Butlerow1 first prepared this alcohol, using the reaction between zinc methyl and carbonyl or acetyl chloride described in Chapter III (The General Chemistry Of The Alcohols). A simpler method, also due to Butlerow, is to take isobutyl alcohol as the starting point, and obtain iso-butylene from it by conversion into the iodide and heating the latter with alcoholic potash; the isobutylene is absorbed by 75 per cent. sulphuric acid, and the ester thus produced is diluted with water and distilled, when it decomposes into the alcohol and sulphuric acid. According to Dobbin,2 the alcohol can also be obtained by letting 2 parts of tertiary butyl iodide remain for two or three days in contact with 5 parts of water, the mixture being shaken occasionally.

Tertiary butyl alcohol forms a deliquescent, crystalline mass, which melts at 255° when anhydrous, and boils at 825° (81.5° to 82°, Perkin3). Its sp. gr. at 30° is 0.7788, and its index of refraction μβ is 13924. The odour of the alcohol is described as spirituous and camphor-like. A liquid hydrate, 2C4H10O + H10, boils at 80°. Young and Fortey (loc. cit.) found that the azeotropic mixture boiled at 79.91°, and contained 88.24 per cent. of alcohol by weight.

A study of tertiary butyl alcohol and its aqueous solutions has also been recorded by Doroschewsky,4 who gives the sp. gr. of the alcohol at 25°/4° as 0.7806, and the index of refraction n20D as 1.38548. With aqueous solutions the index shows no maximum value.

It is noteworthy that in the oxidation of tertiary butyl alcohol some isobutyric acid is produced, as well as acetone, acetic acid, and carbon dioxide.

Amyl alcohols, C5H11OH. Mol. wt., 8810.

The name ' amyl ' was given by Cahours5 to alcohol obtained from fusel oil, as the latter had at that time been found mainly in spirit produced from substances containing starch (amylum). Fusel oil itself was first obtained by Scheele from the "last runnings ' of rye spirit,6 and was subsequently investigated by Dumas, who separated from it by fractional distillation a liquid boiling at 131.5°, and having the elementary composition C5H120. Cahours concluded that this body was "isomeric " with ordinary alcohol; and later Pasteur (1855) separated " amyl alcohol' itself into two isomers by means of the barium amyl sulphates.

1 Ann. Chem. Pharm., 1807, 144, 1. ■ Trans. Chem. Soc, 1880, 37, 238. 3 Ibid., 1884, 45, 468. 4 J. Buss. Phys. Chem. Soc, 1911, 43, 66.

5 Ann. Chim. Phys., 1839, [i], 70, 81. 6 Crell, Annalen, 1785, 1, 61.

Subsequent investigation has shown that eight isomeric amyl alcohols are theoretically possible, and all of them are known.

Of the eight, four are primary, three secondary, and one tertiary. A summary of these is given on p. 116. The formula of the third, fourth, and fifth on the list contains an asymmetric carbon atom, so that three optical modifications of each are possible - name'y, a dextro-, a lævo-, and an inactive form. Including optical isomers, therefore, the possible number is fourteen.

(1) Normal primary amyl alcohol (Butyl carbinol), azeotropic mixture boiling at 9515°, and containing 504 per cent. of alcohol by weight (Young and Fortey, loc. cit.).

CH3(CH1)3CH1OH.

- This is a liquid, of fusel-oil odour, and only slightly soluble in water. It has the boiling-point 137°, and the sp. gr. 08168 at 20°/4°. It may be prepared from amylamine, C5H11NH1, by means of the nitrous acid reaction (p. 117). The first synthesis of the alcohol was carried out by Lieben and Rossi, starting with n-butyl alcohol and using the nitrile reaction.1

(2) Isobutyl carbinol (Inactive or isoamyl alcohol),

(CH3)2CHCH1CH1OH.

- This is the chief ingredient of the ordinary or " fermentation ' amyl alcohol found in fusel oil. As a natural product it is found in Roman chamomile oil, where it occurs as the amyl ester of angelic and tiglic acids. Its constitution was first determined by Erlen-meyer, who found that the acid yielded by oxidation of the alcohol was identical with valeric acid prepared synthetically from isobutyl alcohol. This synthesis, stopping before the oxidation, can be used to prepare the pure isobutyl carbinol, the steps being conversion of isobutyl alcohol into the cyanide, the latter into the corresponding acid, this into the aldehyde, and finally into the alcohol. Isobutyl carbinol boils at 131.6° (corr.), and has the sp. gr. 0.8248 at 0°, 0.8104 at 20°/4°, or 08158 at 15-6°/15-6°. Under 7409 mm. pressure, the boiling point is 1289° to 1292°, and under 7592 mm., 1305° to 131°. The alcohol is soluble in water to the extent of 1 in 50 at 13-14°, and 1 in 39 at 16.5°. It dissolves in all proportions in acetic acid diluted with an equal bulk of water. Oxidation with platinum black converts it into isovaleric acid; distillation with sulphuric acid and potassium dichromate gives isovaleraldehyde and isovaleric acid. With water it forms an

1 Ann. Chem. Pharm., iS71, 159, 70.

(3) Secondary butyl carbinol (Active amyl alcohol),

CH3CH(C2H5)CH1OH.

- This alcohol occurs with the inactive compound in fermentation amyl alcohol. As mentioned above, it was first separated by Pasteur. On dissolving the two alcohols in strong sulphuric acid and neutralising the solution with barium carbonate, two barium amyl sulphates are produced which differ in" solubility, and can therefore be separated by repeated crystallisation. These Pasteur obtained and converted into the sodium salts, afterwards liberating the corresponding alcohols by distillation with sulphuric acid. The active modification is lævorotatory. It boils at 128.7°.

(4) Methyl propyl carbinol, CH3(CH1)2CH(OH)CH3, is a liquid with fusel-oil odour, boiling at 1185° and having the sp. gr. 0824 at 0°. It may be prepared by the reduction of methyl propyl ketone. The alcohol is optically inactive, but the d-component can be destroyed by the action of Penicillium glaucum, thus leaving the substance lævorotatory (Le Bel).

(5) Methyl isopropyl carbinol, (CH3)2CHCH(OH) CH3, is a liquid boiling at 112.5°, and having the sp. gr. 0 833 at 0°. It may be obtained by reduction of the corresponding ketone.

(6) Diethyl carbinol, (C2H5)2CHOH, is a liquid of peculiar odour, boiling at 1165° and having the sp. gr. 08315 at 0°. It is formed by heating ethyl formate with zinc and ethyl iodide.

(7) Dimethyl ethyl carbinol (Tertiary amyl alcohol),

(CH3)2C(OH)C2H5, is a liquid with a camphor-like odour, boiling at 102.5°, and of sp. gr. 0 827 at 0°. It can be prepared by shaking amylene at a low temperature ( - 20°) with sulphuric acid mixed with one-half to an equal volume of water, and then diluting and boiling the solution. It acts as a narcotic.

(8) Tertiary Butyl Carbinol, (Ch3)3c Ch1oh

This alcohol is formed on reducing the chloride of trimethyl-acetic acid with sodium amalgam. It is a solid, melting at 48-50°, and boiling at 112°.