0378-38122980010-0

Fluid Phase Equilibria, 4 (1980) 125-136
0 Elsevier Scientific Publishing Company,
125
Amsterdam
- Printed in The Netherlands
EXTRACTION OF TETRAHYDROFURAN
FROM AQUEOUS
SOLUTIONS. TERNARY LIQUID EQUILIBRIA WITH CHLOROMETHANES AND CHLOROETHANES
AS SOLVENTS
JOSE COCA * , RAMONA
M. DIAZ and CARMEN
PAZOS
Department of Chemical Engineering, University of Oviedo, Oviedo (Spain)
(Received
March 13th,
1979;
accepted
July 30th,
1979)
ABSTRACT
Coca, J., Diaz, R.M. and Pazos, C., 1980. Extraction of tetrahydrofuran
from aqueous
solutions. Ternary liquid equilibria with chloromethanes and chloroethanes as solvents.
Fluid Phase Equilibria, 4: 125-136.
Liquid-liquid
equilibrium data at 25OC for tetrahydrofuran-water
with methylene
chloride, chloroform, carbon tetrachloride,
1,2-dichloroethane
and 1,1,2-trichloroethane
as solvents have been measured. The tie-line data have been correlated by the methods of
Hand, Othmer-Tobias
and Bachman; plait points have been estimated following the
methods of Treybal et al. and Mato and Bueno. All the solvents studied present isopicnic
compositions and selectivity is very similar for all of them.
INTRODUCTION
The separation of tetrahydrofuran (THF) from aqueous solutions is of particular interest due to the significant demand for THF as a solvent for extraction purposes and chemical reactions. THF-water mixtures show a closedloop region of limited miscibility over the temperature range of ‘71.8 to
137.1’C that might be useful to enrich the mixture in THF (Matoug, Novak,
Sobr and Pick, 1972). Liquid-liquid extraction can be used to recover THF
from the resulting phases and also from a mixture which has a composition
(of THF) lower than 25% in weight, in which phase separation does not
occur. THF also forms an azeotropic mixture with water (Cigna and Sebastiani, 1964) and in this case as well liquid-liquid extraction can be a suitable
method of recovering THF by distillation.
In this work liquid-liquid equilibrium data for the ternary systems THFwater with methylene chloride, chloroform, carbon tetrachloride, 1,2-dichloroethane and 1,1,2-trichloroethane as solvents are presented at 25°C.
Solvent selection was made on basis of Ewell’s criteria (1944).
l
To whom correspondence
should be addressed.
126
TABLE
1
Physical properties of the chemicals
Chemical
Property
Exptl.
Tetrahydrofuran
do
0.8875
ng”
1.4072
ds”
n”D”
Methylene
chloride
Chloroform
Carbon tetrachloride
1,2-Dichloroethane
1,1,2-Trichloroethane
a Data taken from “Solvents
Lit.
0.8880
s
1.4073
a
1.3266
1.3264
b
1.4242
1.4242
b
d420
1.4834
1.4832
b
n$O
1.4459
1.4459
b
d420
1.5943
1.5940
b
r&o
1.4603
1.4601
b
4 20
1.2530
1.2531
b
n&O
1.4449
1.4448
b
o.8892"
4 20
1.4401
1.4397
b
r&o
1.4711
1.4714
b
Guide”
b Data taken from “Handbook
(1963).
of Chemistry and Physics” (1971-72).
Ii
l
Ih
I
-7?3-
Fig. 1. Schematic view of the titration assembly.
Fig. 2. Densities and refractive indices for the system THF-water-1,1,2-trichloroethane.
A,O,at24”C;A,o,at
26°C.
127
EXPERIMENTAL
Materials
Tetrahydrofuran, chloroform and 1,1,2+ichloroethane
were supplied by
Fluka and methylene chloride, carbon tetrachloride and 1,bdichloroethane
by Probus. All chemicals were further purified by distillation in a heli-packing column. Distilled water was used in all the systems. The physical properties of the chemicals are given in Table 1.
Apparatus
and operations
The mutual solubility data at 25°C were determined by the method as
described by Othmer et al. (1941); homogeneous binary mixtures were
titrated with the third component until the onset of turbidity. The titration
was carried out in a thermostated erlenmeyer flask, Fig. 1, with a silicone
gum stopper to prevent evaporation, the third component being added
through a needle inserted into the stopper. Under these conditions, at 25°C
for the most volatile solvent used in this work evaporation losses were of the
order of 0.23% in weight for a one hour period. Taking into account that
titrations with this solvent did not last more than 30 min and that it was
mixed with higher boiling point components, evaporation losses can be considered negligible.
