Cymene

Cymene
IUPAC name	1-methyl-4-(1-methylethyl)benzene
Other names	4-isopropyltoluene
Identifiers
CAS number	[99-87-6]
PubChem	7463
EC number	202-796-7
SMILES	CC(C)c1ccc(C)cc1
InChI	InChI=1/C10H14/c1-8(2)10-6-4-9 (3)5-7-10/h4-8H,1-3H3
Properties
Molecular formula	C10H14
Molar mass	134.21 g/mol
Appearance	Colourless liquid
Density	0.857 g/cm3
Melting point	-68°C
Boiling point	177°C
Solubility in water	Negligible
Hazards
R-phrases	R10
S-phrases	S16
Flash point	47°C
Autoignition temperature	435°C
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox references

Cymene, or p-cymene, is a naturally occurring aromatic organic compound. It is classified as a hydrocarbon related to a monoterpene. Its structure consists of a benzene ring para-substituted with a methyl group and an isopropyl group. It is insoluble in water, but miscible with ethanol and ether.

Cymene is a constituent of a number of essential oils, most commonly the oil of cumin and thyme.

There are two less common geometric isomers. o-Cymene, in which the alkyl groups are ortho-substituted, and m-cymene, in which they are meta-substituted. p-Cymene is the only natural isomer.

Cymene is a common ligand for ruthenium. The parent compound is [(η⁶-cymene)RuCl₂]₂. This half-sandwich compound is prepared by the reaction of ruthenium trichloride with the terpene α-phellandrene. The osmium complex is also known.^[1]

References

1. ^ Bennett, M. A.; Huang, T. N.; Matheson, T. W. and Smith, A. K. (1982). "(h6-Hexamethylbenzene)ruthenium complexes". Inorganic Syntheses 21: 74–8. doi:10.1002/9780470132524.ch16.