The Henry's law coefficient of 2-nitrophenol over the temperature range 278–303 K

Abstract

Although 2-nitrophenol has been identified as an important environmental chemical there is scarcity in the literature regarding the temperature dependence of its Henry's law coefficient, H. Here a bubble purge method was used to measure H for 2-nitrophenol over the temperature range 278-303 K. A novel approach in the data treatment allowed correction of the data for non-equilibrium partitioning in the apparatus to obtain the true equilibrium H value. The experimentally derived temperature-dependent expression for H of 2-nitrophenol is lnH (M atm(-1)) = (6290/T (K)) - 16.6. The standard enthalpy and entropy of gas-to-liquid transfer for 2-nitrophenol in aqueous solution are -52.3 +/- 8.1 kJ mol(-1) and -138 +/- 28 J mol(-1) K(-1), respectively. (Errors are 95% confidence intervals.)

Experimentally determined Henry's Law coefficients of phenol, 2-methylphenol and 2-nitrophenol in the temperature range 281–302K

“…The fit to our temperature-dependent data for 2-nitrophenol yields a dln H/d(1/T) coefficient of 6270 K. The three coefficients reported previously are 4600 (Staudinger and Roberts, 1996), 6200 ( Tremp et al, 1993) and 9600 K (Rippen et al, 1987) ( Table 4). The ΔH0 and ΔS0 values for gas-to-liquid equilibrium partitioning of 2nitrophenol (Table 5) agree extremely well with the values of ΔH0=−52.3±8.1 kJ mol−1 and ΔS0=−138±28 J mol−1 K−1 from the preliminary work by Müller and Heal (2001), using the same technique.…”

“…The pressure p nonequil signifies the general case of the gas not being in equilibrium with the aqueous concentration c at the top of the column. Müller and Heal (2001) extended the analysis in order to derive H equil from the measurements of H non-equil as a function of column depth, z. In brief, substitution of Eq.…”

“…The column-stripping apparatus (height 51 cm, internal diameter 2.4 cm) is described by Müller and Heal (2001). Isothermal conditions were maintained by pumping a coolant from a temperature-controlled recirculation bath through a concentric jacket surrounding the column.…”

“…As each bubble rises up through the solution in the column, the solute partitions into the gas phase according to its Henry's Law coefficient. Previously, we reported on a method to derive the true value of Henry's Law coefficient when equilibrium of solute with the gas phase is not quite achieved before the bubble reaches the top of the liquid column, using 2-nitrophenol as an example (Müller and Heal, 2001). Here, we report new primary H data for phenol and 2-methylphenol (o-cresol), and a remeasurement of H for 2-nitrophenol, over a temperature range relevant to environmental processes.…”

Absorption Cross Sections of 2-Nitrophenol in the 295–400 nm Region and Photolysis of 2-Nitrophenol at 308 and 351 nm

“…The partition between the atmospheric gas and the liquid phase is different for different nitrophenols. For example, 2-nitrophenol is much more hydrophobic than 4-nitrophenol, 59 which can displace 2-nitrophenol toward the gas phase and leave the less volatile 4-nitrophenol being preferentially present in the aqueous phase. 7,21,22 For 2-nitrophenol, its Henry's law constant in the aqueous phase 59 is small (81 M atm −1 at 298 K).…”