| 摘要 |
The production which is customary in practice of monoazo compounds based on dichloro- and trichloroanilines or disazo compounds of the chlorinated biphenyl series by conventional coupling methods meets with difficulties in that the resulting pigments are contaminated by traces of polychlorinated biphenyls. According to the invention, it has now been found that by addition of water-soluble olefins of the type (see above formula) (R=H, C1-C4-alk or C1-C4-Oalk; X = -COOR1, -CONHR2,or -NR3COR4, wherein R1 is hydrogen or optionally substituted C1-C4-alkyl, R2 is hydrogen or optionally substituted C1-C4-alkyl, R3 is hydrogen or C1-C4-alkyl and R4 is C1-C4-alkyl) in the azo coupling, the side reactions which form PCBs can be decidedly suppressed during synthesis of the pigments.
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