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IUPAC-NIST Solubility Database
NIST Standard Reference Database 106
Solubility System:
Methanol with p-Xylene and water
Components:
(1) Water; H2O; [7732-18-5]
NIST Chemistry WebBook
for detail
(2) Methanol (methyl alcohol); CH4O; [67-56-1]
NIST Chemistry WebBook
for detail
(3) p-Xylene (1,4-dimethylbenzene, 1,4-xylene); C8H10; [106-42-3]
NIST Chemistry WebBook
for detail
Evaluator:
A. Skrzecz, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland (1997.03)
Critical Evaluation:
A survey of reported compositions along the saturation curve (sat.), compositions of coexisting phases in equilibrium (eq.) for the system methanol-
p
-xylene-water is given in Table 13.
Saturation curve
The system methanol-
p
-xylene-water forms a miscibility gap of type 1. Only one binary system,
p
-xylene-water, is partially miscible. The data for this system were compiled and critically evaluated in a previously published SDS volumes, Ref. 3. The recommended values of mutual solubility of
p
-xylene-water system at 298.2 K are:
x
'
2
=0.9974 and
x
"
2
=0.000 31. The data of Leikola, Ref. 1, taken from the handbook of Kafarov,
4
, 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. All experimental saturation data are consistent. The data of Letcher
et al
.
2
, describe the whole binodal curve. The end points of saturation curve, Ref. 2, were reported to be
x
2
=0.998 and pure water which is inconsistent with recommended values. Data for the water-rich phase in the range of low methanol concentrations, Ref. 2, were reported to be
p
-xylene free. All these results are within the accuracy of experimental measurements which were stated by the authors to be 0.005 mole fraction. Phase equilibrium data, Ref. 2, were also used to construct the saturation curve with the exception of one point (
x
1
=0.058
x
2
=0.916) which appears to contain experimental error. Data at 298.2 K, Ref. 2, presenting both phases (organic-rich and water-rich) were fitted by the equation:
x
1
=1.1424+0.1264 ln(
x
2
)–1.2561
x
2
+0.1108
x
2
2
.
The parameters were calculated by the least-squares method and the standard error of estimate was 0.0194. The points on the saturation curve calculated by this equation for the selected concentrations of
p
-xylene together with the “best” values of Ref. 3 are presented in Table 14.
Phases in equilibrium
Compositions of coexisting phases in equilibrium of the ternary system methanol-
p
-xylene-water were reported only by Letcher
et al
.
2
The tie lines are consistent with one another and cover the whole area of the miscibility gap. One point for organic-rich phase (
x
1
=0.058,
x
2
=0.916) appears to contain an experimental error. The phase equilibrium data are considered tentative. All experimental saturation points together with experimental tie lines at 298.2 K are presented in
Fig. 7
. The plait point of the system at 298.2 K, calculated by Letcher and Siswana,
5
was reported to be
x
1
=0.46,
x
2
=0.49.
Experimental Data:
(Notes on the Nomenclature)
TABLE 13. Summary of experimental data for the system methanol-
p
-xylene-water
Author
T/K
DataType
Reference
Leikola, 1940
294
sat. (4)
1
Letcher
et al
., 1989
298
sat. (17), Eq. (5)
2
TABLE 14. Calculated compositions along the saturation curve at 298.2 K
T/K
Mole Fraction x
1
Mole Fraction x
2
298.2
0.0000
0.000 031 Ref. 3
298.2
0.6228
0.0200
298.2
0.6855
0.0400
298.2
0.7118
0.0600
298.2
0.7234
0.0800
298.2
0.7269
0.1000
298.2
0.7253
0.1200
298.2
0.7202
0.1400
298.2
0.7126
0.1600
298.2
0.7031
0.1800
298.2
0.6922
0.2000
298.2
0.6800
0.2200
298.2
0.6669
0.2400
298.2
0.6530
0.2600
298.2
0.6385
0.2800
298.2
0.6234
0.3000
298.2
0.4365
0.5200
298.2
0.4185
0.5400
298.2
0.4004
0.5600
298.2
0.3823
0.5800
298.2
0.3641
0.6000
298.2
0.3458
0.6200
298.2
0.3275
0.6400
298.2
0.3091
0.6600
298.2
0.2907
0.6800
298.2
0.2723
0.7000
298.2
0.2539
0.7200
298.2
0.2355
0.7400
298.2
0.2171
0.7600
298.2
0.1986
0.7800
298.2
0.1802
0.8000
298.2
0.1618
0.8200
View Figure 1 for this Evaluation
Notes:
Table 13
Number of experimental points in parentheses.
References: (Click a link to see its experimental data associated with the reference)
1 Leikola, E., Suomen Kemistil B. 13, 13 (1940).
2 Letcher, T.M.; Siswana, P.M., Fluid Phase Equilib. 74, 203 (1992).
3 Shaw, D.G., ed., Solubility Data Series, Vol. 37, Hydrocarbons with Water and Seawater, Part I: Hydrocarbons C8 to C36 (Pergamon, New York, 1989).
4 Kafarov, V.V., ed., Spravochnik po Rastvorimosti Vol. 2, Troinye, Mnogokomponentnye Sistemy, Kniga II (Izd. Akademii Nauk SSSR, Moskva, 1963).
5
Letcher, T.M.; Siswana, P.M.; van der Watt, P.; Radloff, S., J. Chem. Thermodyn. 21, 1053 (1989).