Patents by Inventor Hans-Joachim Laakmann

Hans-Joachim Laakmann 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).

  • Patent number: 5763641
    Abstract: In a process, improved in respect of yield, purity and simple procedure, for the preparation of aromatic methoxycarboxylic acid methyl esters by methylation of the corresponding aromatic hydroxycarboxylic acids with dimethyl sulfate in the presence of water and a base, a procedure is followed in which the water, base and aromatic hydroxycarboxylic acid are initially introduced into the reaction vessel, 1 to 2.5 times the molar amount of dimethyl sulfate (based on the methylatable hydroxyl and carboxyl groups) is metered in and, during this procedure, the pH of the reaction mixture is controlled by addition of an aqueous base in finely divided form.
    Type: Grant
    Filed: January 17, 1997
    Date of Patent: June 9, 1998
    Assignee: Bayer Aktiengesellschaft
    Inventors: Willi Streicher, Hans-Joachim Laakmann
  • Patent number: 4946653
    Abstract: Particulate material is discharged continuously from fluidized bed reactors by passing the material emerging at the lowest point of the fluidized bed through a zone which is narrower than the fluidized bed and in which a gas stream flows counter-current to the material, the pressure of the gas stream being above the pressure of the fluidized zone.
    Type: Grant
    Filed: February 1, 1983
    Date of Patent: August 7, 1990
    Assignee: Bayer Aktiengesellschaft
    Inventors: Gerhard Stopp, Karl-Heinz Kreutzer, Horst Karkossa, Karl Mannes, Hans-Joachim Laakmann, Viktor Trescher