Alcohol Specifications



Pharmacopoeia of India, Third Edition, 1985.

Alcohol (95%) I.P.

(a) Description:
Clear, colorless, mobile volatile liquid; odor - characteristic and spirituous; taste - burning. Volatilizes readily, even at low temperatures, and boils at 78°C. Flammable.
(b) Solubility: Miscible in all proportions with water, with solvent ether and with chloroform.
(c) Standards:
Alcohol (95%) is a mixture of ethyl alcohol and water. It contains not less than 92.0% w/w and not more than 92.7 w/w ethyl alcohol, corresponding to not less than 94.7% v/v and not more than 95.2% v/v at 15.56°C.
(d) Identification:
(1) Mix 5 drops in a small beaker with 1 ml of potassium permanganate solution and 5 drops of dilute sulphuric acid, and immediately cover the beaker with a filter paper moistened with a solution recently prepared by dissolving 0.1g of sodium nitroprusside and 0.5g of piperazine hydrate in 5 ml of water. An intense blue color is produced on the filter paper and fades after a few minutes.
(2) To 5 ml of a 0.5% v/v solution, add 1 ml of 1N sodium hydroxide, and then slowly add 2 ml of iodine solution. The odor of iodoform develops, and a yellow precipitate is produced.
(e) Acidity or Alkalinity:
To 20 ml, add 5 drops of phenolphthalein solution. The mixture remains colorless, and requires not more than 0.2 ml of 0.1N sodium hydroxide to produce a pink color.
(f) Clarity of solution:
Dilute 5 ml to 100 ml with water in a glass cylinder. The solution remains clear when examined against a black background. Cool to 10°C for 30 minutes; the solution remains clear.
(g) Methanol:
To one drop of alcohol add one drop of water, one drop of dilute phosphoric acid, and one drop of potassium permanganate solution. Mix, allow to stand for one minute, and then add sodium bisulphite solution dropwise, until the permanganate color disappears. If a brown color remains, add one drop of dilute phosphoric acid. To the colorless solution, add 5 ml of freshly-prepared chromotropic acid solution, and heat on a water bath at 60°C for 10 minutes. No violet color should be produced.
(h) Foreign organic substances:
Clean a glass-stopped cylinder thoroughly with hydrochloric acid, rinse with water, and finally rinse with the alcohol under examination. Put 20 ml in the cylinder, cool to about 15°C, and then add from a carefully-cleaned pippette 0.1 ml of 0.1N potassium permanganate. Mix at once by inverting the stoppered cylinder, and allow to stand at 15°C for 5 minutes. The pink color should not disappear entirely.
(i) Isopropyl alcohol and t-butyl alcohol: To 1 ml add 3 ml of water and 10 ml of mercuric sulphate solution, and heat in a boiling water bath. No precipitate should be formed in 3 minutes.
(j) Aldehydes and ketones: Heat 100 ml of hydroxylamine hydrochloride solution in a loosely-stoppered flask on a water bath for 30 minutes. Then cool, and if necessary, add sufficient 0.05N sodium hydroxide to restore the green color. To 50 ml of this solution add 25 ml of the alcohol, and heat on a water bath for 10 minutes in a loosely-stoppered flask. Cool, transfer to a Nessler cylinder, and titrate with 0.05N sodium hydroxide, until the color matches that of the remainder of the hydroxylamine hydrochloride solution contained in a similar cylinder, when both solutions are viewed down the axis of the cylinder. Not more than 0.9 ml of the 0.05N sodium hydroxide should be required in the titration.
(k) Fusel-oil constituents: Mix 10 ml with 5 ml of water and 1 ml of glycerin, and allow the mixture to evaporate spontaneously from clean, odorless, absorbent paper. No foreign odor should be perceptible at any stage of the evaporation.
(l) Non-volatile matter: Evaporate 40 ml in a tared dish on a water bath, and dry the residue at 105°C for 1 hour. The weight of the residue should not exceed 1 mg.
(m) Specific gravity: The specific gravity should be between 0.8084 and 0.8104 at 25°C, (using the method in Appendix 5.19).

Note: For more details of test procedures and reagents, reference should be made to the Pharmacopoeia of India, published for the Ministry of Health and Family Welfare, by the Controller of Government Publications, Delhi.

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