Patents Examined by Floyd D. Hegel
  • Preparation of azo dyestuffs by diazotization and coupling in the presence of an ester
    Patent number: 4795807
    Abstract: Azo disperse dyestuffs are prepared by diazotization and coupling in an aqueous phase, the coupling being carried out in the presence of an ester of a lower aliphatic carboxylic acid.
    Type: Grant
    Filed: March 30, 1987
    Date of Patent: January 3, 1989
    Assignee: Cassella Aktiengesellschaft
    Inventors: Ulrich Buhler, Friedrich Schophoff, Wolf Weidemuller