Patents by Inventor Otto Arndt

Otto Arndt 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 preparation of isomer-free toluene-4-sulfonic acid
    Patent number: 4242275
    Abstract: Pure toluene-4-sulfonic acid is obtained without forming any by-products by sulfonating toluene with sulfuric acid at an elevated temperature, separating a first batch of toluene-4-sulfonic acid hydrate, washing it free of isomers with sulfuric acid, combining the mother liquor and the washing effluent, heating them, allowing a second batch of hydrate to crystallize and, optionally, working up the final mother liquor by hydrolizing the toluene sulfonic acids therein and recycling the toluene so formed and the sulfuric acid after concentrating it to its initial strength.
    Type: Grant
    Filed: December 5, 1979
    Date of Patent: December 30, 1980
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Otto Arndt, Bernhard Mees