Citral

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 geometric isomers. The E-isomer is known as geranial or citral A. The Z-isomer is known as neral or citral B.

Citral[1]

Geranial

Neral
Names
IUPAC name
3,7-dimethylocta-2,6-dienal
Other names
citral
geranialdehyde
Identifiers
3D model (JSmol)
3DMet
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.023.994
EC Number
  • 226-394-6
KEGG
RTECS number
  • RG5075000
UNII
UN number 2810
Properties
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)
−98.9×10−6 cm3/mol
Hazards
GHS pictograms
GHS Signal word Warning
H315, H317
P261, P264, P272, P280, P302+352, P321, P332+313, P333+313, P362, P363, P501
NFPA 704 (fire diamond)
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilHealth code 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g. sodium chlorideReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
0
0
Flash point 91 °C (196 °F; 364 K)
Related compounds
Related alkenals
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y verify (what is YN ?)
Infobox references

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

Citral has a strong lemon (citrus) odor and is used as an aroma compound in perfumery. (Nerol, another perfumery compound, has a less intense but sweeter lemon odor.) In addition, Citral is used as a flavor and for fortifying lemon oil. It also has strong antimicrobial qualities,[5] and pheromonal effects in acari and insects.[6][7]

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

Health and safety information

Two studies showed 1–1.7% of people to be allergic to citral, with allergies 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, with no known genotoxicity or carcinogenic effect.[8]

See also

References
  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. Microbiol. 9 (3): 105–108. doi:10.1111/j.1472-765X.1989.tb00301.x.
  6. Kuwahara, Yasumasa; Suzuki, Hiroshi; Matsumoto, Katsuhiko; Wada, Yoshitake (1983). "Pheromone study on acarid mites. XI. Function of mite body as geometrical isomerization and reduction of citral (the alarm pheromone)". Applied Entomology and Zoology. 18 (1): 30–39. doi:10.1303/aez.18.30.
  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 Archived 28 June 2007 at the Wayback Machine

This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.