Citral

Citral^[1]
Names
	IUPAC name 3,7-dimethylocta-2,6-dienal
	Other names citral; geranial; neral; geranialdehyde
Identifiers
CAS Number	5392-40-5 ;
3D model (JSmol)	Interactive image; Interactive image;
ChEBI	CHEBI:16980 ;
ChEMBL	ChEMBL1080997 ;
ChemSpider	553578 ;
ECHA InfoCard	100.023.994
KEGG	C01499 ;
PubChem CID	638011;
RTECS number	RG5075000;
UNII	T7EU0O9VPP ;
CompTox Dashboard (EPA)	DTXSID6024836 ;
	InChI InChI=1S/C10H16O/c1-9(2)5-4-6-10(3)7-8-11/h5,7-8H,4,6H2,1-3H3/b10-7+ Key: WTEVQBCEXWBHNA-JXMROGBWSA-N ; 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;
	SMILES O=CC=C(C)CCC=C(C)C; O=C/C=C(/CC/C=C(/C)C)C;
Properties
Chemical formula	C10H16O
Molar mass	152.24 g/mol
Appearance	Pale yellow liquid
Odor	Lemon like
Density	0.893 g/cm³
Boiling point	229 °C (444 °F; 502 K)
Vapor pressure	0.22 mmHg (20 °C)
Hazards
NFPA 704 (fire diamond)	0 1 0
Flash point	91 °C (196 °F; 364 K)
Related compounds
	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

Citral, or 3,7-dimethyl-2,6-octadienal or lemonal, is either a pair, or a mixture 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

Two studies have shown 1-1.7% of people to be allergic to citral, and allergies are frequently reported. Citral on its own is strongly sensitizing to allergies; the International Fragrance Association recommends that citral only be used in association with substances that prevent a sensitizing effect. Citral has been extensively tested and has no known genotoxicity, and no known carcinogenic effect, but animal tests show dose-dependent effects on the kidneys.^[8]

Compendial status

British Pharmacopoeia ^[9]

References

^ Citral, The Merck Index, 12th Edition.
^ Fenaroli, G., Furia, T.E., Bellanca, N., Handbook of Flavor Ingredients, ISBN 0-87819-532-7
^ Lawless, J., The Illustrated Encyclopedia of Essential Oils, ISBN 1-85230-661-0
^ The Aromatic Plant Project
^ 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.
^ 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.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^ 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.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^ Survey and health assessment of chemical substances in massage oils
^ The British Pharmacopoeia Secretariat (2009). "Index, BP 2009" (PDF). Retrieved 31 March 2010. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)

External links

MSDS

[1] Citral, The Merck Index, 12th Edition.

[2] Fenaroli, G., Furia, T.E., Bellanca, N., Handbook of Flavor Ingredients, ISBN 0-87819-532-7

[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.{{cite journal}}: CS1 maint: multiple names: authors list (link)

[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.{{cite journal}}: CS1 maint: multiple names: authors list (link)

[summary-8] Survey and health assessment of chemical substances in massage oils

[ib29-9] The British Pharmacopoeia Secretariat (2009). "Index, BP 2009" (PDF). Retrieved 31 March 2010. {{cite web}}: Cite has empty unknown parameter: |coauthors= (help)

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