Patents by Inventor Klaus Thewalt

Klaus Thewalt 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: 4791210
    Abstract: 5-Methyltetrazole can be produced by reacting acetonitrile with an alkali azide or ammonium azide in high purity and a yield of above 98% by using a trialkyl amine as the solvent or suspension agent and by using the associated hydrochloride of the amine as the catalyst.
    Type: Grant
    Filed: October 13, 1987
    Date of Patent: December 13, 1988
    Assignee: Dynamit Nobel Aktiengesellschaft
    Inventors: Gunter Bison, Johannes Schlupp, Josef Winterscheid, Klaus Thewalt
  • Patent number: 4754079
    Abstract: A safe production of sodium nitro-1,3-propanediol from a reaction solution of nitromethane and paraformaldehyde in methanol by addition of sodium methylate is achieved by evaporative cooling of the methanol; it being possible to maintain reaction temperatures of 35.degree. C. to 50.degree. C.
    Type: Grant
    Filed: March 23, 1987
    Date of Patent: June 28, 1988
    Assignee: Dynamit Nobel AG
    Inventors: Gunter Bison, Hans Leuck, Klaus Thewalt, Hans-Jorg Westerman
  • Patent number: 4652671
    Abstract: It is suggested to produce 5-chloro-1H-tetrazolecarboxylic acid esters by reaction of dichloroisonitriloacetic acid esters with alkali or metal azides or ammonium azide.The dichloroisonitriloacetic acid esters required for this purpose are formed by reacting N-formylaminocarboxylic acid esters with chlorine or with compounds which split off chlorine.
    Type: Grant
    Filed: September 12, 1985
    Date of Patent: March 24, 1987
    Assignee: Dynamit Nobel Aktiengesellschaft
    Inventors: Gunter Bison, Norbert Linkat, Klaus Thewalt
  • Patent number: 4448999
    Abstract: 2-Aminopropanediol-1,3 (serinol) can be prepared by hydrogenation of the alkali salt of 2-nitro-1,3-propanediol with assuredly high yields by maintaining a narrow range of temperatures of extending from 50.degree.-80.degree. C. by use of a cooling device.
    Type: Grant
    Filed: July 30, 1982
    Date of Patent: May 15, 1984
    Assignee: Dynamit Nobel Aktiengesellschaft
    Inventors: Klaus Thewalt, Gunter Bison, Heinz Egger
  • Patent number: 4289895
    Abstract: Oligomeric alkylene terephthalates having an average degree of condensation of 4 to 7 are produced by passing dimethylterephthalate and diol having at least 3 carbon atoms downwardly through a series of reaction chambers, each outfitted with stirring and heating means employed so that the temperature increases from stage to stage. Thereby transeterification is effected. The chambers are interconnected so that the methanol evolved in each chamber is vented without being admixed with the material undergoing transesterification in any of the other chambers. The transesterification product is then condensed at elevated temperature and under vacuum to produce the oligomer. The oligomers are high reactivity so that the further condensation thereof to polyesters is simplified.
    Type: Grant
    Filed: August 13, 1979
    Date of Patent: September 15, 1981
    Assignee: Dynamit Nobel Aktiengesellschaft
    Inventors: Rudolf Burkhardt, Gunther Meyer, Reinhard Schmidt, Klaus Thewalt
  • Patent number: 4138544
    Abstract: An improvement in the method of preparing a linear polycondensate of high molecular weight wherein a precondensate is initially formed and thereafter subjected to a one-step melt condensation in a vacuum while cleavage products are removed therefrom, the reaction mass being exposed in a thin layer by means of a stirrer to the reaction conditions, the improvement residing in employing as the precondensate a molten precondensate having an average condensation degree of at least 3, said precondensate being introduced into the melt condensation zone continuously while the cleavage products are driven off at the particular optimum, product-specific condensation temperature, the contents of the melt condensation zone being subjected to the action of a rotary stirrer until the melt has a melt viscosity of 1000 to 15000 poises and continuously withdrawing molten polycondensate in accordance with the speed of the reaction.
    Type: Grant
    Filed: December 16, 1976
    Date of Patent: February 6, 1979
    Assignee: Dynamit Nobel Aktiengesellschaft
    Inventors: Paul Janssen, deceased, Gunther Meyer, Klaus Thewalt, Reinhard Schmidt