Solubilities in the system comprising acetonitrile and carbon disulfide have been reported in four publications.
Poppe¹ determined the upper critical solution temperature and the effect of pressure (0.58 to 9.8 MPa) by the synthetic method. Dorby² determined the upper critical solution temperature. Mutual solubility of (1) and (2) was studied also by Govindaraian et al.³ between 320 and 323 K by the visual observation method. Sivaraman et al.⁴ between 319 and 324 K and between 0.1 and 4.05 MPa measured the mutual solubilities of (1) and (2) using the synthetic method and these data were reported in graphical form, numerical data were extracted from the published graphs for this evaluation.
The upper critical solution temperature has been reported as 323.36 K^3-4, 324.05 K¹ and 324.2 K². The data^1-3 are in reasonable agreement and thus their average value: UCST = 323.7 ±0.4 K is recommended. The corresponding critical solution composition has been reported in as x_cl = 0.408³ and x_cl = 0.409⁴. These data give an average x_cl = (0.408 ±0.001), which is recommended.
The value of dT_c/dP was reported to be 0.0197 K·kPa^-1 by Poppe¹ and be 0.247 K·MPa^-1 by Sivaraman et al.⁴
All experimental values reported in Govindaraian et al.³ and Sivaraman et al.⁴ 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 = 0.7194, a₂= 1.5113, b₁ = 10.9953, b₂ = -6.4110

(mean standard error of estimate was 0.0115).
For approximation x_cl and UCST from data^3,4 have been used. In the opinion of the evaluator, the mutual solubilities calculated by this equation may be treated as tentative. The results of calculations for the selected temperatures are presented in the following table. This relationship, together with experimental points reported in the data,^3,4 are also presented in Fig. 3.