Patents by Inventor Stefan Deibert

Stefan Deibert 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 of recovering .epsilon.-caprolactam from PA-6 synthesis extract water
    Patent number: 6093788
    Abstract: The invention comprises a process of producing .epsilon.-caprolactam from extract water of polycaprolactam obtained by hydrolytic polymerization, wherein(i) the extract water is concentrated by distillation of water,(ii) from the concentrated extract water from stage (i) an extract of .epsilon.-caprolactam and oligomers including dimers is obtained by separating an .epsilon.-caprolactam/water vapor mixture,(iii) the extract from stage (ii) is depolymerized in the presence of a catalyst and superheated steam, where a vapor mixture of .epsilon.-caprolactam and water is obtained, and(iv) from the .epsilon.-caprolactam/water vapor mixtures of process stages (ii) and (iii) .epsilon.-caprolactam with a dimer content of .ltoreq.0.2 wt-% is obtained by distillation of water.
    Type: Grant
    Filed: October 9, 1998
    Date of Patent: July 25, 2000
    Assignee: Lurgi Zimmer Aktiengesellschaft
    Inventors: Claus Born, Stefan Deibert, Jurgen Schiwek, Konrad Wolf