Thermodynamics of supersaturated solutions: From ternary electrolyte+solute+H2O to binary solute+H2O systems

Han, Guangjun; Tan, Reginald B. H.

doi:10.1016/j.ces.2009.05.040

Cited by 19 publications

(23 citation statements)

References 38 publications

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“…solute and solvent, is allowed to reach equilibrium at a specific temperature, and the concentration of the solute in the system is measured via techniques such as gravimetric analysis, 8 titration, 9 UV−vis spectroscopy, 10 HPLC 11 or solution density. 12 Alternatively, the system is examined for the point of equilibrium as a function of temperature, at a specific concentration of components. The latter can be achieved with techniques such as the synthetic method, 13 using differential scanning calorimetry (DSC), 14 in situ infrared spectroscopy 15 and microscopic methods.…”

Section: ■ Introductionmentioning

confidence: 99%

“…The system, e.g. solute and solvent, is allowed to reach equilibrium at a specific temperature, and the concentration of the solute in the system is measured via techniques such as gravimetric analysis, titration, UV–vis spectroscopy, HPLC or solution density . Alternatively, the system is examined for the point of equilibrium as a function of temperature, at a specific concentration of components.…”

Section: Introductionmentioning

confidence: 99%

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Measuring the Solubility of a Quickly Transforming Metastable Polymorph of Carbamazepine

O’Mahony

Croker

Rasmuson

et al. 2012

Org. Process Res. Dev.

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The solubility of the stable FIII polymorph of the pharmaceutical compound carbamazepine was measured by determining its solubility gravimetrically in ethanol and methanol. Where the metastable FI polymorph was suspended in a solution of ethanol, the stable FIII polymorph nucleated immediately, initiating a solution-mediated transformation from FI to FIII. This meant that the FI polymorph was not in thermodynamic equilibrium with the solution as FI was continually dissolving while FIII was growing. We show that the solubility of FI can be accurately measured by in situ microscopy using an adaption of the bracketing method, and the results show that the solubility is close to but higher than the maximum solution concentration reached during the solution-mediated transformation from FI to FIII carbamazepine in both solvents. The technique demonstrates a relatively simple and robust method for determining the solubility of a metastable crystalline phase which transforms quickly in solution.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Measuring the Solubility of a Quickly Transforming Metastable Polymorph of Carbamazepine

O’Mahony

Croker

Rasmuson

et al. 2012

Org. Process Res. Dev.

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“…27,32 The needle-like γ-glycine seed crystals with identifiable pointed +c end and flat −c end were grown from an aqueous glycine solution in the presence of DL-aspartic acid, 4,6,10 while DL-alanine needle-like seed crystals 6,13 were prepared by evaporation of concentrated pure DLalanine aqueous solutions at room temperature (∼23°C).…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…As simple amino acids which contain both basic group (NH 2 ) and acidic group (COOH), the molecular structures (Figure ) of glycine and alanine are alike (glycine neutral form NH 2 CH 2 COOH versus alanine neutral form NH 2 CH(CH 3 )COOH), though an alanine molecule has an extra methyl group (CH 3 ). The pronounced hydrophilicities of the acidic and basic functional groups make γ-glycine and dl -alanine crystals substantially water-soluble . When dissolved in water, glycine and alanine molecules generally exist as zwitterions (glycine zwitterion NH 3 + CH 2 COO – and alanine zwitterion NH 3 + CH(CH 3 )COO – ) , which are the building units , of γ-glycine and dl -alanine crystals.…”

Section: Introductionmentioning

confidence: 99%

Growth Behaviors of Two Similar Crystals: The Great Difference

Han

Tan

2015

Crystal Growth & Design

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The growth of two structurally similar polar crystals, γ-glycine and DL-alanine, in their aqueous supersaturated solutions in the presence of typical inorganic salts was studied using in situ microscopic observations. Surprisingly, it was found that their growth behaviors largely differ. The most unexpected finding was that the face growth at each of γ-glycine polar c ends is inhibited, while the face growth at each of DL-alanine c ends is accelerated by all the common inorganic salts studied, despite the fact that the structures of the associated faces are strikingly akin. These unusual observations were explained at the molecular level. In particular, the role of the hydrophobic methyl groups exposed at the crystal faces was highlighted, demonstrating an interesting case in which a small variation in crystal face hydrophilicity can lead to a marked difference in face growth behaviors.

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“…Recently, Khoshkbarchi and Vera have studied the system at 298.15 K for m NaCl = (0.1 to 1) mol·kg −1 and m Gly = (0.1 to 2.6) mol·kg −1 . Phang and Steel obtain the data for m NaCl = (0.01 to 1) mol·kg −1 and m Gly = (0.5 to 4) mol·kg −1 at temperatures between (273.15 and 323.15) K. The study of Han and Tan presents the supersaturated solutions of glycine and NaCl at 298.15 K in solubility terms.…”

Section: Introductionmentioning

confidence: 99%

Activity Coefficients from Cell Potential Measurements in the NaCl + Glycine + Water Ternary System at (298.2, 308.2, and 318.2) K

Sîrbu

Iulian

2010

J. Chem. Eng. Data

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Activity coefficient values for NaCl and glycine are determined by studying their aqueous mixtures at different electrolyte and glycine concentrations. The mean ionic activity coefficient of NaCl was calculated from cell potential measurements: Na-ISE/NaCl (m NaCl ); glycine (m Gly )/Ag/AgCl. Measurements were made over the concentration range of (0.005 to 2) mol • kg -1 glycine and of (0.05 to 2) mol • kg -1 NaCl at temperatures (298.2, 308.2, and 318.2) K. The experimental data were correlated with the Roberts-Kirkwood and Scatchard-Prentiss virial expansion series. The activity coefficient of glycine is related to the mean ionic activity coefficient of the electrolyte through the cross-differential relation and evaluated by the standard deviation, σ. The mean ionic activity coefficient of NaCl decreases as the molality of glycine in the solution increases. The presence of NaCl decreases the activity coefficient of glycine and consequently represents a salt-in effect for amino acid.

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Thermodynamics of supersaturated solutions: From ternary electrolyte+solute+H2O to binary solute+H2O systems

Cited by 19 publications

References 38 publications

Measuring the Solubility of a Quickly Transforming Metastable Polymorph of Carbamazepine

Measuring the Solubility of a Quickly Transforming Metastable Polymorph of Carbamazepine

Growth Behaviors of Two Similar Crystals: The Great Difference

Activity Coefficients from Cell Potential Measurements in the NaCl + Glycine + Water Ternary System at (298.2, 308.2, and 318.2) K

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