Acetonitrile with Heptane (IUPAC SDS Volume 78)
Evaluators
Valerii P. Sazonov Department of Physics, Technical University
Nikolai V. Sazonov Technical University
Evaluation
Quantitative solubility data for the system acetonitrile (1) and heptane (2) have been reported in the publications listed in Table 1.

In addition to these data Francis9 reported the upper critical solution temperature and McLure et al.10 determined of the upper critical temperature solution and critical solution composition for binary solutions of acetonitrile and alkanes (C5-C18). All original data are compiled in the data sheets immediately following this Critical Evaluation.
The upper critical solution temperature of this system has been reported as 356.85 K,7 357.2 K,1 357.8 K,9 and 358.0 K,10 these data are in reasonable agreement and thus their mean value: UCST = 357.5 ±0.5 K is recommended. The corresponding critical solution composition has been reported as xcl = 0.63.10
All experimental values reported2-8 have been approximated by an equation based on the scaling law (described in the introduction to this volume) for which the following parameters have been derived:

a1 = 0.9488, a2= -0.3334, b1 = 5.2227, b2 = -4.8685

(mean standard error of estimate was 0.0138).

For this approximation xcl and UCST values from McLure et al.10 have been used. In the opinion of the evaluators, the mutual solubilities calculated by this equation may be treated as tentative. The results of calculations for the selected temperatures are presented in Table 2. This relationship together with experimental points2-8 are also presented in Fig. 9.
Table 2. Calculated mutual solubility of acetonitrile (1) and heptane (2)
C $T$ ($\pu{K}$) D 100w1 D $x_{1}$
283.2 1.6 3.7 x 10-2
293.2 2.2 5.2 x 10-2
303.2 3.1 7.2 x 10-2
313.2 4.3 9.8 x 10-2
318.2 5.1 1.15 x 10-1
323.2 6.0 1.34 x 10-1
328.2 7.0 1.56 x 10-1
333.2 8.4 1.82 x 10-1
338.2 10.0 2.13 x 10-1
343.2 12.1 2.51 x 10-1
348.2 15.0 3.01 x 10-1
353.2 19.7 3.75 x 10-1
354.2 21.1 3.95 x 10-1
355.2 22.9 4.20 x 10-1
356.2 25.1 4.50 x 10-1
357.2 28.7 4.95 x 10-1
357.7 32.0 5.34 x 10-1
283.2 97.4 9.89 x 10-1
293.2 93.4 9.72 x 10-1
303.2 89.7 9.55 x 10-1
313.2 85.9 9.37 x 10-1
318.2 84.1 9.28 x 10-1
323.2 82.3 9.19 x 10-1
328.2 80.2 9.08 x 10-1
333.2 78.1 8.97 x 10-1
338.2 75.7 8.84 x 10-1
343.2 73.1 8.69 x 10-1
348.2 69.7 8.49 x 10-1
353.2 64.4 8.15 x 10-1
354.2 62.8 8.05 x 10-1
355.2 60.9 7.92 x 10-1
356.2 58.5 7.75 x 10-1
357.2 54.6 7.46 x 10-1
357.7 50.9 7.17 x 10-1

Figure
Solubility graph
Sources:

1 Comish, R. E.; Archibald, R. C.; Murphy, E. A.; Evans, H. M.; Ind. Eng. Chem. 26, 397-406 (1934).
2 Kharitonova, G. I.; Ph.D. Dissertation, Saratov University 1971.
3 Palmer D. A.; Smith, B. D.; J. Chem. Eng. Data 17, 71 (1972).
4 Kikic I.; Alessi, P.; Ann. Chim. (Rome) 64, 363 (1974).
5 Tripathi, R.P.; Asselineau, L.; J. Chem. Eng. Data 20, 33 (1975).
6 Lakhanpal, M. L.; Mandal, N. J.; Ahuja, S. C.; Indian J. Chem. 20A, 1008 (1981).
7 Vinogradova L. M.; Shcherbina, A. E.; Zh. Fiz. Khim. 57, 1268 (1983).
8 Nagata, I.; Thermochim. Acta 114, 227 (1987).
9 Francis, A. W.; 'Critical Solution Temperatures' Adv. Chem. Ser. 31 (1961).
10 McLure, I. A.; Rodriguez, A. T.; Ingham, P. A.; Steele, J. F.; Fluid Phase Equilib. 8, 271 (1982).