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| Names | |||
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| IUPAC names α: 2-Methyl-5-(1-methylethyl)-1,3-cyclohexadiene β: 3-Methylene-6-(1-methylethyl)cyclohexene | |||
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| Properties | |||
| C10H16 | |||
| Molar mass | 136.24 g/mol | ||
| Appearance | Colorless oil (α and β) | ||
| Density | α: 0.846 g/cm3 β: 0.85 g/cm3 | ||
| Boiling point | α: 171-172 °C β: 171-172 °C | ||
| Insoluble (α and β) | |||
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
|  (what is   ?) | |||
| Infobox references | |||
Phellandrene is the name for a pair of organic compounds that have a similar molecular structure and similar chemical properties. α-Phellandrene and β-phellandrene are cyclic monoterpenes and are double-bond isomers. In α-phellandrene, both double bonds are endocyclic and in β-phellandrene, one of them is exocyclic. Both are insoluble in water, but miscible with ether.
α-Phellandrene was named after Eucalyptus phellandra, now called Eucalyptus radiata, from which it can be isolated. It is also a constituent of the essential oil of Eucalyptus dives. β-Phellandrene has been isolated from the oil of water fennel and Canada balsam oil.
The phellandrenes are used in fragrances because of their pleasing aromas. The odor of β-phellandrene has been described as peppery-minty and slightly citrusy.
The α-phellandrene isomer can form hazardous and explosive peroxides on contact with air at elevated temperatures.