Hendecanedioic acid

Submitted by Lois J. Durham, Donald J. McLeod, and James Cason.1 

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 1-1. 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 6 A 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 

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 accom- 

Somewhat higher yields appear to be obtained when the mixture is allowed to stand overnight. 

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Hendecanedioic acid has been prepared by hydrolysis of the corresponding dinitrile, obtained from 1,9-dibromononane or 1,9-diiodononane 4-6 by oxidation of 11-hydroxyhendecanoic acid 7,8 by the Arndt-Eistert synthesis from 9-carbethoxynonanoyl9 and nonanedioyl chloride 10 and by the Willgerodt reaction on un-decylenic acid.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... 

Dimethyl hendecanedioate is prepared by heating 23 g. (0.106 mole) of hendecanedioic acid 2 under reflux for 2 hours with a solution of 8 ml. of concentrated sulfuric acid in 80 ml. of methanol. After the reaction mixture has been diluted with 3 volumes of water, it is extracted with two 75-ml. portions of benzene. The benzene extracts are washed successively with 250-ml. portions of water, 5% aqueous sodium carbonate solution, and... 

Hexamethylenediamine, undecanedioic acid/ 6-thio-hendecanedioic acid 100-0 1... 

METHYL HYDROGEN HENDECANEDIOATE (Undecanedioic acid, monomethyl ester)... 

Methyl-2-hexacosenoic acid, 38, 46 Methyl hydrogen adipate, 38, 39 Methyl hydrogen hendecanedioate, 38, 55... 

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