Tetrahydronaphthalene

Structural formula
General
Surname	Tetrahydronaphthalene
other names	Tetralin; 1,2,3,4-tetrahydronaphthalene;
Molecular formula	C 10 H 12
Brief description	colorless liquid with a naphthalene odor
External identifiers / databases
EC number	204-340-2
ECHA InfoCard	100.003.946
PubChem	8404
Wikidata	Q420416
properties
Molar mass	132.20 g mol −1
Physical state	liquid
density	0.97 g cm −3
Melting point	−36 ° C
boiling point	208 ° C
Vapor pressure	0.24 h Pa (20 ° C); 0.8 hPa (30 ° C); 2.8 hPa (50 ° C);
solubility	very bad in water (50 mg l −1 at 20 ° C); good in many organic solvents;
Refractive index	1.5414
safety instructions
H and P phrases	H: 304-315-319-351-411
	EUH: 019
	P: 273-281-301 + 310-305 + 351 + 338-331
MAK	Switzerland: 2 ml m −3 or 11 mg m −3
Toxicological data	1580 mg kg −1 ( LD 50 , rat , oral )
	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

Tetrahydronaphthalene ( 1,2,3,4-tetrahydronaphthalene , IUPAC ) is a hydrocarbon with the empirical formula C ₁₀ H ₁₂ . The historical name Tetralin is still frequently used today, but has been a registered word mark of Dehydag , now Cognis, since 1956 .

Manufacture and extraction

Tetrahydronaphthalene is made by the partial catalytic hydrogenation of naphthalene . Decalin (decahydronaphthalene) is obtained from it through complete hydrogenation .

properties

The colorless, oily liquid solidifies at approximately −36 ° C and boils at 208 ° C. The odor of tetrahydronaphthalene is similar to that of naphthalene . The liquid is highly refractive, the refractive index is 1.541. Tetrahydronaphthalene is almost insoluble in water; it floats on water because its density of 0.973 g · cm ^{−3 is} lower than that of water. It is readily soluble in most organic solvents. With a water content of 80 mol%, an azeotropic boiling point of 99 ° C. is observed at atmospheric pressure .

The compound forms inflammable vapor-air mixtures above its flash point at 71 ° C. The explosion range is between 0.5% by volume (45 g / m³) as the lower explosion limit (LEL) and 5.0% by volume (275 g / m³) as the upper explosion limit (UEL). The ignition temperature is 390 ° C. The substance therefore falls into temperature class T2.

Tetrahydronaphthalene easily forms 1-hydroperoxy-tetrahydronaphthalene ("tetralin hydroperoxide") with atmospheric oxygen. This must be taken into account when distilling older products, as explosions may occur.

use

Tetrahydronaphthalene is used as a solvent for rubbers , paint remover and heat exchange fluid. It is found in paints, paint strippers, and pesticides (as a solvent). Tetrahydronaphthalene is used in the production of 1-naphthol , detergents, plasticizers, shoe polishes, floor polishes and textile auxiliaries.

Isomeric compounds

Of the various theoretically possible tetrahydronaphthalene derivatives, 1,4,5,8-tetrahydronaphthalene ( 2 ) is accessible via a Birch reduction of naphthalene ( 1 ). 1,4,5,8-Tetrahydronaphthalene is the starting material for various heptalene syntheses.

Individual evidence

↑ ^a ^b ^c Entry on tetralin. In: Römpp Online . Georg Thieme Verlag, accessed on March 10, 2014.
↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m Entry on tetrahydronaphthalene in the GESTIS substance database of the IFA , accessed on November 11, 2017(JavaScript required) .
↑ Entry on 1,2,3,4-tetrahydronaphthalene in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
↑ Swiss Accident Insurance Fund (Suva): Limit values - current MAK and BAT values (search for 119-64-2 or tetrahydronaphthalene ), accessed on November 2, 2015.
^ Trademark information from the DPMA : Tetralin , accessed on August 9, 2013.
↑ ^a ^b Brockhaus ABC Chemie , FA Brockhaus Verlag Leipzig 1971, p. 1390.
↑ ^a ^b Data sheet 1,2,3,4-Tetrahydronaphthalene, anhydrous, 99% from Sigma-Aldrich , accessed on November 11, 2017 ( PDF ).
^ IM Smallwood: Handbook of organic solvent properties , Arnold London 1996, ISBN 0-340-64578-4 , pp. 55-57.
^ E. Brandes, W. Möller: Safety-related parameters - Volume 1: Flammable liquids and gases , Wirtschaftsverlag NW - Verlag für neue Wissenschaft GmbH, Bremerhaven 2003.
^ Gerhard Becker, Heinz Kolshorn: Heptalene . In: Heinz Kropf (Ed.): Houben-Weyl Methods of Organic Chemistry . Vol. V / 2c. Georg Thieme Verlag, Stuttgart, New York 1985, ISBN 3-9801412-1-7 , pp. 418 ff . ( limited preview in Google Book search).

[roempp-1] Entry on tetralin. In: Römpp Online . Georg Thieme Verlag, accessed on March 10, 2014.

[GESTIS-2] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l ^m Entry on tetrahydronaphthalene in the GESTIS substance database of the IFA , accessed on November 11, 2017(JavaScript required) .

[CLP_100.003.946-3] Entry on 1,2,3,4-tetrahydronaphthalene in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .

[4] Swiss Accident Insurance Fund (Suva): Limit values - current MAK and BAT values (search for 119-64-2 or tetrahydronaphthalene ), accessed on November 2, 2015.

[5] Trademark information from the DPMA : Tetralin , accessed on August 9, 2013.

[Brockhaus-6] Brockhaus ABC Chemie , FA Brockhaus Verlag Leipzig 1971, p. 1390.

[Sigma-7] Data sheet 1,2,3,4-Tetrahydronaphthalene, anhydrous, 99% from Sigma-Aldrich , accessed on November 11, 2017 ( PDF ).

[Smallwood-8] IM Smallwood: Handbook of organic solvent properties , Arnold London 1996, ISBN 0-340-64578-4 , pp. 55-57.

[9] E. Brandes, W. Möller: Safety-related parameters - Volume 1: Flammable liquids and gases , Wirtschaftsverlag NW - Verlag für neue Wissenschaft GmbH, Bremerhaven 2003.

[10] Gerhard Becker, Heinz Kolshorn: Heptalene . In: Heinz Kropf (Ed.): Houben-Weyl Methods of Organic Chemistry . Vol. V / 2c. Georg Thieme Verlag, Stuttgart, New York 1985, ISBN 3-9801412-1-7 , pp. 418 ff . ( limited preview in Google Book search).