Limonene

Not to be confused with Limonin.

Limonene
Skeletal structure of the (R)-isomer
Skeletal structure of the (R)-isomer
Ball-and-stick model of the (R)-isomer
Ball-and-stick model of the (R)-isomer
Limonene (R)-isomer
Limonene extracted from orange peels.
Limonene extracted from orange peel
Names
Preferred IUPAC name
1-Methyl-4-(prop-1-en-2-yl)cyclohex-1-ene
Other names
1-Methyl-4-(1-methylethenyl)cyclohexene
4-Isopropenyl-1-methylcyclohexene
p-Menth-1,8-diene
Racemic: DL-Limonene; Dipentene
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.004.856 Edit this at Wikidata
KEGG
UNII
  • InChI=1S/C10H16/c1-8(2)10-6-4-9(3)5-7-10/h4,10H,1,5-7H2,2-3H3 checkY
    Key: XMGQYMWWDOXHJM-UHFFFAOYSA-N checkY
  • CC1=CCC(CC1)C(=C)C
Properties
C10H16
Molar mass 136.238 g·mol−1
Appearance colorless liquid
Odor Orange
Density 0.8411 g/cm3
Melting point −74.35 °C (−101.83 °F; 198.80 K)
Boiling point 176 °C (349 °F; 449 K)
Insoluble
Solubility Miscible with benzene, chloroform, ether, CS2, and oils
soluble in CCl4
87–102°
1.4727
Thermochemistry
−6.128 MJ mol−1
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
 Skin sensitizer / Contact dermatitis – After aspiration, pulmonary oedema, pneumonitis, and death[1]
GHS labelling:
GHS02: FlammableGHS07: Exclamation markGHS08: Health hazardGHS09: Environmental hazard
Danger
H226, H304, H315, H317, H410
P210, P233, P235, P240, P241, P242, P243, P261, P264, P272, P273, P280, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P312, P333+P313, P362, P370+P378, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g. diesel fuelInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
2
0
Flash point 50 °C (122 °F; 323 K)
237 °C (459 °F; 510 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Limonene (/ˈlɪmənˌiːn/) is a colorless liquid aliphatic hydrocarbon classified as a cyclic monoterpene, and is the major component in the essential oil of citrus fruit peels.[1] The (+)-isomer, occurring more commonly in nature as the fragrance of oranges, is a flavoring agent in food manufacturing.[1][2] It is also used in chemical synthesis as a precursor to carvone and as a renewables-based solvent in cleaning products.[1] The less common (-)-isomer has a piny, turpentine-like odor, and is found in the edible parts of such plants as caraway, dill, and bergamot orange plants.[3]

Limonene takes its name from Italian limone ("lemon").[4] Limonene is a chiral molecule, and biological sources produce one enantiomer: the principal industrial source, citrus fruit, contains (+)-limonene (d-limonene), which is the (R)-enantiomer.[1] (+)-Limonene is obtained commercially from citrus fruits through two primary methods: centrifugal separation or steam distillation.

  1. ^ a b c d e "D-Limonene". PubChem, US National Library of Medicine. 11 May 2024. Retrieved 18 May 2024.
  2. ^ Cite error: The named reference Ullmann was invoked but never defined (see the help page).
  3. ^ "Molecule of the Week Archive: Limonene". American Chemical Society. 1 November 2021. Retrieved 5 November 2021.
  4. ^ "limonene". merriam-webster.com. Merriam-Webster. 22 September 2023. Retrieved 23 September 2023.