T H E SYSTEM NORMAL BUTYL ALCOHOL-METHYL ALCOHOL-WATER BY A. J. MUELLER, L. I. PUGSLEY A l l D J. B. FERGUSOX
Methyl alcohol is completely miscible in water and in n. butyl alcohol but water and n. butyl alcohol are themselves only partially miscible a t ordinary temperatures. The ternary system composed of these liquids does not appear to have been previously investigated. Our results' include the values for the binodal curves, the tie lines and the plait points a t a series of temperatures ranging from 0°C.to I O ~ O C . Xormal Butyl Alcohol. A carefully prepared product obtained from the British Acetone Company in 1917. After treating with lime in the cold and distillation, it yielded an alcohol with DY = 0.8095 and boiling point I 17.6'C. This density agrees with that given by Reilly and RalphZfor the pure alcohol and therefore we assumed the impurity to be water. Pugsley's stock sample was estimated3 to be 97.25 weight percent alcohol and this he checked by a density determination using a synthetic solution prepared from his dried alcohol and distilled water. hlueller's stock sample was estimated to contain 97.5 weight percent alcohol and on drying he obtained a product with density D'," = 08097. Methyl Alcohol. Eastman Kodak Research Laboratory and Kahlbaum, acetone free. Pugsley's sample gave D't = 0,7938 and Mueller's gave D'," = 0.7923. Upon the assumption that the impurity was water, the former sample was estimated4 to contain 99.3 5 weight percent alcohol and the latter 99.8 percent. We considered that the water content of the experimental charges would be more accurately known by making an allowance for the water present in the stock alcohols than by working with the absolutely dry alcohols which would so readily absorb moisture from the air. Distilled water was used. Apparatus and Procedure
For the measurements at 0°C. a glass thermostat containing ice and water was employed. For higher temperatures the bath contained either water or a strong solution of glycerol. The temperature could be regulated to o.i0C. and the thermometer read t o o.oj°C. 1 Results at 0°C. hy ,Mr. Pupsley (1927-28), those at other temperatures by Mr. Mueller (1928-29-30). 2 Reilly and Ralph: Sci. Proc. Roy. Duhlin SOC., 15, 597 (1919). 3 Young: "Distillation Principles and Processes," 262 (1922). 4 International Critical Tables, 3, 116 (1928).
BUTYL ALCOHOL-METHYL ALCOHOL-WATER
1315
The binodal curves were determined by three methods. At o°C. Pugsley added a suitable component to a known homogeneous solution of the other components and found, by weighing, the amount of this component necessary to give rise to heterogeneity. ,4t IS'C., 3o°C., 45OC. and 6ooC,.Mueller determined in a similar manner the amount of the consolute (methyl alcohol) required to change a heterogeneous system into a homogeneous one. At higher temperatures, the evaporation losses rendered unsuitable this procedure and a method similar to that of Drouilon5was employed. Samples containing equal percentages of methyl alcohol, but different percentages of butyl alcohol and water, were placed in tubes of soda-glass and the tubes sealed, care being taken to leave an air bubble large enough to ensure the presence of a gas phase a t all temperatures and to provide adequate stirring. A tube was placed in the thermostat in an inclined position and slowly rotated (46 times per minute) while the bath was either heated or cooled. The critical solution temperature for each sample was thus obtained. Such temperatures were plotted against the n. butyl alcohol-water, content of the samples. A number of such graphs were thus obtained, each graph relating to systems of constant methyl alcohol content. From these graphs, the points on the binodal curves could be obtained. I n the experiments a t 15~C.-6o~C., a sample was held in a calibrated Pyrex glass tube and the volume of the final homogeneous solution was obtained from cathetometer readings. The densities of these solutions were calculated from the volumes and weights. The volumes of the two phases present in the sample selected for the determination of a tie line were found in a similar manner and the tie lines were then obtained by the graphical method of Miller and McPherson.6 The tie lines a t o°C. were more directly determined since the two phases were separated, weighed and the weights checked against the original total weight. This rendered unnecessary the approximations involving the densities but the whole procedure was more tedious than the former method. At 7 j"C. and 90°C. density determinations were not made and a modification of the latter method was employed. Owing to the high temperatures, certain precautions were necessary since appreciable losses would occur if the sample were exposed to the air even for a short time. A capillary tube was sealed to the bottom of the sample tube and bent so that its upper end was well above the bath liquid. To this end was sealed a stopcock. At 75°C. the phases were separated by forcing the lower layer out through the capillary using compressed air; at 9o°C., the vapour pressure alone was sufficient for this purpose, and in this case the upper end of the sample tube was sealed off after filling. The weight of the phase removed was obtained by difference from the weights of the original charge and of the residual layer since the evaporation of the lower layer during its removal rendered the directly determined weight of this phase of dubious value. Drouilon: J. Chim. phys., 22, 149 (1925): 6LMillerand McPherson: J. Phys. Chem., 12, 709 (1908).
