Patents
The invention relates to a for the preparation of pure high quality 3,3', 4,4'-tetraminobiphenyl (TAB) in high yields. The invention also discloses a for the preparation of 3,3',4,4' tetraminobiphenyl (TAB) comprising a three step: (1) oxidation 3,3'-dichloro 4,4'-diaminobiphenyl (DCB) with 50% aq. H2O2, (2) ammonolysis of the resulting 3,3'-dinitro 4,4'-dinitrobiphenyl (DCDNB) and (3) reduction of 3,3'-diamino-4,4'-dinitrobiphenyl (DADNB) with stannous chloride and concentrated hydrochloric acid.