Patents by Inventor Manfred Hetschko

Manfred Hetschko 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).

  • Process for the manufacture of a violet organic pigment, C.I. Pigment Violet 23
    Patent number: 4345074
    Abstract: In the process for the manufacture of the organic pigment of the formula ##STR1## by condensing and cyclizing 3-amino-9-ethylcarbazole with excess tetrachlorobenzoquinone in an organic solvent in the presence of acid acceptors, the improvement comprises carrying out the condensation reaction in the presence of 0.1 to 4% of water, relative to the total weight of the reaction mixture.
    Type: Grant
    Filed: March 16, 1981
    Date of Patent: August 17, 1982
    Assignee: Cassella Aktiengesellschaft
    Inventors: Theobald Hufnagel, Manfred Hetschko