6
1316
A. J. UUELLER, L. I. PUGSLEY AND J. B. FERGUSON
The plait points at 0°C.-75*C. were obtained graphically by drawing a smooth curve through the bisectors of the tie lines to meet the binodal curves. Solutions with compositions corresponding to the location of these points of contact were then made up. To each solution of five cubic centimeters was added two drops of water and the ratio of the volumes of the phases which formed was noted. Three drops of butyl alcohol and sufficient methyl alcohol (usually three drops) to bring the system to such a state that one more drop would cause homogeneity, were added and the ratio of the volumes of the phases which separated was again noted. In the first case, the volume of the aqueous phase was the greater and in the second case the volume of the alcoholic phase was the greater, the excess in each case not exceeding 0.2 cc. The positions of these plait points were checked and established in this manner. The plait points at 90' and ioj'c'. were obtained by interpolation from the smooth curve on a ternary diagram connecting our experimental points with the point representing; the consolute composition in the binary system. Sources of Error
Measurements ut 0°C. to 60°C. The t,emperature of the thermostat was held to within o . I O C . and the actual temperatures were accurate within these limits. The sample tube was kept stoppered as much as possible during a determination. The time, exclusive of time taken for weighing, required to establish a point on the binodal curve seldom exceeded an hour. A test with methyl alcohol, the most volatile component,, indicated that the loss by evaporation at so°C. in one hour was 0.0135 g. A loss of this amount would correspond to an error of 0.I 7 weight percent in the total composition. Upon the assumption that the solution-air surface was elliptical, a volume reading of 3 cc. was in error not more than 0.3 weight percent. The detection of homogeneity or heterogeneity was not difficult but the composition of the saturated solution could only be determined to one drop of the liquid which was added. Care was taken to use as small drops as possible and the error was not greater than 0.I I weight percent of the composition of the system. The liquid-liquid interface was plainly visible, and the cathetometer reading readily obtained. Measurements above 60°C. Owing to the uncertainty in the stem correction of our mercury thermometer, the accurscy of the temperature measurements was 0.2'C. a t roo°C. and 0.3OC. at IZO'C. The temperature difference between the thermometer bulb and the liquid in the sample tube was probably not in excess of o.I"C. except a t the highest temperatures. The change from heterogeneity to homogeneity and vice versa could be determined for points on the flat parts of the temperaturecomposition curves within a range of 0.2"C. but toward the ends of these
BCTYL ALCOHOL-METHYL ALCOHOL-WATER
1317
curves only to within 0.8~0. An error of not more than 0.j percent in the butyl alcohol or water content (B W = 100)might be caused through this source. In any one series of experiments, the methyl alcohol was maintained as nearly constant as possible. The actual deviations from constancy are indicated in the table of results. This degree of constancy was deemed sufficient in view of the other sources of error but to attain even this degree, with the small samples (4-6 g.) used, it was necessary to discard one in every four samples prepared (approx.) at a time when we were experienced in the art. Jones7 reports a difference between results obtained using soda glass and Pyrex glass when studying the system water-n. butyl alcohol. Since our experiments were made with containers of soda glass, we repeated this comparison and observed with fresh soda glass a consolute temperature 0.4OC. higher than that observed with Pyrex glass. Jones' observation was thus confirmed. If the results with Pyrex glass are the more accurate, then our results are subject to this error, the magnitude of which would vary from experiment to experiment, especially with experiments a t different temperatures and which would probably have a maximum value of 0.4OC. Since most of our experiments were made a t temperatures much lower than the consolute temperature in the binary system, we did not consider that the possible magnitude of this error warranted a repetition of the many measurements which we had previously obtained. Keighings were made to 0.0001g. using carefully standardized weights but owing to the nature of our results, the weights recorded in this paper have usually been rounded off to three significant figures.
