(1,1'-Biphenyl)-4,4'-diamine, 3,3'-dichloro-, sulfate (1:2) 3,3'-DICHLOROBENZIDINE SULFATE 3,3'-Dichlorobenzidine dihydrogen bis(sulphate) 3,3'-Dichlorobenzidine sulphate 64969-34-2 EINECS 265-293-1