IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: Ethanol with Hexane (n-hexane) with Water

Components:
   (1) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail
   (2) Ethanol (ethyl alcohol); C2H6O; [64-17-5]  NIST Chemistry WebBook for detail
   (3) Hexane (n-hexane); C6H14; [110-54-3]  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.) and distribution of ethanol between phases (distr.) for the system ethanol-hexane-water is given in Table 23.

Saturation curve The ternary system ethanol-hexane-water forms a miscibility gap of type 1. The data are discussed on the basis of original papers with the exception of data of Ormandy and Craven,² which wre taken from the handbook of Kafarov,⁸ these data were also taken into account during evaluation but are not reported as compilation sheet because they do not contribute further to knowledge of the system. The influence of pressure over the range 0.1-200 MPa at 298 K was also studied;⁷ the maximum concentration of ethanol on the saturation curve varies from x₁=0.660 at p=0.1 MPa to x₁=0.711 at p=200 MPa. Only the binary system hexane-water forms a miscibility gap. Data for this binary system were compiled and critically evaluated in a previously published SDS volume.⁹ The values of mutual solubility of hexane-water system recommended at 298.2 K are: x'₂=2.3·10^–6 and x"₂=0.999 53. The data of Tarasenkov and Paulsen at 273 and 298 K,³ show larger miscibility gaps than any other data set, they are inconsistent and therefore rejected. The measurements of Vorobeva and Karapetyants,⁵ and Ross and Patterson,⁶ were made with the accuracy of 0.001 mass fraction, and therefore the reported solubilities of binary system hexane-water in these references are outlayers. One of the experimental points measured by Mertslin et al.,⁴ (x₁=0.5582, x₂=0.3033) is inconsistent and therefore is also rejected. Data of Bonner¹ measured at 273 K show a slightly larger immiscability region which is in agreement with general expectation. A maximum vale of ethanol concentration on the saturation curve of x₁=0.66 is observed at 298.2 K (Refs. 5 and 7). The temperature 298.2 K was selected to present the phase behavior; the data sets of Vorobeva and Karapertyants,⁵ and Moriyoshi et al.⁷ are consistent. These data were described by the equation: x₁=1.04385+0.126 03 ln(x₂)–1.046 56 x₂. The least-squares method was used and the standard error of estimate was 0.0165. Compositions on the saturation curve calculated by the proposed equation are presented in Table 24 for selected concentrations of hexane in the mixture. The results of calculations (solid line) are presented graphically in Figure 13 together with experimental data reported at 298.2 K.

Phases in equilibrium The phases in equilibrium were measured at 293 and 298 K over the pressure range 0.1-200 MPa. The tie lines of Ref. 3 are inconsistent and are rejected. The other tie lines cover the whole miscibility gap and are consistent within each data set, within each region and between regions. The differences between compositions of the phases in equilibrium reported in Refs. 5 and 7 do not exceed 0.01 mole fraction. The solubility plait point of the system was reported only by Vorobeva and Karapetyants⁵ at 298.2 K ((x₁=0.478, x₂=0.437) and by Bonner¹ at 273.2 K (x₁=0.498, x₂=0.414). The experimental tie lines at 298.2 K are presented in Figure 13 .

Experimental Data: (Notes on the Nomenclature)

TABLE 23. Summary of experimental data for the system ethanol-hexane-water
Author	T/K	DataType	Reference	Pressure
Bonner, 1909	273	sat. (12)	1	-
Ormandy and Craven, 1922	242-304	sat. (25)	2	-
Tarasenkov and Paulsen, 1937	273, 298	sat. (25), eq. (2)	3	-
Mertslin et al., 1961	293	sat. (8), distr. (18)	4	-
Vorobeva and Karapetyants, 1966	298	sat. (16), eq. (9)	5	-
Ross and Patterson, 1979	293	eq. (9)	6	-
Moriyoshi et al., 1988	298	eq. (50)	7	0.1-200 p/MPa

TABLE 24. Calculated compositions along the saturation at 298.2 K
T/K	Mole Fraction x₁	Mole Fraction x₂
298.2	0.0000	0.5000
298.2	0.3709	0.0050
298.2	0.4530	0.0100
298.2	0.5299	0.0200
298.2	0.5963	0.0400
298.2	0.6265	0.0600
298.2	0.6418	0.0800
298.2	0.6490	0.1000
298.2	0.6510	0.1200
298.2	0.6495	0.1400
298.2	0.6454	0.1600
298.2	0.6393	0.1800
298.2	0.6317	0.2000
298.2	0.6228	0.2200
298.2	0.6128	0.2400
298.2	0.6020	0.2600
298.2	0.5904	0.2800
298.2	0.5781	0.3000
298.2	0.5653	0.3200
298.2	0.5521	0.3400
298.2	0.5383	0.3600
298.2	0.5242	0.3800
298.2	0.5097	0.4000
298.2	0.4950	0.4200
298.2	0.4799	0.4400
298.2	0.4646	0.4600
298.2	0.4490	0.4800
298.2	0.4332	0.5000
298.2	0.4172	0.5200
298.2	0.4010	0.5400
298.2	0.3847	0.5600
298.2	0.3682	0.5800
298.2	0.3515	0.6000
298.2	0.3347	0.6200
298.2	0.3178	0.6400
298.2	0.3008	0.6600
298.2	0.2836	0.6800
298.2	0.2663	0.7000
298.2	0.2489	0.7200
298.2	0.2314	0.7400
298.2	0.2139	0.7600
298.2	0.1962	0.7800
298.2	0.1785	0.8000
298.2	0.1607	0.8200
298.2	0.1428	0.8400
298.2	0.1248	0.8600
298.2	0.1068	0.8800
298.2	0.0887	0.9000
298.2	0.0705	0.9200
298.2	0.0523	0.9400
298.2	0.0340	0.9600
298.2	0.0157	0.9800
298.2	0.0065	0.9900
298.2	0.0019	0.9950
298.2	0.0000	0.99953	Ref. 9

View Figure 1 for this Evaluation

Notes:
Table 23  Number of experimental points in parentheses.

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

   1  Bonner, W.D., J. Phys. Chem. 14, 738 (1909-1910).
   2  Ormandy, W.R.; Craven, E.C., J. Inst. Petrol. Technol. 8, 181, 213 (1922).
   3  Tarasenkov, D.N.; Paulsen, I.A., Zh. Obshch. Khim. 7, 2143 (1937).
   4  Mertslin, R.V.; Nikurashina, N.I.; Petrov, V.A., Zh. Fiz. Khim. 35, 2770 (1961).
   5  Vorobeva, A.I.; Karapetyants, M., Kh., Zh. Fiz. Khim. 40, 3018 (1966).
   6  Ross,S.; Patterson, R.E., J. Chem. Eng. Data. 24, 111 (1979).
   7  Moriyoshi, T.; Uosaki, Y.; Matsuura, H.; Nishimoto, W., J. Chem. Thermodyn, 20, 551 (1988).
   8  Kafarov, V.V., ed., Spravochnik po Rastvorimosti Vol. 2, Troinye, Mnogokomponentnye Sistemy, Kniga II (Izd. Akademii Nauk SSSR, Moskva, 1963).
   9  Shaw, D.G., ed., Solubility Data Series, Vol. 37, Hydrocarbons with Water and Seawater, Part I: Hydrocarbons C5 to C7 (Pergamon, New York, 1989).