IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

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 Solubility System: 2-Propanol with Cyclohexane and Water

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Components:
   (1) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail
   (2) 2-Propanol (isopropanol, isopropyl alcohol); C3H8O; [67-63-0]  NIST Chemistry WebBook for detail
   (3) Cyclohexane; C6H12; [110-82-7]  NIST Chemistry WebBook for detail

Evaluator:
   A. Skrzecz, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland (1997.04)

Critical Evaluation:

      A survey of reported compositions along the saturation curve (sat), and compositions of coexisting phases in equilibrium (eq.) for the system 2-propanol-cyclohexane-water is given in Table 59.

Saturation curve    The ternary system 2-propanol-cyclohexane-water forms a miscibility gap of type 1. The system was studied five times at the same temperature, 298.2 K. Saturation data are consistent within and between each reference. The exceptions are two points for the cyclohexane-rich phase reported with the evident experimental errors in the paper of Verhoeye² (x₁=0.213 and x₁=0.040). Only one binary system, cyclohexane-water, forms a miscibility gap. The data for this binary system were compiled and critically evaluated in a previously published SDS volume, Ref. 6; the recommended values at 298.2 K are x"₂1.2·10^–5 and x'₃=3.7·10^–4. All experimental solubility and equilibrium data reported at 298.2 K were used for calculation of saturation curve. (Water-rich and hydrocarbon-rich branches were treated together.) These data were described by the equation: x₁=0.475 90+0.056 28 ln(x₂)–0.113 24x₂–058 67x²₂.    The parameters were calculated by the least-squares method and the standard error of estimate was 0.0156. Selected points on the saturation curve, calculated by the above equation are presented in Table 60 for selected concentrations of cyclohexane in the mixture and in Figure 30 as calculated binodal curve (solid line).

Phases in equilibrium    Compositions of coexisting phases in equilibrium for the ternary system 2-propanol-cyclohexane-water were reported in all references at 298.2 K and tie lines cover the full miscibility gap. The reported plait point, Ref. 3, was x=0.3982 and x₂=0.2776. In the area close to the plait point there are small differences in the direction of tie lines. There is a nearly uniform distribution of alcohol between the phases, the concentration of 2-propanol in the equilibrium phases differs by no more than 0.03 mole fraction. In the water-rich phase, when x₁<0.15, the concentration of cyclohexane is very low, x₂<0.002. The reported equilibrium data sets are consistent with one another and within each data set. The exceptions are two points of the cyclohexane-rich phase reported with evident experimental errors in the paper of Verhoeye² (as discussed above in the description of saturation curve). The data for phases in equilibrium are considered tentative. All experimental tie lines as well as all experimental points, Refs. 1-5, at 298.2 K, are reported in Figure 30 .

Experimental Data:   (Notes on the Nomenclature)

TABLE 59. Summary of experimental data for the system 2-propanol-cyclohexane-water

Author	T/K	DataType	Reference
Washburn et al., 1942	298	sat. (13), eq. (8)	1
Verhoeye, 1968	298	sat. (27), eq. (8)	2
Nikurashina and Sinegubova, 1973	298	sat. (20), eq. (14)	3
Letcher et al., 1991	298	sat. (14), eq. (6)	4
Plackov and Stern, 1992	298	sat. (21), eq. (7)	5

TABLE 60. Calculated composition along the saturation curve at 298.2 K

T/K	Mole Fraction x1	Mole Fraction x2
298.2	0.0000	0.000 012 Ref. 6
298.2	0.0873	0.0010
298.2	0.2178	0.0100
298.2	0.2578	0.0200
298.2	0.2983	0.0400
298.2	0.3222	0.0600
298.2	0.3390	0.0800
298.2	0.3517	0.1000
298.2	0.3615	0.1200
298.2	0.3694	0.1400
298.2	0.3756	0.1600
298.2	0.3804	0.1800
298.2	0.3840	0.2000
298.2	0.3866	0.2200
298.2	0.3883	0.2400
298.2	0.3891	0.2600
298.2	0.3890	0.2800
298.2	0.3882	0.3000
298.2	0.3867	0.3200
298.2	0.3745	0.3400
298.2	0.3816	0.3600
298.2	0.3780	0.3800
298.2	0.3738	0.4000
298.2	0.3690	0.4200
298.2	0.3636	0.4400
298.2	0.3576	0.4600
298.2	0.3510	0.4800
298.2	0.3438	0.5000
298.2	0.3361	0.5200
298.2	0.3278	0.5400
298.2	0.3189	0.5600
298.2	0.3095	0.5800
298.2	0.2996	0.6000
298.2	0.2891	0.6200
298.2	0.2780	0.6400
298.2	0.2665	0.6600
298.2	0.2544	0.6800
298.2	0.2417	0.7000
298.2	0.2286	0.7200
298.2	0.2149	0.7400
298.2	0.2007	0.7600
298.2	0.1860	0.7800
298.2	0.1708	0.8000
298.2	0.1550	0.8200
298.2	0.1388	0.8400
298.2	0.1220	0.8600
298.2	0.1047	0.8800
298.2	0.0870	0.9000
298.2	0.0687	0.9200
298.2	0.0499	0.9400
298.2	0.0306	0.9600
298.2	0.0108	0.9800
298.2	0.0007	0.9900
298.2	0.0000	0.999 63 Ref. 6

View Figure 1 for this Evaluation

Notes:
Table 59  Number of experimental points in parentheses.

References: (Click a link to see its experimental data associated with the reference)

   1  Washburn, E.R.; Graham, C.L.; Arnold, G.B.; Transue, L.F., J. Am. Chem. Soc. 62, 1454 (1940).
   2  Verhoeye, L.A.J., J. Chem. Eng. Data 13, 462 (1968).
   3  Nikurashina, N.I.; Sinegubova, S.I., Zh. Obshch. Khim. 43, 2100 (1973).
   4  Letcher, T.M.; Siswana, P.; Radloff, S.E., S. Afr. J. Chem. 44, 118 (1991).
   5  Plackov, D.; Stern, I., Fluid. Phase Equilib. 71, 189 (1992).
   6  Shaw, D.G., ed., Solubility Data Series, Vol. 37, Hydrocarbons with Water and Seawater, Part I: Hydrocarbons C5 to C7 (Pergamon, New York, 1989).

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Last updated: February 18, 2015 (Created: August 17, 2007)