AMYL ALCOHOLS. There are eight of these alcohols theoretically possible. All are known, and the most important is zsobutyl carbinol (or isoamyl alcohol), the chief constituent of fermentation amyl alcohol, and consequently present in fusel oil (q.v.) . It can be extracted from fusel oil by shaking this with strong brine, discarding the brine layer and collecting the portion boiling between 125° and 140°C. By shaking this product with hot milk of lime, separating the oily layer, drying it with cal cium chloride and collecting the fraction boiling between 128° and 132°C, a further degree of purification may be effected.
Isoamyl alcohol is a colourless liquid of specific gravity 0.8248 (o°C), boiling at 131.6°C, slightly soluble in water, easily soluble in alcohol, ether, chloroform, and benzene. It possesses a charac teristic strong smell and a sharp burning taste. It is oxidized by chromic acid mixture to isovalerylaldehyde.
The eight amyl alcohols all have the general formula the differences being due to the different ways in which the carbon atoms are linked together and to the hydrogen and oxygen atoms. In normal amyl alcohol, we have a "straight chain" primary alcohol, which can be re garded as derived from the hydrocarbon n-pentane (normal pentane) by replacement of one end hydrogen atom with the alcoholic (hydroxyl) group. Methyl-n-propyl carbinol, and di-ethyl carbinol, are two secondary amyl alcohols, also derivable from n-pentane. From the hydrocarbon can be derived isobutyl carbinol or isoamyl alcohol, methyl isopropyl carbinol, dimethyl ethyl carbinol, and active amyl alcohol And from the hydrocarbon can be derived tertiary butyl carbinol, Three of these contain "asymmetric carbonations" (marked *) and can therefore exist each in two optically active forms and one optically inactive form (see STEREO-CHEMISTRY) ; the amyl alcohols include four primary alcohols (containing the group .CH2OH), three secondary alcohols (containing the group :CHOH) and one tertiary alcohol (con taining the group ; COH).
All the amyl alcohols can be obtained synthetically, isoamyl alcohol by the action of trioxy-methylene on isobutyl magnesium bromide, an example of Grignard's reaction. The syn thesis of tertiary butyl carbinol proved the most difficult and was finally achieved in 1891 by L. Tissier who reduced a mixture of trimethylacetic acid and trimethylacetyl chloride with sodium amalgam. It is a solid which melts at 48°-50°C and boils at 112