Limonene

Limonene () is a slightly yellow-green liquid aliphatic hydrocarbon classified as a cyclic monoterpene, and is the major component in the fragrance and essential oil of citrus fruit peels, taking its name from Italian limone ("lemon"). Limonene is a chiral molecule, and most biological sources produce just one enantiomer (isomer). The (+)-isomer, d-limonene, which is the (R)-enantiomer, occurs more commonly in nature in citrus fruit peels, the principal commercial source, from which it is obtained commercially by two primary methods: centrifugal separation and steam distillation. d-Limonene is used as a flavoring agent in food manufacturing, in chemical synthesis as a precursor to carvone, and as a renewables-based solvent in cleaning products. It has a "citrus, orange, fresh, sweet, peely" aroma. The less common (−)-isomer, l-limonene, which is the (S)-enantiomer, has a piny, turpentine-like odor, and is found in the edible parts of such plants as caraway, dill, and bergamot orange plants.