Patents by Inventor Walter Hohmann

Walter Hohmann 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 producing 1,5-dinitroanthraquinone and 1,8-dinitroanthraquinone
    Patent number: 3963762
    Abstract: Substantially pure 1,5- and/or 1,8-dinitroanthraquinone is recovered from dinitration mixtures which may contain sulfuric acid or a perfluoralkane sulfonic acid by adjusting the nitric acid concentration in the nitration mixture to a value of 91 to 96% for a ratio by weight of nitric acid to solids of from 2.5 : 1 to 10 : 1; separating off the insoluble crude 1,5-dinitroanthranthraquinone at 15.degree. to 50.degree.C; taking up the 1,5-dinitroanthraquinone with 90 to 100% nitric acid in a ratio by weight of nitric acid to solids of from 0.5 : 1 to 3.5 : 1; stirring at 15.degree. to 80.degree. C; separating off the insoluble pure 1,5-dinitroanthraquinone thus obtained; adjusting the mother liquid left following separation of the crude 1,5-dinitroanthraquinone to a nitric acid concentration of from 88 to 94% for a ratio by weight of nitric acid to solids of from 3.0 : 1 to 12 : 1, with the proviso that the nitric acid concentration is at least 1.
    Type: Grant
    Filed: October 10, 1974
    Date of Patent: June 15, 1976
    Assignee: Bayer Aktiengesellschaft
    Inventor: Walter Hohmann