+
Experimental Results and Discussion In the tables the following abbreviations are used: n. butyl alcohol, B , methyl alcohol, M ; water, W. The results have been calculated on the basis B W = 100,since the infinite diagram enables one to select a scale suitable for the indication of the methyl alcohol content. Tables I to V, inclusive, give our results a t o°C., I S O C . , 3ooC,,45OC., and 6ooC. In Table VI are tabulated the critical temperatures observed with the various series of samples, each series a t constant methyl alcohol content. The results on the binodal curves a t 75'C., 9ooC., and I O ~ O C . are given in Table VII, and those on the tie lines a t 7j°C.and 90°C. in Table VIII. The composition of the plait points a t various temperatures are given in Table IX. The temperatures of a series of points on the saturation surface (solid model) corresponding to systems of constant butyl alcohol and water contents but variable methyl alcohol content are given in Table X.
+
Jones: J. Chem. SOC.,1929, i99.
1318
.4.
J. MCELLER, L. I. PUGSLES AND J. B. FERGUSON
TABLE I Binodal Curve, Tie Lines and Plait Point a t 0°C. Binodal Curve Composition in grams
w.
M.
2.89
90.45 90.21
4.68 9.68
90.07 89.26
13.03
86.72
16.73 19.03 18.52
83.63 76. 7 0 66.55
* H.
&
M.
B.
9.55* 9.79 9 ' 93 10.74 13.28 16.37 23.30 33.45
Composition in grams
m.
B.
16.87
j 6 . 76
43.24
15.70
46.77
14.34 12.38
44.52 37.20
9.80 6.47
32.33 2j.86
53.23 55.48 62.80 67.67
3 ,j I 8
22.91 19.62
-
74. I 4 77.09 80.38*
M.extrapolated.
Tie Lines
w.
B.
Phase weight ratio
14.30
62.46 60.68 63.18
37.54 39.32 36.82
o 697 0.870 0.840
(d) 16.72 (e) 1 7 . 6 2
64.60
35.40
o
63.31
36.69
0.941
M.
(a) 5 . 8 1 (b) 1 0 . 6 9 (c)
Comp. of system
702
Comp. upper phase
M.
(a) 4 . 2 0 (b) 8 . 7 5
(c)
12.25
(4
14.50
(e) 1 6 . 5 0
Comp. lower phase
W.
B.
M.
w.
B.
23.30 30. IO 36.90
76. i o 79.90
7.00
90.00
10.00
12.50
87 ' 5 0 84.80 79.50 74.50
44.25 jI.50
Plait Point 18. j o M.
63. I O 57 . 2 0 48. jo 6 3 . I O W.
15.50
18.90 19.40 3 6 . 9 0 B.
12.50 15.20 2 0 . 50
26.50
13'9
BUTYL ALCOHOL-METHYL ALCOHOL-WATER
TABLE I1 Binodal Curve, Tie Lines, Plait Point and Density Determinations at I S O C . Binodal Curve Comp. in grams LV . B.
Density
Comp. in grams
M.
M.
LV.
16.0
91.7 8.30* 6.29 91.4 8.56 89.3 1 0 . 7 12.2 14.4 86.8 13.2 15.7 16.2 16.7
83.9 80.5 j6.0 71.3
15.7
0.~88 0.981 0.981 0.970 0.960
-
16.1 19.5 24.0 28.7
16.3 * (H. & bl. interpolated).
66.1 33.9 61.1 38.9
j4.5 14.6 4 8 . 7 13.3 4 2 . 8 36.2 11.1 7.63 29.0 2.jj 21.9 19.9 15.1
0,954 0.945 0.934
Density
B.
