Equilibria Data for Two Viscous Ternary Liquid Systems J. H. GARY', JORGE S. CRICHTON, Jr., and ROBERT FEILD, Jr.' University of Virginia, Charlottesville, Va. F o r research being initiated a t t h e University of Virginia on liquid-liquid extraction i t w a s desired t o determine the effect of v i s c o s i t y on t h e efficiency of extraction. T h e problem a r o s e of finding v i s c o u s s y s t e m s for which d a t a h a v e b e e n determined. Of a l l t h e ternary liquid s y s t e m s of pure components known to b e reported i n t h e literature, the only o n e composed of v i s c o u s components is furfuraldocosane-diphenylhexane (5) and only furfural is commerc i a l l y available. Most of t h e d a t a reported on liquid-liquid extraction u s i n g v i s c o u s l i q u i d s a r e b a s e d upon petroleum or vegetable hydrocarbon mixtures which cannot b e exactly duplicated, and i t is difficult t o compare operating s y s t e m s and conditions. To conduct research with v i s c o u s s y s t e m s , about 30 liquids of high v i s c o s i t i e s were t e s t e d for mutual solubility. P o s s i b l e ternary s y s t e m s were noted and t e s t e d to determine whether t h e region of immiscibility w a s great enough for liquid-liquid extraction. With t h i s preliminary information, two systems-propylene glycol-tributyrin-di(methoxyethyl) phthalate a t 2 5 C . a n d diethylene dycol-di(2-ethylC.-were sehexyl) phthalate4etrabromoethane a t 30 l e c t e d and their equilibria d a t a obtained. 'Present address, University of Alabama, University, Ala. 'Present address, Olin-Mathieson Co., Pisgah Forest, N. C.
METHODS OF INVESTIGATION
To define liquid-liquid isothermal s y s t e m s of pure components, i t is n e c e s s a r y to determine t h e curve or curves of saturation compositions of mixtures of t h e three components and t h e equilibrium compositions, represented by t h e extremities of t h e conjugation or t i e lines, a t t h e specified temperature. All d a t a reported here were a t atmospheric pressure, and pressure variations were neglected. Saturation Curve. In t h e s y s t e m s studied, t h e saturation compositions were determined a s follows: Mixtures of varying amounts of t h e solvent a n d s o l u t e were made, and titrated to t h e cloud point with t h e carrier. Similarly, mixtures of varying amounts of the carrier and s o l u t e were titrated t o t h e cloud point (at which the system clouds from t h e l a s t drop added and f a i l s to clear i n 2 0 minutes) with t h e solvent. Cylinders, containing t h e liquids, were weighed a s t h e components were added and t h e weight per c e n t w a s calculated a t t h e cloud point. T h e saturation curve w a s obtained a t T o C . by placing t h e cylinders in a constant t e m perature bath. T h e refractive index w a s measured a t t h e cloud point by raising t h e temperature s e v e r a l d e g r e e s centigrade t o clear up t h e system. T h e d a t a (Table I) s e r v e a s t h e b a s i s for a simple a n a l y s i s of any p h a s e known t o be saturated.
Table 1. Properties o f Pure Materials
Substance Propylene glycol
Source Fisher Scientific
Boiling Point (Lit.), O c .
Density (Lit.), G. /MI.
185-6
1.040
at
Viscosity a Refractive Index Lit. Temp., Cps. 35OC. (Abbe Refractomer) Cited "C.
20°C.
0
10 20 30
40 Diethylene glycol
Tributyrin
Union Carbide
Tennessee Eastman
20
245
1.1184 20
315
1.0350 a t 2OoC.
0
10 20 30 40 1.430 1
Di(methoxyethy1) phthalate
Tennessee Eastman and Union Carbide
340
1.170 a t 2OoC.
1.4972
Di(2-ethylhexyl) phthalate
Tennessee Eastman Union Carbide
230 at 5 mm.
20 0.98620
1.4762
Matheson, Coleman & Bell
151 at 54 mm
20 2.9642;
1.6312
Tetrabromoethane
% o w e of data Dow Chemical Co. Propylene glycol Tetrabmmoethane
1958
Union Carbide Chemicals Co. Diethylene glycol Di(2-ethy1hexyl)phthalate
310 140 65 32 19 107 60 35.7 23 17
20 30 40
24.2 14.5 10.1 7.2 5.3
10 20 30 40
104 53 30 17.7
0 10
0
20 40
381
81.4 22.3
25
37.8 71.1
9.27 6.58 3.27
Eastman Chemical Products Diethylene glycol Tributyrin Di(methoxyethy1) phthalate
C H E M I C A L AND E N G I N E E R I N G D A T A SERIES
111
Table II. Saturation and Equilibrium Data on Viscous Systems Propylene Glycol-Tributyrin-Di(methoxyethy1) P h t h d a te
Diethylene Glycol-Tetrabromoethane-Di(2-ethylhexyl) Phthalate
Saturation Data (25OC.)
