IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

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 Solubility System: Octane with Water

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Components:
   (1) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail
   (2) Octane; C8H18; [111-65-9]  NIST Chemistry WebBook for detail

Evaluator:
   G.T. Hefter, School of Mathematical and Physical Sciences, Murdoch University, Perth, W.A., Australia. October 1986.

Critical Evaluation:

   Quantitative solubility data for the n-octane (1) – water (2) system have been reported in the publications listed in Table 1.

The original data in all these publications are compiled in the Data Sheets immediately following this Critical Evaluation. In addition critical phenomena have been investigated by Roof (ref 8). These are considered along with solubility data at high pressures in Section 3 below.

For convenience further discussion of this system will be in three parts.


1. THE SOLUBILITY OF OCTANE (1) IN WATER (2)

Agreement amongst the independent determinations of the solubility of octane in water is not particularly good and no data have been Recommended.

At 298K the value reported by Price (ref 11) is substantially lower than all other studies (ref 5,9,10,15) and has been rejected. At higher temperatures the values of Price (ref 12) are also considerably lower than those of Heidman et al. (ref 16). In the absence of confirmatory studies, it is not reasonable to reject Price’s data outright but they have not been used in the calculation of “Best” values. Application of the van’t Hoff equation to both data sets gives values of ΔH_s1n = -3.3 (ref 12) and +13.3 (ref 16) kJ mo1^-1 and ΔC_p,s1n = 568 (ref 12) and 284 (ref 16) J K ^-1 mo1^-1. Neither set of values are close to those reported for related systems although those of Heidman et al. are somewhat more reasonable.

At other temperatures the data of Fuhner (ref 1), Nelson and De Ligny (ref 6), and Budantseva et al. (ref 11) are markedly higher than all other studies and are therefore rejected. All the remaining data are summarized in Table 2 and selected data are plotted in Figure 1.

It is interesting to note that the averaged “Best” value at 298K is very close to the value which would be predicted by an extrapolation of the lower n-alkane solubilities.


2. THE SOLUBILITY OF WATER (2) IN OCTANE (1)

Only limited data are available for the solubility of water in n-octane and agreement amongst independent determinations is only fair. The datum of Black et al. (ref 2) is much higher than all other values and is therefore rejected. The remaining data are collected in Table 3 and plotted in Figure 2.


3. SOLUBILTY STUDIES OF THE OCTANE (1) – WATER (2) SYSTEM AT ELEVATED PRESSURES

This system exhibits phase behavior which is topographically similar to that of benzene + water, i.e., it belongs to type III phase behavior using Scott and von Konynenburg’s (ref 17) classification (see Figure 3 and then Introduction to this volume).

Quantitative solubility data on the octane –water system at elevated pressures have been reported in the studies listed in Table 4.

As can be seen from Table 4 data have not generally been obtained under comparable conditions, making Critical Evaluation difficult. However, it may be noted that the solubility of 9.95 g(2)/100g s1n of water in octane at 7.4 MPa and 538.2 K reported by Skripka (ref 14) differs markedly from the value of 14.9 g(2)/100g s1n reported at 7.41 MPa and 539.1 K by Heidman et al. (ref 16). Further studies are necessary before any preference can be expressed for either data set. Previous mention (Section 1 above) has already been made of the fact that the solubilities of octane in water reported by Heidman et al. (ref 16) are much higher than those of Price (ref 12).

On the other hand the properties of the critical end point (Figure 3) reported by Roof: 7.41 MPa and 540.4 K, are in good agreement with those reported by Heidman et al. (ref 16): 7.41 MPa and 539.1 K.



