5493. Limonene

Nomenclature

CAS number: 138-86-3
1-Methyl-4-(1-methylethenyl)cyclohexene; p-mentha-1,8-diene; cinene; cajeputene; kautschin.
C10H16; mol wt 136.23.
C 88.16%, H 11.84%.

Description and references

Occurs in various ethereal oils, particularly in oils of lemon, orange, caraway, dill and bergamot. Isoln of d-limonene from mandarin peel oil (Citrus reticulata Blanco, Rutaceae): Kugler, Kováts, Helv. Chim. Acta 46, 1480 (1963). Review: J. L. Simonsen, The Terpenes vol. I (University Press, Cambridge, 2nd ed., 1947) pp 143-165.

Chemical structure

Derivative

dl-Form.

Nomenclature

Inactive limonene; dipentene.

Properties

Liquid. Pleasant lemon-like odor. bp763 175.5-176.5°. d420.85 0.8402. nD 1.4744. Practically insol in water. Miscible with alcohol. With dry HCl or HBr it forms monohalides, and with aq HCl or HBr, the dihalide.

Derivative

d-Form.

Properties

Liquid. bp763 175.5-176°. d421 0.8402. nD21 1.4743. [α]D19.5 +123.8°.

Derivative

l-Form.

Properties

Liquid. bp763 175.5-176.5°. d420.5 0.8407. nD21 1.474. [α]D19.5 101.3°.

Caution

Skin irritant, sensitizer.

Use

Solvent, manuf resins; wetting and dispersing agent.