.alpha.,.alpha.'-Bi-p-toluidine 1,2-Bis(4-Aminophenyl)ethane 1,2-Bis(p-aminophenyl)ethane 4,4'-Diaminobibenzyl 621-95-4 Aniline, 4,4'-ethylenedi- Benzenamine, 4,4'-(1,2-ethanediyl)bis- NSC580