0.926 0.922
57.2
0.913 0.899 0.890
63.8
0.881
71.0
0.870
j8.1
0.861
80.2*
0.8j3
4j.j
51.3
Tie Lines Phase volume ratio
Comp of system M. LV. B.
(a) 3.64
61.1 38.9 (b) 6.55 61.1 38.9 (c) 8.90 61.1 38.9 (d) 1 1 . 4 61.1 38.9 ( e ) 14.1 61.1 38.9 ( f ) 15.3 64 2 35.8
hl .
(4
2.3 (b) 4.3 (c) 6.7 (4 9.3 (e) 12 . 7 (f) 14.4
Phase weight ratio
I , 13
1.29
1.11
I.2j
I.oj
I . I8
0.965 I .07 0.830 0.900 0.975 1.06
Comp. upper phase
IT. 7 24.0
21.
Comp. lower phasc
B.
51.
78.3 76.0
w.
B.
4.8
91.6
8.4
8.4
90.7
9.3
27.5
72.5
10.7
89.7
10.3
32.4 40.5 4i.8
67.6 59.5
13.2
88.0
12.0
1j.6 16.3
83.9
16.I
80.0
20.0
Plait Point 16.0XI.
52.2
64.j W.
35.5 B.
1320
A. J. MUELLER, L. I. PUGSLEY AND J. B . FERGUSON
TABLE 111 Binodal Curve, Tie Lines, Plait Point and Density Determinations at 30OC. Binodal Curve Comp. in grams IT. B.
Density
Comp. in grams
M.
-
92.92
7.08*
0.985
4.71 6.12 7,jj 8.23
92.3 92.1 91.1 90.8
7.67 7.94 8.87 9.17
0.975 0.961
9.08 90.7 11.06 89.1 12.3 87.1
9.34 10.91 12.9 16.4
13.5 14.1 13.9 14.3 14.2
83.6 82.0
0.979 0,971
* H.
w.
14.3 14.2 14.2 13.9 13.8 13.4
75.9 73.1 71.8 67.3 61.9 57.2
48.0 11.0 44.4 9.jo 39.0 8.21 35.2 6.54 3 1 . 0 11.2
0.9j8 0.953
18.0
0.946
80.6 19.4 79.0 2 1 . 0 76.1 23.9
AI.
Density
B.
24.1 26.9 28.2
32.7 38.1 42.8 52.0
55.6 61.0 64.8 69.0
0.928 0.918 0.911 0,904 0.888 0.881 0.874 0.870 0.863
0.938
& M.
Tie Lines ComP. of system
W.
M.
(a)
(b) (c)
3.98 7.95 9.83
(d)
11.1
(e)
12.3
(f)
13.6 M.
(a) (b)
71.0
68.5 68 5 65.5 68.5
29.0 29.0
31.5 31.5 31.5
1.64
1.77
31.5
1.78
1.88
Comp. upper phase R.
(e)
10.0
(f)
12.3
52.2
(4
Plait Point 13.9&I.
Phase Phase volume weight ratio ratio
1.93 2 . 2 0 1.93 2 . 1 5 1.62 1 . 7 8 1.64 1 . 7 8
23.8 28.4 33 . o 35.9 41.5
(c)
2.4 5.3 7.5 8.5
71.0
B.
Comp. lower phase
n.
31.
76.2 71.6 6j.o 64.I
4.7 9.1 11.2 12.5
58.5
I3 5 '
47.8 65.5 K,
14.2 34.5 B.
LT .
92.4
90.7 88.8 86.7 83.8 77.2
B.
7.6 9.3 11.2
13.3
16.2 22.8
B C'TTL ALCOHOL-METHYL ALCOHOL-WATER
1321
TABLE Is' Binodal Curve, Tie Lines, Plait Point and Density Determinations at 45OC Binodal Curve hl.
Cornp in grams
\v.
-
,789 3.89 8.14 9.87
93.5 93.82 93,' 90.3 8j.3
10.;
84.2
11.1
81.3 78.6 jj.8 jI.8 6j.4
11.3 12.0
11.9 11.8
-
Density
B.
