Aqueous solubility, Henry’s law constants and air/water partition coefficients of n-octane and two halogenated octanes

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New data on the aqueous solubility of n-octane, 1-chlorooctane and 1-bromooctane are reported between 1 °C and 45 °C. Henry’s law constants, K H, and air/water partition coefficients, K AW, were calculated by associating the measured solubility values to vapor pressures taken from literature. The mole fraction aqueous solubility varies between (1.13–1.60) × 10 −7 for n-octane with a minimum at approximately 23 °C, (3.99–5.07) × 10 −7 for 1-chlorooctane increasing monotonically with temperature and (1.60–3.44) × 10 −7 for 1-bromooctane with a minimum near 18 °C. The calculated air–water partition coefficients increase with temperature and are two orders of magnitude lower for the halogenated derivatives compared to octane. The precision of the results, taken as the average absolute deviations of the aqueous solubility, the Henry’s law constants, or the air/water partition coefficients, from appropriate smoothing equations as a function of temperature is of 3% for n-octane and of 2% and 4% for 1-chlorooctane and 1-bromooctane, respectively. A new apparatus based on the dynamic saturation column method was used for the solubility measurements. Test measurements with n-octane indicated the capability of measuring solubilities between 10 −6 and 10 −10 in mole fraction, with an estimated accuracy better than ±10%. A thorough thermodynamic analysis of converting measured data to air/water partition coefficients is presented.