| Title: | Temperature dependence of Henry's law constant in an extended temperature range |
| Author(s): | Gorgenyi M; Dewulf J; Van Langenhove H; |
| Address: | "Institute of Physical Chemistry, University of Szeged, P.O. Box 105, H-6701 Szeged, Hungary. gorgenyi@chem.u-szeged.hu" |
| DOI: | 10.1016/s0045-6535(02)00131-5 |
| ISSN/ISBN: | 0045-6535 (Print) 0045-6535 (Linking) |
| Abstract: | "The Henry's law constants H for chloroform, 1,1-dichloroethane, 1,2-dichloropropane, trichloroethene, chlorobenzene, benzene and toluene were determined by the EPICS-SPME technique (equilibrium partitioning in closed systems--solid phase microextraction) in the temperature range 275-343 K. The curvature observed in the ln H vs. 1/T plot was due to the temperature dependence of the change in enthalpy delta H0 during the transfer of 1 mol solute from the aqueous solution to the gas phase. The nonlinearity of the plot was explained by means of a thermodynamic model which involves the temperature dependence of delta H0 of the compounds and the thermal expansion of water in the three-parameter equation ln (H rho TT) = A2/T + BTB + C2, where rho T is the density of water at temperature T, TB = ln(T/298) + (298-T)/T, A2 = -delta H298(0)/R, delta H298(0) is the delta H0 value at 298 K, B = delta Cp0/R, and C2 is a constant. delta Cp0 is the molar heat capacity change in volatilization from the aqueous solution. A statistical comparison of the two models demonstrates the superiority of the three-parameter equation over the two-parameter one ln H vs. 1/T). The new, three-parameter equation allows a more accurate description of the temperature dependence of H, and of the solubility of volatile organic compounds in water at higher temperatures" |
| Keywords: | Organic Chemicals/*chemistry Temperature *Thermodynamics; |
| Notes: | "MedlineGorgenyi, Miklos Dewulf, Jo Van Langenhove, Herman eng Research Support, Non-U.S. Gov't England 2002/08/31 Chemosphere. 2002 Aug; 48(7):757-62. doi: 10.1016/s0045-6535(02)00131-5" |
