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p-Cymene

Names
Preferred IUPAC name 1-Methyl-4-(propan-2-yl)benzene
Other names para-Cymene 4-Isopropyltoluene 4-Methylcumene Paracymene
Identifiers
CAS Number	99-87-6
3D model (JSmol)	Interactive image
3DMet	B00975
Beilstein Reference	1903377
ChEBI	CHEBI:28768
ChEMBL	ChEMBL442915
ChemSpider	7183
ECHA InfoCard	100.002.542
EC Number	202-796-7
Gmelin Reference	305912
KEGG	C06575
PubChem CID	7463
RTECS number	GZ5950000
UNII	1G1C8T1N7Q
UN number	2046
CompTox Dashboard (EPA)	DTXSID3026645
InChI InChI=1S/C10H14/c1-8(2)10-6-4-9(3)5-7-10/h4-8H,1-3H3Key: HFPZCAJZSCWRBC-UHFFFAOYSA-N InChI=1/C10H14/c1-8(2)10-6-4-9(3)5-7-10/h4-8H,1-3H3Key: HFPZCAJZSCWRBC-UHFFFAOYAD
SMILES c1cc(ccc1C(C)C)C
Properties
Chemical formula	C10H14
Molar mass	134.222 g·mol
Appearance	Colourless liquid
Density	0.857 g/cm
Melting point	−68 °C (−90 °F; 205 K)
Boiling point	177 °C (351 °F; 450 K)
Solubility in water	23.4 mg/L
Magnetic susceptibility (χ)	−1.028×10 cm/mol
Refractive index (nD)	1.4908 (at 20 °C)
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H226, H304, H411
Precautionary statements	P210, P233, P240, P241, P242, P243, P273, P280, P301+P310, P303+P361+P353, P331, P370+P378, P391, P403+P235, P405, P501
Flash point	47 °C (117 °F; 320 K)
Autoignition temperature	435 °C (815 °F; 708 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). Y verify (what is  ?) Infobox references

p-Cymene is a naturally occurring aromatic organic compound. It is classified as an alkylbenzene related to monocyclic monoterpenes. 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.

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 propene.

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 ₂. This half-sandwich compound is prepared by the reaction of ruthenium trichloride with the terpene α-phellandrene. The osmium complex is also known.

Hydrogenation gives the saturated derivative p-menthane.

References

1. 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.
2. Pabst, Florian; Blochowicz, Thomas (December 2022). "On the intensity of light scattered by molecular liquids - Comparison of experiment and quantum chemical calculations". The Journal of Chemical Physics. 157 (24): 244501. Bibcode:2022JChPh.157x4501P. doi:10.1063/5.0133511. PMID 36586992.
3. Balahbib, Abdelaali; El Omari, Nasreddine; Hachlafi, Naoufal EL.; Lakhdar, Fatima; El Menyiy, Naoual; Salhi, Najoua; Mrabti, Hanae Naceiri; Bakrim, Saad; Zengin, Gokhan; Bouyahya, Abdelhakim (2021-07-01). "Health beneficial and pharmacological properties of p-cymene". Food and Chemical Toxicology. 153: 112259. doi:10.1016/j.fct.2021.112259. ISSN 0278-6915.
4. Vora, Bipin V.; Kocal, Joseph A.; Barger, Paul T.; Schmidt, Robert J.; Johnson, James A. (2003). "Alkylation". Kirk‐Othmer Encyclopedia of Chemical Technology. doi:10.1002/0471238961.0112112508011313.a01.pub2. ISBN 0471238961.
5. Bennett, M. A.; Huang, T.-N.; Matheson, T. W.; Smith, A. K. (1982). "(η-Hexamethylbenzene)Ruthenium Complexes". Inorganic Syntheses. 21: 74–78. doi:10.1002/9780470132524.ch16. ISBN 9780470132524.

• Flavors
• Alkylbenzenes
• C4-Benzenes
• Monoterpenes
• Isopropyl compounds