IUPAC-NIST Solubility Database
NIST Standard Reference Database 106

---

 Solubility System: 2-Methyl-2-propanol with 2,2,4-Trimethylpentane (isooctane) and Water

---

Components:
   (1) Water; H2O; [7732-18-5]  NIST Chemistry WebBook for detail
   (2) 2,2,4-Trimethylpentane (isooctane); C8H18; [540-84-1]  NIST Chemistry WebBook for detail
   (3) 2-Methyl-2-propanol (tert-butanol,tert-butyl alcohol); C4H10O; [75-65-0]  NIST Chemistry WebBook for detail

Original Measurements:
   Dubovskaya, A.S.; Karapetyants, M.Kh., Tr. Inst.-Mosk., Khim.-Tekhnol. Inst. Im. D. I. Mendeleeva 58, 92 (1968).

Variables:
   Temperature = 298 K - 303 K

Prepared By:
   A. Skrzecz

Experimental Remarks:

   The authors calculated critical points: (a) by Alekseev's, Ref. 1, (b) by Izmailov's, Ref. 2, and (c) by Zilberman's, Ref. 3, methods, respectively.

Experimental Data:   (Notes on the Nomenclature)
  

Compositions along the saturation curve

t/°C	T/K	Mass Fraction w1	Mass Fraction w2	Mole Fraction x1 (compiler)	Mole Fraction x2 (compiler)
0.0	273.2	0.1515	0.8370	0.2042	0.7320
0.0	273.2	0.0811	0.9050	0.1118	0.8094
0.0	273.2	0.0925	0.8897	0.1245	0.7770
0.0	273.2	0.3280	0.6340	0.3662	0.4593
0.0	273.2	0.3810	0.5760	0.4089	0.4012
0.0	273.2	0.4420	0.4973	0.4357	0.3181
0.0	273.2	0.4900	0.4145	0.4254	0.2335
0.0	273.2	0.4950	0.4083	0.4275	0.2288
0.0	273.2	0.5760	0.2550	0.4009	0.1152
0.0	273.2	0.5790	0.2500	0.4008	0.1123
0.0	273.2	0.5880	0.2270	0.3929	0.0984
0.0	273.2	0.5920	0.1650	0.3485	0.0630
0.0	273.2	0.5930	0.1520	0.3406	0.0567
0.0	273.2	0.5925	0.1315	0.3267	0.0471
0.0	273.2	0.5780	0.1350	0.3130	0.0474
0.0	273.2	0.5225	0.0605	0.2294	0.0172
0.0	273.2	0.5100	0.0525	0.2176	0.0145
0.0	273.2	0.4520	0.0240	0.1723	0.0059
20.0	293.2	0.1515	0.8370	0.2042	0.7320
20.0	293.2	0.0811	0.9050	0.1118	0.8094
20.0	293.2	0.0925	0.8897	0.1245	0.7770
20.0	293.2	0.3280	0.6340	0.3662	0.4593
20.0	293.2	0.3810	0.5760	0.4089	0.4012
20.0	293.2	0.4900	0.4145	0.4254	0.2335
20.0	293.2	0.4950	0.4083	0.4275	0.2288
20.0	293.2	0.5520	0.3290	0.4398	0.1701
20.0	293.2	0.5450	0.3310	0.4291	0.1691
20.0	293.2	0.5680	0.2940	0.4282	0.1438
20.0	293.2	0.5950	0.2225	0.3993	0.0969
20.0	293.2	0.5960	0.1360	0.3335	0.0494
20.0	293.2	0.5910	0.1330	0.3260	0.0476
20.0	293.2	0.5850	0.1270	0.3158	0.0445
20.0	293.2	0.5540	0.0960	0.2694	0.0303
20.0	293.2	0.5044	0.0531	0.2138	0.0146
20.0	293.2	0.4980	0.0500	0.2084	0.0136
20.0	293.2	0.4502	0.0298	0.1726	0.0074
20.0	293.2	0.3688	0.0202	0.1274	0.0045
30.0	303.2	0.0840	0.9006	0.1148	0.7986
30.0	303.2	0.1145	0.8670	0.1520	0.7469
30.0	303.2	0.2155	0.7650	0.2721	0.6267
30.0	303.2	0.1206	0.8580	0.1576	0.7274
30.0	303.2	0.4050	0.5425	0.4162	0.3618
30.0	303.2	0.4800	0.4400	0.4385	0.2608
30.0	303.2	0.5550	0.3260	0.4418	0.1684
30.0	303.2	0.6015	0.2290	0.4155	0.1027
30.0	303.2	0.5990	0.2300	0.4126	0.1028
30.0	303.2	0.6055	0.1395	0.3470	0.0519
30.0	303.2	0.6030	0.1380	0.3430	0.0509
30.0	303.2	0.6080	0.1385	0.3492	0.0516
30.0	303.2	0.5630	0.0980	0.2785	0.0315
30.0	303.2	0.5185	0.0685	0.2292	0.0196
30.0	303.2	0.5085	0.0515	0.2162	0.0142
30.0	303.2	0.4990	0.0535	0.2101	0.0146
30.0	303.2	0.4550	0.0300	0.1754	0.0075
30.0	303.2	0.4140	0.0195	0.1501	0.0046
30.0	303.2	0.4100	0.0178	0.1477	0.0042
30.0	303.2	0.4070	0.0190	0.1463	0.0044
30.0	303.2	0.3916	0.0144	0.1376	0.0033
30.0	303.2	0.3526	0.0074	0.1179	0.0016
30.0	303.2	0.3160	0.0019	0.1012	0.0004
30.0	303.2	0.2850	0.0000	0.0883	0.0000

