EUGENOL (allyl guaiacol, eugenic

See also:

• ACID (from the Lat. root ac-, sharp; acere, to be sour)

acid), C10H1202  , an odoriferous principle; it is the chief constituent of oil of cloves, and occurs in many other essential oils . It can be synthetically prepared by the reduction of con iferyl alcohol, (HO) (CH3O) C 6H3 • CH :CH • CH2OH, which occurs in combination with glucose in the glucoside coniferin, C16H2208 . It is a colourless oil boiling at 247° C., and having a spicy odour; On oxidation with potassium permanganate it gives homovanillin, vanillin, &c.; with chromic acid in acetic acid solution it is converted into carbon dioxide and acetic acid, whilst nitric acid oxidizes it to oxalic acid . By the action of alkalis it is converted into iso-eugenol, which on oxidation yields vanillin, the odorous principle of vanilla (q.v.) . This transformation of allyl phenols into propenyl phenols is very general (see Ber., 1889, 22, p . 2747; 1890, 23, p . 862) . Alkali fusion of eugenol gives protocatechuic acid . The amount of eugenol in oil of cloves can be estimated by acetylation, in presence of pyridine (A . Verley and Fr . Baelsing, Bee., 1901, 34, p . 3359) .

Chavibetol, an isomer of eugenol, occurs in the ethereal oil obtained from

Piper belle .