During titration, the mixture was stirred with a magnetic stirrer. Mutual
solubilities of the solvent-water systems are given in Table 2 and also
TABLE
2
Mutual solubilities of the solvent-water
Chemical
systems
Solubility
Exptl.
in water
water in
1.37%
0.18%
(25’C)
(25°C)
1.32 g/100 g (25°C)
0.198 g/100 g (25°C)
a
s
Chloroform
in water
water in
1.19%
0.08%
(25°C)
(25°C)
0.822
0.072
g/100
g/100
g (20°C)
g (23°C)
*
a
Carbon tetrachloride
in water
water in
0.07%
0.01%
(25°C)
(25°C)
0.077
0.010
g/100
g/100
ml (25°C)
ml (24°C)
1,2-Dichloroethane
in water
water in
1.10%
0.18%
(25°C)
(25°C)
0.81%
0.15%
(20°C)
(20°C)
1,1,2-Trichloroethane
in water
water in
0.50%
0.085%
(25’C)
(2VC)
0.45%
0.05%
(2OOC) b*c
(20°C) b*c
Methylene
chloride
s Data taken from “Organic Solvents” (1955).
b Data taken from “Solvents Guide” (1963).
c Weight percent.
=
Lit.
a.c
a&
a
a
THF
WATER
SOLVENT
20
10
Fig. 3. Mutual solubility
chloride; +, chloroform;
ethane.
TABLE
30
LO
50
60
70
80
curves for THF-water-solvent
90
systems at 25” C. n, methylene
A, 1,1,2-trichloro-
x , carbon tetrachloride; 0, l,Z-dichloroethane;
3
Mutual solubility and tie-line data for THF-water(W
(values expressed in weight percent)
Mutual solubility
jmethylene
chloride(MC)
data
THF
W
MC
THF
W
0.00
18.23
31.93
43.37
55.64
63.74
68.35
72.10
75.66
76.64
76.55
74.87
0.18
0.54
1.19
1.91
2.89
4.07
5.09
6.34
8.47
10.33
13.79
17.32
99.82
81.23
66.89
54.72
41.47
32.19
26.56
21.66
15.85
13.03
9.66
7.81
72.35
68.70
65.48
57.49
50.11
42.27
34.09
26.33
18.86
11.04
3.83
0.00
21.41
26.17
30.08
39.38
47.78
56.31
64.93
72.77
80.32
87.84
94.87
98.63
MC
6.24
5.13
4.44
3.12
2.11
1.42
0.98
0.90
0.82
1.12
1.30
1.37
Tie-line data
Aqueous
phase
Organic phase
THF
W
48.55
30.80
25.12
17.80
13.22
8.39
2.20
49.39
68.23
74.08
81.36
85.86
90.52
96.61
MC
2.06
0.97
0.80
0.84
0.92
1.09
1.19
THF
W
MC
71.94
76.50
73.50
64.25
53.82
42.04
24.40
21.88
10.05
6.95
4.32
2.66
1.59
1.20
6.18
13.45
19.55
31.43
43.52
56.37
74.40
at 25°C
129
reported literature values. Densities and refractive indices corresponding to
the points on the binodal curve were determined at 24°C and 26°C depending on the concentration range to avoid turbidity and phase separation. Tieline data were determined by analysis of the two layers of a synthetic heterogeneous mixture. The mixture was shaken thoroughly and allowed to settle
for at least 5 h in a thermostated settling cell until complete separation was
achieved. The analysis of both layers was made by measuring densities and
refractive indices, and using the standard plots obtained when the binodal
curve was determined. Figure 2 shows one of these standard plots for the
system THF-waterl,1,2-trichloroethane.
In the vicinity of the plait point
only density measurements were used, because refractive indices could not
be measured with precision at the plait point composition, as shown in Fig. 2.
