mixtures

The solubility of cefpiramide sodium in binary solvent mixtures of ethanol + water and 2-propanol + water was determined by a steady-state method from (278.2 to 303.2) K and in the initial mole fraction range of alcohol (ethanol or 2-propanol) in the solvent mixture at about 0.4 to 0.8. Cefpiramide sodium exhibits the same order of magnitude of solubility in both binary systems. The solubility decreases with the increase of the initial mole fraction of alcohol and increases with increasing temperature. Dilution crystallization or dilution crystallization incorporated with cooling crystallization will be more suitable than pure cooling crystallization for the purification of cefpiramide sodium. The Jouyban–Acree model, combined with the van’t Hoff equation, was used to correlate the solubility data. The combined model was further simplified so that each item in the model is statistically significant at the 5 % level. The simplified combined model gives a mean relative deviation of 5.3 % for the ethanol + w...

Determination and Correlation of Solubility of Tris(3-hydroxypropyl)phosphine Oxide in Selected Solvents

The solubility of tris(3-hydroxypropyl)phosphine oxide (THPPO) in selected solvents was measured by a static analytic method over the temperature range from (293 to 328) K in methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, acetone, and a binary solvent mixture of ethanol + acetone. Several widely used thermodynamic models, such as the empirical equation and the Buchowski–Ksiazaczak (λh), Scatchard–Hildebrand, Wilson, nonrandom two-liquid (NRTL), and universal quasichemical (UNIQUAC) equations were applied to represent the measurement results. The binary interaction parameters of the above models were found to have a linear dependency on temperature, and the coefficients were regressed. The results show that all of these models can satisfactorily reproduce the experimental data and the NRTL equation can provide the best correlation with an overall relative standard deviation of 0.46 %.

Solubilities of m-phthalic acid in petroleum ether and its binary solvent mixture of alcohol + petroleum ether

The solubility of m-phthalic acid in petroleum ether and in binary solvent mixture of ethanol + petroleum ether and 1-propanol + petroleum ether was measured in temperature range of 293–347 K using the analytical gravimetric method. The components and their compositions in the petroleum ethers used in this work were identified by GC–MS analyses. The solubility measurements show that petroleum ethers have much lower solubility to m-phthalic acid than ethanol and 1-propanol. In addition, the petroleum ether of higher boiling range shows much lower solubility than that of lower boiling range. For binary solvents the addition of petroleum ether into alcohol remarkably lower the solubility of the alcohol. The solubility data was correlated with the Apelblat equation and the Buchowski–Ksiazczak equation (the λh equation). Good agreements were obtained with the average absolute percent deviations of 1.55% and 3.32%, respectively. Furthermore, the mixed solvent systems were found to exhibit a synergistic effect (maximum solubility effect) on the solubility at high temperature, which may be attributed to the intermolecular association between the solute and the solvent mixture. The positive synergistic effect was well modeled by the modified Wilson equation.

Block‐Selective Solvent Influence on Morphology of the Micelles Self‐Assembled by PS38‐b‐P(AA190‐co‐MA20)

AbstractSummary: The influence of block‐selective solvent on the self‐assembly of polystyrene‐block‐poly[(acrylic acid)‐co‐(methyl acrylate)] was studied. The nature of the block‐selective solvent, which is a binary solvent mixture with different composition, exerts remarkable influence on the morphology of the resulting micelles. When the block‐selective solvent is a binary solvent mixture of acetone and water with acetone content ranging from 0 to 90 vol.‐%, the resulting aggregates are core‐shell spheres with diameter about 60 nm, porous aggregates with diameter of 100, 180 and 250 nm, and core‐shell cauliflower‐like aggregates with size about 200 nm, respectively. The reason that the morphology of resulting micelles changes with acetone content has been discussed. The structure of the resulting micelles is further characterized in detail by DLS and SLS. Morphological tuning is also achieved by using a binary solvent mixture of ethanol and water or a binary solvent mixture of DMF and water as block‐selective solvent. In these cases, core‐shell spheres, hollow aggregates, and incompact aggregates are formed with the ethanol or DMF concentration ranging from 10 to 80 vol.‐%. magnified image

Spectroscopic Studies of Nonamphiphilic Coronene Assembled in Langmuir−Blodgett Films: Aggregation-Induced Reabsorption Effects

