Diphenylamine is the organic compound with the formula (C6H5)2NH. It is a colourless solid, but samples are often yellow due to oxidized impurities.
Preparation and reactivity
Diphenylamine is manufactured by the thermal deamination of aniline
over oxide catalysts
- 2 C6H5NH2 → (C6H5)2NH + NH3
It is a weak base, with a KB
. With strong acids, it forms the water soluble salt.
Diphenylaniline itself has few applications but its derivatives are more useful. Ring-alkylated derivatives of diphenylamine are used as "antiozinates" in the manufacture of rubber products, reflecting the antioxidant nature of aniline derivatives. The compound undergoes various cyclisaton reactions. With sulfur
, it gives phenothiazine
, a precursor to certain pharmaceuticals.
- (C6H5)2NH + 2 S → S(C6H4)2NH + H2S
With iodine, it cyclises to carbazole
- (C6H5)2NH + I2 → (C6H4)2NH + 2 HI
Arylation with iodobenzene
Diphenylamine, like other arylamines, is toxic. Exposure is highly regulated in most countries. See MSDS.