INDUSTRIAL AND ENGINEERING CHEMISTRY
232
Literature Cited
When desired, the floc could be removed either by settling
or in the centrifuge. In stabilizing zein dispersions by the aldehyde-heat treateffectis improved merit, it has been found that the as the concentration of aldehyde is increased, and that if too low concentrations of aldehyde are used, prolonged heat treatment causes the dispersion t o gel despite the presence of the aldehyde.
Vol. 35, No. 2
(1) Evans, c. D.8 and 31anleY. R.H., IND. EN^. CHEM.,33, 1416-17 (1941). (2) Evans, C. D, (to Prolamine Produ&, Ino.)U. S. patentapplication. (3) Manley, R. H., and Evans, C. D., J. Biol. Chem., 143, 701-2 (1942). (4) Swallen, L. C., IXD.EXG.CHEM.,33,394-8 (1941).
Vapor Pressure Nomograph for Isomeric Octanols
D. S. DAVIS Michigan Alkali Co., Wyandotte, Mich.
R
ECENT vapor pressure data' covering twenty-two isomeric octanols appeared as a table of boiling points for pressures of 20, 100, 300, and 760 mm. mercury, supplemented by pressure-temperature curves for twelve of the series. The accompanying line coordinate chart enables convenient estimation of boiling points at other pressures or vapor pressures a t any temperature in the range of the data. It is based upon the expression log p = A / ( t
where p
= t =
+ +B
/80
/60
I40
/40
*7/
067
/
+/+ /& I
7s
J
L
o
44 51 5
i54d
0
X
/40
No. 41 42 43
55 56 57
01)
vapor pressure, mm. mercury temperature, C .
'~~
and A , B , and as follow:
,
a
A -2340 -1155 -2258
a!
have values, depending upon the compound,
B
a
8.040 6.586 8.190
0
-1130 6.638 -1074 6.383 -1678 7.393 -1483 7.078 -1580 7.214 -1326 7.032 -1580 7.197 -1782 7.500 = 270 - 1Os.s84-Q.Q6Q47t,
140 270 140 120 200 200 200
160 200 200
Key No. 61 62 63 64 65 66 67 71 72 73 74
A -1144 -1802 -1126 -1341 -1335 -1782 -1105 -1170 -1066 -940 -992
B
a
6.599 7.726 6.417 8.990 6.961 7.885 6.385 6.596 6.434 6.089 6.229
120 200 160 160 160 200 140 120 120 120 120
With respect t o the key numbers which appear on the chart and in the table, the original investigators stated, "The first digit locates the methyl group and the second the hydroxyl group: thus 72 is 7-methyl-2-heptano1, i. e., 2-octanol, and 53 is 5-methyl-3heptanol. Sometimes the key numbers depart, for convenience, from official nomenclature.'' The temperature scales on the chart bear symbols or numbers which must correspond with those of the gage points for the various compounds. The circled points, for instance, are employed with the temperature scale headed by a circle. The use of the chart is illustrated as follows: What is the vapor pressure of 5-methyl-3-heptanol a t 85" C.? The key number for this compound is 53 which appears as a circled point on the chart. Connect this point with 85 on the t scale topped by a circle and produce the line to the p scale where the vapor pressure is read as 75 mm. mercury. Vapor pressures read from the chart deviate from the original data by an average of about 0.8 per cent. 1 Dorough, G.L., Glass, H. B., Gresham, T. L., Malone, G . B., and Reid, E. E., J . A m . Chem. SOC.,63, 3100 (1941).
