IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: 1-Proponal with Toluene and Water

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) Toluene (methylbenzene); C7H8; [108-88-3]  NIST Chemistry WebBook for detail

Evaluator:
   A. Skrzecz, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland (1997.02)

Critical Evaluation:

      A survey of reported compositions along the saturation curve (sat), and compositions of coexisting phases in equilibrium (eq.) and distribution of 1-propanol between phases (distr.) for the system 1-propanol-tolene-water is given in Table 48.

Saturation curve The ternary system 1-propanol-tolene-water forms a miscibility gap of type 1. Studies of the system were reported in four references and are discussed on the basis of original papers with the exception of data of Leikola,¹ which were taken from the handbook of Kafarov,⁵ this data set was also taken into account during evaluation but is not reported as a compilation sheet because it does not contribute further to knowledge of the system. Only the toluene-water binary system forms a miscibility gap. The data for this binary system were compiled and critically evaluated in a previously published SDS volume.⁶ The recommended values of mutaul solubility of toluene-water system at 298 K are x'₂=0.9972 and x"₂=0.000 104.⁶ The end points of saturation curve at 298.2 K,⁴ were reported to be x'₂=0.999 and x"₂=0.000. These numerical results are limited by the accuracy of experimental measurements which were estimated by the authors to be 0.005 mole fraction; the data are within accuracy limit, but are not adequate to describe the regions of low concentrations of ethanol. Data reported by Ref. 4 show also a somewhat smaller (up to 0.03 mole fraction) concentration of water in the organic-rich phase (the region of 0.4–07 mole fraction of toluene) than data of other authors. A maximum value of 1-propanol concentration on the saturation curve at 298.2 K is reported to be x₁=0.44.⁴ Concentration of toluene in the water-rich phase is very low, <0.002 mole fraction, so toluene was not reported in some experimental points in equilibrium, Ref. 4 (authors estimated composition of tie lines was within 0.01 mole fraction). All data describing the saturation curve are treated as tentative; they are consistent within each data set as well as between the references. Temperature of 298.2 K was selected to present the behavior of the system. The water-rich phase was not described by any equation and this phase is not presented in Table 48. All experimental saturation and equilibrium points of the hydrocarbon-rich phase at 298.2 K, were used to construct the equation: x₁=0.788 09+0.146 55 ln(x₂)–0.542 22x₂–0.245 63x²₂. The least-squares method was used and the standard error of estimate was 0.0068. Calculated compositions of the hydrocarbon-rich part of the saturation curve are presented in Table 49 for the selected concentrations of toluene in the mixture. The results of calculations (solid line) are also presented graphically in Fig. 24 together with all experimental data reported at 298.2 K.

Phases in equilibrium The phases in equilibrium were measured at 298.2 K (Refs. 2 and 4). The tie lines cover the whole area of the miscibility gap and are consistent with one another. All experimental tie lines at 298.2 K together with the saturation curve are presented in Fig. 24. The plait point of the system at 298.2 K estimated by Letcher and Siswana⁴ was x₁=0.18, x₂=0.01. Distribution of 1-propanol between hydrocarbon and water phases reported in Ref. 3 is in agreement with other equilibrium data. The characteristic point of the system, the same mass fraction concentrations of 1-propanol in both phases (0.150),³ after recalculation gives the values 0.21 and 0.048 mole fraction of 1-propanol in organic and water-rich phases, respectively.

Experimental Data: (Notes on the Nomenclature)

TABLE 48. Summary of experimental data for the system 1-propanol-toluene-water
Author	T/K	DataType	Reference
Leikola, 1940	293	sat. (4)	1
Baker, 1955	298	sat. (16), eq (11)	2
Nikurashina and Ilin, 1972	298	sat. (20), distr. (15)	3
Letcher and Siswana, 1992	298	sat. (15), eq. (8)	4

TABLE 49. Calculated compositions along the saturation curve (hydrocarbon-rich phase) at 298.2 K
T/K	Mole Fraction x₁	Mole Fraction x₂
298.2	0.0000	0.000 104 Ref. 6
298.2	0.2038	0.0200
298.2	0.2943	0.0400
298.2	0.3424	0.0600
298.2	0.3730	0.0800
298.2	0.3940	0.1000
298.2	0.4088	0.1200
298.2	0.4192	0.1400
298.2	0.4265	0.1600
298.2	0.4312	0.1800
298.2	0.4340	0.2000
298.2	0.4350	0.2200
298.2	0.4347	0.2400
298.2	0.4331	0.2600
298.2	0.4305	0.2800
298.2	0.4269	0.3000
298.2	0.4224	0.3200
298.2	0.4172	0.3400
298.2	0.4113	0.3600
298.2	0.4048	0.3800
298.2	0.3976	0.4000
298.2	0.3899	0.4200
298.2	0.3816	0.4400
298.2	0.3729	0.4600
298.2	0.3637	0.4800
298.2	0.3540	0.5000
298.2	0.3439	0.5200
298.2	0.3334	0.5400
298.2	0.3224	0.5600
298.2	0.3111	0.5800
298.2	0.2995	0.6000
298.2	0.2874	0.6200
298.2	0.2751	0.6400
298.2	0.2623	0.6600
298.2	0.2493	0.6800
298.2	0.2359	0.7000
298.2	0.2222	0.7200
298.2	0.2082	0.7400
298.2	0.1939	0.7600
298.2	0.1793	0.7800
298.2	0.1644	0.8000
298.2	0.1492	0.8200
298.2	0.1338	0.8400
298.2	0.1180	0.8600
298.2	0.1020	0.8800
298.2	0.0857	0.9000
298.2	0.0691	0.9200
298.2	0.0523	0.9400
298.2	0.0352	0.9600
298.2	0.0179	0.9800
298.2	0.0091	0.9900
298.2	0.0000	0.9972 Ref.6

View Figure 1 for this Evaluation

Notes:
Table 48  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  Baker, E.M., J. Phys. Chem. 59, 1182 (1955).
   3  Nikurashina, N.I.; Ilin, K.K., Zh. Obshch. Khim. 42, 1657 (1972).
   4  Letcher, T.M.; Siswana, P.M., Fluid Phase Equilib. 74, 203 (1992).
   5  Kafarov, V.V., ed., Spravochnik po Rastvorimosti Vol. 2, Troinye, Mnogokomponentnye Sistemy, Kniga II (Izd. Akademii Nauk SSSR, Moskva, 1963).
   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).