Compositions of coexisting phases

t/°C	T/K	Mass Fraction w1	Mass Fraction w2	Mole Fraction x1 (compiler)	Mole Fraction x2 (compiler)	Comment(s)
30.0	303.2	0.1040	0.8800	0.1404	0.7708	hydrocarbon-rich phase
30.0	303.2	0.2480	0.7280	0.3028	0.5767	hydrocarbon-rich phase
30.0	303.2	0.3360	0.6280	0.3768	0.4570	hydrocarbon-rich phase
30.0	303.2	0.4500	0.4800	0.4288	0.2968	hydrocarbon-rich phase
30.0	303.2	0.5320	0.3600	0.4397	0.1931	hydrocarbon-rich phase
30.0	303.2	0.5880	0.2580	0.4233	0.1205	hydrocarbon-rich phase
30.0	303.2	0.5960	0.2320	0.4098	0.1035	hydrocarbon-rich phase
30.0	303.2	0.6080	0.1900	0.3891	0.0789	hydrocarbon-rich phase
30.0	303.2	0.6080	0.1480	0.3560	0.0562	hydrocarbon-rich phase
30.0	303.2	0.5740	0.0860	0.2829	0.0275	hydrocarbon-rich phase
30.0	303.2	0.468	0.034	0.1844	0.0087	hydrocarbon-rich phase
30.0	303.2	0.468	0.032	0.1839	0.0082	hydrocarbon-rich phase
30.0	303.2	0.465	0.022	0.1797	0.0055	hydrocarbon-rich phase
30.0	303.2	0.1020	<0.0010	0.0269	0.0002	water-rich phase
30.0	303.2	0.1400	<0.0010	0.0381	0.0002	water-rich phase
30.0	303.2	0.1640	<0.0010	0.0456	0.0002	water-rich phase
30.0	303.2	0.1960	<0.0010	0.0560	0.0002	water-rich phase
30.0	303.2	0.2180	0.0020	0.0636	0.0004	water-rich phase
30.0	303.2	0.2480	0.0020	0.0744	0.0004	water-rich phase
30.0	303.2	0.2640	<0.0010	0.0803	0.0002	water-rich phase
30.0	303.2	0.2740	<0.0010	0.0841	0.0002	water-rich phase
30.0	303.2	0.2900	<0.0010	0.0904	0.0002	water-rich phase
30.0	303.2	0.3520	0.0040	0.1172	0.0009	water-rich phase
30.0	303.2	0.468	0.034 (a)	0.1844	0.0087	water-rich phase
30.0	303.2	0.468	0.032 (b)	0.1839	0.0082	water-rich phase
30.0	303.2	0.465	0.022 (c)	0.1797	0.0055	water-rich phase

Notes:

Method/Apparatus/Procedure:
   The titration method was used to determine the solubility curve. Binary hydrocarbon-alcohol mixtures were titrated with water until turbidity was observed, as described in Ref. 4. The titration was repeated several times to eliminate errors. The relationship of density versus composition of saturated mixture was used later to calculate equilibrium. The method was tested on the ethanol-heptane-water system and the results were in agreement with literature  data. The analytical method was used to determine liquid-liquid equilibria. A binary mixture of known composition was placed in a special thermostated vessel and the third component was added to obtain a two-phase mixture. This mixture was agitated for 3-4 h to ensure equilibrium. The mixture was allowed to stand 1-2 h to become clear and then both phases were taken for density measurements.  On the basis the previously constructed relationship of density versus composition of the saturated mixture, the composition of the mixture in equilibrium was calculated. Concentrations of 2,2,4-trimethylpentane in the water rich phase were reported in the paper for several experimental points as <0.0010 of mass fraction while the sums of water and alcohol concentrations were equal to 1.000.0 Recalculations to mole fraction were made treating them as real values.

Source and Purity of Materials:
   (1) Source not specified; d(20°C,20°C)=0.7894, n(25°C,D)=1.3860, m.p.=25°C; used as received.
   (2) Source not specified; d(20°C,20°C)=0.6890, n(25°C,D)=1.3890.
   (3) Doubly distilled.

Estimated Errors:
   Solubility: Not reported.
   Temperature: Temp. ±0.1 K; conc. ±0.0001.

References:
   ¹ V. F. Alekseev, Gorn. Zh. 2, 385 (1985).
   ² N. A. Izmajlov and A. K. Franke, Zh. Fiz. Khim. 29, 120 (1955).
   ³ E. N. Zilberman, Zh. Fiz. Khim. 28, 1458 (1952).
   ⁴ W. D. Bancroft, Phys. Rev. 3, 21 (1896).

---

Distributed by the Office of Data and Informatics of the National Institute of Standards and Technology (NIST) Material Measurement Laboratory (MML).
Website is owned by NIST (an agency of the U.S. Department of Commerce)

---

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