Patents by Inventor Wolf Weidemuller

Wolf Weidemuller 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).

  • Preparation of azo dyestuffs by diazotization and coupling in the presence of an ester
    Patent number: 4795807
    Abstract: Azo disperse dyestuffs are prepared by diazotization and coupling in an aqueous phase, the coupling being carried out in the presence of an ester of a lower aliphatic carboxylic acid.
    Type: Grant
    Filed: March 30, 1987
    Date of Patent: January 3, 1989
    Assignee: Cassella Aktiengesellschaft
    Inventors: Ulrich Buhler, Friedrich Schophoff, Wolf Weidemuller
  • Sulphur dyestuffs of the carbazole series
    Patent number: 4360459
    Abstract: Carbazoleazomethines are prepared and sulfur dyestuffs are prepared by sulphurizing a carbazoleazomethine of the formula ##STR1## wherein R.sup.1 is hydrogen, hydroxyl, halogen, nitro, alkyl having 1 to 8 carbon atoms, alkoxy having 1 to 8 carbon atoms, dialkylamino having 1 to 4 carbon atoms per alkyl, alkanoyloxy having 1 to 8 carbon atoms, benzoyloxy, alkanoylamino having 1 to 8 carbon atoms or benzoylamino;R.sup.2 is hydrogen, hydroxyl, halogen, alkyl having 1 to 8 carbon atoms or alkoxy having 1 to 8 carbon atoms;R.sup.3 is hydrogen or alkyl having 1 to 7 carbon atoms;R.sup.4 is hydrogen or halogen; andR.sup.5 is hydrogen or alkyl having 1 to 8 carbon atoms.
    Type: Grant
    Filed: April 6, 1981
    Date of Patent: November 23, 1982
    Assignee: Cassella Aktiengesellschaft
    Inventors: Steffen Piesch, Wolf Weidemuller
  • Process for the preparation of derivatives of 3-(4-hydroxy-anilino)carbazole
    Patent number: 4320060
    Abstract: The process for the preparation of a 3-(4-hydroxyanilino)carbazole of the formula ##STR1## wherein R is hydrogen, alkyl having 1 to 8 carbon atoms or halogenoalkyl having 1 to 8 carbon atoms, comprising reacting a 3-aminocarbazole of the formula ##STR2## with p-hydroquinone or p-aminophenol or a mixture of p-hydroquinone and p-aminophenol in at least stoichiometric amounts by heating to a temperature of 150.degree. to 300.degree. C. with exclusion of oxygen.
    Type: Grant
    Filed: December 31, 1979
    Date of Patent: March 16, 1982
    Assignee: Cassella Aktiengesellschaft
    Inventors: Steffen Piesch, