Alcohol Specifications


Farmacopeo Nacional Argentina - Sixth Edition 1978

(Translated from Spanish. Reference should be made to the original Spanish version for authenticity.)

Alcohol (Alcohol aethylicum)

(a) Definition: Contains not less than 92.3% w/w, or 94.9% v/v (at 15°C) of ethanol.
(b) General characteristics: Colorless, mobile, transparent liquid, with a burning taste and characteristic pleasant odor. Volatile and flammable. Miscible with distilled water in any proportion, without producing turbidity, and miscible with ether, glycerine, chloroform and acetone.
(c) Specific gravity: Not greater than 0.8168 at 15°C.
(d) Boiling point: 78°C
(e) Refractive index: Between 1.3637 and 1.3639, at 20°C.
(f) Identification: (1) To ten drops of alcohol, add 2 drops of potassium hydroxide solution, and a few drops of potassium iodide solution until a yellow color appears. Heating the mixture gently should produce an odor and a precipitate of iodoform.
(2) Gently heat 20 drops of alcohol, 20 drops of acetic acid and 10 drops of sulphuric acid. This should produce the characteristic odor of ethyl acetate.
(g) Limit of acidity: To 50 ml of alcohol in a glass-stoppered flask, add 50 ml of distilled water and 5 drops of a solution of phenolphthalein, and then titrate with 0.02 N sodium hydroxide until the red color persists for about 30 seconds. It should not require more than 0.9 ml of the sodium hydroxide solution.
(h) Non-volatile matter: Evaporate 50 ml of alcohol in a tared dish in a water bath and then dry at 100°C. There should not be more than 1 mg of residue.
(i) Heavy metals: To 100 ml of alcohol, add 10 ml of dilute acetic acid, and 10 ml of distilled water. Then evaporate in a water bath until the volume has been reduced to about 20 ml. Subject this residue to the standard F.N.A. test for heavy metals.
(j) Fusel-oil components: Mix 10 ml of alcohol with 5 ml of distilled water and 1 ml of glycerine. Then allow the mixture to evaporate spontaneously on a clear odorless filter paper. There should not be any perceptible foreign odor as the last traces of the mixture evaporate.
(k) Amyl alcohol and carbonizable organic residues: Allow 25 ml of alcohol to evaporate spontaneously from a porcelain dish (protected from dust), until the surface of the dish is just slightly moist. Then, the addition of 2 or 3 drops of sulphuric acid should not produce any red or brown color.
(l) Methanol: Dilute 0.5 ml of alcohol to 10 ml with distilled water; add 2 ml of a fresh solution of potassium permanganate and 15 ml phosphoric acid; then make up to 100 ml with distilled water, and allow to stand for 10 minutes. Then add 2 ml of a 5% solution of oxalic acid in a mixture of equal volumes of distilled water and sulphuric acid. When the solution has been decolorized, take 5 ml and add 2 ml of a 0.3% solution of phenylhydrazine chlorate and 2.5 ml of a 0.5% solution of potassium ferricyanide. Then, after standing for 5 minutes, add 2.5 ml of hydrochloric acid. There should be no red coloration.
(m) Aldehydes and organic impurities: Add 20 ml of alcohol to a thoroughly-cleaned, glass-stoppered cylinder, and cool to about 15°C. Then add 0.1 ml of a 0.1 N potassium permanganate solution, and note the precise time. Then mix by inverting the cylinder, and allow it to stand at 15°C. The red color should not have disappeared completely in under 5 minutes.
(n) Acetone, other ketones, isopropanol and tertiary butanol: Mix 1 ml of alcohol with 4 ml of distilled water, then add 10 ml of an acidified solution of mercuric sulphate and heat in a water bath. It should not produce a precipitate within 3 minutes.

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