TABLE
4
Mutual solubility and tie-line data for THF-water(W)-chloroform(C)
expressed in weight percent)
Mutual solubility
at 25°C (values
data
THF
W
C
THF
W
0.00
16.67
29.68
40.69
53.14
62.13
66.90
71.02
73.03
74.96
76.34
77.08
76.42
75.21
72.27
0.08
0.41
0.86
1.81
2.38
3.38
4.25
5.44
6.16
7.36
8.94
11.21
14.68
17.05
21.66
99.92
69.08
82.92
69.45
67.49
44.48
34.49
28.86
23.54
20.81
17.69
14.72
11.72
8.90
7.73
6.07
65.31
62.00
66.11
60.37
44.35
38.30
32.48
26.63
20.77
14.93
9.23
3.04
0.00
26.89
30.48
34.51
41.44
47.92
54.51
60.94
66.91
73.10
78.89
84.69
90.23
96.19
98.81
C
6.03
4.20
3.49
2.45
1.71
1.14
0.76
0.61
0.37
0.34
0.38
0.54
0.77
1.19
Tie-line data
Aqueous
phase
Organic phase
THF
W
44.30
33.50
28.80
20.77
14.90
10.10
4.00
54.60
65.94
70.74
78.84
84.70
89.40
96.06
C
1.10
0.56
0.46
0.39
0.40
0.50
0.95
THF
W
C
75.20
76.50
73.61
63.60
63.10
41.50
22.37
16.98
8.94
6.39
3.80
2.33
1.73
0.45
7.82
14.56
20.00
32.60
44.57
56.77
77.18
-
130
RESULTS
AND DISCUSSION
The experimental liquid-liquid equilibrium data at 25°C for the systems
tetrahydrofuran-water with the solvents methylene chloride (MC), chloroform (C), carbon tetrachloride (CT), 1,2-dichloroethane (DE) and 1,1,2-trichloroethane (TE) are given in Tables 3, 4, 5,6 and 7 respectively. The
binodal curves for the five systems are shown in Fig. 3.
All systems studied in this work show the isopicnic compositions of
extract and raffinate listed in Table 8.
From the tie-line correlations available the following have been considered
here:
TABLE
5
Mutual solubility and tie-line data for THF-water(W)-carbon
(values expressed in weight percent)
tetrachloride(CT)
Mutual solubility data
THF
W
CT
THF
W
0.00
15.62
28.49
39.47
51.81
60.96
64.02
67.86
70.41
74.31
75.83
76.49
75.54
0.01
0.14
0.38
0.81
1.54
2.66
3.08
3.73
4.75
6.71
8.75
11.35
14.47
99.99
84.23
71.12
59.72
46.65
36.38
32.90
28.41
24.84
18.98
15.42
12.16
9.99
74.53
71.85
68.62
64.96
57.85
50.05
42.28
34.32
26.77
18.91
11.12
0.00
16.83
21.22
25.73
30.42
39.20
48.29
56.79
65.18
72.90
80.83
88.59
99.93
CT
8.64
6.93
5.65
4.62
2.95
1.66
0.93
0.50
0.33
0.26
0.29
0.07
Tie-line data
Organic phase
Aqueous phase
THF
W
CT
THF
W
CT
39.89
35.63
30.40
24.75
18.91
15.02
7.91
59.39
68.83
69.19
74.94
80.86
84.79
91.97
0.72
0.54
0.41
0.31
0.23
0.19
0.12
76.10
75.04
69.95
61.89
50.39
39.20
19.75
13.13
7.45
4.30
2.67
1.56
0.63
0.41
10.77
17.51
25.75
35.44
48.05
60.17
79.84
at 25OC
131
Hand (1930)
lo&O(YA/%)
=A
hhO(~A/Xw)
Othmer-Tobias
+ B
(1)
(1942)
lo&o [(IO0 - YSUYSI = C log,o[(100
- xw)/xw 1 +D
(2)
Bachman, as modified by Brown (1948)
(3)
YSIXW = EYS + F
Parameters in the former equations obtained by the least-squares method
are given in Table 9 for the different solvents.
