Alcohol Specifications


Farmacopea Ufficiale Della Repubblica Italiana

(Italian Pharmacopoeia) Ninth Edition 1985
(and supplements to 1995)


Alcohol (Alcool, Spiritus vini rectificatus, Alcool etilico)

(Note: This is translated from the Italian original, to which reference should be made for authenticity.

Definition: Contains not less than 950 ml per litre (95% v/v) and not more than 96.5 ml per litre (96.5% v/v) of ethanol, (corresponding to a weight range of 923 grams to 947 grams per kg).
Characteristics: A colorless, mobile, transparent, volatile liquid, with a characteristic, pleasant odor, and a burning taste. It is flammable, and burns with a blue flame.
Solubility: Miscible with water, ether, chloroform and with glycerol.
Specific Gravity: Between 0.8125 and 0.8055.
Boiling-point range:

From 77°C to 78.5°C.
(Four ml of the distillate obtained from this test should be retained for subsequent tests, as listed below.)


(A) Dilute 1 ml of alcohol to 100 ml with water. Then, to 5 ml of this solution, add 3 ml of dilute sodium hydroxide and then slowly add 2 ml of 0.1 N iodine solution. There should be an odor of iodoform, and a yellow precipitate.

(B) When heated with sulphuric acid and potassium dichromate solution, there should be a green coloration and an odor of acetaldehyde.

(C) Mix 0.1 ml in a 10 ml beaker with 1 ml of an aqueous solution of potassium permanganate (10 g/li) and 0.2 ml of dilute sulphuric acid. Cover the beaker with a filter paper soaked in a fresh solution containing 0.1 g of sodium nitroprusside and 0.5 g of piperazine in 5 ml of water. An intense blue color should form on the filter paper, and it should fade in a few minutes.

Test for Purity:  
Appearance: There should be no color or turbidity in the alcohol, using standard tests. When diluted 1:20, it should remain clear for at least 5 minutes.
Acidity/alkalinity: To 50 ml of alcohol, add 5 ml of water and 0.1 ml of phenolphthalein solution. The mixture should be colorless. If 0.2 ml of 0.01 N sodium hydroxide are added, the solution should become red. If 0.3 ml of 0.01 N hydrochloric acid are added, the solution should become colorless. If 0.2 ml of methyl red solution are added, the solution should become reddish or orange.
Acetone: Dilute 1 ml of alcohol distillate (obtained from the boiling-point test) with 9 ml of water in a test tube, and add 0.01 g of finely-powdered vanillin and approximately 1.5 g of potassium hydroxide in tablet form. Heat and agitate in a water bath for 15 minutes. It should form a yellow layer on the potassium hydroxide, which does not turn orange or red.
Methanol: Take 0.4 ml of alcohol distillate (obtained from the boiling-point test), add 5 ml of 0.1 N potassium permanganate, 0.2 ml of sulphuric acid and then after at least 2 minutes, add 1 ml of oxalic acid solution and 1 ml of sulphuric acid. To this colorless mixture, add 5 ml of decolorized fuchsin solution and hold at a temperature of 15 - 30°C for 20 minutes. No blue-violet or red coloration should be produced.
Aldehydes: Mix 10 ml of alcohol with 1 ml of m-phenylenediamine hydrochloride solution. When viewed from the top, it should not develop as intense a yellow color as is formed in a mixture of 0.4 ml of tropaeolin oo (diphenylamine orange) solution in 100 ml of water.
Ketones, isopropanol and tertiary butanol: Dilute 1 ml of alcohol with 3 ml of water, and add 10 ml of mercuric sulphate solution. Heat in a boiling-water bath. There should not be any precipitate formed within 3 minutes.
Furfural: To 10 ml of alcohol, add 1 ml of glacial acetic acid and 0.5 mg of aniline. The mixture should not develop a reddish color within 5 minutes.
Amyl alcohol and carbonizable substances of low volatility: When 25 ml of alcohol is allowed to evaporate spontaneously, from a porcelain dish, (protected from dust), until the surface of the dish is barely moist, there should be no foreign odor (of fusels), and the addition of 1 ml of sulphuric acid should not produce a red or dark coloration.
Oily and resinous substances: The alcohol mixed with water in any proportion should remain clear, when cooled to 5 - 10°C for 30 minutes.
U.V. Absorbance: Record the U.V. absorbance between 235 and 275 nm, in a 5 cm cell, using water in a matched cell for reference. There should not be any absorbance greater than 0.35 at 240 nm, or 0.20 between 250 and 260 nm, or 0.15 at 270 nm.
Foreign organic substances: Add 20 ml of alcohol to a thoroughly cleaned, glass-stoppered cylinder, and cool to 15°C. Then add 0.1 ml of a 0.1N potassium permanganate solution, and note the exact time. Then mix by inverting the cylinder and allow it to stand at 15°C for 5 minutes. The reddish coloration should disappear completely in that time.
Tannins: If 5 drops of dilute ammonia are added to 3 ml of alcohol, the mixture should remain colorless.
Denatured alcohol: 10 ml of alcohol which have been acidified with dilute sulphuric acid, are allowed to evaporate in a water bath. The residue, when treated with potassium hydroxide solution, should not give any pyridine-like odor.
Chlorine: 4 ml of alcohol diluted to 15 ml with water should comply with the standard test for chlorine (at the 1.5 ppm level) using for comparison 1 ml of a 5 ppm solution of chlorine diluted with water to 15 ml.
Heavy metals:
50 ml of alcohol are evaporated in a water bath to 5 ml, and diluted to 25 ml with water. 12 ml of the solution should comply with the standard test for heavy metals (at the 0.3 ppm level), using for comparison, a mixture of 5 ml of a 1 ppm solution of lead, and 5 ml of water.
(p) Residue on evaporation: If 100 ml of alcohol are evaporated in a water bath, and the dish is dried at 100 - 105°C, the weight of the residue should not exceed 2 mg (or 0.002 percent).

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