Posted in Contact Angle, D L Williams, Hansen Solubility Parameters, Solubility

Solubility Spheres

When working with industrial scale recrystallizations, a few more grams per liter improvement in solubility can save a substantial amount of time and MONEY. 

Williams, D. L.; Kuklenz, K. D., A Determination of the Hansen Solubility Parameters of Hexanitrostilbene (HNS), Propellants Explosives and Pyrotechnics, 34(5), 452-457, (2009) 

Abstract
The temperature-dependent solubility of hexanitrostilbene (HNS) [CAS# 20062-22-0] was determined in ten solvents and solvent blends using the Tyndall effect. Thermodynamic modeling of the data yielded Flory interaction parameters, the molar enthalpy of mixing, the molar entropy of mixing, and the molar Gibbs energy of mixing. All solutions exhibited endothermic enthalpies and positive entropies of mixing. The presence of water in some of the solvent blends made dissolution increasingly endothermic and disfavored solubility. The solubilities of HNS at 25 °C were used to determine the three-component Hansen solubility parameters (HSP) (δD=18.6, δP=13.5, δH=6.1 MPa1/2) and the radius of the solubility sphere (R0=5.8 MPa1/2). The HSP determined for HNS using group-additivity (δD=21.0, δP=13.3, and δH=8.6 MPa1/2) also correctly predicted the optimum solvents for this explosive.

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Author:

Dr. Darren L. Williams (pchem4u) is an Associate Professor of Physical Chemistry at Sam Houston State University. When he is not blending solvents, he is tinkering with contact angle measurements, FTIR microspectroscopy, etc. http://www.shsu.edu/~chm_dlw/ . He welcomes your comments and questions by phone (936-294-1529) and by email (williams “at” shsu.edu).

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