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A colourless liquid hydrocarbon. Limonene has been found to be an irritant and a skin sensitizer, which means that it makes you skin more vulnerable to the sun.

Limonene (Wikipedia)
Not to be confused with Lemonene.
Skeletal structure of the R-isomer
Ball-and-stick model of the R-isomer
Limonene extracted from orange peels.
IUPAC name
Other names
Racemic: DL-limonene; Dipentene
138-86-3 N
5989-27-5 (R) N
5989-54-8 (S) N
ChEBI CHEBI:15384 YesY
ChEMBL ChEMBL449062 (R) N
ChemSpider 20939 (R/S) YesY
388386 (S) YesY
389747 (R) YesY
Jmol 3D image Interactive graph
KEGG D00194 YesY
PubChem 22311 (R/S)
439250 (S)
Molar mass 136.24 g·mol−1
Appearance colorless to pale-yellow liquid
Odor Lemon
Density 0.8411 g/cm3
Melting point −74.35 °C (−101.83 °F; 198.80 K)
Boiling point 176 °C (349 °F; 449 K)
Solubility miscible in alcohol, benzene, chloroform, ether, CS2, and oils
soluble in CCl4
87° - 102°
R-phrases R10 R38 R43 R50/53
S-phrases (S2) S24 S37 S60 S61
NFPA 704
Flammability code 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 fuelHealth code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentineReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored diamond
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).
N verify (what is YesYN ?)
Infobox references

Limonene is a colorless liquid hydrocarbon classified as a cyclic terpene. The more common d-isomer possesses a strong smell of oranges. It is used in chemical synthesis as a precursor to carvone and as a renewables-based solvent in cleaning products.

Limonene takes its name from the lemon, as the rind of the lemon, like other citrus fruits, contains considerable amounts of this compound, which contributes to their odor. Limonene is a chiral molecule, and biological sources produce one enantiomer: the principal industrial source, citrus fruit, contains d-limonene ((+)-limonene), which is the (R)-enantiomer. Racemic limonene is known as dipentene. d-Limonene is obtained commercially from citrus fruits through two primary methods: centrifugal separation or steam distillation.

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