Two sets of experimental data have been reported in the literature for the solubility of liquid l,4-dichlorobenzene in water (1,2). Klemenc and Low (1) reported measurements in the temperature range between 328 and 333 K while Wauchope and Getzen (2) reported data in the narrow temperature interval between 332 and 346 K, see Figure 1. There is, however, a considerable discrepancy between the two results. For example, at 333 K, the difference is about 25 percent between the reported solubility values.
While the early solubility measurements of Klemenc and Low (1) in 1930 used the volumetric determination of the excess solute, the more recent determination of Wauchope and Getzen (2) in 1972 employed the extraction method followed by spectrophotometric analysis. The reagents used in the latter investigation were of higher purity.
Klemenc and Low (1) did not state the accuracy or the reliability of their method; neither duplicate nor triplicate samples were taken. Their temperature control during the equilibration periods of their measurements was about ± 1 K. Therefore, a conservative estimate of the possible errors in their solubility determinations is about ± 10 percent. The investigation of Wauchope and Getzen (2) was done under much more controlled conditions. The time required for completion of the equilibrium was assured in the experiment and replicate samples were always withdrawn and analyzed. The shorter equilibration times in the measurements of Klemenc and Low (1) may well account for the low solubility values at 328 and 333 K.
The solubility data of Wauchope and Getzen (2) have been assigned a higher weight in the establishment of recommended solubility values. The data have been correlated against Absolute temperature using the following second degree polynomial equation:
S1(g(l)/kg) = 13.974 - 8.5829 x 10-2 T +
1.3365 x 10-4 T2 [1]
Recommended solubility values calculated from equation [1] together with corresponding molarity and mole fraction values are listed 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. The recommended molar concentrations and mole fractions have been calculated from the g(1)/kg and the densities of thw two components at the equilibrium temperatures indicated.