Title: a-Pinene
CAS Registry Number: 80-56-8
CAS Name: 2,6,6-Trimethylbicyclo[3.1.1]hept-2-ene
Additional Names: 2-pinene; pinene
Molecular Formula: C10H16
Molecular Weight: 136.23
Percent Composition: C 88.16%, H 11.84%
Literature References: Obtained from oil of turpentine which contains 58-65% a-pinene along with 30% b-pinene, q.v.: E. Gildemeister, F. Hoffmann, Die ätherischen Ole Band IV (Akademie-Verlag, Berlin, 4th ed., 1956) p 39. a-Pinene in North American oils is dextrorotatory, in most European oils it is levorotatory. Constituent of many volatile oils. Isoln of d-a-pinene from Port Oxford cedar wood oil (Chamaecyparis lawsoniana Parl., Pinaceae): Thurber, Roll, Ind. Eng. Chem. 19, 739 (1927). Isoln of l-a-pinene from mandarin peel oil (Citrus reticulata Blando, Rutaceae): Kugler, Kováts, Helv. Chim. Acta 46, 1480 (1963). Total synthesis of a- and b-forms: Komppa, Ann. Acad. Sci. Fenn. A59, 3 (1943), C.A. 41, 425 (1947); Thomas, Fallis, Tetrahedron Lett. 1973, 4687; eidem, J. Am. Chem. Soc. 98, 1227 (1976). Review: Palmer, Ind. Eng. Chem. 34, 1028 (1942); J. L. Simonsen, The Terpenes vol. II (Cambridge Univ. Press, 2nd ed., 1949) pp 105-191; D. V. Banthorpe, D. Whittaker, Chem. Rev. 66, 643-654 (1966); Food Cosmet. Toxicol. 16, Suppl. I, 853-857 (1978).
Derivative Type: dl-Form
Properties: Liquid, characteristic odor of turpentine. bp760 155-156°; bp20 52.5°. d420 0.8592. nD20 1.4664. Practically insol in water. Sol in alc, chloroform, ether, glacial acetic acid.
Boiling point: bp760 155-156°; bp20 52.5°
Index of refraction: nD20 1.4664
Density: d420 0.8592
Derivative Type: Hydrochloride
Molecular Formula: C10H17Cl
Molecular Weight: 172.69
Percent Composition: C 69.55%, H 9.92%, Cl 20.53%
Properties: mp 132°.
Melting point: mp 132°
Derivative Type: d-Form
Properties: bp760 155-156°. d420 0.8591. nD20 1.4663. [a]D20 +51.14°.
Boiling point: bp760 155-156°
Optical Rotation: [a]D20 +51.14°
Index of refraction: nD20 1.4663
Density: d420 0.8591
Derivative Type: Hydrochloride
Properties: mp 132°. [a]D20 +33.52° (alcohol).
Melting point: mp 132°
Optical Rotation: [a]D20 +33.52° (alcohol)
Derivative Type: l-Form
Properties: bp760 155-156°. d420 0.8590. nD20 1.4662. [a]D20 -51.28°.
Boiling point: bp760 155-156°
Optical Rotation: [a]D20 -51.28°
Index of refraction: nD20 1.4662
Density: d420 0.8590
Derivative Type: Hydrochloride
Properties: mp 132°. [a]D20 -33.24° (alcohol).
Melting point: mp 132°
Optical Rotation: [a]D20 -33.24° (alcohol)
CAUTION: Toxic effects similar to turpentine, q.v.
Use: Manufacture of camphor, insecticides, solvents, plasticizers, perfume bases, synthetic pine oil.
Alphaprodine alpha-Ribazole alpha-Santonin alpha-Spinasterol alpha-Terpineol

Alpha-Pinene Isomers.svg
CAS number 80-56-8 unspecified YesY, 7785-70-8 (+)-α-Pinene, 7785-26-4 (−)-α-Pinene
PubChem 440968
ChemSpider 389795 YesY
KEGG C06308 YesY
ChEBI CHEBI:28660 YesY
RTECS number DT7000000 (unspec. isomer)
Jmol-3D images Image 1
Molecular formula C10H16
Molar mass 136.23 g mol−1
Appearance Clear colorless liquid
Density 0.858 g/mL (liquid at 20 °C)
Melting point −64 °C; −83 °F; 209 K
Boiling point 155 °C; 311 °F; 428 K
Solubility in water Very low
Solubility in acetic acid miscible
Solubility in ethanol miscible
Solubility in acetone miscible
Chiral rotation [α]D −50.7° (1S,5S-Pinene)
R-phrases R10 R20/21/22 R36/37/38 R43 R51
S-phrases S16 S26 S36 S37 S60 S61
Main hazards flammable
NFPA 704
NFPA 704.svg
Flash point 33 °C; 91 °F; 306 K
Related compounds
Related alkene β-Pinene, Camphene, 3-Carene, Limonene
Related compounds Borneol, Camphor, Terpineol
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

α-Pinene is an organic compound of the terpene class, one of two isomers of pinene.[1] It is an alkene and it contains a reactive four-membered ring. It is found in the oils of many species of many coniferous trees, notably the pine. It is also found in the essential oil of rosemary (Rosmarinus officinalis).[2] Both enantiomers are known in nature; (1S,5S)- or (−)-α-pinene is more common in European pines, whereas the (1R,5R)- or (+)-α-isomer is more common in North America. The racemic mixture is present in some oils such as eucalyptus oil and orange peel oil.