Patents by Inventor Pierre Pessonneaux

Pierre Pessonneaux has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Preparation of cationic azo or hydrazone dyes in which the alkylation and the separation of the cationic dye are carried out continuously
    Patent number: 4925926
    Abstract: The invention relates to a continuous process for the preparation of cationic azo or hydrazone dyes from heterocyclic diazo components and coupling components. The diazo component is diazotised in water and an acid, the diazo solution is coupled with the coupling component and continuously alkylated, preferably using sufficient acid that, after the alkylation, a two-phase system forms, consisting of an aqueous solution which is substantially free from dye and a highly concentrated oil phase or solid dye.
    Type: Grant
    Filed: December 7, 1987
    Date of Patent: May 15, 1990
    Assignee: Ciba-Geigy Corporation
    Inventors: Roland Ronco, Ermanno Ciapponi, Pierre Pessonneaux