[CONTRIBUTION FROM
THE
RESEARCHLABORATORY O F ARMOUR AND COMPANY]
SOLUBILITIES OF HIGH MOLECULAR WEIGHT SYMMETRICAL NORMAL ALIPHATIC KETONES F. M. GARLAND, C. W. HOERR, W. 0. POOL,
AND
A. W. RALSTON,
Received May 20, 1943
No systematic investigation of the physico-chemical properties of high molecular weight aliphatic ketones has been reported. With the exception of a reference to the solubility of stearone (1) and a few isolated studies on enolization (2, 3), measurements of dipole moments and dielectric constants (4-8) and ebullioscopic behavior (9), very little is known of the behavior of the ketones containing more than nine carbon atoms. Since a knowledge of the solubilities of these compounds is of appreciable value in the further investigation of their behavior, as well as being essential to a wide variety of experimental procedures, the solubilities of five of the higher homologs were determined in a series of common solvents of widely differing polarities. This paper presents the solubilities of 10-nonadecanone, 12tricosanone, 14-heptacosanone, 16-hentriacontanone, and 18-pentatriacontanone in the following solvents: benzene, cyclohexane, tetrachloromethane, ethyl acetate, butyl acetate,acetone, 2-butanone, methanol, 95% ethanol, isopropanol, n-butanol, nitroethane, and acetonitrile. EXPERIMENTAL
The ketones used in this investigation were prepared from fatty acids1 which had been highly purified by previously described methods (10, 11). The ketones were prepared from the ethyl esters of these acids by the acetoacetic ester condensation. This method has been employed for the synthesis of high molecular weight ketones by McElvain (12, 13). Sodium ethoxide was used as the condensing agent. The ketones were obtained from the resulting keto esters by hydrolyzing the latter with 5% alcoholic potassium hydroxide, and were purified by several crystallizations from ethanol. The freezing points of these ketones are listed in Table I. The methanol used in this investigation was commercial "absolute" (99.9% by weight). The ethanol was commercial "absolute" which was diluted to 95.0% by weight with conductivity water by checking its measured density against known values (20). The benzene was Baker C.P. thiophene-free grade and was dried over sodium wire. The other solvents were of the best grade obtainable and were dried with the usual drying agents and distilled twice before using. The solubilities of the ketones in these solvents were determined in sealed tubes by the method and with the apparatus previously described (10, 21, 22, 23). Temperatures were measured with an accurately calibrated thermometer which was graduated in 0.1"intervals. Solution temperatures of the ketones were reproducible to f 0.1', and are, in general, considered accurate within f 0.2". The freezing points of these acids were 30.62' for capric, 43.77" for lauric, 54.15' for myristic, 62.30" for palmitic, and 69.28"for stearic acid. 344
345
SOLUBILITIES OF ALIPHATIC KETONES RESULTS AND DISCUSSION
The solubilities of the ketones in the non-polar solvents benzene, cyclohexane, and tetrachloromethane are listed in Tables 11-IV, and are shown graphically* in Figs. 1-3, respectively. TABLE I FREEZING POINTS OF PURIFIED KETONES NO. OF
c ATOMS
F.P., 'C.
KFTONE
19
10-nonadecanone (caprione)
57.8
23
12-tricosanone (laurone)
69.3
27 31 35
14-heptacosanone (myristone) 16-hentriacontanone (palmitone) 18-pentatriacontanone (stearone)
77.2 83.7 88.7
PEP.
(Y.P., "c.)
58-59 58.0 68-69 69 69.5-69.8 78-79 82 88.0 88.0 88-89 88.7-89
(13) (14) (13) (15) (16) (13) (15) (14) (17) (18) (19)
TABLE I1 SOLUBILITIES OF KETONES IN BENZENE 0. PEP NO. OF
1ocl G. BENZENE
c ATOMS
19 23 27 31 35
10.0"
30.0'
50.0'
13.8 1.2 0.3 20.1
