Ethyl hydrogen sebacate

In a i-l. modified Claisen flask (Note i), the side arm of which is corked, is placed a mixture of 202 g. (1 mole) of sebacic acid, 150 g. (o 58 mole) of diethyl sebacate (Note 2), 50 cc. of di-w-butyl ether (Note 3), and 30 g. (25 cc.) of concentrated hydrochloric acid (sp. gr. 1.19). A reflux condenser is connected to the top of the distilling flask. 

The flask is heated in a Wood s metal bath at 160-170° until the mixture is completely homogeneous. The temperature of the bath is then lowered to 120-130°, and 60 cc. (1 mole) of 95 per cent ethyl alcohol is added to the solution through the condenser. The mixture is allowed to reflux for two hours. At the end of this period an additional 20-cc. portion of ethyl alcohol is poured into the solution and refluxing is continued for two hours longer. 

The Wood s metal bath is allowed to cool to about 75° and the reaction mixture is subjected to distillation under reduced pressure, using a water pump (Note 4). The temperature of the bath is increased slowly and distillation is continued, with a water pump, until the bath reaches a temperature of about 125°. The bath is again cooled to 75-80° and the distillation is continued at lower pressure, using an oil pump. 

The first fractions consist of a little alcohol, water, and di-w-butyl ether (Note 5). The next fraction is diethyl sebacate, b.p. 156-158° at 6 mm. (Note 6). Ethyl hydrogen sebacate is collected at 183-187° at 6 mm. The product melts at 34-36° and weighs 114-124 g. (50-54 per cent of the calculated amount, based on the sebacic acid used). Refracfionation of the fore-run (b.p. i75-i83°/6 mm.) and after-run (b.p. i87-i95°/6 mm.) gives an additional 24-26 g. of pure monoester. The total yield is 138-150 g. (60-65 per cent of the theoretical amount) (Notes 7 and 8). 

The column of the flask should be at least 35 cm. in length and well insulated. Wrapping the column with 10-mm. asbestos rope is satisfactory. 

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Ethyl hydrogen sebacate, 21, 48 electrolysis of, 21, 48 Ethyl isothiocyanate, 21, 82 Ethyl lactate, 21, 71 Ethyl laurate, 20, 69 Ethyl linoleate, 22, 77 Ethyl linolenate, 22, 83 Ethyl malonate, 23, 16 Ethyl mercaptan, 22, 59 Ethyl 1V-methyl-/3-aminopropionate, 20, 37... 

Dimethyl and diethyl octadecanedioate have been prepared by the electrolysis of the sodium or potassium salts of methyl or ethyl hydrogen sebacate in water8 or in methanol. ... 

To 86 5 g. (o 38 mole) of ethyl hydrogen sebacate (Org. Syn. 19, 45) is added slowly and with cooling 125-130 cc. of approximately 3 N potassium hydroxide. The solution is then diluted to approximately 250 cc., yielding a 1.5IV solution of potassium ethyl sebacate. 

Ethyl hydrogen adipate and ethyl hydrogen sebacate may be converted to the corresponding ester acid chlorides by this procedure in about the same yields. Distillation should be carried out rapidly at a pressure of 4 mm. or lower. 

Methyl hydrogen sebacate (b.p. 168-170°/3 mm.) was prepared by the checkers in yields of 52-61% from sebacic acid and methanol by the procedure described for the ethyl analog.1 The ethyl ester can be used to obtain ethyl sebacamate. The preparation of the acid chloride from ethyl hydrogen sebacate is mentioned in Note 12, page 21. 

Ethyl hydrogen sebacate has been prepared by the direct esterification of sebacic acid with ethyl alcohol, by the halfsaponification of diethyl sebacate, and by heating equimolecular quantities of sebacic acid and diethyl sebacate for several hours. ... 

Ethyl hydrazinecarboxylate, 24, 58 Ethyl hydrazodicarboxylate, 28, 58 Ethyl hydrogen adipate, 25, 21 Ethyl hydrogen sebacate, 21, 48 26, 21 electrolysis of, 21, 48 Ethyl 4-hydro benzoate, 29, 35 Ethyl a-ISOPROPYLACETOACETATE, 27, 35... 

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