Citral

Citral[1]
IUPAC name 3,7-dimethylocta-2,6-dienal
Other names citral geranial neral geranialdehyde
Identifiers
CAS number	5392-40-5 Y
PubChem	638011
ChemSpider	553578 Y
UNII	T7EU0O9VPP Y
KEGG	C01499 Y
ChEBI	CHEBI:16980 Y
ChEMBL	CHEMBL1080997 Y
RTECS number	RG5075000
Jmol-3D images	Image 1 Image 2
SMILES O=CC=C(C)CCC=C(C)C O=C/C=C(/CC/C=C(/C)C)C
InChI InChI=1S/C10H16O/c1-9(2)5-4-6-10(3)7-8-11/h5,7-8H,4,6H2,1-3H3/b10-7+ Y Key: WTEVQBCEXWBHNA-JXMROGBWSA-N Y InChI=1/C10H16O/c1-9(2)5-4-6-10(3)7-8-11/h5,7-8H,4,6H2,1-3H3/b10-7+ Key: WTEVQBCEXWBHNA-JXMROGBWBB
Properties
Molecular formula	C10H16O
Molar mass	152.24 g/mol
Appearance	Pale yellow liquid
Odor	Lemon like
Density	0.893 g/cm³
Boiling point	229 °C, 502 K, 444 °F
Hazards
R-phrases	R36, R37, R38
NFPA 704	1 0 0
Flash point	91 °C
Related compounds
Related alkenals	Citronellal Methacrolein trans-2-Methyl-2-butenal
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Citral, or 3,7-dimethyl-2,6-octadienal or lemonal, is either of, or a mixture of, a pair of terpenoids with the molecular formula C₁₀H₁₆O. The two compounds are double bond isomers. The E-isomer is known as geranial or citral A. The Z-isomer is known as neral or citral B.

Occurrence

Citral is present in the oils of several plants, including lemon myrtle (90-98%), Litsea citrata (90%), Litsea cubeba (70-85%), lemongrass (65-85%), lemon tea-tree (70-80%), Ocimum gratissimum (66.5%), Lindera citriodora (about 65%), Calypranthes parriculata (about 62%), petitgrain (36%), lemon verbena (30-35%), lemon ironbark (26%), lemon balm (11%), lime (6-9%), lemon (2-5%), and orange.^[2][3][4]

Uses

Geranial has a strong lemon odor. Neral's lemon odor is less intense, but sweeter. Citral is therefore an aroma compound used in perfumery for its citrus effect. Citral is also used as a flavor and for fortifying lemon oil. It also has strong antimicrobial qualities,^[5] and pheromonal effects in insects.^[6][7]

Citral is used in the synthesis of vitamin A, ionone, and methylionone, and to mask the smell of smoke.

Health and safety information

Citral should be avoided by people with perfume allergies.^[8]

Compendial status

• British Pharmacopoeia ^[9]

See also

• Lemon
• Limonene
• Citronellal
• Geraniol
• Nerol
• Vaporizer

References

1. ^ Citral, The Merck Index, 12th Edition.
2. ^ Fenaroli, G., Furia, T.E., Bellanca, N., Handbook of Flavor Ingredients, ISBN 0878195327
3. ^ Lawless, J., The Illustrated Encyclopedia of Essential Oils, ISBN 1-85230-661-0
4. ^ The Aromatic Plant Project
5. ^ Onawunmi, G.O. (1989). "Evaluation of the antimicrobial activity of citral". Lett. Appl. Microbial. 9 (3): 105–108. doi:10.1111/j.1472-765X.1989.tb00301.x. 
6. ^ Kuwahara, Y., Suzuki, H., Matsumoto, K. & Wada, Y. (1983). "Pheromone study on acarid mites. XI. Function of mite body as geometrical isomerization and reduction of citral (the alarm pheromone) Carpoglyphus lactis". Appl. Entomol. Zool. 18: 30–39. 
7. ^ Robacker, D.C. & Hendry, L.B. (1977). "Neral and geranial: components of the sex pheromone of the parasitic wasp, Itoplectis conquisitor". J. Chem. Ecol. 3 (5): 563–577. doi:10.1007/BF00989077. 
8. ^ Survey and health assessment of chemical substances in massage oils
9. ^ The British Pharmacopoeia Secretariat (2009). "Index, BP 2009". http://www.pharmacopoeia.co.uk/pdf/2009_index.pdf. Retrieved 31 March 2010. 

External links

• MSDS