Cymene(redirected from P-cymene)
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(also methyl-isopropyl-benzene), an aromatic hydrocarbon having the structural formula
The meta-, ortho-, and para-isomers of cymene are known; the most important is para-cymene, which is a component of turpentine and many essential oils, including cumin oil and eucalyptus oil. A colorless liquid with a characteristic odor, para-cymene has a boiling point of 177.1°C, a melting point of –67.9°C, and a density of 0.857 g/cm3 at 20°C. Cymene is insoluble in water, but it is miscible with many organic solvents.
The similarity of the carbon skeleton of para-cymene with the skeletons of many cyclic terpenes is a result of their common origin. Thus, para-cymene may be produced by the pyrolysis of α-pinene, the dehydrogenation of limonene, or the heating of camphor with P2O5. In the chemical industry, para-cymene is produced from sulfite turpentine and is used as a raw material and a solvent.