Five experimental determinations have been published on the solubility of iodobenzene in water in the temperature interval between 278 and 318 K (1-4,8), see Figure 1. The serious discrepancies between the various solubility measurements for iodobenzene in water are evident in Figure 1. The solubility of water in iodobenzene between 298 and 308 K has been reported in two publications (5,6), see Figure 2.
Some of the more recent data for the solubility of iodobenzene in water is that of Nelson and Smit (3) in the temperature range between 278 and 318 K. However, despite equilibrium periods of 24 hours (which might not have been long enough), the measured solubilities are substantially lower than those found by earlier investigators. It is not possible to establish any shortcomings of the experimental procedures from the very brief description. No information was provided on the source and purity of materials used. Also, it was not indicated whether or not a water stripper had been employed for the analysis of the very dilute aqueous solutions by gas chromatography, or whether or not an internal standard had been used for the calibration of the gas chromatograph which employed a flame ionization detector. However, the authors agreed to re-examine their raw data in order to verify the reported values (7). Consequently, for the present evaluation, their results have not been considered for inclusion in the selected solubility values.
The solubility value for iodobenzene in water reported by Gross et al. (2) is too high in relation to other reported values (1,4). While the equilibration time was 20 hours for measurements made by Andrews and Keefer (1), the time was 48 hours for those of Vesala (4). This equilibration time difference may have affected the reported results. For this reason, the higher solubility value given by Vesala is recommended, see Table 1. The remaining available data have been correlated relative to Absolute temperature using a normal polynomial equation:
S1(g)1)/kg) = 0.59293 - 4.8616 x 10-3T
+ 1.21754 x 10-5T2 [1]
The values calculated from equation [1] for the saturation of iodobenzene in water in the range of temperatures between 283 and 318 K together with corresponding molarities and mole fractions are given in Table 1. Also, the solubility values calculated from equation [1] are shown in Figure 1 as a solid line along with the measured values.
For the solubility of water in iodobenzene, the agreement between the two solubilities reported by Jones and Monk (5) and by Wing and Johnston (6) at 298.15 K is quite good. At higher temperatures, measurements were made only by Jones and Monk (5); therefore, there are no other data for comparison. The data from both investigations (5,6) were correlated using the following equation:
1og10 x(2) = 0.792324 - 985.707/T [2]
In this equation, x(2) is the mole fraction solubility of water in the water-iodobenzene system and I is the Absolute temperature. The calculated solubility values in the 283 to 308 K range are shown in Figure 2 along with the reported values.
The calculated mole fraction values for the solubility of water in iodobenzene from equation [2] are included in Table 2 together with the corresponding molarities and g(2)/kg values in the temperature range between 293 and 313 K.