Solubility System: Nitroethane with 2,2,4-Trimethylpentane (Original Report)

Critical Review (-):
Quantitative solubility data for the system nitroethane (1) + 2,2,4-trimethylpentane (2) were reported in the publications listed in Table 1.

Beysens and Tufeu7 determined of the variation of the critical temperature as a function of pressure (from 500 to 12500 kPa). All original data are compiled immediately following this Critical Evaluation.
The data point for the nitroethane-rich phase at 298 K (Hsu and Clever3) is marked disagreement with other studies and is therefore rejected. The table below has been prepared on the basis of all other reported data. Values obtained by the evaluator by graphical interpolation or extrapolation from the data sheets are presented in the Table 2 and Table 3. Data are "recommended" if two or more apparently reliable studies are is reasonable (±5% relative) agreement. All other data are regarded as tentative only.

The upper critical solution temperature (USCT) has been reported as 302.15 K,6 302.7 K,2 303.0 K,1 303.18 K,4 and 303.20 K.5 The UCST of Battler and Rowley6 is rejected. Thus, the recommended value is: Tc = (303.0 ±0.2) K.
The corresponding critical solution composition has been reported as xcl = 0.491 (Vreeland and Dunlap1), xcl = 0.569 (Beysens4) and xcl = 0.5692 (Tanaka and Wada5). The xcl of Vreeland and Dunlap1 is rejected. The data average xcl = 0.569. This value is recommended.
The recommended and tentative values for the mutual solubility reported in Table 2 and Table 3 have been approximated by an equation based on the scaling law (described in the preface to this volume) for which the following parameters were derived: a1 = 0.95870, a2 = -0.24393, b1 = 1.50442, b2 = 1.68914 (mean standard error of estimate was 0.0118).
For this approximation, recommended values of UCST and xcl have been used. This relationship is presented in Fig. 7 together with experimental data reported in several references.1,2,4

Experimental Data:
Table 1
T (K)w1 (tentative)x1 (tentative)
278.2 8.7 x 10-20.126
283.210.7 x 10-20.155
288.213.2 x 10-20.188
293.215.3 x 10-20.212
298.222.3 x 10-20.304
300.228.9 x 10-20.382
302.233.3 x 10-20.432
Table 2
T (K)w2 (tentative)x2 (tentative)
278.214.5 x 1020.1
283.216.6 x 1020.115
288.219.5 x 1020.137
293.223.4 x 1020.167
298.228.7 x 1020.209
300.231.8 x 1020.234
302.238.2 x 1020.288
Figure 1

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