Saturation Data (3OOC.) ( 2 )
Propylene glycol, wt. % 81.2 70.8 62.2 52.1 42.8 32.7 24.7 16.0 12.8 118 9.2 8.7 6.3 5.9
Tributyrin,
Di(methoxyethy1) phthalate,
wt%
wt. %
10.5 11.9 11.7 13.8 15.7 18.2 21.0 34.2 43.5 53.1 63.3 73.8 84.5 94.1
8.3 17.3 26. I 34. I 41.5 49.0 54.3 49.8 43.7 35.2 27.5 17.5 9.2 0.0
Refractive index (350 C.) 1.4320 L 437 1 1.4434 1.4485 14534 1.4589 1.4627 1.450 1 1.4560 1.4505 I. 4460 1.4398 1.4347 1.4293
Di(2- ethylhexyl) phthalate, wt. %
Tetrabromoethane, wt. %
0.6 0.8 0.9 1.0 1.2 1.7 2.5 4.2 7.8 19.4 24.4 29.4 39.2 48.4 54.4 59.5 64.5 69.1 79.0 88.5 98.9
0.0 9.9 19.8 29.7 39.5 50.7 58.5 67.0 76.1 77.6 73.2 68.5 59.5 50.6 44.5 39.6 34.7 29.6 19.8 10.6 0.0
Diethylene glycol, wt. % 99.4 89.4 79.4 69.3 59.3 47.6 39.0 28.8 15.0 3.0 2.4 2. 1 1.3 1.0 1.0 1.0 0.9 1.3 1. 1 1.1 1.1
Refractive index (340 c. ) 1.441 1 1.4480 1.4565 1.4650 1.476 1 1.4909 1.5036 1.5190 6 . .
1.5558 1.5465 1.5380 1.5248 1.5 146 1.5086 1.5042 1.5002 1.4968 1.4905 1.4854 1.4807
Equilibrium Data (25’C.) Heavy Layer Propylene glycol, wt. %
Tributyrin, wt. %
14.9 14.0 13.3
Light Layer
Di(methoxyethy1) phthalate, wt. %
Refractive index (35OC.)
Propylene glycol, wt. %
Di(methoyxathy1) phthal at e, wt. %
Refractive index (35%)
36.8 39.5 41.9
48.2 46.4 44.8
1.4590 1.4579 1.4568
73.4 74.9 76.2
10.6 10.4 10.4
16.0 14.7 13.4
1.4364 1.4356 1.4347
12.1 11.3 10.3
46.1 49.9 54.7
41.7 38.8 35.0
1.4550 1.4532 1.4510
78.2 78.9 80.4
10.3 10.2 10.2
11.5 10.9 9.3
1.4335 14331 1.4320
9.3 7.8 7.0
60.7 70.9 75.3
30.0 21.3 17.7
1.4477 1.4423 1.4403
82.4 84.9 86.2
10.1 10.1 10.1
7.5 5.0 3.7
1.4308 1.4292 1.4283
6.5 6.1
79.7 84.6
13.8 9.3
1.4377 1.4350
87.8 89.9
10.1 10.1
2.1 0.0
1.4272 1.4259
Tributyrin, wt. %
Equilibrium Data (3OOC.) (2) Heavy Layer Di( 2-ethylhexyl) phthalate, wt. %
Tetrabromoethane. wt. %
0.9 1.0 1.0
Light Layer
Diethylene glycol,
Tetrabromoethane.
Diethylene glycol,
wt. %
wt%
wt. %
0.0 10.0
1.0
wt. %
Refractive index (34OC.)
10.0 20.0
99.1 89.0 79.0
1.4412 1.4488 1.4564
99.0 89.0 79.0
1.1 1.3 1.7
30.0 40.0 50.0
68.9 58.7 48.3
1.4657 1.4768 1.4900
69.0 59.0 48.9
40.0
2.9 5.0
60.0 70.0
37.1 25.0
1.5066
38.6 27.8
0.0
...
Conjugate Lines. T h e conjugate or t i e l i n e s were obtained by placing various mixtures of the three components in pointed t e s t tubes. T h e mixtures were agitated i n t h e constant-temperature bath for 6 hours, and allowed t o stand 2 hours, and then the refractive index of e a c h p h a s e w a s read. A drop w a s taken from t h e top layer, the tube broken a t the pointed bottom, and a drop taken from t h e bottom layer. T h e s e two indices were used with the data of the saturation curve t o locate the tie lines. (If t h e index of the conjugate phase is known, i t s position on the saturation curve can b e determined by the i n d i c e s of the saturation curve.)
A l l refractive indices were determined with a n accuracy of 3 units in the fourth place by means of an Abbe refractometer with thermostatically controlled heating stage.
112
Di( 2-ethylhexyl) phthalate,
INDUSTRIAL A N D E N G I N E E R I N G CHEMISTRY
Refractive index (34Oc.)
1.0 1.0
1.4807 1.4852 1.4908
50.0
1.0 1.1 1.1
1.4972 1.5047 1.5 139
60.0 70.0
1.4 2.2
1.5252 1.5406
20.0 30.0
T h e data for t h e two systems determined a r e presented in T a b l e 11. Both systems have a single solubility curve. LITE RAT URE CITED (1) Carbide and Carbon Chemicals Co., New York, “Synthetic &gar& Chemicals,” 13th ed., 1952. (2) Crichton, J. S., “Experimental Study of Performance of Perforated Plates, Slotted Plates, and Raschig Rings in a Column Extractor Ooerated with a Viscous Ternarv- Liauid - SYStem,” unpublished M.S. thesis, Library, University of Virginia, Charlottesville, Va., 1955. (3) Eastman Chemical Products, Inc., Kingsport, Tenn., “Eastman Plasticizers,” 1954. (4) “Handbook of Chemistry and Physics,” 33rd ed., Chemical Rubber Publishing Co., Cleveland, Ohio, 1951. (5) Hunter, T. G., Brown, T., Ind. Eng. Chsm. 38, 1343 (1947). (6) Perry, J. i-L, ed., “Chemical Engineers’ Handbook,” 3rd ed., p. 727, McGraw-Hill, New York, 1950. Received fareview November 23, 1956. Accepted August 23, 1957. VOL. 3, NO. 1
