Terpinene

Source: Wikipedia, the free encyclopedia.
Terpinenes
α-Terpinene
β-Terpinene
γ-Terpinene
δ-Terpinene
(terpinolene)
Names
IUPAC names
α: 4-Methyl-1-(1-methylethyl)-1,3-cyclohexadiene
β: 4-Methylene-1-(1-methylethyl)cyclohexene
γ: 4-Methyl-1-(1-methylethyl)-1,4-cyclohexadiene
δ: 1-Methyl-4-(propan-2-ylidene)cyclohex-1-ene
Identifiers
3D model (
JSmol
)
ChEBI
ChemSpider
ECHA InfoCard
100.029.440 Edit this at Wikidata
EC Number
  • (α): 202-795-1
  • (β): 202-793-0
  • (γ): 202-794-6
  • (δ): 209-578-0
KEGG
UNII
  • InChI=1S/C10H16/c1-8(2)10-6-4-9(3)5-7-10/h6,8H,3-5,7H2,1-2H3 checkY
    Key: SCWPFSIZUZUCCE-UHFFFAOYSA-N checkY
  • (β): InChI=1S/C10H16/c1-8(2)10-6-4-9(3)5-7-10/h6,8H,3-5,7H2,1-2H3
    Key: SCWPFSIZUZUCCE-UHFFFAOYSA-N
  • (γ): InChI=1S/C10H16/c1-8(2)10-6-4-9(3)5-7-10/h4,7-8H,5-6H2,1-3H3
    Key: YKFLAYDHMOASIY-UHFFFAOYSA-N
  • (δ): InChI=1S/C10H16/c1-8(2)10-6-4-9(3)5-7-10/h4H,5-7H2,1-3H3
    Key: MOYAFQVGZZPNRA-UHFFFAOYSA-N
  • (α): CC1=CC=C(C(C)C)CC1
  • (β): C=C1CC=C(C(C)C)CC1
  • (γ): CC1=CCC(C(C)C)=CC1
  • (δ): C/C(C)=C1CCC(C)=CC/1
Properties
C10H16
Molar mass 136.238 g·mol−1
Density α: 0.8375 g/cm3
β: 0.838 g/cm3
γ: 0.853 g/cm3
Melting point α: 60-61 °C
Boiling point α: 173.5-174.8 °C
β: 173-174 °C
γ: 183 °C
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

The terpinenes are a group of isomeric hydrocarbons that are classified as monoterpenes. They each have the same molecular formula and carbon framework, but they differ in the position of carbon-carbon double bonds. α-Terpinene has been isolated from cardamom and marjoram oils, and from other natural sources. β-Terpinene has no known natural source but has been prepared from sabinene. γ-Terpinene and δ-terpinene (also known as terpinolene) have been isolated from a variety of plant sources. They are all colorless liquids with a turpentine-like odor.[1]

Production and uses

α-Terpinene is produced industrially by acid-catalyzed rearrangement of α-pinene. It has perfume and flavoring properties but is mainly used to confer pleasant odor to industrial fluids. Hydrogenation gives the saturated derivative p-menthane.[1]

Biosynthesis of α-terpinene

Biosynthetic pathway to alpha-terpinene from geranyl pyrophosphate.[2]

The biosynthesis of α-terpinene and other terpenoids starts with the isomerization of

Wagner-Meerwein rearrangement
produces the terpinen-4-yl cation. It is the loss of a hydrogen from this cation that generates α-terpinene.

Plants that produce terpinene

References