1474
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
(16) Sage, B. H., Yale, W, D., and L a c e y , W.K., ISD.ENG.CHEW, 31,223 (1939). (17) Scheuer, O., d n z . fie?^. A k a d . , 48, 307 (191 1). (18) Schlinger, W.G., and Sage, E. H.. IND.EXG.CHEM,,42, 2158 (1950). (19) Selleck, F. T., Reamer. H,H., a ~ l dSage, B.H., Ibid., 45, 814 (1953). Phil. Trans. Roy. (Lon(20) Thorpe, T. E., and Rodger, J. IT,, d o n ) , A185,397 (1895). (2i) Watson, K. M., IND. EXG.CHnr., 35, 398 (1943).
( 2 2 ) Wittorf,
Vol. 45, No. 7'
K.V., Z.anorg. Chen., 41,85 (1904).
RECEIVEDfor review November 9, 1953. ACCEPTEDJanuary 19, 1954. A more detailed form of this paper (or extended version, or material supplementary t o this article) has been deposited as Document KO.4199 with t h e AD1 Auxiliary Publications Project, Photoduplication Service, Library of Congress, Tashington 25, D. C. h copy may be secured by citing the document number and by remitting 61.26 for photoprints or S1.25 for 35-mm. microfilm. Adrance payment is required. Make checks or money orders payable t o Chief, Photoduplication Serrice, Library of Congress.
Ternary iquid-Liqui Equilibria ETHY LBENZENE-DIACETBNE ALCOHOL-W ATER AND STYRENEDIACETOKE ALCOHOL-WATER L. F. CROOKE, J R . ~ , AND MATTHEV VAY WINKLE University of Texas, Austin 12, Tex.
I
S CERTAIK separation processee an extracting agent is used which has affinity for one of the materials being sepa-
rated. Subsequently the cxtracting agent must be removed fiom the extracted material by distillation, liquid-liquid extraction, or other means. Systems composed of certain hydrocarbons, alcohols, and water are of interest in this connection. The systems ethylbenzene-diacetone alcohol-water and styrene-diacetone alcohol-ivater xvere st,udied in this investigation, and the phase boundary compositions and equilibrium tie-line data a t 25' C. were determined. This is one of a series of investigations in which the selectivities of certain solvents for certain materials produced in commercial processes are being studied. Previous investigations (6, 8)in the series involved the determination of the selectivity of heptadecanol and 3-heptanol for acetic acid and ethyl alcohol in water solutions and the evaluation of the liquid-liquid equilibrium data. MATERIALS
The diacetone alcohol (4-hydroxy--l-methy1-2-pentanone) used in this investigation waa obtained from the Eastern Chemical Co. The alcohol was purified by distillation in a 48-inch column, 1 inch in diameter, packed with glass helices. The column was operated a t a 5 t o 1 reflux ratio ( L I D ) . Two successive "heart" or middle cuts of 80% were made to obtain material of satisfactory purity. The index of refraction of the final distillate product was determined as 1.4235 and compared with the literature value of 1.4232 (6). The ethylbenzene specified as 99.1 to 99.4% purity was supplied by the hlonsanto Chemical Co. The styrene, also supplied by the Rlonsanto Chemical Co., ~ ' a of 4 99.9% purity. Distilled water was used throughout the investigation. PROCEDURE
The procedure described by Othmer et at. (4)was used to find points on the solubility curve in this investigation. Because a portion of the final solution had t o be removed and examined in a refractometer, the stepwise method of determination of the solubility curve was considered inadvisable. The modification used has been discussed (6, 8).
h known quantity of the solvent (ethylbenzene or styrene)
xvas placed in a clean, weighed flask, The flask was weighed again and a known quantity of the solute (diacetone alcohol) was added. The flask containing the mixture was weighed again and then placed in a bath controlled a t a constant temperature of 25' C. After 20 to 30 minutes the flask was removed and distilled water was added from a buret t o the mixture. After each addition the mixture was agitated vigorously. Water addition was continued until a cloudiness appeared which did not disap1
Present address, Creole Petroleum Go., Caracas, Venezuela.
pear with mixing. The flask containing the mixture was again placed in the constant temperature bath. If after a period of time the solution cleared, more water was added. If the mixture remained turbid for 20 minutes, the flask was reweighed. The v-eight of the water in the saturated mixture was determined by difference. From the weights of the components in the saturated mixture, the weight fraction of each was calculated. A sample of the saturated phase was removed and the refractive index determined in a refractometer using a monochromatic sodium d light source. The prisms were maintained at 30" C. This small increase in temperature waq enough t o produce a single-phase solution.
