IUPAC-NIST Solubilities Database

IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

Solubility System: 2-Propanol with Benzene and Water

Components:
   (1) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail
   (2) 2-Propanol (isopropanol, isopropyl alcohol); C3H8O; [67-63-0]  NIST Chemistry WebBook for detail
   (3) Benzene; C6H6; [71-43-2]  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 2-propanol-benzene-water is given in Table 56.

Saturation curve The ternary system 2-propanol-benzene-water forms a miscibility gap of type 1. Ten references describes this system over the temperature range 293-343 K. The data are evaluated on the basis of the original papers with the exception of the data of Leikola,³ which were taken from the handbook of Kafarov.¹¹ Experimental points reported in all ten papers are in general agreement. The data of Letcher et al.¹⁰ were presented in graphical form only and therefore are not given as a compilation sheet. Only one binary system, benzene-water, is partially miscible. The data for this system were compiled and critically evaluated in a previously published SDS volume.¹² The recommended values of mutual solubility at 298.2 K¹² are x'₂=0.9970 and x"₂=0.000409. Olsen and Washburn² and Rajendran et al.⁹ reported mutual solubility for the binary system. These values at 298.2 K² and at 303.2 K⁹ are x'₂=0.9970, x"₂=0.0003 and x'₂=0.9961, x"₂=0.0043, respectively. The experimental results for the 2-propanol-benzene-water system of Perraksis¹ aat 292 K are in agreement with other data sets, but the results for other alcohol-benzene-water systems reported in Ref. 1 differed very much from the recommended values. Therefore these data are not compiled. Data reported by Olsen and Washburn² at 298 K present a larger miscibility gap (by about 0.05 mole fraction) than any other data at a similar temperature. This was observed in the range x₂=0.014-0.58. The two points of lowest 2-propanol concentration in benzene-rich phase at 303 K., Rajendran et al.⁹ are not located on the expected binodal curve. This is presumably the result of an experimental error. (Compositions are expected to contain of about 0.01 mole fraction less water.) Therefore the data of Refs. 2 and 9 are rejected. Udovenko and Mazanko⁴ report five solubility-temperature curves of constant alcohol-benzene ratio and another four curves of constant alcohol-water ratio over the temperature range 292-343 K. These were used by the authors to construct solubility isotherms at 303, 318, and 333 K. Morachevskii and Legochkina⁵ report equilibrium data in the temperature range 307-339 K. No significant compositional differences with temperature were observed on the binodal curve on the basis of these data sets. Saturation points at boiling temperatures as a function of pressure are also presented. The influence of composition on boiling temperature over two liquid phases at constant pressure is very weak; it changes no more than 0.5 K. All saturation data are treated as tentative. The temperature of 298.2 K was chosen to present the behavior of the system since several studies included this standard temperature. Saturation and equilibrium data of Nikurashina and Sinegubova⁷ (0.0004<x₂<0.9635), including water-rich and hydrocarbon-rich branches were described by the equation: x₁=0.346 81+0.042 11 ln(x₂)+0.470 10x₂–0.843 39x²₂. The least-squares method was used and the standard error of estimate was 0.0125. The compositions on the saturation curve calculated by the proposed equation are presented in Table 57 for selected concentrations of benzene in the mixture. The results of calculations (solid line) are presented graphically in Figure 29 together with all experimental data reported at 298.2 K.
No large differences in the maximum 2-propanol concentration were observed with temperature. The maximum 2-propanol concentration in benzene-rich phase of this ternary system at 298.2 K was measured to be x₁=0.371,⁷ and x₁=0.38,¹⁰ the value x₁=0.41 reported in Ref. 2 seems to be too large.

Phases in equilibrium Compositions of coexisting phases in equilibrium of the ternary system 2-propanol-benzene-water were reported in seven references in the temperature range 293-340 K as 17 isotherms. The lines cover the full miscibility gap. Udovenko et al.^4,6,8 and Morachevskii and Legochikina⁵ report the equilibrium data over the temperature range 303-340 K and 293-339 K, respectively. At various temperatures, tie lines systematically change direction slightly according to the final position of plait points. For constant water-phase composition, the benzene-rich phase in equilibrium contains less benzene at higher temperature. Reported data are consistent within each data set but several points are inconsistent between data sets, e.g., Ref. 4 at 303.2 K the composition of water-rich phase (x₁=0.3251 and x₂=0.4885) contains more alcohol than expected. Equilibrium data of Morachevskii and Legochkina at 293.2 K,⁵ and Nikurashina and Sinegubova at 298.2 K,⁷ are inconsistent with one another. All equilibrium data are treated as tentative. Plait point composition, reported in Refs. 4, 7, 10 and presented in Table 58 changes on slightly with temperature and contains less than 2-propanol and more water at highter temperatures (concentration of benzene is nearly constant). This behavior is also confirmed by weak systematical changes of tie lines directions.⁵ All experimental points at 298.2 K, both saturation and phases in equilibrium,^2,7 are presented in Figure 29 .

