In the former measurements (1), a conventional experimental procedure was employed. Commercial reagents without further purification were used for the measurements which were done at room temperature (25 ± 1°C). The time for sample equilibration varied from 4 to 48 hours. The exact time was not reported in single cases. The saturated sample analyses were carried out spectrophotometrically either after dilution or after concentration by extraction with methylene chloride. At least two independent determinations were made. However, the separate measurements were not reported and the precision of the measurements is difficult to estimate. According to the authors in a private communication (3), the error in their solubility measurement may be as great as 10 percent. The estimate seems reasonable for the following reasons. First, the variation of temperature was considerable. Second, the sample equilibration time was sufficiently long to assure an accuracy of ± 5 percent but hardly better. The filtering and extraction procedures may well have produced further errors, so the total 10 percent error seems reasonable. The possible systematic errors should have no effect on the correlations obtained. Therefore, solubilities of comparable accuracy for many purposes may be calculated from the reported solubility correlations.

The latter investigation (2) was based upon a radiochemical analysis. Although temperature regulation and time for equilibration seemed to have received sufficient attention, the result deviates far more than 10 percent from the value reported in (1). The accuracy of the latter measurements also depends upon the radiochemical purity of the substrate, a property which was not tested. The uncertainty of radiochemical purity may account in part for the deviation from the spectrophotometrically determined value.

The solubility of 1,2,3,5-tetrachlorobenzene in water is reported here as a tentative value based upon the spectrophotometric determinations (1):

Experimental Data:   (Notes on the Nomenclature)