Cyclic compounds (1)
Cadalene or cadalin (4-isopropyl-1,6-dimethylnaphthalene) is a polycyclic aromatic hydrocarbon with a chemical formula C15H18 and a cadinane skeleton. It is derived from generic sesquiterpenes, and ubiquitous in essential oils of many higher plants. Cadalene, together with retene, simonellite and ip-iHMN, is a biomarker of higher plants, which makes it useful for paleobotanic analysis of rock sediments.
Biphenyl (92-52-4, 68409-73-4)
diphenyl · diphenyl, 14C-labeled
Biphenyl (or diphenyl or phenylbenzene or 1,1′-biphenyl or lemonene) is an organic compound that forms colorless crystals. Particularly in older literature, compounds containing the functional group consisting of biphenyl less one hydrogen (the site at which it is attached) may use the prefixes xenyl or diphenylyl. It has a distinctively pleasant smell.
1-METHYLNAPHTHALENE (90-12-0, 1321-94-4)
1-Methylnaphthalene is a polycyclic aromatic hydrocarbon (PAH). It has a cetane number of zero, and was previously used as the lower reference for cetane number. However, due to the expense and handling difficulty of 1-methylnaphthalene, it was replaced in this capacity by isocetane, with a CN of 15.