Patents by Inventor Stephan Kleemann

Stephan Kleemann 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 vinyldiphosphonic acid and salts thereof
    Patent number: 4828766
    Abstract: An improved process for the preparation of vinyldiphosphonic acid is disclosed. The process involves elimination of a volatile acid from a 1-(O-acyl)-ethane-1,1-diphosphonic acid. The starting materials may be prepared by reacting 1-hydroxyethane-1,1-diphosphonic acid with the corresponding acid or directly by reacting the acid with phosphorous acid and an acyl anhydride.
    Type: Grant
    Filed: June 30, 1987
    Date of Patent: May 9, 1989
    Assignee: Benckiser-Knapsack GmbH
    Inventors: Stephan Kleemann, Werner Ehret
  • Process for the production of Maddrell's salt
    Patent number: 4780293
    Abstract: The invention provides a process for the production of Maddrell's salt, wherein solid sodium dihydrogen phosphate and/or disodium dihydrogen pyrophosphate, containing catalytic amounts of an acid or of an acid-generating compound statistically distributed therein, is brought to condensation at an elevated temperature.
    Type: Grant
    Filed: December 1, 1986
    Date of Patent: October 25, 1988
    Assignee: Benckiser-Knapsack GmbH
    Inventors: Stephan Kleemann, Alexander Maurer, Albert Erasmus, Wilhelm Spatz
  • Process for dyeing leathers, water-soluble cationic polymers suitable for that purpose, and process for their preparation
    Patent number: 4775385
    Abstract: The invention relates to water-soluble cationic polymers and to their use in leather dyeing. The polymers preferably have K values of from about 20-45 and are obtained by reacting polyacrylonitrile or acrylonitrile copolymers in the presence of alcohols or polyols, optionally in the presence of a sulfur-containing catalyst.
    Type: Grant
    Filed: August 20, 1986
    Date of Patent: October 4, 1988
    Assignee: Benckiser-Knapsack GmbH
    Inventors: Rudolf Schmidt, Stephan Kleemann, Fritz Wahl