TABLE
6
Mutual solubility and tie-line data for THF-water(W)-l,Z-dichloroethane(DE)
(values expressed in weight percent)
Mutual solubility
THF
data
DE
THF
W
0.18
99.82
0.72
1.33
1.79
2.43
3.32
4.08
4.75
5.91
7.46
8.45
9.91
12.41
16.68
80.64
65.47
57.58
49.01
40.42
35.02
30.53
25.47
20.48
17.99
15.30
12.07
8.88
71.73
68.50
64.99
61.41
57.85
52.14
46.10
38.31
30.28
22.65
14.86
7.43
0.00
21.33
25.78
30.16
34.54
38.73
45.37
52.17
60.61
69.02
76.79
84.56
91.80
98.90
W
0.00
18.64
33.21
40.63
48.56
56.26
60.90
64.71
68.62
72.06
73.56
74.79
75.52
74.44
at 25’C
DE
6.93
5.72
4.85
4.05
3.42
2.49
1.73
1.08
0.70
0.56
0.58
0.78
1.10
Tie-line data
Aqueous
phase
Organic phase
THF
W
45.40
35.50
30.20
27.38
20.50
14.86
11.20
7.60
3.80
53.00
63.59
69.10
71.99
78.94
84.56
88.14
91.63
95.28
DE
1.60
0.91
0.70
0.63
0.56
0.58
0.66
0.77
0.92
THF
W
DE
72.21
75.52
74.50
73.04
65.47
55.09
44.64
32.60
18.65
20.69
7.10
12.10
16.00
19.02
29.49
41.89
53.40
66.10
80.60
12.38
9.50
7.94
5.04
3.02
1.96
1.30
0.75
132
TABLE
7
Mutual solubility and tie-line data for THF-water(W)-1,1,2-trichloroethane
25°C (values expressed in weight percent)
Mutual solubility
(TC)
at
data
TI-IF
W
0.00
17.10
23.07
30.27
37.42
45.42
53.72
62.35
66.65
71.07
72.73
74.73
76.07
76.54
0.92
0.75
0.99
1.36
1.80
2.45
3.61
4.29
5.73
6.53
7.76
9.64
12.76
0.09
TC
THF
W
99.92
75.18
72.20
68.68
65.31
61.74
58.13
50.09
42.36
34.77
26.67
22.97
18.71
11.27
0.00
16.62
21.48
26.17
30.38
34.69
39.00
48.26
56.71
64.67
72.94
76.75
81.06
88.42
99.49
82.38
76.18
68.74
61.21
52.78
43.83
33.86
29.05
23.19
20.74
17.51
14.29
10.70
TC
8.19
6.32
5.15
4.31
3.56
2.87
1.65
0.93
0.57
0.39
0.28
0.22
0.31
0.51
Tie-line data
Aqueous
phase
Organic phase
THF
W
TC
THF
W
TC
51.58
45.18
37.75
32.98
27.70
23.93
20.40
16.87
13.33
10.35
6.07
46.73
53.69
61.49
66.49
71.92
75.78
79.36
82.91
86.43
89.38
93.58
1.69
1.13
0.71
0.53
0.38
0.29
0.24
0.22
0.24
0.27
0.35
72.20
75.30
76.52
75.41
71.59
67.75
62.10
55.59
48.70
39.71
25.53
21.50
16.49
11.18
8.57
6.11
4.75
3.60
2.62
2.00
1.39
0.97
6.30
8.21
12.30
16.02
22.30
27.50
34.30
41.79
49.30
58.90
73.50
TABLE
8
Isopicnic compositions
at 25°C
(in weight percent of TI-IF) for the THF-watersolvent
Solvent
YA
XA
Methylene chloride
Chloroform
Carbon tetrachloride
1,2-Dichloroethane
1,1,2-Trichloroethane
64.9
71.6
74.5
61.4
70.6
18.0
26.8
35.0
18.1
26.7
systems
133
TABLE 9
Parameters for correlation
of equilibrium
data in THF-water-solvent
at 25°C
Hand
OthmerTobias
Bachman
A = 0.9940
B = 1.0183
(r = 0.9830)
c = 1.1753
D = 1.1328
(r = 0.9897)
E = 0.0096
F = 0.0757
(r = 0.9988)
Chloroform
A = 1.2003
B = 1.0402
(r = 0.9948)
c = 1.3351
D = 1.1301
(r = 0.9970)
E = 0.0096
F = 0.0851
(r = 0.9986)
Carbon tetrachloride
A = 1.5878
B = 1.0739
(r = 0.9878)
C = 1.7125
D = 1.1457
(1. = 0.9883)
E = 0.0100
F = 0.0968
(r = 0.9962)
1,2-Dichloroethane
A = 1.2755
B = 1.1020
(r = 0.9987)
C = 1.3466
D = 1.1644
(r = 0.9987)
E = 0.0097
F = 0.0773
(r = 0.9993)
1,1,2-Trichloroethane
A = 1.2823
B = 1.0373
(r = 0.9989)
c = 1.3650
D = 1.1092
(r = 0.9992)
E = 0.0098
F = 0.0843
(r = 0.9989)
Solvent
Methylene
chloride
Plait point data have been determined by the method of Treybal et al.
