IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

---

 Solubility System: Ethanol with p-Xylene and 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) o-Xylene (1,2-dimethylbenzene, 1,2-xylene); C8H10; [95-47-6]  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 ethanol-p-xylene-water is given in Table 35.

Saturation curve    The system ethanol-p-xylene-water forms a miscibility gap of type 1. Solubility data for the saturation curve obtained by the titration method were reported in all three references. Data for phases in equilibrium reported in Refs. 2 and 3, were also used for construction of binodal curve. Only one binary pair of componenets p-xylene-water, is partially miscible. Data of this system were compiled and critically evaluated in a previously published SDS volume⁴. The recommended values of mutual solubility of p-xylene-water system at 298.2 K are x"₂=3.1·10^–5 and x'₂=0.9974. The end points of the saturation curve, Ref. 3, were reported to be x₁=0.000, x₂=0.998 and x₁=0.065, x₂=0.000, which suggests that ethanol is only partially soluble in water. These numerical results are within the accuracy of experimental measurements which was stated by the authors to be 0.005 mole fraction, however, they are not adequate to describe the region of low ethanol concentration. Data of Bonner, Ref. 1, reported at 288.2 K, are consistent with the results of Refs. 2 and 3. All experimental saturation data reported at 298.2 K^2,3 are in agreement. For x₂>0.003, the results were fitted to the equation: x₁=0.845 30+0.111 30 ln(x₂)–0.704 79x₂–0.144 88x²₂.    The parameters were calculated by the least-squares method and the standard error of estimate was 0.0246. Selected points on the saturation curve, calculated by this equation together with the “best” values of Ref. 4 are presented in Table 36. Experimental points at 298.2 K are also presented in Figure 18 .

Phases in equilibrium    Compositons of equilibrium phases of the ternary system ethanol-p-xylene-water at 298.2 K were reported in Refs. 2 and 3. These data are presented in Figure 18 . The reported tie lines cross one another. For similar compositions of the hydrocarbon-rich phase, the concentration of ethanol at equilibrium in the water-rich phase is always reported to be lower by Nam et al.,² than by Letcher et al.,³ e.g.: x'₁=0.044, x'₂=0.939, x"₂=0.0728 x"₂=0.0004 (Ref. 2) and x'₁=0.031 x'₂=0.960 x"₁=0.0292 x"₂=0.0007 (Ref. 3) or x'₁=0.163 x'₂=0.806, x"₁=0.4457 x"₂=0.0369 (Ref. 2) and x'₁=0.168 x'₂=0.795, x"₁=0.514 x"₂=0.074 (Ref. 3). These equilibrium data sets are not consistent with one another, although each is internally consistent. The plait point of the system at 298.2 K, calculated by Letcher and Siswana⁵ was reported to be x₁=0.48 x₂=0.35. The plait point reported by Bonner at 288.2 K¹ was x₁=0.486, x₂=0.340. The equilibrium and saturation data are presented together with calculated binodal curve in Figure 18 .

Experimental Data:   (Notes on the Nomenclature)

TABLE 35. Summary of experimental data for the system ethanol-p-xylene-water

Author	T/K	DataType	Reference
Bonner, 1909	288	sat. (12)	1
Nam et al., 1972	298	sat. (16), eq. (9)	2
Letcher et al., 1989	298	sat. (15), eq. (6)	3

TABLE 36. Calculated compositions along the saturation curve at 298.2 K

T/K	Mole Fraction x1	Mole Fraction x2
298.2	0.0000	0.000 031
298.2	0.0758	0.0010
298.2	0.3257	0.0100
298.2	0.3957	0.0200
298.2	0.4586	0.0400
298.2	0.4894	0.0600
298.2	0.5069	0.0800
298.2	0.5171	0.1000
298.2	0.5226	0.1200
298.2	0.5250	0.1400
298.2	0.5249	0.1600
298.2	0.5229	0.1800
298.2	0.5194	0.2000
298.2	0.5147	0.2200
298.2	0.5090	0.2400
298.2	0.5023	0.2600
298.2	0.4949	0.2800
298.2	0.4868	0.3000
298.2	0.4781	0.3200
298.2	0.4688	0.3400
298.2	0.4591	0.3600
298.2	0.4489	0.3800
298.2	0.4382	0.4000
298.2	0.4272	0.4200
298.2	0.4158	0.4400
298.2	0.4040	0.4600
298.2	0.3919	0.4800
298.2	0.3795	0.5000
298.2	0.3668	0.5200
298.2	0.3539	0.5400
298.2	0.3406	0.5600
298.2	0.3272	0.5800
298.2	0.3134	0.6000
298.2	0.2994	0.6200
298.2	0.2852	0.6400
298.2	0.2708	0.6600
298.2	0.2561	0.6800
298.2	0.2413	0.7000
298.2	0.2262	0.7200
298.2	0.2109	0.7400
298.2	0.1954	0.7600
298.2	0.1798	0.7800
298.2	0.1639	0.8000
298.2	0.1479	0.8200
298.2	0.1316	0.8400
298.2	0.1152	0.8600
298.2	0.0987	0.8800
298.2	0.0819	0.9000
298.2	0.0650	0.9200
298.2	0.0479	0.9400
298.2	0.0306	0.9600
298.2	0.0132	0.9800
298.2	0.0044	0.9900
298.2	0.0000	0.9974 Ref. 4

View Figure 1 for this Evaluation

Notes:
Table 35  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  Nam, S.; Hayakawa, T.; Fujita, S., J. Chem. Eng. Jpn. 5, 327 (1972).
   3  Letcher, T.M.; Siswana, P.M.; van der Watt, P.; Radloff, S., J. Chem. Thermodyn. 21, 1053 (1989).
   4  Shaw, D.G., ed., Solubility Data Series, Vol. 37, Hydrocarbons with Water and Seawater, Part I: Hydrocarbons C8 to C36 (Pergamon, New York, 1989).
   5  Letcher, T.M.; Siswana, P.M., Fluid Phase Equilib. 74, 203 (1992).

Distributed by the Office of Data and Informatics of the National Institute of Standards and Technology (NIST) Material Measurement Laboratory (MML).
Website is owned by NIST (an agency of the U.S. Department of Commerce)

---

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