Variation with temperature of octanol/water partition coefficient for the homologous series from benzene to propylbenzene

Abstract

Variation of octanol/water partition coefficient, log Kow, with temperature is seldom reported in the literature. A precise method for the evaluation of log Kow has been developed and the values of this parameter were measured for benzene, toluene, ethylbenzene, and n‐propylbenzene at six temperatures between 15 and 60°C. The procedure is based on a direct “shake flask” method, but utilizes a gas chromatography with mass spectrometry method for the measurement of the concentration of analytes in the water and octanol extracts. The results indicate that log Kow values for these analytes have only small variations with the temperature, and that this variation does not depend linearly on 1/T. The results for log Kow in the evaluated temperature interval are close to the values reported in the literature for log Kow at 25°C. The variations of log Kow were found to be small and are non‐linear in 1/T. Based on these variations the enthalpy ΔH0 and entropy ΔS° for the partition process were calculated. The obtained values for ΔH0 and ΔS0 indicated that for temperatures below about 40°C the process is entropy‐driven and does not involve large Gibbs free energies.

A critical review of the influence of groundwater level fluctuations and temperature on LNAPL contaminations in the context of climate change

“…However, a striking opposite effect is, nevertheless, observed for BTEX (Tab. 1, David and Moldoveanu, 2019).…”