Tetralin

Tetralin (1,2,3,4-tetrahydronaphthalene) is a hydrocarbon having the chemical formula C₁₀H₁₂. It is a partially hydrogenated derivative of naphthalene. It is a colorless liquid that is used as a hydrogen-donor solvent.^[2]

Tetralin

Names
Preferred IUPAC name 1,2,3,4-Tetrahydronaphthalene
Other names 1,2,3,4-Tetrahydronaphthalene, Benzocyclohexane, NSC 77451, Tetrahydronaphthalene, Tetranap
Identifiers
CAS Number	119-64-2 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:35008 Y
ChemSpider	8097 Y
ECHA InfoCard	100.003.946
KEGG	C14114 Y
PubChem CID	8404
UNII	FT6XMI58YQ Y
CompTox Dashboard (EPA)	DTXSID1026118
InChI InChI=1S/C10H12/c1-2-6-10-8-4-3-7-9(10)5-1/h1-2,5-6H,3-4,7-8H2 Y Key: CXWXQJXEFPUFDZ-UHFFFAOYSA-N Y InChI=1/C10H12/c1-2-6-10-8-4-3-7-9(10)5-1/h1-2,5-6H,3-4,7-8H2 Key: CXWXQJXEFPUFDZ-UHFFFAOYAG
SMILES c1ccc2c(c1)CCCC2
Properties
Chemical formula	C10H12
Molar mass	132.206 g·mol−1
Appearance	colorless liquid
Density	0.970 g/cm3
Melting point	−35.8 °C (−32.4 °F; 237.3 K)
Boiling point	206 to 208 °C (403 to 406 °F; 479 to 481 K)
Solubility in water	Insoluble
Viscosity	2.02 cP at 25 °C[1]
Hazards
Flash point	77 °C (171 °F; 350 K)
Autoignition temperature	385 °C (725 °F; 658 K)
Safety data sheet (SDS)	JT Baker MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Production

Tetralin is produced by the catalytic hydrogenation of naphthalene.^[2]

Although nickel catalysts are traditionally employed, many variations have been evaluated.^[3] Over-hydrogenation converts tetralin into decahydronaphthalene (decalin). Rarely encountered is dihydronaphthalene (dialin).

Laboratory methods

In a classic named reaction called the Darzens tetralin synthesis, named for Auguste Georges Darzens (1926), derivatives can be prepared by intramolecular electrophilic aromatic substitution reaction of a 1-aryl-pent-4-ene using concentrated sulfuric acid,^[4]

Darzens synthesis of tetralin derivatives

Uses

Tetralin is used as a hydrogen-donor solvent, for example in coal liquifaction. It functions as a source of H₂, which is transferred to the coal. The partially hydrogenated coal is more soluble.^[5][2]

It has been used in sodium-cooled fast reactors as a secondary coolant to keep sodium seals around pump impellers solidified; however its use has been superseded by NaK.^[6]: 24:30

It is also used for the laboratory synthesis of hydrogen bromide:

C₁₀H₁₂ + 4 Br₂ → C₁₀H₈Br₄ + 4 HBr

The facility of this reaction is in part a consequence of the moderated strength of the benzylic C-H bonds.

Safety

LD₅₀ (rats, oral) is 2.68 g/kg. Tetralin induces methemoglobinemia.^[2]