6.
    发明专利
    未知

    公开(公告)号:BR7600563A

    公开(公告)日:1976-08-31

    申请号:BR7600563

    申请日:1976-01-29

    Applicant: HOECHST AG

    Inventor: LANDLER J WORFEL E

    Abstract: A new and very advantageous Process had been found for the preparation of azo dyestuffs by diazotation and coupling in which the synthesis is carried out without the hitherto usual addition of an acid, with the proviso that at least one of the diazo and coupling components contains at least one acid group. Besides the saving of reaction material and subsequently of alkali for neutralization of the reaction medium and isolation of the dyestuff, highly concentrated solutions of the dyestuff and salt-free or practically salt-free dyestuffs can be obtained, and waste-water is no longer charged with big amounts of salts.

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