Patents by Inventor Bruno Wollemann

Bruno Wollemann 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 preparing N,N-disubstituted p-phenylenediamine derivatives
    Patent number: 4474987
    Abstract: A process for preparing an N,N-disubstituted p-phenylenediamine of the formula ##STR1## wherein R.sup.1 is alkyl of 1-6 C atoms, R.sup.2 is alkyl of 1-6 C atoms or alkyl of 1-6 C atoms which is substituted by OH, lower alkoxy, a sulfo group or an alkylsulfonamido group and R.sup.3 is hydrogen or lower alkylor an acid addition salt thereof,comprises adding an alkyl nitrite, as a nitrosation agent,to an aqueous, acid suspension of the corresponding aniline derivative of the formula ##STR2## thereby forming the corresponding N,N-disubstituted p-nitroso-aniline, and subsequently hydrogenating the latter without isolation thereof from the reaction mixture.
    Type: Grant
    Filed: April 5, 1982
    Date of Patent: October 2, 1984
    Assignee: Merck Patent Gesellschaft mit beschrankter Haftung
    Inventors: Bruno Wollemann, Hartmut Hartner, Hans Bardonner