This paper reports the incoroporation of large flat molecules of coronene in Langmuir−Blodgett (LB) films mixed with stearic acid (SA). The spectroscopic characteristics of these films have been investigated here. An outstanding feature of this study is the appearance of the S1−S0 absorption band at 420 nm in the LB films. Interestingly, in solution this band is never observed owing to this transition being a electric-dipole forbidden arising from the D6h symmetry of the molecule. Spectroscopic studies of these mixed LB films of coronene and SA indicate the formation of aggregates. The spectroscopic characteristics of the aggregates formed in the LB films were found to be identical to those formed in a binary solvent mixture of ethanol and water that confirm the formation of microcrystallites in the mixed LB films and binary solvent mixtures. A comparative study of the fluorescence excitation spectra of the aggregates formed in the binary solvent mixtures and in the LB films reveals the hidden S0−S1 transition in LB films in contrast to that in solution where the S0−S1 transition is not manifested. Furthermore, the excitation spectra of the aggregates formed in different systems were found to be different suggesting different packing configuration of the molecules in the aggregates formed in different systems.

Spectroscopic Study of Nonamphiphilic Carbazole Assembled in Langmuir−Blodgett Films: Aggregation Induced Reabsorption Effects

Mono- and multilayers of carbazole mixed with stearic acid (SA) have been prepared by the Langmuit−Blodgett (LB) technique. Surface pressure studies at the air−water interface show that pure carbazole does not form a stable film and collapses at a low surface pressure of about 12 mN/m only. However, carbazole mixed with SA forms excellent films that may be easily transferred onto solid supports. The surface pressure versus area per molecule isotherm studies show that the average area per molecule initially increases and then decreases with increasing mole fraction of carbazole. These results indicate that the carbazole moieties are accommodated in the SA matrix at low concentrations but with increasing concentration are very likely squeezed out of the air−water interface to remain sandwiched in between the fatty acid chains and on the surface of the monolayer. The positive deviation of the observed area per molecule from the ideal curve corresponding to the additivity rule suggests a repulsive interaction between the components in the mixed films. Spectroscopic studies of the LB films reveal a broadening and red shift of the absorption spectra compared to the solution absorption spectrum that confirms the formation of organized aggregates of carbazole in the mixed LB films. Fluorescence studies of the mixed LB films reveal new bands in the low-energy region of the fluorescence emission spectrum. Increasing the concentration of carbazole in the mixed films results in the enhancement of the intensity of these low-energy emission bands and quenching of the high energy bands that may be attributed to aggregation-induced reabsorption effects indicating the formation of crystallites in the LB films. A comparative study of the spectroscopic characteristics of these aggregates formed in the LB films and in the binary solvent mixtures of ethanol and water reveals identical spectra that confirm formation of crystallites in both the systems.

Diffusion of small molecules in glassy polymer thin films studied by waveguide Raman techniques

Waveguide Raman spectroscopy (WRS) allows one to monitor the spectrum of a polymer film in contact with a liquid phase. A unique advantage of WRS is its ability to monitor as a function of time all of the molecular species involved in the diffusion process simultaneously with minimal interference from the bulk solvents or substrate. Combining the linear Raman response with the integrated optical field in the polymer waveguide allows the mass sorption to be measured. If an adequate model is available, diffusion profiles, at any particular time in the experiment, can be calculated. The system studied in the present work consists of a polystyrene waveguide on a fused quartz substrate in contact with a binary solvent mixture of ethanol and perdeuteriotoluene. In this case the diffusion takes place over a distance of approximately 1 {mu}m. Finally, experimental results will be compared to several diffusion models.

ChemInform Abstract: Role of Aqueous Media in Specific Recognition of Nonpolar Groups in Molecular Aggregates.

Oxidation of a pair of associating thiols (1 and 2), each having a binding site [−C(=O)NHC(=O)NH−] and a recognition site (R 1 or R 2 ), is examined in mainly one set of binary solvent mixtures of ethanol with water and organic cosolvents at various temperatures. The selectivity (r) ― a measure of degree of recognition of 1 by 2 (or of 2 by 1) ― in the oxidation is represented by the logarithmic ratio of the yield of an unsymmetrical disulfide to twice that of a symmetrical one