Cornp. i n grams
6.50" 6.18 6.8;
0.982 0.982 0.9;s
11.;
K. 60.8
10.8
54,4
IO.5
51.1
9.67
0.963
IO.I
12.7
0.961
'5.8 '8.7
0.949 0.942 0.935 0.930 0.92j
21.4
24.2 28.2 32.6
M.
Density
B. 905 0.900 0.898 0.89j 0,885 0.864 0.8j9
30.2 45.6 48 9
0
'
47.4 5 2 . 6 9.16 42 9 5: ' I y.20 40.8 j9.2 i .94 36.1 63.9 5.77 30.7 69.3 '
'
0.8j1
2.40
23.4
jj.6
0.837
-
21.8
j8.2"
0.833
0.918
* (€1. & AI. interpolated).
Tie Lines Phase volume ratio
- Cornp. of system M. R. B. (a) 3 . 1 0
60.8 39.2
Phase we,Rht ratio
0.930
1.08 0,963 0.768 0.86;
(b) 6.2: 60.8 39.2 0.850 (c) 8.25
60.8 39
2
(d) 9.86 60.8 39.2 0.670 ( e ) 1 1 . 0 66.2 33.8 1.00
M.
Cornp upper phase v! .
(a) 3 4 (b) 5 . 9 (c) 7.8 (49.3
(e)
10.7
Plait Point
25.9 30.9 36.1 43 . O 52.7 11.j
PVI.
0.758 0.964
A1 .
B. 74. 1
2.7
69.1
6.3 8.5
63.9 jj.0
10.5
47.3
11.;
66.0FV.
34.0 B.
Comp. lower phase .
w
93,3 91.8 89.5 8j.0 79.0
B. 6.j 8.2 10.5 15.0 21
.o
1322
A. J. MUELLER, L. I. PUGSLET AND J. B. FERGUSON
TABLE V Binodal Curve, Tie Lines, Plait Point and Density Determinations a t 60°C. Binodal Curve Comp. in grams
w.
M.
Density
Comp. in grams M. R. B.
B.
93.5 6.52* 5.54 90.89 9.11 6.12 90.3 9.67 6.42 90.2 9.80 8.59 86.4 13.6 9.05 82.4 17.6 9.93 73.7 26.3 9.80 68.7 31.3 'H. & M .
Density
9.64 61.0 39.0 8.5; 52.8 47.2 8.13 45.4 54.6 6.78 39.0 61.0 4.44 32.0 68.0 2,49 28.1 71.9 23.6 76.4%
0.977 0.962 0.960 0.957
0.940 0.936 0.921 0,894
0.877 0.875
0.858 0.847 0.836 0.830 0.825
Tie Lines Camp. hl.
Phase Phase volume weight ratio ratio
system
B.
It-.
(a) 5.36 (b) 7.41 (c) 8.37 (d) 1.91 i M.
Of
66.9 33.1 66.8 3 3 . 2 66.8 33.2 67.0 33.0
1.53 1.36 1.18 1.29 1.34 1 . 5 7 1.32 1.22
Comp. lower phase
Comp. upper phase
(a) 1 . 5 (b) 4.I (c) 6.5 ( 4 7.7 Plait Point
w.
B.
26.3 31.3 38.3 43.3 9.7I M.
73.7 68.7 61.7
2 . 2
6.2 8.0 8.8
56.7 66.8W.
B.
W. 92.8 90.3 87.7 85.2
51.
7.2
9.7 12.3 14.8
33.2 €3.
TABLE VI The Critical Temperatures of Various Series of Systems, Each a t Constant Methyl Alcohol Content IFr = IOO Methyl Alcohol M = 2.0 when B
+
Composition of system
M.
W.
,105
4.60 4.5' 4.42
,398 503 '587
IO1
4.21
,804
.io3
3.71 3.03 2.08 1.36
2.15
1.14
2.37
.I02
. IO2
,102
,0885
,0709 ,0700
B.
Critical Temperature "C 82 .o
.
7*dev. of
M.
from series unit
Average range of critical temperature "C.
