Citral

Chemical compound From Wikipedia, the free encyclopedia

Citral is an acyclic monoterpene aldehyde. Being a monoterpene, it is made of two isoprene units. Citral is a collective term which covers two geometric isomers that have their own separate names; the E-isomer is named geranial (trans-citral; α-citral[2]) or citral A. The Z-isomer is named neral (cis-citral; β-citral[2]) or citral B. These stereoisomers occur as a mixture, often not in equal proportions; e.g. in essential oil of Australian ginger, the neral to geranial ratio is 0.61.[3]

Quick facts Names, Identifiers ...
Citral[1]
Skeletal formula of geranial
Geranial
Ball-and-stick model of the geranial molecule
Skeletal formula of neral
Neral
Ball-and-stick model of the neral molecule
Names
IUPAC name
3,7-dimethylocta-2,6-dienal
Other names
citral
geranialdehyde
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.023.994 Edit this at Wikidata
EC Number
  • 226-394-6
KEGG
RTECS number
  • RG5075000
UNII
UN number 2810
  • InChI=1S/C10H16O/c1-9(2)5-4-6-10(3)7-8-11/h5,7-8H,4,6H2,1-3H3/b10-7+ checkY
    Key: WTEVQBCEXWBHNA-JXMROGBWSA-N checkY
  • 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
  • O=CC=C(C)CCC=C(C)C
  • O=C/C=C(/CC/C=C(/C)C)C
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 labelling:
GHS07: Exclamation mark
Warning
H315, H317
P261, P264, P272, P280, P302+P352, P321, P332+P313, P333+P313, P362, P363, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g. sodium chlorideFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
0
1
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).
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Natural Occurrence

Citral is present in the volatile oils of several plants:[4][5][6]

Of the many sources of citral, the Australian tree Backhousia citriodora (family Myrtaceae) is considered superior.[7]

Uses

Citral is a precursor in the industrial production of vitamin A, vitamin E, vitamin K.

Citral is also precursor to lycopene, ionone and methylionone.

Fragrances

Citral has a strong lemon (citrus) scent and is used as an aroma compound in perfumery. It is used to fortify lemon oil presenting as sharp, lemon, sweet, fresh, juicy, lemon peel, tart, and green.[8] (Neral, the (E)-isomer, has a less sweeter citrus, lemon, lemon peel note,[9] whilst Geranial, the (E)-isomer is described as citrus, lemon.[10]) The aldehydes citronellal and citral are considered key components responsible for the lemon note with citral preferred.[7]

It also has pheromonal effects in acari and insects.[11][12]

The herb Cymbopogon citratus has shown promising insecticidal and antifungal activity against storage pests.[13]

Food additive

Citral is commonly used as a food additive ingredient.[14]

It has been tested (2016) in vitro against the food-borne pathogen Cronobacter sakazakii.[15]

See also

References

External links

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