Org. Synth. 1958, 38, 34
DOI: 10.15227/orgsyn.038.0034
HENDECANEDIOIC ACID
[Undecanedioic acid]
Submitted by Lois J. Durham, Donald J. McLeod, and James Cason
1.
Checked by N. J. Leonard, D. H. Dybvig, and K. L. Rinehart, Jr..
1. Procedure
A
500-ml. round-bottomed flask is attached by a well-lubricated ground-glass joint to a
reflux condenser with a side take-off having a
stopcock which may be opened to permit distillation. In the flask are placed
170 ml. of commercial diethylene glycol and
30 g. (0.46 mole) of potassium hydroxide (U.S.P., or reagent grade, 85%). This mixture is heated carefully
(Caution! (Note 1)) until the
potassium hydroxide begins to melt and go into solution; then the heat is removed intermittently until the exothermic dissolution is completed. After the solution has been cooled to 80–100°, the condenser is removed and there are added to the flask
35 g. (0.152 mole) of 6-ketohendecanedioic acid (
p. 555) and
22 ml. (22.4 g., 0.38 mole) of commercial 85% hydrazine hydrate. The condenser is immediately replaced, and the mixture is warmed cautiously until any exothermic reaction is complete and then heated under reflux for 1 hour.
A thermometer is suspended through the condenser by copper wire so that the bulb is in the heated liquid, the stopcock of the take-off attachment is opened, and the mixture is distilled sufficiently slowly so that the froth does not rise out of the flask. When the liquid temperature has reached 205–210° (after about 30 ml. of distillate has been collected), the stopcock in the takeoff is closed, the thermometer is removed, and the mixture is heated under reflux for 3 hours. If the temperature is checked during this heating period, it is usually found to be in the range 190–200°.
At the end of the heating period the reaction mixture is cooled to about 100–110° (at lower temperatures a gelatinous precipitate separates) and is then poured into 150 ml. of water contained in a 1-l. Erlenmeyer flask. An additional 100 ml. of water is used to rinse the reaction flask. The diluted mixture is acidified to Congo red by slow addition of 6N hydrochloric acid as the mixture is stirred vigorously to ensure conversion of any precipitated potassium salt to the free acid. The mixture is then cooled by tap water for at least 30 minutes (Note 2). The white precipitate is collected by suction filtration, transferred to a beaker, and is heated with about 250 ml. of water until the solid has melted (Note 3). As the mixture is cooled, it is stirred vigorously by hand until the oil has resolidified. After the mixture has been cooled again, the precipitated acid is collected by suction filtration, washed with water, and dried (Note 4). The yield of hendecanedioic acid, m.p. 110.5–112° (Note 5), is 28.5–30.6 g. (87–93%).
2. Notes
1.
When the temperature becomes high enough for the
potassium hydroxide to melt under the
diethylene glycol, solution occurs rapidly with evolution of heat sufficient to drive material out of the top of the condenser if the source of external heat is not removed immediately. For this reason it is wise not to add the compound being reduced until after solution has been accomplished; moreover, in the case of keto acids there is some evidence that yields are lowered somewhat if the acid is added before solution of the
potassium hydroxide. Since
diethylene glycol does not present a serious fire hazard, this initial heating is probably best done with a small flame which may be easily removed quickly. Subsequent heating with an electric mantle is recommended.
2.
Somewhat higher yields appear to be obtained when the mixture is allowed to stand overnight.
3.
Remelting the solid acid over water removes occluded impurities, including salt and
diethylene glycol. Moreover, acid which has crystallized in lumps is dried faster than the initial fine precipitate.
4.
The submitters suggest recrystallization from
benzene as a means of purification.
5.
The acid is probably polymorphic,
2 since the melting point varies somewhat with the rate of heating and a solidified melt remelts more sharply than do the original crystals.
3. Discussion
Hendecanedioic acid has been prepared by hydrolysis of the corresponding dinitrile, obtained from
1,9-dibromononane or
1,9-diiodononane;
3,4,5 by oxidation of
11-hydroxyhendecanoic acid;
6,7 by the Arndt-Eistert synthesis from
9-carbethoxynonanoyl8 and
nonanedioyl chloride;
9 by the Willgerodt reaction on
undecylenic acid;
10 and by treatment of
(5,5'-dicarboxy-2,2'-dithienyl)-methane with
Raney nickel catalyst and alkali.
11 The present method, previously described briefly,
12,13 appears to represent the most convenient preparation of dibasic acids having an odd number of carbon atoms greater than ten. It has been applied to several other dibasic acids.
14
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
(5,5'-dicarboxy-2,2'-dithienyl)-methane
hydrochloric acid (7647-01-0)
Benzene (71-43-2)
Raney nickel (7440-02-0)
potassium hydroxide (1310-58-3)
hydrazine hydrate (7803-57-8)
1,9-dibromononane (4549-33-1)
diethylene glycol (111-46-6)
9-carbethoxynonanoyl chloride
Hendecanedioic acid,
Undecanedioic acid (1852-04-6)
6-Ketohendecanedioic acid (3242-53-3)
1,9-diiodononane (24613-65-8)
11-hydroxyhendecanoic acid (3669-80-5)
nonanedioyl chloride (123-98-8)
undecylenic acid (112-38-9)
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