INDUSTRIAL AND ENGINEERING CHEMISTRY
2Z92 nominal oil “component” consisted of two or more constituents, some lighter and some heavier than the primary solvent and also more soluble in it. However, this is unlikely in an actual case because the solvents lighter than oil, such as methanol and acetonitrile, usually lack the requisite selectivity for each type of hydrocarbon. The choice of components in Figure 5 is not very critical. Methanol could be replaced with acetonitrile or other liqiud
Vol. 45, No. 12
benzene (d:’ 0.859) to one volume of n-hexadecane or cetane (d:’ 0.7737). The density of the mixture was 0.832. The solid line is a phase boundary curve, and no tie lines are shown. They would not terminate on the phase boundary curve. The twin density line intersects it just above the base line a t each side. If any component of a nominally ternary system is impure, as in the last system of Table I, an isopycnic is not rigorously straight.
c
E g
\
I 80” 70; 65 55 O
LAVENDER MAGENTA RLD AMBER
45O
YELLOW
25 O
YELLOW
60”
NTTROBENZENC:
PURPLE
U-UPPER LAYER L -LOWER LAYER
METHANOL
CETANE +
Figure 6.
T w i n Density Line for System w i t h I m p u r e Component
20588
NITROBENZEN
LITERATURE CITED
Barbaudy, J., Compt. rend., 182, 1279 (1926). (2) Conway, J. B., and Philip, J. B., IND.ENG.CHEM.,45, 1083 (1)
(1953). (3)
(4)
(5) (6)
(7)
Francis, A. W., in “Solubilities of Inorganic and Organic Compounds,” A. Seidell and W.Linke, eds., Suppl. t o 3rd ed., New York, D. Van Nostrand Co., 1952. Francis, 9.W,, IND. ENG CHEM., in press. Francis, A. W., J . Phys. Chem., 56, 510 (1952). Janecke, J., 2. physik. Chem., 184,71-5 (1939). Mondain-Monval, P., and Quiquerea, J., Bull. SOC. chini., 7, 240-53 (1940).
(8) Peake, J. S., and Thompson, K. E., Jr., IND.ENG.CHEV., 44, 2439 (1952).
Smith, J. C., and Drexel, R. E., Ibid., 37, 601 (1945). ( I O ) Webster’s New International Dictionary, p. 1318, Springfield, Mass., C. C llerriam Co., 1946. (9)
RECEIVED for review June 6, 1953. ACCEPTED August 7, 1953. Presented before the Division of Chemical Education a t the 124th Meeting the AMERICAN CHEMICAL SOCIETY, Chicago, I11
Figure 5. Twin Density Line o f S y s t e m w i t h Lubricating Oil portion of it. Similarly, the less soluble hydrocarbon in the oil layer, which is more paraffinic, dissolves less methanol than does the whole oil. The equilibrium mixture curve (not shown) forms the ends of these tie lines, but is indefinite, since it would vary in position with the relative volumes of the solvent and oil layers. This fuzziness of a binodal curve always results when one component is made t o represent more than one actual substance. As with the twin density lines, the twin index lines (marked with names of colors in Figure 5 ) of a lubricating oil system are not quite the same as tie lines. They have a different slope, and they are presumably slightly curved at their ends, although their precise determination is more difficult because of the color in the oil sample. Another system with a curved twin density line is illustrated in Figure 6. The same two solvents are used, but the hydrocarbon oomponent consists of a mixture of two volumes of di-secbutyl-
Kinetics of Carbon Gasification by Steam-Correction I n the article on ‘(Kineticsof Carbon Gasification by Steam” ENG.CHEM.,45, 2586 (1953)] on page 2587, the sixth and seventh lines of the first column should read: “the curves of Figures 1 and 2.” On page 2589, the first line of the sixth paragraph should read: “It is clear from 1 , 2 , and 4,” as these numbers refer to the paragraphs above and not to literature cited. GEOFFREYE. GORING [IN&
Atmospheric Pollution-Correction Atmospheric Pollution column, November 1953, page 109 A, first paragraph, address of Grindle Corp. is Markham, Ill.
