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Structural formula
Structural formula of biphenyl
Surname Biphenyl
other names
  • Diphenyl
  • Phenylbenzene
  • Dibenzene
Molecular formula C 12 H 10
Brief description

colorless to yellowish, aromatic smelling leaflets

External identifiers / databases
CAS number 92-52-4
EC number 202-163-5
ECHA InfoCard 100,001,967
PubChem 7095
Wikidata Q410915
Molar mass 154.21 g mol −1
Physical state



1.04 g cm −3

Melting point
  • 69 ° C
  • 68-70 ° C
boiling point

255 ° C

Vapor pressure

7 Pa (20 ° C)

Refractive index

1.588 (77 ° C)

safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary
07 - Warning 09 - Dangerous for the environment


H and P phrases H: 319-335-315-410
P: 273-302 + 352-304 + 340-305 + 351 + 338

Switzerland: 0.2 ml m −3 or 1.3 mg m −3

Toxicological data
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

Biphenyl (also diphenyl, phenylbenzene and dibenzene) is a colorless, crystalline solid from the class of aromatic hydrocarbons , more precisely the biaryls . It inhibits the growth of mold and therefore acts as a fungicide or preservative for food, but is no longer approved in the EU.


Biphenyl is obtained from the distilled oils of coal tar or through the reaction of two phenyl radicals:

Reaction of two phenyl radicals to biphenyl


Physical Properties

Biphenyl forms colorless to yellowish, glossy crystals that melt at 69.2 ° C. The enthalpy of fusion is 18.576 kJ mol −1 . The boiling point at normal pressure is 255 ° C. The enthalpy of vaporization at the boiling point is 47.95 kJ mol −1 . The vapor pressure function results according to Antoine according to log 10 (P) = A− (B / (T + C)) (P in bar, T in K) with A = 4.35685, B = 1987.623 and C = −71.556 in the temperature range from 342 K to 544 K. Biphenyl is insoluble in water, but it dissolves easily in non-polar organic solvents such as petroleum ether or toluene . The flash point is 113 ° C, the ignition temperature 540 ° C.

Chemical properties

Biphenyl is relatively inert. The hydrogenation on platinum catalysts is through the cyclohexylbenzene to cyclohexylcyclohexane .


In the past, biphenyl was applied to the peel of citrus fruits as a preservative ( food additive E 230, often in combination with E 231 , E 232 , E 233 and Imazalil ) because it inhibits the growth of mold . However, the shells treated in this way are no longer suitable for consumption. The active ingredient biphenyl (formerly: diphenyl) was removed from the list of permitted surface treatment agents in the EU in 2005.

Because of its effects, it can also be used as a pesticide , but such use is not permitted in the EU (not included in Annex I of Directive 91/414 / EEC ). In addition, biphenyl is or was required for the production of pharmaceutical products and polychlorinated biphenyls .

Biphenyl is the basic body for the first commercially successful nematic liquid crystals ( cyanobiphenyls ), which were used in digital watches and pocket calculators in the early 1970s .

Because of the high decomposition temperature in the absence of air, biphenyl is suitable as a heat transfer medium and as a working medium in steam power plants . A eutectic mixture of biphenyl and diphenyl ether has the trade name of Dowtherm A .

safety instructions

Biphenyl is irritating to the skin, eyes and respiratory tract and is harmful to the environment. Biphenyl is hazardous to water (WGK 2) and is suspected of causing cancer.

Biphenyl was included by the EU in 2012 in accordance with Regulation (EC) No. 1907/2006 (REACH) in the context of substance evaluation in the Community's ongoing action plan ( CoRAP ). The effects of the substance on human health and the environment are re-evaluated and, if necessary, follow-up measures are initiated. The reasons for the uptake of biphenyl were concerns about high (aggregated) tonnage and the dangers arising from a possible assignment to the group of PBT / vPvB substances. The re-evaluation took place from 2013 and was carried out by Portugal .


Individual evidence

  1. a b entry on biphenyl. In: Römpp Online . Georg Thieme Verlag, accessed on May 25, 2014.
  2. a b c d e f g h i j k l Entry on biphenyl in the GESTIS substance database of the IFA , accessed on February 18, 2017(JavaScript required) .
  3. European Pharmacopoeia. 6th edition. Deutscher Apotheker Verlag, Stuttgart 2008, ISBN 978-3-7692-3962-1 , p. 543.
  4. Biphenyl data sheet (PDF) from Merck , accessed on March 29, 2017.
  5. David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Physical Constants of Organic Compounds, pp. 3-46.
  6. Entry on biphenyl 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 .
  7. Swiss Accident Insurance Fund (Suva): Limit values ​​- current MAK and BAT values (search for 92-52-4 or biphenyl ), accessed on November 2, 2015.
  8. RD Chirico, SE Knipmeyer, A. Nguyen, WV Steele: The thermodynamic properties of biphenyl. In: J. Chem. Thermodyn. 21, 1989, pp. 1307-1331. doi: 10.1016 / 0021-9614 (89) 90119-5 .
  9. F. Glaser, H. Rüland: Investigations into vapor pressure curves and critical data of some technically important organic substances. In: Chem. Ing. Techn. 29, 1957, pp. 772-775. doi: 10.1002 / cite.330291204 .
  10. ^ GB Cunningham: Diphenyl (C 6 H 5 -C 6 H 5 ). May Solve Reheating Problem. In: Power. 72, 1930, pp. 374-377.
  11. ^ CG Frye: Equilibria in the hydrogenation of polycyclic aromatics. In: J. Chem. Eng. Data. 7, 1962, pp. 592-595. doi: 10.1021 / je60015a048 .
  12. ^ Peter Hahn: Lexicon of food law . 2nd Edition. Behr's Verlag, 1998, ISBN 3-86022-334-8 ( limited preview in Google book search).
  13. DOWTHERM ™ Synthetic Organic Fluids
  14. Community rolling action plan ( CoRAP ) of the European Chemicals Agency (ECHA): Biphenyl , accessed on March 26, 2019.Template: CoRAP status / 2013