'OO/\\ 901
- \
Figure 1. Phase Diagram of Ternary System WaterDi a c e t o n e Alcohol-Ethylbenzene at 23' C.
L w
5
60
w 0
5 c z
0 w
50
40
D: w 0.
30 L
2
3
20
IO
1 0
10
20
30 WEIGHT
I 40 PER
50
CENT
€0
70
80
90
100
WATER
This procedure was repeated as the ratio of 3Olverlt (ethylbenzene) t o solute (diacetone alcohol) was varied to determine the composition of the ethylbenzene- or solvent-rich laver. A second series of mixtures was made up of water and diacetone alcohol. The solvent, ethyl benzene or styrene, was added dropwise with vigorous mixing until a "stable" turbidity was produced. This procedure made it possible to determine the composition of the rvater-rich phase portion of the solubility curve. Compositions of these mixtures were also determined by refractive index methods.
July 1954
INDUSTRIAL AND ENGINEERING CHEMISTRY
1475
The tie-line data were determined as follows: TABLE
A clean separatory funnel was weighed and known amounts of water, diacetone alcohol, and ethylbenzene or styrene were weighed separately into the funnel. This mixture was agitated vigorously and then placed in the bath and kept there a t 25' C. for 3 hours. If the mixture separated rapidly into clear layers, the contents were mixed again. If after 3 hours the mixture had not separated into two clear layers, it was kept in the bath until separation occurred. At this point the heavier or water-rich layer was drawn o f f into a clean vial and the cdmposition of the water layer was determined by the refractive index method. The weight of the solvent-rich layer remaining was det'ermined and then a sample was examined in the refractometer. The curve of saturated phaEe composition versus refractive index was used to establish the equilibrium phase compositions from the experimental refractive indices of the saturated layers. The compositions of each pair of points determined in this manner were plotted and connected with straight lines. The point representing the composition of the original mixture was also plotted on the same graph. The location of the total compoloop,
I\
I. EQUILIBRIUM DATAFOR ETHYLBENZENE-DIACETOXE ALCOHOL-WATER SYSTEM AT 25" C.
Water, Weight % 0.1 0.5 2.1 3.4 6.0 9.1 11.0 15.4 19.6 22.0 30.5 46.8 55.3 70.9 79.8 90.1
Diacetone Alcohol, Weight ?& 16.2 24.4 36.3 43.2 51.9 58.0 61.4 66.1 67.6 67.6 54.7 51.8 44.0 29.1 20.2 9.1
Ethylbenzene, Weight % ' 83.6 75.1 61.5 53.5 42.1 32.9 27.7 18.6 12.8 10.4 4.8 1.4
0.7
0.1 0.05 0.05
Tie-Line Data at 25' C. Diaoetone alcohol Diacetone alcohol in water layer, in benzene layer, weight % weight % 5.6 16.7 7.4 23.2 11.2 33.6 14.6 38.9 23.5 55.2 29.2 62.6 27 fi7 -. ."fi ". . .?51.2 64.2 57.3a 57.3a
90
Figure 2. Phase Diagram of Ternary S y s t e m WaterDiacetone Alcohol-Styrene at 25' C.
eo
bition with relation to the tie line served as a n indication of the accuracy of the analytical procedure. When this point did not fall on or very near the line, some error in procedure or analysis was indicated. In both systems studied the plait point was estimated from the intersection of the extension of the conjugate line and the solubility curve. This point was checked by its position on the curvep (,orrelating the tie-line data.
70
60
50
40
30
RESULTS
20
to 0 0
10
20
30
40
WEIGHT
w In
PER
50
60
CENT
WATER
70
90
80
70
DATAFOR STYREXE-DIACETOXE TABLE11. EQUILIBRIUM
a
ALCOHOL-WATER SYSTEM AT 25
I
O60
Water, Weight % 0.2 2.2 5.2 12.8 20.4 24.4 36.3 60.0 53.6 55.0 57.9 73.6 82.0
a W
5 z 2 c 2
50
40 30
-I
E
-I
= 2 8 3
10
' 0
Diacetone Alcohol, Weight % 29.3 35.0 48.6 58.8 62.4 62.9 58.7 48.7 46.2 44.0 41.4 26.3 18.0
c.
