- limonene
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/lim"euh neen'/, n. Chem.a liquid terpene, C40H16, occurring in two optically different forms, the dextrorotatory form being present in the essential oils of lemon, orange, etc., and the levorotatory form in Douglas fir needle oil.[1835-45; < NL Limon(um) lemon + -ENE]
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a colourless liquid abundant in the essential oils of pine and citrus trees and used as a lemonlike odorant in industrial and household products and as a chemical intermediate.Limonene exists in two isomeric forms (compounds with the same molecular formula—in this case, C10H16—but with different structures), namely l-limonene, the isomer that rotates the plane of polarized light counterclockwise, and d-limonene, the isomer that causes rotation in the opposite direction. In the extraction of citrus juices d-limonene is obtained as a by-product, and it also occurs in caraway oil; l-limonene is present in pine needles and cones; dl-limonene, or dipentene, the mixture of equal amounts of the l- and d-isomers, is a component of turpentine.Dipentene may be sulfurized to produce additives that improve the performance of lubricating oils under heavy loads; d-limonene is commercially converted to l-carvone, which has a caraway-seed flavour.* * *
Universalium. 2010.