Chem. [f. L. all(ium) garlic, onion + -YL = Gr. ὔλη substance.]
1. A monovalent hydro-carbon radical, C3H5, =CH,CH=CH′, obtained in the free state as a very volatile liquid, with a pungent odor resembling that of horse-radish.
1854. Pereira, Mat. Med., I. 225. Oils obtained from alliaceous and cruciferous plants whose hypothetical radical is allyle.
1863. Watts, Dict. Chem., I. 140. Berthelot and De Luca in the same year [1857], isolated the radical allyl.
1870. Tyndall, Heat, xv. § 763. 528. The liquid here employed is the iodide of allyl.
2. attrib. as in allyl series, allyl compounds, allyl alcohol C3H5OH, di-allyl ether (C3H5)2O, allyl sulphide (C3H5)2S, allyl sulphocyanide C3H5.S.CN, allyl oxalate, etc.
1863. Watts, Dict. Chem. (1879), I. 56. Acrolein the aldehyde of the allyl series.
1869. Roscoe, Elem. Chem., 389. The allyl sulphide is remarkable as occurring in nature as the essential oil of garlic. In like manner allyl sulphocyanide is found as the essential oil of black mustard seed.