Styrene, Weight % 70.5 62.9 46.2 28.5 17.2 12.7 5.0 1.3 1.2 1.0 0.7 0.05 0.05
Tie-Line Data at 25' C . Diacetone alcohol Diacetone alcohol in water layer, in styrene layer, weight ?& weight %
20
a W
100
The equilibrium data for the system ethylbenzene-diacetne alcohol-water are presented in Table I and shown graphically in Figure 1. The equilibrium data for the system styrene-diacetone alcohol-water are presented in Table I1 and shown grsphically in Figure 2. The distribution of the solute, diacetone alcohol, between each pair of the immiscible solvents is shown in Figure 3. The diace-
IO
DIACETONE
20 ALCOHOL
30 ( W t %)
40 IN
50
60
AROMATIC
70 PHASE
Figure 3. Distribution of Diacetone Alcohol
INDUSTRIAL AND E N G I N E E R I N G C H E M I S T R Y
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Vol, 46, No. 7
40
E
30
0
w
i;l
20
to
10
0
20
30
40
50
60
W t % DIACETONE ALCOHOL IN AROMATIC P H A S E 100 - Wt % Wder in Water Phase Wt % Water in Water Phase
(-
1oo-xww
Figure 5 , Selectivity of Aromatics for Diacetone Alcohol
)
X W W
Figure 4. Othmer-Tobias Plot
tone alcohol has a marked affinity for the water phase in both systems, and there is no significant difference between the behavior of the two systems. A similar type of distribution curve has been presented for a water-benxene-1,4-dioxanesystem ( 7 ) . A criterion of solvent performance in a given mixture is selectivity. Selectivity is the ratio of solute in the solvent phase to raffinate in the solvent phase, divided by the ratio of solute in the raffinate phase to raffinate in the raffinate phase. Thus, the selectivity, p, of the solvent, A , for the solute, C, is:
In Figure 5 the selectivitv of the aromatic for the solute is presented. Figure 6 is a plot of the selectivity of water for the solute.
H,O-
DAA- ETHYL
BENZENE
1
'
'
~
i-I -
H,O-DAA-
A comparison of the curves indicates that the selectivity of water for diacetone alcohol is slightly greater than the selectivity of the aromatic for diacetone alcohol. The method of Othmer and Tobias (3)is used to determine the consistency of liquid-liquid equilibrium data. A plot of their empirical equation:
on a log-log scale is a straight line having a slope, n, and an intercept, m. A plot of this type wa5 prepared for both systems and essentially straight lines resulted, as shown in Figure 4. The adherence of the data to the correlation is a check on the consistency and not on the accuracy of the data. The curvature a t the extremities is not unusual. The data were also plotted with the coordinates suggested by Bachman ( 1 ) and Hand ( 2 ) . These methods were recommended for smoothing and interpolation of the tie-line data. The Bachman-type plot, Figure 7 waE prepared by plotting the weight fraction of the solvent in the solvent layer, (X)AA, against the ratio of the w i g h t fraction of the solvent in the solvent layer di-
STYRENE
40 >-
I-
L
5 30 W W
tn
20 IO
" 20
A
-33 .40 50 60 WI % MCETONE ALCWOb IN AROMATIC P H A S E Figure 6. Selectivity of Water for Diacetone Alcohol
t-
%
01 IO
!
I
,
14 18 22 26 30 34 38 WT % AROMATIC IN AROMATIC PHASE XAA W T % WATER IN WATER P H A S E
Figure 7 . Bachman Plot
INDUSTRIAL AND ENGINEERING CHEMISTRY
July 1954
from the Othmer-Tobias correlation. immiscibility of the solvent phases.
