IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Glass Ball as Bullet Solubility System: 1-Butanol with Toluene and Water
Components:
   (1) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail
   (2) 1-Butanol (n-butanol, butyl alcohol, n-butyl alcohol); C4H10O; [71-36-3]  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 (1996.12)

 Critical Evaluation:
      A survey of reported compositions along the saturation curve (sat), and compositions of coexisting phases in equilibrium (eq.) for the system 1-butanol-toluene-water is given in Table 77.

Saturation curve
   The system 1-butanol-toluene-water forms a miscibility gap of type 2. Two binary systems, 1-butanol-water and toluene-water, are partially miscible. The data of these systems were compiled and critically evaluated in previously published SDS volumes, Refs. 4 and 5, respectively. The recommended values of mutual solubility at 298.2 K are x'2=0.9972, x"2=0.000 104 for toluene-water system4 and x'1=0.488, x"1=0.0191 for 1-butanol-water.5 The saturation curve for the organic-rich phase was measured by Fuoss1 by the conductance method; the water-rich phase was assumed to be toluene free. Shanahan2 measured only the saturation curve at 293 K. Letcher and Siswana reported both saturation and equilibrium results at 298 K. Each of these reported measurements was made at a different temperature and therefore no recommendation can be made. However, all these data are consistent with one another. All three data sets are treated as tentative. The maximum 1-butanol concentration was observed in the organic-rich branch of the saturation curve at each reported temperatures, in the area of x1=0.54±0.01 and x2=0.11±0.02. The saturation mixtures of the water-rich branch contained undetectably small amounts of toluene; the water-rich phase was reported as a binary 1-butanol-water mixture by both Refs. 1 and 3. The temperature of 298 K was chosen for graphical presentation and therefore only experimental data of Letcher and Siswana3 are shown in Figure 41 . The binary data reported with ternary data sets are in agreement with the previously recommended binary solubility data.

Phases in equilibrium
   Compositions of coexisting phases in equilibrium for the ternary 1-butanol-toluene-water system were reported in Refs. 1 and 3, at 303 and 298 K respectively, and cover the whole range of the miscibility gap. The tie lines are consistent within each data set, but the data sets are inconsistent with one another because tie lines cross. It is unlikely that a temperature difference of 5 K gives such large changes in phase composition e.g., water-rich phase x1=0.007 in equilibrium with organic-rich phase x1=0.341, x2=0.570 at T/K=298, Ref. 3; and water-rich phase x1=0.0063 in equilibrium with organic-rich phase x1=0.0609, x2=0.9291 at T/K=303, Ref. 1. Both equilibrium data sets are treated as tentative. The experimental tie lines at 298 K by Letcher and Siswana, Ref. 3, are presented in Figure 41 .

 Experimental Data:   (Notes on the Nomenclature)
TABLE 77. Summary of experimental data for the system 1-butanol-toluene-water
AuthorT/KDataTypeReference
Fuoss, 1943303sat. (27), eq. (14)1
Shanahan, 1948293sat. (5)2
Letcher and Siswana, 1992298sat. (15), eq. (5)3
 View Figure 1 for this Evaluation

Notes:
Table 77  Number of experimental points in parentheses.

 References: (Click a link to see its experimental data associated with the reference)
   1  Fuoss, R.M., J. Am. Chem. Soc. 65, 78 (1943).
   2  Shanahan, C.E., A. Analyst (London) 73, 502 (1948).
   3  Letcher, T.M.; Siswana, P.M., Fluid Phase Equilib. 74, 203 (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  Barton, A.F. M., ed., Solubility Data Series, Vol. 15, Alcohols with Water (Pergamon, New York 1984).