Chem. [f. terp- in terp-entin, obs. f. TURPENTINE, with suffix -ENE, used in forming the names of hydrocarbons related to BENZENE. Formerly called TEREBENE.] A general name of hydrocarbons having the formula C10H16, many of which occur in the volatile oils of plants, chiefly of the coniferous and aurantiaceous orders. The commonest is PINENE, the chief constituent of turpentine-oil.
Sometimes used to include hydrocarbons of formula C5H8, and its polymers C10H16, C15H24, C20H32, etc.
[1866. Kekulé. Lehrb. Organ. Chemie, II. 437.].
1873. Watts, Fownes’ Chem. (ed. 11), 778. Terpenes are volatile oils, existing in plants.
1885. Remsen, Org. Chem. (1888), 311. Artificial camphor … when heated alone, or with bases,… gives off hydrochloric acid, and a terpene different from the oil of turpentine is formed.
1902. Pond, trans. Heusler’s Chem. Terpenes, 17. Those hydrocarbons which have the empirical constitution C5H8 are termed terpenes. Four main classes are recognised: Hemiterpenes, C5H8, Terpenes proper, C10H16, Sesquiterpenes, C15H24, Polyterpenes, (C5H8)x.
Hence Terpenylic [f. TERPENE + -YL + -IC], in terpenylic acid, a white crystalline compound, C8H12O4, obtained by oxidizing a terpene, as turpentine-oil, with chromic acid.
1881. Watts, Dict. Chem., VIII. 1907. Terpenylic acid … is obtained at first in the form of a syrup resembling glycerol…. Terpenylic acid is monobasic.
