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.[1]
Production
Tetralin is produced by the catalytic hydrogenation of naphthalene.[1]
File:Tetralin synthesis 01.svg
Although nickel catalysts are traditionally employed, many variations have been evaluated.[2] 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,[3]
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.[4][1]
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fast reactors as a secondary coolant to keep sodium seals around pump impellers solidified; however its use has been superseded by NaK.[5]Template:Rp
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.[1]
References
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- ↑ a b c d Template:Ullmann
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- ↑ US Atomic Energy Commission (1961) SRE Core Recovery Remediation method after a failure in the moderator cans due to a crack in the secondary coolant tubes in the SRE, Spring 1959. This caused a leak of Tetralin into the reactor.
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