Example 4: Preparation of compound (III-1)
160 g of N,N,N',N'-tetrakis(p-nitrophenyl)p-phenylenediamine (II-1), 1.07 g of ferric chloride (III) hexahydrate, 1.55 g of iron (III) oxide, 16.2 g of activated carbon and 1400 ml of 1 -methyl-2-pyrrolidinone were added into a three-necked flask and heated under stirring to an internal temperature of 100 °C. Subsequently, 450 g of 80% hydrazine monohydrate aqueous solution was slowly added dropwise, the reaction temperature was maintained in the range of 100-110 °C, and the reaction was continuously stirred for 5 hours. Upon completion of the reaction, it was cooled to room temperature. The reaction mixture was filtered to remove the activated carbon, followed by the sequential dropwise addition of 800 ml of methanol and 1200 ml of water to the filtrate, and the precipitated crystals were collected by filtration by pumping to afford 126.3 g of N1,N1'-(1,4-phenylene)bis(N1-(4-aminophenyl)benzene-1,4-diamine (III-1) in 99% yield. Spectral analysis of the product showed M/e = 472.
