FORMULA: C5H11OH. MOLECULAR WEIGHT: 88.
SYNONYMS: Fusel oil, Oil of potato spirit, Corn spirit oil, Amyl alcohol, Pentyl alcohol, Grain oil, Amyl hydrate, Amyl hydroxide, Primary amyl alcohol.
Preparation and History.—"Take of the light liquid, which may be obtained at any large distillery, by continuing the distillation for some time after the pure spirit has all been drawn off, any quantity. Introduce it into a small still or retort connected with a condenser, and apply heat so as to cause distillation; as soon as the oil begins to come over unmixed with water, the receiver should be changed, and the distillation being resumed and carried nearly to dryness, the desired product will be obtained. The liquid drawn over during the first part of the distillation, will consist of an aqueous fluid, surmounted by a stratum of the amylic alcohol. This latter, though impregnated with a minute quantity of water, should be separated and preserved, as being sufficiently pure for use"—(Dub.). It is usually prepared from fermented cereals, or potatoes, by distillation.
Amylic alcohol was first noticed by Scheele, in the spirit obtained by distilling fermented potatoes, and was called Oil of potato spirit; since his time its general character has been more fully investigated by several chemists. It is now found not only in potato spirit, but among the products of alcoholic fermentation generally, in which it exists in the 1/400 or 1/500 part. When alcohol is distilled from potatoes, toward the termination of the process a whitish fluid passes over, which, when allowed to rest, yields a deposit of amylic alcohol, combined with nearly equal parts of water and alcohol. This is washed several times in water, then placed in contact with chloride of calcium to remove the water, and distilled over again, in order to purify it. Alcohol and water pass over at first, but as the heat becomes elevated to 132.2° C. (270° F.), a clean receiver is substituted for the one just used, into which the pure amylic alcohol is received as it passes over. It is viewed as a hydrated oxide of amyl.
Description.—Amyl alcohol is a limpid, transparent, very mobile, oily liquid, colorless, or of a light-yellow color, having a very nauseous odor, producing stupefaction, and an acrid, sickening taste. Its vapor, when inhaled, causes cough and spasmodic dyspnoea resembling asthma, often followed by vomiting. It produces an evanescent stain on paper; gives a bluish-white flame when burned with a wick, or heated to 55° C. (131° F.); boils at about 132° C. (269.5° F.); has the specific gravity 0.818; and absorbs hydrochloric acid gas largely, heat accompanying the process. It unites in any quantity with alcohol, ether, fixed and volatile oils, and concentrated acetic acid; is hardly dissolved by water, to which it imparts its odor, and the property of becoming beaded when shaken. Iodine, camphor, phosphorus, resins, fatty matters, sulphur, etc., are dissolved by it; and it combines with solutions of potash or soda without alteration. Heated with dry potash, it undergoes decomposition, evolving hydrogen, and forming valerianate of potassium by absorption of oxygen. According to Pasteur, ordinary amylic alcohol consists of a mixture of two metameric bodies, one being inactive on polarized light, the other producing left-handed rotation of a polarized ray; these two alcohols can be separated. Fusel oil may be detected in alcohol by introducing the suspected fluid into a burette, diluting it with its volume of rectified ether, and an equal volume of distilled water; slightly agitate and allow it to rest. The ether will float upon the surface of the liquid, holding all the fusel oil in solution. Separate the ether by the usual method, allow it to evaporate spontaneously, and the fusel oil remains behind, known by its bad odor. Amyl alcohol of commerce contains from 20 to 30 per cent of common alcohol. By exposure to the atmosphere in the presence of platinum-black, slow oxidation takes place, with the formation of valerianic acid as the result.
Hirsch (Amer. Jour. Pharm., 1862) has proposed to remove alcohol from fusel oil by the following process: Shake fusel oil with an equal volume of saturated salt solution, repeat the operation, finally shaking out with pure water. Then distill the washed fusel oil with 3 to 4 times its weight of distilled water in a retort; the distillate will then consist of an oily layer of almost pure amyl alcohol, and an aqueous layer containing what little alcohol has remained unabstracted in the preceding treatment.
Action and Medical Uses.—Valerianic acid, and several medicinal valerianates, are prepared by the aid of amylic alcohol. It is also used in preparing amyl nitrite, artificial fruit essences, and in the production of certain proximate principles, alkaloids, etc., notably the cinchona alkaloids. Fusel oil is said to produce the peculiar nervous and dyspeptic symptoms of those accustomed to consuming large amounts of alcoholics; the rapid intoxication produced sometimes, is likewise attributed to this body, occurring as an adulterant. Even in small doses, amylic alcohol induces a tensive pain in the head, while in excessive amounts, insensibility and profound narcosis result. The breath exhales a fruit-like odor. Among the poisonous symptoms are giddiness, staggering, headache, diplopia, unconsciousness, reduction in temperature, rigidity and subsequent relaxation of the muscles, marked cyanosis, and death. In cases of poisoning by it, ether and other stimulants may be subcutaneously injected. Amylic alcohol, in very small doses, is a nerve stimulant. It has been used in phthisis, with negative results. The nervous irritability and weakness of habitual drunkards, is said to be relieved by small doses of fusel oil.
King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.