f. L. citr-us citron, used as combining form of citric and its derivatives; as Citraconic a. [see ACONIC], in Citraconic acid, C5 H6 O4, an acid isomeric with itaconic and mesaconic acids, obtained in a crystalline form in the distillation of citric acid. Also called pyrocitric acid. Its salts are Citraconates. Citraconic anhydride, C5 H4 O3. Citraconic chloride, C5 H4 O2 Cl2. Citraconic ether, C9 H14 O4. Citramide, an amide of citric acid. Citrene [see -ENE], a liquid hydrocarbon, C10 H16, of the terpene series, existing in the essential oils of lemon, orange, bergamot, neroli, etc.: also known as limonene. Also used as a general term to include all hydrocarbons having the same formula and similar properties. Citrin or Citroglycerin, a citrate of glyceryl, obtained by heating citric acid with excess of glycerin. Citromalic a., composed of citric and malic acids; citromalic acid, C5 H8 O5, a dibasic acid. Citronyl, a name applied to one of the constituents of oil of lemons; also to Citryl, C6 H5 O4, the triatomic radical of citric acid. Citro-tartaric acid, C5 H8 O6; its salts are Citro-tartrates.
1863–72. Watts, Dict. Chem., I. 993. Citraconate of Ethyl, or Citraconic Ether … is a colourless, bitter, somewhat aromatic liquid. Ibid. (18[?]), Fownes’ Chem., 73. (a) Terpenes or pinenes, boiling point 156°–160°, (b) citrenes, boiling point 174°–176°. Ibid. (1873), 726. Itaconic, and Citraconic acid are produced by the action of heat on citric acid.
