Estimating Enthalpy of Vaporization from Vapor Pressure Using Trouton's Rule

The enthalpy of vaporization of liquids and subcooled liquids at 298 K ( ) is an important parameter in environmental fate assessments that consider spatial and temporal variability in environmental conditions. It has been shown that for non-hydrogen-bonding substances can be estimated from vapor pressure at 298 K ( ) using an empirically derived linear relationship. Here, we demonstrate that the relationship between and is consistent with Trouton's rule and the Clausius-Clapeyron equation under the assumption that is linearly dependent on temperature between 298 K and the boiling point temperature. Our interpretation based on Trouton's rule substantiates the empirical relationship between and for non-hydrogen-bonding chemicals with subcooled liquid vapor pressures ranging over 15 orders of magnitude. We apply the relationship between and to evaluate data reported in literature reviews for several important classes of semivolatile environmental contaminants, including polycyclic aromatic hydrocarbons, chlorobenzenes, polychlorinated biphenyls and polychlorinated dibenzo-dioxins and -furans and illustrate the temperature dependence of results from a multimedia model presented as a partitioning map. The uncertainty associated with estimating from using this relationship is acceptable for most environmental fate modeling of non-hydrogen-bonding semivolatile organic chemicals.