Experimental Data:   (Notes on the Nomenclature)

Table 1. Quantitative Solubility Studies of the Octane (1) - Water (2) System

Author	T/K	T/KNote	Reference	Solubility	Method
Fühner	289	-	1	(1) in (2)	titration
Black et al.	293	-	2	(2) in (1)	radiotracer
Baker	unspecified	-	3	(1) in (2)	radiotracer
Englin	283-303	-	4	(2) in (1)	analytical
McAuliffe	298	-	5	(1) in (2)	GLC
Nelson and De Ligny	278-318	-	6	(1) in (2)	GLC
Krasnoshchekova and Gubergrits	298	-	9	(1) in (2)	GLC
Polak and Lu	273, 298	-	10	mutual	GLC, Karl Fischer
Budantseva et al.	293	-	11	mutual	unspecified
Price	298-423	-	12	(1) in (2)	GLC
Krzyzanowska and Szeliga	298	-	13	(1) in (2)	GLC
Skripka	498-538	a	14	(2) in (1)	unspecified
Jonsson et al.	288-308	-	15	(1) in (2)	partition coefficient
Heidman et al.	311-539	a	16	mutual	synthetic

Table 2. Tentative Values of the Solubility of Octane (1) in Water (2)

T/K	Reference	Sol. Power	Solubility	Best Sol. Power	Best Solubility	Best Sol. Note	x1 Power	x1	x1 Note
273	10	4	1.35 g(1)/100g sln	4	1.4 g(1)/100g sln	a	7	2.2	a
293	15	4	0.628 g(1)/100g sln	4	0.63 g(1)/100g sln	a	7	0.99	a
298	5, 9, 10, 15	4	0.66, 0.70, 0.85, 0.615 g(1)/100g sln	4	0.71 ± 0.09a g(1)/100g sln	a	7	1.1	a
303	12, 15	4	0.46b, 0.612 g(1)/100g sln	4	0.61 g(1)/100g sln	a	7	0.96	a
313	12, 16	4	0.52b, 0.80c g(1)/100g sln	4	0.8 g(1)/100g sln	a	7	1.3	a
323	12, 16	4	0.61b, 0.96c g(1)/100g sln	4	1.0 g(1)/100g sln	a	7	1.6	a
333	12, 16	4	0.74b, 1.2c g(1)/100g sln	4	1.2 g(1)/100g sln	a	7	1.9	a
343	12, 16	4	0.91b, 1.5c g(1)/100g sln	4	1.5 g(1)/100g sln	a	7	2.4	a
353	12, 16	4	1.0b, 1.99c g(1)/100g sln	4	2.0 g(1)/100g sln	a	7	3.2	a
363	12, 16	4	1.1b, 2.67c g(1)/100g sln	4	2.7 g(1)/100g sln	a	7	4.3	a
373	12, 16	4	1.2b, 3.66c g(1)/100g sln	4	3.7 g(1)/100g sln	a	7	5.8	a
393	12, 16	4	4.5b, 7.23c g(1)/100g sln	4	7.2 g(1)/100g sln	a	7	11	a
413	12, 16	4	9.5b, 15.1c g(1)/100g sln	4	15 g(1)/100g sln	a	7	24	a
433	12, 16	4	12.0b, 22.2c g(1)/100g sln	4	22 g(1)/100g sln	a	7	35	a

Table 3. Tentative Values of the Solubility of Water (2) in Octane (1)

T/K	Reference	Sol. Power	Solubility	Sol. Note	Best Sol. Power	Best Solubility	Best Sol. Note	x2 Power	x2	x2 Note
273	9	2	0.23 g(2)/100g sln	-	2	0.2 g(2)/100g sln	a	4	1	a
283	4	2	0.51 g(2)/100g sln	-	2	0.5 g(2)/100g sln	a	4	3	a
293	4, 10	2	0.95, 0.68 g(2)/100g sln	-	2	0.8 ± 0.1 g(2)/100g sln	a	4	5	a
298	4, 9	2	1.26 b, 0.79 g(2)/100g sln	-	2	1.0 ± 0.2 g(2)/100g sln	a	4	6	a
303	4	2	1.68 g(2)/100g sln	-	2	1.7 g(2)/100g sln	a	4	11	a
313	14	2	1.58 g(2)/100g sln	c	2	1.6 g(2)/100g sln	a	4	10	a
323	14	2	2.40 g(2)/100g sln	c	2	2.4 g(2)/100g sln	a	4	15	a
333	14	2	3.54 g(2)/100g sln	c	2	3.5 g(2)/100g sln	a	4	22	a
343	14	2	5.14 g(2)/100g sln	c	2	5.1 g(2)/100g sln	a	4	32	a
353	14	2	7.30 g(2)/100g sln	c	2	7.3 g(2)/100g sln	a	4	46	a
363	14	2	10.2 g(2)/100g sln	c	2	10 g(2)/100g sln	a	4	63	a
373	14	2	14.0 g(2)/100g sln	c	2	14 g(2)/100g sln	a	4	89	a

