Patents by Inventor Michael Schelhaas

Michael Schelhaas 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 a dinitronaphthalene isomer mixture having an increased proportion of 1,5- dinitronaphthalene
    Patent number: 6420616
    Abstract: The present invention relates to a process for preparing a dinitronaphthalene isomer mixture having an increased proportion of 1,5-dinitronaphthalene by nitrating naphthalene in the presence of at least one ionic liquid.
    Type: Grant
    Filed: November 29, 2000
    Date of Patent: July 16, 2002
    Assignee: Bayer Aktiengesellschaft
    Inventors: Christoph Gürtler, Manfred Jautelat, Michael Schelhaas
  • Process for preparing 4-aminodiphenylamine
    Patent number: 6414192
    Abstract: The invention provides a process for preparing 4-aminodiphenylamine, an important starting product for synthesizing antioxidants and stabilizers in the rubber and polymer industry, by hydrogenating nitrosobenzene with hydrogen in the presence of a proton acid as catalyst and in the presence of a hydrogenating catalyst, optionally in the presence of an inert organic solvent and thermally decomposing the 4-ADPA ammonium salt produced in this way, wherein 4-ADPA is obtained. 4-aminodiphenylamine is produced in good yields and high purity by the process according to the present invention. Furthermore, no effluent is produced, which makes the process particularly economic and ecological.
    Type: Grant
    Filed: November 6, 2001
    Date of Patent: July 2, 2002
    Assignee: Bayer Aktiengesellschaft
    Inventors: Michael Schelhaas, Carl Casser, Dietmar Bielefeldt, Pieter Ooms, Joachim Haider, Manfred Jautelat, Christian Laue, Henry Giera
  • Process for preparing4-aminodiphenylamine
    Publication number: 20020055652
    Abstract: The invention provides a process for preparing 4-aminodiphenylamine, an important starting product for synthesizing antioxidants and stabilizers in the rubber and polymer industry, by hydrogenating nitrosobenzene with hydrogen in the presence of a proton acid as catalyst and in the presence of a hydrogenating catalyst, optionally in the presence of an inert organic solvent and thermally decomposing the 4-ADPA ammonium salt produced in this way, wherein 4-ADPA is obtained.
    Type: Application
    Filed: November 6, 2001
    Publication date: May 9, 2002
    Inventors: Michael Schelhaas, Carl Casser, Dietmar Bielefeldt, Pieter OOms, Joachim Haider, Manfred Jautelat, Christian Laue, Henry Giera
  • Process for producing aliphatic tricarbonitriles
    Publication number: 20020007081
    Abstract: The present invention relates to a process for producing tricarbonitriles corresponding to formula I 1
    Type: Application
    Filed: June 28, 2001
    Publication date: January 17, 2002
    Inventors: Michael Schelhaas, Manfred Jautelat
  • Process for preparing (4-nitro-sophenyl)phenylhydroxylamine
    Patent number: 6166256
    Abstract: The present invention provides a process for preparing (4-nitroso-phenyl)phenyl-hydroxylamine which is characterized in that nitrobenzene is reacted in the presence of hydroxide and/or oxide-containing bases, optionally in the presence of solvents, at temperatures of 20 to 180.degree. C. and pressures of 0.1 to 10 bar.The process according to the invention has the particular advantage that it uses inexpensive and cost-effective nitrobenzene as starting material instead of the nitrosobenzene conventionally used hitherto.
    Type: Grant
    Filed: May 8, 2000
    Date of Patent: December 26, 2000
    Assignee: Bayer Aktiengesellschaft
    Inventors: Henry Giera, Carl Casser, Pieter Ooms, Michael Schelhaas, Christian Laue, Michaela Meiers, Gerhard Braun