Terpinene

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The Terpinene (stress on the third syllable: Terpin e ne ) are a group of three isomeric hydrocarbons with a p-menthane skeleton. Their representatives, which appear as secondary plant substances, are counted among the monoterpenes .

history

Otto Wallach received the Nobel Prize in Chemistry in 1910 for identifying terpinenes and other aliphatic compounds in plants . The Otto Wallach badge , a prize donated by the Otto Wallach Fund roughly every three to five years from the mid-1960s to 2002, shows the structural formula of the α-terpine on the reverse.

Occurrence

Terpinenes, especially α- and γ-terpinene, are part of many essential oils , such as B. tea tree oil or bergamot oil . Terpinene is also the name given to the mixture of α-, β- and γ-terpinene that is produced by the action of acids on limonene or pinene .

properties

Structural formulas of the three terpinenes

Terpinene are colorless liquids with specific smells. They are isomeric hydrocarbons with a p- menthane structure with the empirical formula C 10 H 16 and a molar mass of 136.23 g / mol, which differ only in the different positions of their two double bonds :

  • α-terpinene , p- mentha-1,3-diene, lime-like odor, boiling point 173.5-174.8 ° C
  • β-terpinene , p- mentha-1,7-diene, solvent odor with a hint of menthol, boiling point 173-174 ° C
  • γ-terpinene , p- mentha-1,4-diene, pine-like “plastic” odor, boiling point 183 ° C

Mixtures of terpinene are difficult to separate by distillation . The isomeric limonenes and phellandrenes also have a p -methane structure with two double bonds , but are not counted among the terpinenes. The isomer α- terpinolene is also sometimes - but not uniformly - referred to as δ-terpinene .

Structure of α- terpinolene ( δ-terpinene )

Terpinen is considered to be allergenic, therefore the Working Group of Ecological Research Institutes eV (AGÖF) specifies the indoor air concentration of 1 µg / m³ as an "abnormality value", which gives cause for further investigations up to remediation (status Jan. 2006). Incompatibilities with naturopathic substances such as tea tree oil , which has an antimicrobial effect, are z. T. attributed to terpinene and 1,8-cineole .

Individual evidence

  1. ↑ US Patent 2097744
  2. ↑ a b c The Merck Index . An Encyclopaedia of Chemicals, Drugs and Biologicals . 14th edition, 2006, p. 1578, ISBN 978-0-911910-00-1 .

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