4.4
0.I
95.6
I .2
0.2
101.7
1.7
0.4
2.42
107.2
0.3 3.2 I .4 I .6
0.I
1.29 1.97
IO9,4 113.2 113.3
'
96.8 82.2
0.2 0.I
1.2
0.8 0.7
0.2
0.2
BUTYL ALCOHOL-METHYL ALCOHOL-WATER T.4BLE
Methyl Alcohol
hl =
2.5
Composition of system 33. w. n.
,128 ,126 ,099
4.20 3,78 2.60
,100
2.17
,132
2.33
hlethyl Alcohol ,161 ,159 ,161
111
= 3.2
M
.64
2
.os
= 4.0
3 . 59 2.93 2.97
.Ij7
2.41
,160 ,179
1.87
,408 ,556 I .03 1.59 2.13
I , j 2
2 .
,177 ,175
M
= j.0
,251
. 2j I
2.52
1.99 2.48
,250
2
.oo
3.00
,253
Methyl Alcohol ,272 .275
.274 ,313 ,316 ,360 ,362
,389 ,389
0 . 2
0.I
5.5
0.1
0.4 0.4 0.3
0 .I
3.8
0.3
.6 0.3 1.7
0.3
0.4
0.4
0.5
0.7
0.6 0.6
when B
when B
93.5 82.4
= 7.2
'
+ JV = +W
= 7.8 when B 1.31 1.80
+W
=
77.1 749
0 . 2
0 .I
1.1
0. I
0.0
0.4
0.4 0.5
1.1
0.0
0.2
0.0
0.4
0.0
I .O
0.3
0.3 0.4
0.3 0.5
0 .I
0.6 0.4
0.I
IOO
= IOO
76.5 76.4
+W
0.7
IOO
77.8 77.1
when B
0 . 2
0.8 0.4 0.6
0.0
89.9 90.4 89.6
when B
0.I
IOO
88.8 92 9 93.0 89.6 78.1
,898 2.30
M
+ IT = 74.7
,692 2.68
31
I
100.4
when B
0 . 2
= IOO
81. j 95.6 99.8
2.05
= 6.3
+W
Average range of critical temperature "C.
= IOO
105.6 105.4
1.61
M
+ JT
from series unit
105.0
1.1;
2.70
3.69 3.20
108.7 103.3
h l = 5 . 5 when B
4.11
Methyl Alcohol
0.3
1.24
4.31 2.32
hlethyl Alcohol
2.3 0.6 0.9
,353 ,332
3.85 3'39 2.95
Methyl Alcohol
105.8 109.9 110.4
78
3.15 2.98 3.77 3.01
IOO
yo dev. of M
I .Oj I
+ IT =
Critical Temperature "C.
24
,166 .I42 ,160
hlethyl Alcohol
when B
1.40 1.83 2.68
3.94 3.36 2.92
Methyl Alcohol
1'1 (continued)
800 I.
I323
=
0.5
IOO
0.5
4.J. MUELLER, L. I. PUGSLEY AND J. B. FERGUSON
1324
B
+W
Temp. 75°C.
TABLE 1’11 Binodal Curves at 7 j”C., 90°C. and I O ~ O C . = IOO
__
Composition 0.0 2 . 0
4.0 5.0
6.3 7.2 7.8
Temp. 90°C.
B.
11.
6.8and 7.4 ‘’ 9.1 I’ 10.6 ’ I 12.7
16.6 19.5
”
’‘
Composition
M.
73.7 69.8
0.0
64.8
4.0
61.4
.; . 0
34.8
3 ’ 3
B. i . 8 and 69.8
2.0
__
9.0 13.0 16.5 23.0
” ” “
”
64.5 56.5 49.0 39.5
4i.8
35.4 Temp. 10j”C.
- Composition B.
hl. 0.0 2 .O
9.8and 64.3 13.3 ” 56.1
2 , s
15.7
”
52 I
3.2
21.7
”
42.7
TABLE TI11 Tie Lines a t 75’C. and 90°C. Comp. of system
Phase weight
Comp. upper phase hl. W. B.
