Determination of air-water partitioning of volatile halogenated hydrocarbons by the inert gas stripping method
- Inst. of Chemical Technology, Prague (Czech Republic). Dept. of Physical Chemistry
Air-water partitioning for 21 volatile chlorinated or brominated alkanes, alkenes, and aromatics was measured at 20 C by the inert gas stripping method. Results of the measurements are presented in the form of Henry`s law constants (H{sub 12}), air-water partition coefficients (K{sub aw}), and limiting activity coefficients ({gamma}), accurate {gamma} values being obtained only if accurate pure solute vapor pressure data are available. The halocarbons studied in this work are hydrophobic and exhibit enhanced volatilities from their dilute aqueous solutions representing approximately ranges of {gamma} from 230 to 70,000 and H{sub 12} from 2 to 70 MPa. Correct performance of the stripping method for such systems requires special precautions. As confirmed by test measurements on benzene, chlorobenzene, 1,1,1-trichloroethane, and 1,1,2-trichloroethane, the complete equilibration in the stripping cell can be achieved under vigorous mixing of the cell, low stripping gas flow rates (approximately 10 cm{sup 3}/min), and low relative elution rates (0.01 min{sup {minus}1}). Choosing for each system a cell of a suitable volume made it possible to comply with the latter requirement. The results compare well with recent literature values obtained by various methods for some of the halocarbons. For two selected halocarbons (bromobenzene and 1,1-dichloroethane), detailed measurements of the temperature dependence of air-water partitioning were carried out in the range of 10--50 C. These measurements corresponding to the range of H{sub 12} from 5 to 72 MPa provide additional support for the validity of the method.
- OSTI ID:
- 556787
- Journal Information:
- Journal of Chemical and Engineering Data, Vol. 42, Issue 5; Other Information: PBD: Sep-Oct 1997
- Country of Publication:
- United States
- Language:
- English
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