Tetralin
Chemical compound
From Wikipedia, the free encyclopedia
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]
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| Names | |
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| Preferred IUPAC name
1,2,3,4-Tetrahydronaphthalene | |
| Other names
1,2,3,4-Tetrahydronaphthalene, Benzocyclohexane, NSC 77451, Tetrahydronaphthalene, Tetranap | |
| Identifiers | |
3D model (JSmol) |
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| ChEBI | |
| ChemSpider | |
| ECHA InfoCard | 100.003.946 |
| KEGG | |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| 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) |
| Insoluble | |
| Viscosity | 2.02 cP at 25 °C[1] |
| Hazards | |
| Flash point | 77 °C (171 °F; 350 K) |
| 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).
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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]
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fast reactors as a secondary coolant to keep sodium seals around pump impellers solidified; however its use has been superseded by NaK.[6]: 24:30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]