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Structural formula
Structure of diphenylamine
Surname Diphenylamine
other names
  • N -phenylaniline
  • N- phenylaminobenzene
Molecular formula C 12 H 11 N
Brief description

colorless, leafy crystals with a faint floral odor

External identifiers / databases
CAS number 122-39-4
EC number 204-539-4
ECHA InfoCard 100.004.128
PubChem 11487
ChemSpider 11003
Wikidata Q412265
Molar mass 169.23 g mol −1
Physical state



1.16 g cm −3

Melting point

53 ° C

boiling point

302 ° C

Vapor pressure

0.33 Pa at 20 ° C

  • very bad in water (40 mg l −1 at 20 ° C)
  • Easily soluble in ethanol and acids
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary
06 - Toxic or very toxic 08 - Dangerous to health 09 - Dangerous for the environment


H and P phrases H: 301 + 311 + 331-373-410
P: 273-280-302 + 352-304 + 340-308 + 310

Switzerland: 10 mg m −3 (measured as inhalable dust )

Toxicological data

1120 mg kg −1 ( LD 50ratoral )

As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Diphenylamine or N-phenylaniline is an aromatic organic compound with the empirical formula C 12 H 11 N. It belongs to the class of secondary amines .


Diphenylamine occurs as a natural substance in onions , black and green tea and in peel of citrus fruits .


Diphenylamine is produced industrially by the oxide-catalyzed deamination of aniline .


Physical Properties

Diphenylamine forms colorless to gray, light-sensitive, leafy crystals with a floral odor.

Chemical properties

Diphenylamine is a redox indicator . A color change takes place between the oxidized form (blue-violet) and the reduced form (colorless).

Diphenylamine can react thermally or photochemically to form carbazole through oxidative intramolecular ring closure .

As an aromatic amine , diphenylamine reacts as a weak base , but it can also be deprotonated by strong bases to form the ( mesomeric-stabilized ) diphenylamide anion .


Diphenylamine is used as a fungicide in agriculture . Diphenylamine inhibits the oxidation of the terpene α- farnese . It played an important role in combating peel tan . No plant protection products containing this active ingredient are permitted in the EU or Switzerland .

Diphenylamine is used to detect nitrite , nitrate and chlorate ions . It is dimerized to tetraphenylhydrazine , which then undergoes a benzidine rearrangement and is oxidized to a colored quinoid system ( quinonimine dye ). This detection reaction is used in the paraffin test , with which the use of firearms can be proven.

Diphenylamine (DPA) is one of the most widely used stabilizers for gunpowder . Its task is to intercept nitrous gases (NO x ) and acidic components. It was therefore initially used in the manufacture of ballistite . It is converted into N -nitrosodiphenylamine, which is suspected to be a carcinogen . DPA is incompatible with nitroglycerin (NG). Other stabilizers ( Centralit , 2-Nitro-DPA or Akardit ) are used from a nitroglycerin content of 20% (often even below) . DPA is also incompatible with potassium nitrate .

It can also be used in the production of dyes (such as Acid Yellow 36 , Acid Yellow 63 and Acid Orange 5 ) and in rubber production as an antioxidant and vulcanization accelerator.

Diphenylamine is also suitable for stabilizing ethers .

Diphenylamine with concentrated sulfuric acid in glacial acetic acid ( Dische reagent ) reacts with deoxyribose when heated to form a blue dye.

Arylation with iodobenzene leads to triphenylamine .

Pharmacological importance

Tricyclic diphenylamine derivatives were used as antidepressants from the 1960s . Diphenylamine has a strong blood sugar lowering effect.

safety instructions

Diphenylamine is toxic if inhaled, swallowed and on contact with skin. There is a risk of cumulative effects. Local irritation of the skin, eyes and airways occurs on contact. Skin absorption is low. Methaemoglobin formation occurs after absorption of large quantities .

If absorbed into the body, irreversible serious damage to health up to and including death is to be expected. Therefore any contact with the human body must be avoided.

Diphenylamine must not be brought into contact with hexachloromelamine , trichloromelamine and oxidizing agents . In the event of a fire, dangerous decomposition products such as nitrous gases and amines occur .

Diphenylamine should be stored under protection from light because of the photochemical formation of carbazole. Protective gloves offer short-term dust protection.

Web links

Individual evidence

  1. a b entry on diphenylamine. In: Römpp Online . Georg Thieme Verlag, accessed on March 20, 2014.
  2. a b c d e f g h i j Entry on diphenylamine in the GESTIS substance database of the IFA , accessed on July 23, 2016(JavaScript required) .
  3. Entry on Diphenylamine in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on August 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
  4. Swiss Accident Insurance Fund (Suva): Limit values ​​- current MAK and BAT values (search for 122-39-4 or diphenylamine ), accessed on November 2, 2015.
  5. Oliver Drzyzga: Environmental relevance of diphenylamine - a substance of the 3rd EU list of existing substances. In: Environmental sciences and pollutant research 11 (6): 365-373, November 1999, DOI: 10.1007 / BF03037729. Retrieved June 5, 2020 .
  6. Alanwood
  7. FE Huelin, IM Coggiola: Superficial scald, a functional disorder of stored apples. V. - Oxidation of α-farnesene and its inhibition by diphenylamine . In: Journal of the Science of Food and Agriculture . tape 21 , no. 1 , January 1970, p. 44-48 , doi : 10.1002 / jsfa.2740210113 ( PDF ).
  8. ↑ Peeling tan - prevention without diphenylamine (DPA)
  9. ^ Directorate-General for Health and Food Safety of the European Commission: Entry on diphenylamines in the EU pesticide database; Entry in the national registers of plant protection products in Switzerland , Austria and Germany ; accessed on March 26, 2016.
  10. Data sheet from Lanxess , accessed on October 13, 2018.
  11. FD Hager: Triphenylamine In: Organic Syntheses . 8, 1928, p. 116, doi : 10.15227 / orgsyn.008.0116 ; Coll. Vol. 1, 1941, p. 544 ( PDF ).
  12. Gustav Ehrhart / Heinrich Ruschig : Arzneimittel , 1968, page 446 f.