α-terpinene

Structural formula
General
Surname	α-terpinene
other names	Mentha-1,3-diene; 1-isopropyl-4-methyl-1,3-cyclohexadiene;
Molecular formula	C 10 H 16
Brief description	colorless lemon-like smelling oil
External identifiers / databases
EC number	202-795-1
ECHA InfoCard	100.002.541
PubChem	7462
ChemSpider	7182
Wikidata	Q423851
properties
Molar mass	136.24 g mol −1
Physical state	liquid
density	0.84 g cm −3
boiling point	~ 174 ° C
solubility	almost insoluble in water; soluble in ethanol and diethyl ether ;
Refractive index	1.477 (19 ° C)
safety instructions
H and P phrases	H: 226-302-315-319-335
	P: 261-305 + 351 + 338
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

α-Terpinene is a naturally occurring chemical compound from the terpinene group .

In the pure state it is a colorless, lemon-like scented oil that is contained in tea tree oil and nutmeg as well as in numerous essential oils of other aromatic plants . Chemically it is a cyclic monoterpenic hydrocarbon with the backbone of p-menthane and is isomeric with other terpinenes. It differs from γ-terpinene in its tart aroma. α-Terpinen has an antimicrobial effect and is allergenic .

Occurrence

In addition to tea tree oil , orange oil , bergamot oil , mandarin oil and oils of nutmeg , oregano , marjoram , celery , cardamom and coriander can contain large amounts of α-terpinene. The maximum content in relation to the plant is 0.5 percent in tea tree leaves.

Extraction

α-Terpinene was previously obtained by fractional distillation from the mixture of terpinene , which is obtained from limonene or pinene by acidic isomerization . Nowadays it is distilled from the abundant sweet orange oil ; 8 to 10 percent of the monoterpene fraction of oranges contains it.

properties

α-Terpinene is soluble in ethanol and ether as well as other organic solvents ; it is insoluble in water, but can be extracted by steam distillation . It oxidizes and gums in the air.

use

α-Terpinene is mainly used as a component of essential oils in flavors. As a pure substance, α-terpinene is an intermediate product in the organic synthesis of terpenes and copolymers that are processed into resins and paints. It is also part of biodegradable paint removers as well as degradable antimicrobial detergents. It also serves as a polymerization inhibitor for tetrafluoroethylene . Ascaridol can be produced by photochemical cycloaddition of oxygen to α-terpinene .

pharmacology

α-Terpinene inhibits the enzymes acetylcholinesterase , aldose reductase and P450 -2B1. It is considered to be allergenic; Therefore, the Working Group of Ecological Research Institutes eV (AGÖF) specifies the indoor air concentration of 1 µg / m³ (!) (Jan. 2006) as the "abnormality value", which gives cause for further investigations up to and including renovation. Incompatibilities with naturopathic substances such as tea tree oil , which is often used fungicidal / antibacterial, are z. T. attributed to terpinene and cineole . Up to three percent of the people tested were sensitized to tea tree oil in 2003.

Individual evidence

↑ ^a ^b ^c data sheet Α-Terpinen (PDF) from Carl Roth , accessed on December 14, 2010.
↑ ^a ^b ^c ^d Entry on Terpinene. In: Römpp Online . Georg Thieme Verlag, accessed on June 12, 2014.
↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-466.
↑ ^a ^b data sheet α-terpinene from Sigma-Aldrich , accessed on April 26, 2011 ( PDF ).
↑ BM Hausen et al .: Degradation products of monoterpenes are the sensitizing agents in tea tree oil. Am J Contact Dermat. 10/2/ 1999 . Pp. 68-77. PMID 10357714 .
↑ MA Bergstrom et al .: Conjugated dienes as prohaptens in contact allergy: in vivo and in vitro studies of structure-activity relationships, sensitizing capacity, and metabolic activation. Chem Res Toxicol. 19/6/ 2006 . Pp. 760-769. PMID 16780354 .
↑ C. Pirker and BM Hausen et al .: Sensitization to tea tree oil in Germany and Austria - a multicenter study by the German contact allergy group. J Dtsch Dermatol Ges. 1, / 8/ 2003 S. 629-634. doi : 10.1046 / j.1610-0387.2003.03727.x .

literature

George A. Burdock: Encyclopedia of Food and Color Additives. CRC Press 1996, ISBN 0-8493-9416-3

Web links

alpha-terpinene in Dr. Duke's Phytochemical Databases

[roth-1] ta sheet Α-Terpinen (PDF) from Carl Roth , accessed on December 14, 2010.

[roempp-2] Entry on Terpinene. In: Römpp Online . Georg Thieme Verlag, accessed on June 12, 2014.

[CRC90_3_466-3] David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-466.

[Sigma-4] ta sheet α-terpinene from Sigma-Aldrich , accessed on April 26, 2011 ( PDF ).

[5] BM Hausen et al .: Degradation products of monoterpenes are the sensitizing agents in tea tree oil. Am J Contact Dermat. 10/2/ 1999 . Pp. 68-77. PMID 10357714 .

[6] MA Bergstrom et al .: Conjugated dienes as prohaptens in contact allergy: in vivo and in vitro studies of structure-activity relationships, sensitizing capacity, and metabolic activation. Chem Res Toxicol. 19/6/ 2006 . Pp. 760-769. PMID 16780354 .

[7] C. Pirker and BM Hausen et al .: Sensitization to tea tree oil in Germany and Austria - a multicenter study by the German contact allergy group. J Dtsch Dermatol Ges. 1, / 8/ 2003 S. 629-634. doi : 10.1046 / j.1610-0387.2003.03727.x .