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Journal ArticleDOI

Solubility and Thermodynamic Stability of the Enantiotropic Polymorphs of 2,3,5-Trimethyl-1,4-diacetoxybenzene

TLDR
In this paper, the transition point between two polymorphs of 2,3,5-trimethyl-1,4-diacetoxybenzene (TMHQ-DA) in ethanol, 1-propanol, 2-Propanol and 1-butanol at various temperatures were experimentally measured using gravimetrical method and correlated by the modified Apelblat model and the van-t Hoff equation, respectively.
Abstract
The solubility data of two polymorphs of 2,3,5-trimethyl-1,4-diacetoxybenzene (TMHQ-DA) in ethanol, 1-propanol, 2-propanol, and 1-butanol at various temperatures were experimentally measured using gravimetrical method and correlated by the modified Apelblat model and the van’t Hoff equation, respectively. Differential scanning calorimetry (DSC) and thermogravimetry (TG) analyses were performed to investigate the thermodynamic stability and the transition of the two forms of TMHQ-DA. An enantiotropic relationship was found between TMHQ-DA Form A and TMHQ-DA Form B, and the transition point between them was experimentally determined to be 314.50 ± 1 K. A thermodynamic model for estimation of the transition point was also derived, and the estimated results are satisfactorily consistent with the experimental values. Finally, the accuracy of the transition point obtained in this research was validated by the polymorphic transformation experiments monitored using Raman spectroscopy.

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Journal ArticleDOI

Phase Transition Enthalpy Measurements of Organic and Organometallic Compounds and Ionic Liquids. Sublimation, Vaporization, and Fusion Enthalpies from 1880 to 2015. Part 2. C11–C192

TL;DR: A collection of phase change enthalpies of organic molecules including fusion, vaporization, and sublimation enthalphies for organometallic, ionic liquids, and a few inorganic compounds can be found in this paper.
Journal ArticleDOI

Effects of Solvent on Polymorph Formation and Nucleation of Prasugrel Hydrochloride

TL;DR: In this paper, three intrinsic properties of solvent were used to evaluate the effects of solvent on polymorph formation of prasugrel hydrochloride, and it was found that polymorph formation directly depends on the solvents used in the experiments.
Journal ArticleDOI

A Spontaneous Single-Crystal-to-Single-Crystal Polymorphic Transition Involving Major Packing Changes

TL;DR: Polarized light microscopy experiments not only proved the SCSC nature of the transition but also suggested nucleation and growth mechanism for the transition.
Journal ArticleDOI

Solution-Mediated Polymorphic Transformation of Prasugrel Hydrochloride from Form II to Form I

TL;DR: In situ Raman spectroscopy was applied for the analysis of the solution-mediated polymorphic transformation of prasugrel hydrochloride from the metastable form II to the stable form I.
Journal ArticleDOI

Measurement and correlation of solubility of thiourea in two solvent mixtures from T = (283.15 to 313.15) K

TL;DR: In this paper, the solubility data of thiourea in methanol + n-propanol mixtures were determined from T = (283.15 to 313.15) K by gravimetric method under atmospheric pressure.
References
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Journal ArticleDOI

Solubilities ofo-acetylsalicylic, 4-aminosalicylic, 3,5-dinitrosalicylic, andp-toluic acid, and magnesium-DL-aspartate in water fromT=(278 to 348) K

TL;DR: In this article, the apparent molar enthalpies of solution atT =298.15 K were derived from these solubilities, and the resulting values are ΔsolHm(o-C9H8O4,m=0.0226 mol kg−1)=22.9 kJ mol−1.
BookDOI

Polymorphism: in the Pharmaceutical Industry

Rolf Hilfiker
TL;DR: This handbook emphasizes why solid-state issues are important, which approaches should be taken to avoid problems and exploit the opportunities and Polymorphism in the pharmaceutical industry.
Journal ArticleDOI

On the polymorphism of pharmaceuticals and other molecular crystals. II@@@ber die Polymorphie von Arzneistoffen und anderen Moleklkristallen. II: Applicability of thermodynamic rules

A. Burger, +1 more
- 01 May 1979 - 
TL;DR: In this paper, it is shown that the relative stability of polymorphic modifications of enantiotropic forms is always positive at temperatures above their transition point, and negative at temperatures below the transition point or between monotropic forms.
Journal ArticleDOI

Inferring thermodynamic stability relationship of polymorphs from melting data

TL;DR: The qualitative rule introduced this way for inferring the presence of monotropy or enantiotropy is approximately the same as The Heat of Fusion Rule introduced previously on a statistical mechanical basis.
Journal ArticleDOI

Estimating the relative stability of polymorphs and hydrates from heats of solution and solubility data

TL;DR: The thermodynamic stability relationships of the polymorphs are predicted from the value of T(t) and the melting temperature, and are in good agreement with those reported using other methods, such as differential scanning calorimetry and interpretation of melting data.
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