I,J7DCSTRIAL A.VD EIYGINEERIA-G CHE.WIXTRY
42
point a t 92.3 mm. absolute (corresponding to a boiling point of 50.0' C. for pure water) was read and the slope calculated. (Table 111) A plot was made of the boiling points a t 92.3 mm., and from this and Figure 2 data were read for plotting the Diihring lines for even concentrations of caustic. These data are given in Table 111, and it is believed that it Dill be more satisfactory for the user t o plot them so that they may be read a t any degree of precision he desires, rather than reproducing the plot in this article.* Table 11-Boiling
100
HzO
Parts
B.P.
ABS.
PRESSUREHz0 M m . Hg C.
B. P. SOLN. C.
XaOH PER
100
94.9 224.4 315.9 398.1 510.4 613.3 676.4 708.7
50.55 56.77 69.06 76.18 77.14 84.48 82.85 90.68 89.22 97.37 94.10 102.57 96.77 105.32 98.06 106.68
RUN B
10.35
312.2 76.86 85,SZ 418.7 84.12 93.22 678.1 96.84 107.01
27.07
129.1 179.8 251.0 307.0 385.8 463.0 543.9 648.3
RUN C
56.91 69.00 64.08 76.51 71.67 84.62 76.45 89.70 82.06 95.57 86.69 100,35 90.90 104.59 05.60 109.65
119.2 197.3 286.5 375.0 463.9 573.4 694.2
51.75
55.22 67.22 66.16 78,S3 74.79 88.14 81.35 95.26 86.74 100.96 92.29 106.87 97.47 112.10
130.2 215.0 299.3 396.4 533.8 702.9
57.09 72.92 68.10 85.10 75.83 93.28 82.74 100.73 90.39 109.07 97.83 116.91
133.9 204.5 275.7 373.1 468.4 584.0 680.5
138.4 234.9 350.4 475.9 567.3 674.4
58.38 70.13 79.67 87.40 92.01 96.69
197.8 230.1 336.4 439.5
65,Ol
118.6 254.6 387.0 546.1
I
!
I
I
I
/
~
I I
t
I/-&$
G
El(
LIi A
-20 A -40'
I
,
I
I
I
i
i 1
'
1
I
I
I
I
78.25
140.4 205.4 307.2 418.3 512.8 617.9 694.0
80.46
159.3 160.8 385.0 658.0
97.98
147.1 220.9 321.8 469.5 667.7
RUN J
55.13 82.47 72.01 100.18 82.133 110.73 91.00 119.14
RCN K
58.69 67.06 76.45 84.10 89.34 94.30 97.47
90.66 99.67 109.53 117.87 122.82 128.49 131.60 0
RUN L
61.41 94.96 61.61 55.11 82.00 116.60 96.00 131.40
57.57 74.65 84.53 116.0 66.84 92.08 73.75 81.10 99.86 86.85 105.64 92.64 112.20 96,79 116.69
59.70 68.62 77.51 87.04 96.41
100.10 109.50 119.30 129.31 139.64
RUN N
112.4 193.2
tt;:; 560.8 688.5
54.02 65.64
56.10 57.65 59.65 62.30 6585 70.20 74.90 78.7'5 82.50 86.25 90.35 94,60 9s,95
10 20 30 40 50 60
RUN M
101.82 114.88
91.70 144.17 97.25 160.24
51.16 71.70 69.65 91.58 78.67 101.20 85.35 108.24
The most notable thing in Table I11 is the variation of the slope of the Duhring lines. A similar variation in slope was found in unpublished w o r k b y Baker and Carr done in t h i s laboratory. This slope is plotted against concentration in Figure 3, and a t first s i g h t i t w a s t h o u g h t that there must be some e r r o r because of the apparently erratic changes of slope. The work o of Von Antropoff and Parts NaOH /IOOH20 Sommer gives t h e Figure 3-Slope of Duhring Lines NaOII- phase diagram for the NaCI-Hz0 system NaOH-NaC 1H20. From this the freezing points of NaOH solutions satu-
*
I
I
RUN I
RUN G
50.87
Tt o
2
80.30 92.44 102.80 111.01 115.83 120.76
137.6 58.26 81.62 218.3 68.45 92.55 349.8 79.62 104.17 468.3 86.99 111.34
RUN F
40.74
B P. SOLN. O C.
55.04
RUN E
39.73
*Oi
RUN H
RUN D
27.55
B.P.
ARS.
PRESSUREHnO Parts M m . H g . C.
H20
RUN A
0
rated with NaCl have been plotted in Figure 4. On comparing Figure 3 with Figure 4 it will be seen that each decided change of slope of the curve of Figure 3 corresponds almost exactly to a change of phase shown in Figire 4. While there is no particular theory to indicate what effect should appear
Points of Caustic Solutions at Various Pressures
NaOH PER
Vol. 21, No. 1
Blue-printed charts reproducing these data on a scale that can be read to 0.1' C. can be obtained from the authors.
70 80 90 100 110 120
As a matter of interest, Table IV is appended, which shows the order of magnitude of the differences in the work of previous experimenters. The work of Pink is not included in this comparison, as he did not express his work in terms of even concentrations of KaOH, and the authors were not inclined t o take the responsibility of interpolations for such a comparison as this. SaOH
Table IV-Comparison of Boiling Points at 760 m m . PER 100 HzO EXPERIMENTAL V O N ANTROPOFF Parts = c. c. Q
0
10 20 30 40
50 60
io 80 90 100 110 120
Acknowledgment
The authors wish to acknowledge their indebtedness to the Swenson Evaporator Company, who financed all of this work.
Correction In our article on "Miscibility of Castor Oil with Gasoline Hydrocarbons" [IND.ENG.CHEM.,20, 1185 (1928)],thenumbers in the last line of Table 111, after the words "castor oil per gram, lower layer" should read: 0.6268-0.6278-0.62874.6293. GEORGE H. TABER AND DONALD R. STEVENS
