p-Cymene
p-Cymene is a naturally occurring aromatic organic compound. It is classified as an alkylbenzene related to a monoterpene. Its structure consists of a benzene ring para-substituted with a methyl group and an isopropyl group. p-Cymene is insoluble in water, but miscible with organic solvents.
| |||
Names | |||
---|---|---|---|
Preferred IUPAC name
1-Methyl-4-(propan-2-yl)benzene[1] | |||
Other names
para-Cymene 4-Isopropyltoluene 4-Methylcumene Paracymene | |||
Identifiers | |||
3D model (JSmol) |
|||
3DMet | |||
1903377 | |||
ChEBI | |||
ChEMBL | |||
ChemSpider | |||
ECHA InfoCard | 100.002.542 | ||
EC Number |
| ||
305912 | |||
KEGG | |||
PubChem CID |
|||
RTECS number |
| ||
UNII | |||
UN number | 2046 | ||
CompTox Dashboard (EPA) |
|||
| |||
| |||
Properties | |||
C10H14 | |||
Molar mass | 134.222 g·mol−1 | ||
Appearance | Colourless liquid | ||
Density | 0.857 g/cm3 | ||
Melting point | −68 °C (−90 °F; 205 K) | ||
Boiling point | 177 °C (351 °F; 450 K) | ||
23.4 mg/L | |||
−1.028×10−4 cm3/mol | |||
Hazards | |||
GHS pictograms | |||
GHS Signal word | Danger | ||
H226, H304, H411 | |||
P210, P233, P240, P241, P242, P243, P273, P280, P301+310, P303+361+353, P331, P370+378, P391, P403+235, P405, P501 | |||
Flash point | 47 °C (117 °F; 320 K) | ||
435 °C (815 °F; 708 K) | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |||
verify (what is ?) | |||
Infobox references | |||
Isomers and production
In addition to p-cymene, two less common geometric isomers are 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, as expected from the terpene rule. All three isomers form the group of cymenes.
Cymene is also produced by alkylation of toluene with propylene.[2]
Related compounds
It is a constituent of a number of essential oils, most commonly the oil of cumin and thyme. Significant amounts are formed in sulfite pulping process from the wood terpenes.
p-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.[3]
Hydrogenation gives the saturated derivative p-menthane.
References
- Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. pp. 139, 597. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.
- Vora, Bipin V.; Kocal, Joseph A.; Barger, Paul T.; Schmidt, Robert J.; Johnson, James A. (2003). "Alkylation". Kirk-Othmer Encyclopedia of Chemical Technology. Kirk‐Othmer Encyclopedia of Chemical Technology. doi:10.1002/0471238961.0112112508011313.a01.pub2. ISBN 0471238961.
- Bennett, M. A.; Huang, T.-N.; Matheson, T. W.; Smith, A. K. (1982). "(η6-Hexamethylbenzene)Ruthenium Complexes". Inorganic Syntheses. 21: 74–78. doi:10.1002/9780470132524.ch16.