Quantitative solubility data for the nitromethane + 1-pentanol have been reported in the publications listed in Table 1.All the original data are compiled in the data sheets immediately following this Critical Evaluation. Among the available data, the values of Anisimov and Shakhparonov2 were excluded from further consideration as only a graphical presentation was given. Some individual points in the alcohol-rich phase, in otherwiswe satisfactory studies, are in marked disagreement with other studies and have been rejected: Ref. 3 (298 K) and Ref. 5 (288 K). All other reported data are included in the tables below.
Values, obtained by the Evaluators by graphical interpolation or extrapolation from the data sheets, are indicated by an asterisk (*). "Best" values have been obtained by simple averaging. The uncertainty limits (σn) attached to these values do not have statistical significance and should be regarded only as a convenient representation of the spread of values rather than as error limits.
It will be noted from the tables following that there are serious disagreements among the solubility data reported by independent workers for the system nitromethane + 1-pentanol. This is reflected in the large σn values. No one study or any of the averaged values can be singled out for recommendation and clearly this system requires a careful and thorough reinvestigation over the entire temperature range. The values given in Tables 2 and 3 should be regarded as tentative only until further independent studies can be made.
The upper critical solution temperature has been reported as 298.2 K,1 299.2 K,4 300.9 K,2 300.93 K,3 and 301.0 K.5 The UCSTs reported in both Refs. 1 and 4 are rather lower than the remaining data and are therefore rejected. The values of Refs 2, 3 and 5 are in excellent agreement and their averaged value UCST = (300.9 ± 0.1) K is recommended.
The corresponding critical solution composition has been reported as xc1 = 0.614,2 xc1 = 0.615,5 xc1 = 0.616,3 xc1 = 0.624,4 and xc1 = 0.629.1 Again the values of Refs. 1 and 4 are rejected and the average of the remaining three references, xc1 = 0.615 ± 0.001, (100 w1 = 52.5) is recommended. It is noteworthy that the critical solution composition (even including the rejected data) does not appear to suffer from the uncertainties seen in the solubilities at other temperatures (Tables 2 and 3).
The recommended UCST and critical solution composition are consistent with the values calculated from the respective relationships in the nitromethane - alcohol series, discussed at the beginning of this volume (the calculated values are: UCST = 300.9 K and xc1 = 0.615).
The "best" values for the mutual solubility reported in the above tables have been approximated by the equation based on scaling law (described in the Introduction material to this volume "Relations of Solubility Data in Binary Systems Containing Nitromethane") and the following parameters have been adjusted:
a1 = 0.85156, a2 = 0.12663, b1 = 0.72213, b2 = -1.05905(mean standard error of estimate was 0.0106).
For an approximation, recommended values of UCST and xc1 have been used. This relationship is presented in Fig. 24 together with experimental data reported in Refs. 1, 3, 4, and 5.