Table 4. Solubility Studies of the Octane (1) - Water (2) System at Elevated Pressures

Author	T/K	T/KNote	Reference	Pressure	Pressure Note	Solubility	Sol. Note
Roof	-	a	8	-	a	-	a
Price	298-423	-	12	-	b	(1) in (2)	-
Skripka	498-538	-	14	3.5-78.5 MPa	-	(2) in (1)	-
Heidman et al.	311-539	-	16	0.01-8.9 MPa	b	mutual	-

View Figure 1 for this Evaluation

View Figure 2 for this Evaluation

View Figure 3 for this Evaluation

Notes:
Table 1^a  High pressure data
Table 2^a  Obtained by averaging where appropriate; σ_n has no statistical significance. Data from ref 12 have been excluded in the calculation of "Best" values, see text.
Table 2^b  Obtained by the Evaluator by graphical interpolation of the author's original data.
Table 2^c  Calculated from the authors' fitting equation over the range of their experimental values.
Table 3^a  Obtained by averaging where appropriate; σ_n has no statistical significance.
Table 3^b  Obtained by graphical interpolation (Evaluator) of authors' original data.
Table 3^c  Calculated (Evaluator) from fitting equation given by authors, over the range of their experimental values.
Table 4^a  Critical point of unspecified composition.
Table 4^b  Along the three-phase line

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

   1  Fühner, H., Ber. Dtsch. Chem. Ges. 1924, 57, 510-15.
   2  Black, C.; Joris, G.G.; Taylor, H.S., J. Chem. Phys. 1948, 16, 537-43.
   3  Baker, E.G., Geochim. Cosmochim. Acta 1960, 19, 309-17.
   4  Englin, B.A.; Plate, A.F.; Tugolukov, V.M. Pryanishnikova, M.A., Khim. Tekhnol. Topl. Masel 1965, 10, 42-6.
   5  McAuliffe, C., J. Phys. Chem. 1966, 70, 1267-75.
   6  Nelson, H.D.; De Ligny, C.L., Rec. Trav. Chim. Pays-Bas 1968, 87, 528-44.
   7  Alwani, Z.; Schneider, G.M., Ber. Bunsenges. Phys. Chem. 1969, 73, 294-301.
   8  Roof, J.G., J. Chem. Eng. Data 1970, 15, 301-3.
   9  Krasnoschchekova, R.Ya.; Gubergrits, M.Ya., Neftekhimiya 1973, 13, 885-8.
   10  Polak, J.; Lu, B.C.Y., Can. J. Chem. 1973, 51, 4018-23.
   11  Budantseva, L.S.; Lesteva, T.M.; Nemstov, M.S., Zh. Fiz. Khim. 1976, 50, 1344. Deposited doc. 1976, VINITI 437-76.
   12  Price, L.C., Am. Assoc. Petrol. Geol. Bull. 1976, 60, 213-44.
   13  Krzyzanowska, T.; Szeliga, J., Nafta (Katowice) 1978, 12, 413-7.
   14  Skripka, V.G., Tr. Vses. Neftegazov. Nauch. Issled. Inst. 1976, 61, 139-51. Sultanov, R.G.; Skripka, V.G., Zh. Fiz. Khim. 1973, 47, 1035.
   15  Jonsson, J.A.; Vejrosta, J.; Novak, J., Fluid Phase Equil. 1982, 9, 279-86.
   16  Heidman, J.L.; Tsonopoulos, C.; Brady, C.J.; Wilson, G.M., A. I. Ch. E. J. 1985, 31, 376-84.
   17  Scott, R.L.; van Konynenburg, P.H., Phil. Trans. Roy. Soc., London 1980, A298, 495.

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