W’. B. Ratio .61; 6.66 3.j7 ,983 .525 6.78 3.59 ,830 ,268 6.59 3 . 5 1 ,758 90°C. ,213 6.;4 3.72 ,973 ,421 6.66 3.68 1.16 M.
6 . 0 44.8 5 5 . 2 4 . 5 36.8 6 3 . 2 2 . 1 30.0 7 0 . 0 35.4 64.6 4.10 43.9 56.1 2.00
Comp. lower phase M. R. B.
6.8 8j.o 1 5 . 0 ; . j 88.7 1 1 . 3 3 . 1 92.0 8 o 2 . 2 0
90.8
3.92 87.8
9.2 12.2
TABLE IX The Plait Points Temgerature C. 0
15
30 45 60 75 90
Comoosition of svstem R.
n.
9.7 7.8 5.6
63.I 64.5 6j.5 66.0 66.8 67 .o 67.3
36.9 35.5 34.5 34.0 33.2 33 . o 32.7
3.5
67.4
32.6
0
67.5
32.5
M.
18.5 16.0 13.9 Il..;
(interpolated) IOj
(interpolated) (H&M) 125.15
BCTYL ALCOHOL-METHYL ALCOHOL-WATER
TABLE X The Effect of Methyl Alcohol on the Critical Temperature for Systems containing Constant Amounts of TTater and S Butyl Alcohol Temperature Composition "C. (B. 3j, W = 6j)
Tem gerature
M.
C.
Composition
(B. = 3j, W. = 65)
18.5
-+
13
7.8
15 30 45
16.2
90
60
0
13.8
'05
5.5 3.5
11.8
110.9
2.4
9.8
120.6
1.1
IZj.15
o (H&M)
e,
I YO 100 II.& T I L A U O M O L
FIG.I . Binodal curves and Plait Points
The solubility relations in the binary system n. butyl alcohol-water have been investigated, especially by Jones and by Hill and PIIIalissoff.8 Their results differ chiefly in the values assigned to the composition of the aqueous phase at low temperatures, the maximum difference occurring a t zo°C. When we extrapolated our binodal curves, we obtained a series of values for the composition of this aqueous phase and noted that a t I ~ T and . 3 0 T . our values agreed best with those of Hill and Malissoff. At 0°C. and 4j"C. where the differences were Dot so great, our values were a little closer to those of Jones and at temperatures above 4j°C., our extrapolation was too inaccurate for us to differentiate between the results of these previous workers. I n order to make the comparison, the results of these investigators were plotted and the values taken from the smooth curve drawn. The curve of Hill and Malissoff's results was extrapolated to o°C. Since our results agreed best with those of Hill and Malissoff a t those temperatures where the really significant differences occur, we have used their results for the correlation of our determinations. 8
Hill and hlalissoff: J. rlm. Chem. SOC., 48, 918 (1926).
1326
A . J. MUELLER, I.. I. PCGSLEY A S D J . B . FERGUSOS
16
I2 J
"
-I
U
$4 c
0
IO
20
30
40
50
60
70
80
n. BUTYL ALCOHDL
WATCR
FIG.2. Tie lines a t r.j°C,
FIG.3,
-
BCTYL ALCOHOL-METHYL ALCOHOL-WATER
1327
I n Fig. I , are given our results for the binodal curves combined with those of Hill and Malissoff for the binary system, n. butyl alcohol-water. An inspection of this graph indicates that the values of the plait points at 90°C. and 10j'C. obtained by interpolation cannot be much in error. I t seems hardly necessary for us to indicate graphically the various tie lines which we have determined. Perhaps the most useful series would be that obtained at I 5°C. which is shown in Fig. 2 . The slope of the saturation surface (solid model) at 3 5 weight percent n. butyl alcohol (B 15' = 100)is nearly linear. This is indicated by the plot of the results given in Table X, which is reproduced in Fig. 3. Summary
+
The binodal curves, tie lines and plait points of the system n. butyl alcohol-methyl alcohol-water have been determined at temperatures ranging from 0°C.to 1oj"C. These results have been presented in tabular form and in part graphically. Certain additional results (particularly densities) which were required for these determinations have been indicated. Department of' Chemistry, University of Toronto, January 16, 1931.
