Method of preparing 4-aminodiphenylamine

A method of producing 4-ADPA is disclosed wherein aniline or substituted aniline derivatives and nitrobenzene are reacted under suitable conditions to produce 4-nitrodiphenylamine or substituted derivatives thereof and/or 4-nitrosodiphenylamine or substituted derivatives thereof and/or their salts, either or both of which are subsequently reduced to produce 4-ADPA or substituted derivatives thereof. The 4-ADPA or substituted derivatives thereof can be reductively alkylated to produce p-phenylenediamine products or substituted derivatives thereof which are useful as antiozonants. A second embodiment of the invention is the tetrasubstituted ammonium salts or alkyl substituted diammonium salts of 4-nitrodiphenylamine, 4-nitrosodiphenylamine and the substituted derivatives thereof wherein each substituent of the tetrasubstituted ammonium ion is independently selected from the group consisting of alkyl, aryl and arylalkyl groups and each alkyl substituent of the alkyl substituted diammonium salt is independently selected.