IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

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 Solubility System: 1-Proponal with Cyclohexane and Water

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Components:
   (1) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail
   (2) 1-Proponal (n-propanol, propyl alcohol, n-propyl alcohol); C3H8O; [71-23-8]  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 1-propanol-cyclohexane-water is given in Table 44.

Saturation Curve    The ternary system 1-propanol-cyclohexane-water forms a miscibility gap of type 1 covering the majority of the concentration triangle. Studies of the system were reported in three references at 298.2 K. Only Washburn et al.,¹ also investigated this system at 308.2 K. All saturation data are consistent. Only the cyclohexane-water binary system forms a miscibility gap. The data for the binary system were compiled and critically evaluated in a previously published SDS volume;⁴ the recommended values at 298.2 K are x"₂=1.2·10^–5 and x'₃=3.7·10^–4. The end points of the saturation curve, Ref. 2 were reported to be x₂=0.998 and pure water which is not consistent with recommended values. However, these results are within the accuracy of experimental measurements (0.005 mole fraction) stated by the authors. One experimental point in the water-rich phases³ was reported to be x₁=0.053, x₂=0.000, which may suggest that 1-propanol is only partially soluble in water. This numerical result reflects a lack of sensitivity of the analytical method used for cyclohexane in the water-rich phase. All experimental solubility and equilibrium data reported at 298.2 K in Refs. 1,2, and 3, were used to consturct the equation: x₁=a₁·(ln z₁)^a2·z₁^a23. where z₁=(x₂+0.5· x₁–x"₂₀)/(x'₂₀–x"₂₀), x₁, x₂–mole fractions of component (1) and (2), respectively, x'₂₀, x"₂₀–values of x₂ on the binodal curve which cuts the x₁=0 axis. This equation has been proposed by Letcher et al.⁵ for the description of saturation curves of the ternary alcohol-ether-water systems. It gives better results (the smallest standard deviation) for the investigated system than any other tested equation. The parameters obtained by the least-squares method for the whole range of miscibility gap (water-rich and hydrocarbon-rich branches were described together) are: a₁=1.50825, a₂=0.98056, a₃=1.28405. The standard error of estimate was 0.0084. For selected concentrations of cyclohexane in the mixture, saturation curve was calculated by the above equation. The results are presented in the Table 45 and in Figure. 22 as solid line.

Phases in equilibrium    Compositions of coexisting phases in the ternary system 1-propanol-cyclohexane-water at equilibrium were reported in all three references at 298.2 and at 308.2 K (Ref. 1). The tie lines cover the full area of the miscibility gap. The reported equilibrium data sets are not always consistent with one another, although they are consistent within each data set. Inconsistency is observed at the region near the plait point (the water-rich phase in equilibrium with the organic phase containing more than 0.25 mole fraction of alcohol). The data for phases in equilibrium are considered tentative. All experimental tie lines as well as experimental points, Refs. 1, 2, and 3 at 298.2 K are shown in Figure. 22 .

Experimental Data:   (Notes on the Nomenclature)

TABLE 44. Summary of experimental data for the system 1-propanol-cyclohexane-water

Author	T/K	DataType	Reference
Washburn et al., 1942	298, 308	sat. (32), eq. (18)	1
Letcher et al., 1991	298	sat. (15), eq. (5)	2
Plackov and Stern, 1992	298	sat. (20), eq. (5)	3

TABLE 45. 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. 4
298.2	0.0288	0.0010
298.2	0.1697	0.0100
298.2	0.2233	0.0200
298.2	0.2870	0.0400
298.2	0.3279	0.0600
298.2	0.3572	0.0800
298.2	0.3791	0.1000
298.2	0.3958	0.1200
298.2	0.4085	0.1400
298.2	0.4181	0.1600
298.2	0.4251	0.1800
298.2	0.4299	0.2000
298.2	0.4328	0.2200
298.2	0.4342	0.2400
298.2	0.4341	0.2600
298.2	0.4327	0.2800
298.2	0.4303	0.3000
298.2	0.4267	0.3200
298.2	0.4223	0.3400
298.2	0.4170	0.3600
298.2	0.4109	0.3800
298.2	0.4041	0.4000
298.2	0.3966	0.4200
298.2	0.3885	0.4400
298.2	0.3798	0.4600
298.2	0.3705	0.4800
298.2	0.3607	0.5000
298.2	0.3504	0.5200
298.2	0.3397	0.5400
298.2	0.3285	0.5600
298.2	0.3169	0.5800
298.2	0.3049	0.6000
298.2	0.2925	0.6200
298.2	0.2797	0.6400
298.2	0.2666	0.6600
298.2	0.2531	0.6800
298.2	0.2394	0.7000
298.2	0.2253	0.7200
298.2	0.2109	0.7400
298.2	0.1963	0.7600
298.2	0.1813	0.7800
298.2	0.1661	0.8000
298.2	0.1506	0.8200
298.2	0.1349	0.8400
298.2	0.1189	0.8600
298.2	0.1026	0.8800
298.2	0.0861	0.9000
298.2	0.0694	0.9200
298.2	0.0524	0.9400
298.2	0.0352	0.9600
298.2	0.0176	0.9800
298.2	0.0088	0.9900
298.2	0.0000	0.999 63 Ref. 4

View Figure 1 for this Evaluation

Notes:
Table 44  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  Letcher, T.M.; Siswana, P.; Radloff, S.E., S. Afr. J. Chem. 44, 118 (1991).
   3  Plackov, D.; Stern, I., Fluid. Phase Equilib. 71, 189 (1992).
   4  Shaw, D.G., ed., Solubility Data Series, Vol. 37, Hydrocarbons with Water and Seawater, Part I: Hydrocarbons C5 to C7 (Pergamon, New York, 1989).
   5  Letcher, T.M.; Ravindran, S.; Radloff, S.E., Fluid Phase Equilib, 69, 251 (1991).

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