Patents by Inventor Gerd Dumbgen

Gerd Dumbgen 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).

  • Continuous isolation of phthalic anhydride and maleic anhydride from reaction gases
    Patent number: 4568427
    Abstract: A process for the continuous isolation of phthalic anhydride and maleic anhydride from the reaction gases obtained by catalytic oxidation of o-xylene or naphthalene with air, wherein the reaction gases are treated with a hydrocarbon of boiling range from 115.degree. to 175.degree. C. as the solvent in a column, and are then treated with an organic solvent of boiling range from 180.degree. to 290.degree. C. in a second column, the phthalic anhydride and maleic anhydride being isolated from the liquid bottom product of the first column.
    Type: Grant
    Filed: February 11, 1983
    Date of Patent: February 4, 1986
    Assignee: BASF Aktiengesellschaft
    Inventors: Eckehard Danz, Gerd Dumbgen, Ernest Miesen, Johannes E. Schmidt, Friedrich Wirth