(1946) using the Othmer-Tobias and Hand correlations, and also by a method proposed by Mato and Bueno (1968) that consists of plotting log(yA/xA)
vs. xA (at the plait point Iog(yA/xA) = 0). Plait point compositions are given
in Table 10. As shown in Table 10, plait point compositions as obtained by
Mato-Bueno method are higher than those obtained by Treybal’s method.
Values obtained by the first method could be more realistic as sufficient tie-
TABLE
10
Plait point data in THF-water-solvent
System
systems at 25’C
Treybal et al.
Hand
THF-water-MC
THF-water-C
THF-water-CT
‘M-IF-water-DE
THF-watet-TE
Othmer-Tobias
Mato-Bueno
THF
Water
Solvent
THF
Water
Solvent
THF
Water
Solvent
60.5
61.0
57.1
55.6
59.1
35.9
36.7
40.0
41.3
37.9
3.6
3.3
2.9
3.1
3.0
60.8
59.7
58.4
57.3
60.8
35.5
39.2
38.5
39.4
35.9
3.7
3.1
3.1
3.3
3.3
62.4
65.6
33.7
30.1
3.9
4.3
62.2
64.4
33.6
31.5
4.2
4.1
0
10
%A
20
30
LO
% tetrahydrofuran
50
60
in aqueous
70
I
60
phase
Fig. 4. Equilibrium distribution diagram. l , methylene chloride; +, chloroform;
tetrachloride; 0, 1,2-dichloroethane;
A, 1,1,2_trichloroethane.
X ,
carbon
line data have to be obtained in the proximity of the plait point in order to
obtain reliable results.
The distribution diagrams and selectivities for the systems studied in this
work are shown in Figs. 4 and 5. The distribution coefficient, in a wide range
0.6
1
I
I
I
10
20
30
LO
YA
% tetrahydrofuron
50
!
I
60
70
in organic
60
90
phase
Fig. 5. Selectivities in THF-water-solvent
systems. I, methylene chloride; +, chloroform;
X , carbon tetrachloride; 0, 1,2_dichloroethane;
A, 1,1,2-trichloroethane.
135
of concentrations, is greatest with methylene chloride as solvent and carbon
tetrachloride exhibits the lowest values. The effectiveness of the extraction
of a solute by a solvent was given by the selectivity (Treybal, 1963), which
in the present work may be considered as the ability of chlorinated hydrocarbons to separate water and THF. Selectivities are very similar for all the
solvents studied, and, as with the distribution coefficient, methylene chloride shows some higher values than the other solvents.
NOTATION
C
CT
DE
ME
TE
W
d
nD
r
xA
xw
YA
f&3,C,D,E,F
chloroform
carbon tetrachloride
1,Bdichloroethane
methylene chloride
1,1,24richloroethane
water
density
refractive index
regression
weight percent of solute in the aqueous phase
weight percent of water in the aqueous phase
weight percent of solute in the organic phase
weight percent of solvent in the organic phase
constants in the correlation equations
Greek letters
PA.W
solvent selectivity
Subscripts
A
S
W
solute
solvent
water
REFERENCES
Brown, T.F., 1948. Ind. Eng. Chem., 40: 103.
Bueno, J. and Mato, F., 1968. Personal communication.
Cigna, R. and Sebastiani, E., 1964. Ann. Chim., 64: 1048.
Ewell, R.H., Harrison, J.M. and Berg, L., 1944. Ind. Eng. Chem., 36: 871.
Hand, D.B., 1930. J. Phys. Chem., 40: 103.
Marsden, C. and Mann, S., 1963. Solvents Guide, in Marsden, C. (Ed.), Cleaver-Hume
Ltd., London, 9. 514.
MatouH, J., Novak, J.P., Sobr, J. and Pick, J., 1972. Collect. Czech. Chem. Commun.,
2653.
Press
37:
136
Othmer, D.F. and Tobias, P.E., 1942. Ind. Eng. Chem., 34: 693.
Othmer, D.F., White, R.E. and Trueger, E., 1941. Ind. Eng. Chem., 33: 1240.
Treybal, R.E., 1963. Liquid Extraction. McGraw-Hill, New York.
Treybal, R.E., Weber, L.D. and Daley, J-F., 1946. Ind. Eng. Chem., 38: 817.
Weast, R.C. (Ed.), 1971. Handbook of Chemistry and Physics, The Chemical Rubber Co.,
Cleveland, Ohio.
Weissberger, A., Proskauer, ES., Riddick, J.A. and Toops, E.E., 1955. Organic Solvents:
Technique of Organic Chemistry, in Weissberger, A. (Ed.), Interscience Publishers, Inc.,
New York.