1477 This is due to the extreme
NOMENCLATURE
x = concentration (weight per cent) A = aromatic, styrene or ethylbenzene C = solute, diacetone alcohol W = diluent, water = selectivity defined in Equation 1 The first subscript denotes the com onent The second subscript denotes the pffase ZCA = diacetone alcohol in aromatic phase = the mutually soluble component Solute Solvent = one of the immiscible pair of liquids, usually the one in which the solute is originally dissolved Diluent = the remaining liquid of the immiscible pair, usually the one used to extract or remove the solute from the solvent Raffinate = the phase or layer rich in the diluent, usually discarded after removal of the solute Extract = the phase or layer rich in the solvent, usually recirculated after removal of the solute LITERATURE CITED
xcw
W t % Solute in Water Phase Water in Water Phase
( G )W t % Figure 8.
(1) Bachman, I., IKD.ENG.CHEY., ANAL.ED.,12,38 (1940). (2) Hand, B. D., J. Phys. Chem., 34, 1961 (1930). (3) Othmer, D. F., and Tobias, P. E., IND.ENG.CHEM.,33, 1240
Hand Plot
vided by the weight fraction of the diluent (water) in the diluent l a w , (X)AA/(X)TW. The Hand-type plot, Figure 8, was prepared by plotting the ratio X C W / X W W , the weight fraction of the solute in the water layer divided by the weight fraction of the water in the water’ layer, against the ratio X C A / X A A , the weight fraction of solute in the aromatic layer divided by the weight fraction of the aromatic in the aromatic layer. The straight lines resulting from the Hand-type correlation are nearly identical to those resulting
(1941). (4) Othmer, D. F., White, R. E., and Trueger, E., Ibid., 33, 1240 (1941). ( 5 ) Oualline, C. M., and Van Winkle, AI., Ibid., 44, 1688 (1952). (6) Shell Chemical Co., “Organic Chemicals,” Tech. Pub. SC:52-10 (1952). ( 7 ) Treybal, R. E., “Liquid Extraction,” p. 28, New York, LIcGrawHill Rook Co., 1951. (8) Upchurch, J. O., and Van Winkle, M., IND.ENG.CHEM.,44, 618 (1952). RECEITEDfor review November 16, 1953. ACCEPTEDFebruary 15, 1954. Abstracted from a thesis submitted in partial fulfillment of the requirements of the degree of master of science in chemical engineering.
Vapor-Liquid Equilibria of NanhthaleneLl-Oetadecene Svstem I ,, AT SUBATMOSPHERIC PRESSURES WILLIAM L. MARTIN1 AND JIATTHEW VAN WINKLE University of Texas, Austin 12, Tex.
HIS study is part of a research program designed to provide equilibrium data necessary for design calculations for vacuum fractionating equipment of the type used by the petroleum industry. I n addition, the binary and ternary vaporliquid equilibrium behavior of the hydrocarbons of higher molecular s eight, in relation to hydrocarbon type, should furnish a basis for predicting the vaporization characteristics of the components in multicomponent and complex mixtures. Equilibrium vaporizatiori data were obtained and are reported here for the binary system naphthalene- 1-octadecene a t seven pressures ranging from 760 to 10 mm. of mercury. Other systems investigated in this research program are tetradecane-1-hcxadecene ( I I ) , dodecane-1-hexadecene (81, dodecane-l-octadecene (?), tetradecane-naphthalene (S), and tetradecane-1-hexadecene-naphthalene( 14). MATERIALS
The naphthalene used in this investigation was material supplied by the J. T. Baker Chemical Co. 1
Piesent address, Continental Oil Co , Ponca City, Olda
grade No effort
C.P.
was made to increase the purity, as satisfactory results had been obtained in this laboratory using material of the same purity. Experimentally determined physical constants and values obtained from the literature are given in Table I. The vapor pressure of the naphthalene used in this investigation as determined as a function of temperature by boiling under fixed pressures in the Colburn still. Thme data and values from the literature are reported in Table 11. The data fell on a smooth curve of slight curvature when the logarithm of vapor pressure was plotted against the reciprocal of absolute temperature. The octadecene used in this investigation was obtained from the Humphre3.-T~-iIkinsonCo , New Haven, Conn. Earlier investigations showed that the refractive index of similar material changed appreciably on boiling a t atmospheric pressure ( 7 , 8, 14) The change became less marked as the pressure was lowered Since the equilibrium samples were to be analyzed by refractive index, considerable effort was expended to improve the heat stability of the octadecene by refluxing and distilling the olefin in the presence of solid ferrous sulfate ( 7 , If).
