Tetralin

Tetralin

Names
IUPAC name 1,2,3,4-tetrahydronaphthalene
Other names naphthalene 1,2,3,4-tetrahydride Bacticin benzocyclohexane THN
Identifiers
CAS Number	119-64-2
ChEBI	CHEBI:35008
ChemSpider	8097
Jmol interactive 3D	Image
KEGG	C14114
PubChem	8404
UNII	FT6XMI58YQ
InChI InChI=1S/C10H12/c1-2-6-10-8-4-3-7-9(10)5-1/h1-2,5-6H,3-4,7-8H2 Key: CXWXQJXEFPUFDZ-UHFFFAOYSA-N 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	132.21 g·mol^−1
Appearance	Clear, colorless liquid with an odor similar to naphthalene
Density	0.970 g/cm^3
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
Safety data sheet	JT Baker MSDS
Flash point	77 °C (171 °F; 350 K)
Autoignition temperature	385 °C (725 °F; 658 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Tetralin (1,2,3,4-tetrahydronaphthalene) is a hydrocarbon having the chemical formula C₁₀H₁₂. This molecule is similar to the naphthalene chemical structure except that one ring is saturated.

Synthesis

The compound can be synthesized in a Bergman cyclization. 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 an 1-aryl-4-pentene using concentrated sulfuric acid,^[2]

Darzens synthesis of tetralin derivatives

It can also be prepared by partial hydrogenation of naphthalene in the presence of a platinum catalyst.

Production

Tetralin is produced by the catalytic hydrogenation of naphthalene.

A large amount of work has been devoted to the hydrogenation of naphthalene into tetralin. Mixtures containing different proportions of naphthalene, tetralin, and decalin can be produced depending on the pressure and temperature of the process. Tetralin has been obtained from pressed naphthalene isolated from coal tar by hydrogenating it over commercial catalyst WS₂ + NiS + Al₂O₃ and CoO + MoO₃ + Al₂O₃ under pressure of 50–300 atm. The extent to which naphthalene is hydrogenated at pressures up to 60–70 atm is determined by catalyst activity; it is maximum if CoO + MoO₃ + Al₂O₃ or WS₂ + NiS + Al₂O₃ catalyst are used at 300–370 °C.^[3]

Uses

Tetralin is used as a solvent.

It is also used for the laboratory synthesis of dry HBr gas:

C₁₀H₁₂ + 4 Br₂ → C₁₀H₈Br₄ + 4 HBr

See also

• Decalin
• Dialin
• Naphthalene

References

1. Gonçalves, F. A.; Hamano, K.; Sengers, J. V. (1989). "Density and viscosity of tetralin and trans-decalin". International Journal of Thermophysics 10 (4): 845. doi:10.1007/BF00514480.
2. Michael B. Smith (2011). Organic Synthesis (third ed.). Academic Press. pp. 1209–1210. ISBN 9780124158849.
3. Krichko, A. A.; Skvortsov, D. V.; Titova, T. A.; Filippov, B. S.; Dogadkina, N. E. (1969). "Production of tetralin by the hydrogenation of naphthalene-containing fractions". Chemistry and Technology of Fuels and Oils 5: 18. doi:10.1007/BF00727949.