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Air-Liquid Partition Coefficient for a Diverse Set of Organic Compounds: Henry’s Law Constant in Water and Hexadecane
Citation:
HILAL, S. H., S. N. Ayyampalayam, AND L. A. Carreira. Air-Liquid Partition Coefficient for a Diverse Set of Organic Compounds: Henry’s Law Constant in Water and Hexadecane. ENVIRONMENTAL SCIENCE & TECHNOLOGY. American Chemical Society, Washington, DC, 42(24):9231-9236, (2008).
Impact/Purpose:
The aim of this study was to use the coupled SPARC vapor pressure and activity coefficient models to estimate HLC for molecules with a wide range of functional groups, dipolarities, and H-bonding capabilities in non-polar and polar liquid phases (solvents) strictly from molecular structure, without modification to/or additional parameterization of any of the SPARC physical processes sub- models.
Description:
The SPARC vapor pressure and activity coefficient models were coupled to estimate Henry’s Law Constant (HLC) in water and in hexadecane for a wide range of non-polar and polar solute organic compounds without modification to/or additional parameterization of the vapor pressure or activity coefficient models. The vapor pressure model describes the solute-solute intermolecular interactions in the pure liquid phase while the activity coefficient model describes the solute-solvent and solvent-solvent (in addition to the solute-solute) intermolecular interactions upon placing solute, i, in solvent, j. These intermolecular interactions are factored into dispersion, induction, H-bonding and dipole-dipole components upon moving a solute molecule from the gas to the liquid phase. These models were tested and validated on the largest experimental HLC data set to date; 1354 organic solutes, spanning a wide range of functional groups, dipolarities, and hydrogen-bonding capabilities. The RMS deviation error for the SPARC-calculated versus the experimental log HLC for 1221 compounds in water and for 562 compounds in hexadecane were 0.456 and 0.192 (log (mole/L)/(mole/L)), respectively, spanning a range of more than 13 and 20 log units in water and hexadecane, respectively.
