Patents by Inventor Petrus J. H. Thomissen

Petrus J. H. Thomissen 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).

  • Depolymerization of polyamides
    Patent number: 6087494
    Abstract: Process for the depolymerization of one or more polyamides into its monomeric components in the presence of water by means of at least one alkali metal compound, at least one alkaline-earth metal compound or a combination thereof. The depolymerization takes place at a pressure of between 0.2 and 2.0 MPa, so that high conversions are achieved and the depolymerization reaction proceeds faster, even in the presence of a high content of cyclic oligomers.
    Type: Grant
    Filed: April 29, 1998
    Date of Patent: July 11, 2000
    Assignee: DSM N.V.
    Inventor: Petrus J. H. Thomissen
  • Process for preparing a lactam
    Patent number: 5571913
    Abstract: The invention relates to a process for preparing a lactam from an alicyclic ketoxime in the presence of a lactim-O-sulphonic acid and a solvent, the reaction being carried out in the presence of an acid cation exchanger. The invention relates in particular to a process in which the alicyclic ketoxime is represented by the following general formula: ##STR1## where R is a linear or branched alkylidene group containing from 3 to 20 carbon atoms.
    Type: Grant
    Filed: August 19, 1994
    Date of Patent: November 5, 1996
    Assignee: DSM N.V.
    Inventor: Petrus J. H. Thomissen
  • Process for treating amides
    Patent number: 5227028
    Abstract: A process of treating a ketoxime or aldoxime-containing amide mixture resulting from a Beckmann rearrangement of the corresponding ketoxime or aldoxime. The process involves hydrolysis of the mixture to remove the remaining ketoxime or aldoxime which are converted to the corresponding ketone or aldehyde and then separated off from the mixture. Any amino acid resulting from the hydrolysis can be reconverted to the corresponding amide by raising the temperature of the mixture.
    Type: Grant
    Filed: July 3, 1991
    Date of Patent: July 13, 1993
    Assignee: DSM N.V.
    Inventors: Hubertus J. M. Bosman, Paul C. Van Geem, Petrus J. H. Thomissen
  • Process for the preparation of cyclohexyl cyclohexanone
    Patent number: 4484005
    Abstract: Disclosed is a process for the preparation of cyclohexyl cyclohexanone (CHA). Cyclohexanone is self-condensed to yield a mixture of cyclohexylidene cyclohexanone (CHDA), water, and unconverted cyclohexanone. The CHDA in the mixture is directly hydrogenated to CHA under an atmosphere of hydrogen and in the presence of a suitable catalyst, the presence of water and cyclohexanone not affecting the reaction. The CHA may be separated from the other components by, for example, fractional distillation following the hydrogenation.
    Type: Grant
    Filed: February 14, 1983
    Date of Patent: November 20, 1984
    Assignee: Stamicarbon B.V.
    Inventor: Petrus J. H. Thomissen