Patents by Inventor John G. Lee

John G. Lee 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 production of 4-nitrotoluene-2-sulfonic acid
    Patent number: 4922008
    Abstract: A process for the preparation of 4-nitrotoluene-2-sulfonic acid by sulfonating 4-nitrotoluene with oleum or liquid SO.sub.3 is described. The sulfonation is carried out continuously with oleum of at least 50% concentration or liquid 100% SO.sub.3 while keeping the conversion of 4-nitro-toluene in the reaction mixture at .gtoreq.90% during the entire reaction course.The process is inherently non-polluting, and provides the product in high yield and low sulfuric acid content in a form usable for 4,4'-dinitrostilbene-2,2'-disulfonic acid production without further purification.
    Type: Grant
    Filed: April 29, 1987
    Date of Patent: May 1, 1990
    Assignee: Ciba-Geigy Corporation
    Inventors: Gottfried Seifert, Sebastian Staubli, Josef H. Wieland, Willy Regenass, Martin Buerli, John G. Lee, Richard B. Lund