Experimental Data: (Notes on the Nomenclature)

TABLE 56. Summary of experimental data for the system 2-propanol-benzene-water
Author	T/K	DataType	Reference
Perrakis, 1925	292	sat. (11)	1
Olsen and Washburn, 1935	298	sat. (16), distr. (15)	2
Leikola, 1940	293	sat. (4)	3
Udovenko and Mazanko, 1964	292-343	sat. (48), eq. (45)	4
Morchevskii and Legochkina, 1965	293-340	eq. (35)	5
Udovenko and Mazanko, 1967	303-323	eq. (23)	6
Nikurashina and Sinegubova, 1973	298	sat. (18), eq. (22)	7
Udovenko et al., 1985	340	eq. (9)	8
Rajendran et al., 1989	303	sat. (15), eq. (6)	9
Letcher et al., 1990	298	sat. (13), eq. (5)	10

TABLE 58. Experimental plait points for the system 2-propanol-benzene-water
T/K	Reference	x₁	x₂
298.2	7	0.2299	0.0496
298.2	10	0.22	0.05
303.2	4	0.2248	0.0456
318.2	4	0.2188	0.0478
333.2	4	0.1970	0.0417

TABLE 57. Calculated compositions along the saturation curve at 298.2 K
T/K	Mole Fraction x₁	Mole Fraction x₂
298.2	0.0000	0.000 409 Ref. 12
298.2	0.0564	0.0010
298.2	0.1575	0.0100
298.2	0.1911	0.0200
298.2	0.2287	0.0400
298.2	0.2535	0.0600
298.2	0.2727	0.0800
298.2	0.2884	0.1000
298.2	0.3018	0.1200
298.2	0.3133	0.1400
298.2	0.3233	0.1600
298.2	0.3319	0.1800
298.2	0.3393	0.2000
298.2	0.3456	0.2200
298.2	0.3523	0.2400
298.2	0.3510	0.2600
298.2	0.3587	0.2800
298.2	0.3612	0.3000
298.2	0.3629	0.3200
298.2	0.3637	0.3400
298.2	0.3637	0.3600
298.2	0.3629	0.3800
298.2	0.3613	0.4000
298.2	0.3589	0.4200
298.2	0.3558	0.4400
298.2	0.3519	0.4600
298.2	0.3472	0.4800
298.2	0.3418	0.5000
298.2	0.3357	0.5200
298.2	0.3288	0.5400
298.2	0.3212	0.5600
298.2	0.3128	0.5800
298.2	0.3037	0.6000
298.2	0.2939	0.6200
298.2	0.2834	0.6400
298.2	0.2722	0.6600
298.2	0.2603	0.6800
298.2	0.2476	0.7000
298.2	0.2342	0.7200
298.2	0.2202	0.7400
298.2	0.2054	0.7600
298.2	0.1899	0.7800
298.2	0.1737	0.8000
298.2	0.1568	0.8200
298.2	0.1393	0.8400
298.2	0.1210	0.8600
298.2	0.1020	0.8800
298.2	0.0810	0.9000
298.2	0.0620	0.9200
298.2	0.0409	0.9400
298.2	0.0191	0.9600
298.2	0.0000	0.9970 Ref. 12

View Figure 1 for this Evaluation

Notes:
Table 56  Number of experimental points in parentheses.

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

   1  Perrakis, N., J. Chim. Phys. 22, 280 (1925).
   2  Olsen, A.L.; Washburn, E.R., J. Am. Chem. Soc. 57, 303 (1935).
   3  Leikola, E., Suomen Kemistil B. 13, 13 (1940).
   4  Udovenko, V.V.; Mazanko, T.E., Zh. Fiz. Khim. 38, 2984 (1964).
   5  Morachevski, A.G.; Legochkina, L.A., Zh. Prikl. Khim. (Leningrad) 38, 1789-93 (1965).
   6  Udovenko, V.V.; Mazanko, T.E., Zh. Fiz. Khim. 41, 395 (1967).
   7  Perrakis, N., J. Chim. Phys. 22, 280 (1925).
   8  Udovenko, V.V.; Mazanko, T.E.; Plyngeu, V.Ya., Izv. Akad. Nauk Mold. SSR, Ser. Biol. Khim. Nauk 3, 52 (1985).
   9  Rajendran, M.; Renganarayanan, S.; Srinivasan, D., Fluid Phase Equilib. 50, 133 (1989).
   10  Letcher, T.M.; Sewry, J.; Radloff, S., S. Afr. J. Chem. 43, 56 (1990).
   11  Kafarov, V.V., ed., Spravochnik po Rastvorimosti Vol. 2, Troinye, Mnogokomponentnye Sistemy, Kniga II (Izd. Akademii Nauk SSSR, Moskva, 1963).
   12  Shaw, D.G., ed., Solubility Data Series, Vol. 37, Hydrocarbons with Water and Seawater, Part I: Hydrocarbons C5 to C7 (Pergamon, New York, 1989).