Patents by Inventor Klaus Herbig

Klaus Herbig 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).

  • Method for producing 4-amino-5-chloro-1-phenyl pyridazinone-(6)
    Patent number: 6538135
    Abstract: In a process for preparing 4-amino-5-chloro-1-phenylpyridazin-6-one by reacting 4,5-dichloro-1-phenylpyridazin-6-one with aqueous ammonia in the presence of a catalyst, the catalyst used is soluble in the aqueous alkaline reaction medium but is essentially insoluble in the reaction medium which has been acidified after removal of the 4-amino-5-chloro-1-phenylpyridazin-6-one. The process of the present invention makes it possible for the catalyst to be recovered and reused in a simple manner.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: March 25, 2003
    Assignee: BASF Aktiengesellschaft
    Inventors: Hans Rupert Merkle, Klaus Herbig, Erich Fretschner, Helmut Fröhlich