Patents by Inventor Jurgen Dahmer

Jurgen Dahmer 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 continuous production of aryl carbonates
    Patent number: 5831111
    Abstract: The present invention relates to a process for the continuous production of carbonates having aromatic ester groups by reacting aromatic hydroxy compounds with phosgene in the gas phase in the presence of heterogeneous catalysts.
    Type: Grant
    Filed: May 5, 1997
    Date of Patent: November 3, 1998
    Assignee: Bayer AG
    Inventors: Pieter Ooms, Eric Bischof, Hans-Josef Buysch, Steffen Kuhling, Gottfried Zaby, Wolfgang Jakob, Jurgen Dahmer, Norbert Schon
  • Process for the preparation of 2-methyl-2,4-diaminopentane
    Patent number: 5801285
    Abstract: The present invention relates to a process for preparing 2-methyl-2,4-diaminopentane by introducing acetone, ammonia and hydrogen into a two-zone reactor at a temperature of 20.degree. to 130.degree. C. and a pressure of 30 to 250 bar, wherein the first zone contains a cationic exchange resin containing NH.sub.4.sup..sym. groups or an aluminum oxide and/or silicon oxide catalyst and the second zone contains a hydrogenation catalyst containing nickel.
    Type: Grant
    Filed: October 31, 1997
    Date of Patent: September 1, 1998
    Assignee: Bayer Aktiengesellschaft
    Inventors: Helmut Waldmann, Jurgen Dahmer, Anatoly Bazanov, Alexandre Timofeev, Natalja Zubritskaya, Gennady Terechtchenko
  • Process for the preparation of 1,4-bis(aminomethyl) cyclohexane
    Patent number: 5789620
    Abstract: The present invention relates to a process for preparing 1,4-bis(aminomethyl)cyclohexane by reacting a 40 to 80 wt. % aqueous solution of 1,4-bis(hydroxymethyl)cyclohexane with a mixture of hydrogen and ammonia in the presence of a nickel/copper/chromium catalyst at a pressure of 100 to 250 bar and a temperature of 150.degree. to 250.degree. C.
    Type: Grant
    Filed: October 31, 1997
    Date of Patent: August 4, 1998
    Assignee: Bayer Aktiengesellschaft
    Inventors: Helmut Waldmann, Jurgen Dahmer, Klaus Nachtkamp, Anatoly Bazanov, Alexandre Timofeev, Natalja Zubritskaya, Gennady Terechtchenko
  • Process for thermally cracking carbamic acid esters
    Patent number: 5731458
    Abstract: This present invention relates to a process for thermally cracking carbamic acid esters into the corresponding isocyanate and hydroxyl compounds in the liquid phase, wherein the reaction proceeds as a reactive rectification in the stripping zone of a column and in an inert, high-boiling solvent, which acts as a buffer to keep the reaction away from the evaporator region of the column.
    Type: Grant
    Filed: March 6, 1997
    Date of Patent: March 24, 1998
    Assignee: Bayer Aktiengesellschaft
    Inventors: Jurgen Dahmer, Dieter Schleenstein, Heinrich Steude, Oswald Wilmes, Christian Rasp, Georg Ronge, Klaus Nachtkamp, Wilfried Litz, Stephan Kabelac
  • Process for removing by-products from diurethanes
    Patent number: 5646328
    Abstract: Low-boiling by-products are removed from diurethanes prepared by a phosgene-free process by carrier vapor distillation using alcohol vapor, preferably the vapor of the basic alcohol found in the diurethane, as the carrier vapor. The diurethanes freed of low-boiling by-products in this manner may be thermally decomposed to produce diisocyanates.
    Type: Grant
    Filed: June 20, 1996
    Date of Patent: July 8, 1997
    Assignee: Bayer Aktiengesellschaft
    Inventors: Ludwig Deibele, Oswald Wilmes, Jurgen Dahmer
  • Process for the production of diisocyanates
    Patent number: 5516935
    Abstract: Diisocyanates are produced by gas-phase phosgenation of aliphatic diamines having two primary amino groups in the 1,2- or 1,3-position to one another or by cycloaliphatic diamines having two primary amino groups in the 1,2- or 1,3-position to one another.
    Type: Grant
    Filed: March 30, 1995
    Date of Patent: May 14, 1996
    Assignee: Bayer Aktiengesellschaft
    Inventors: Eric Bischof, Peter Briedenbach, Jurgen Dahmer, Andreas Flink, Attila Molnar, Herbert Stutz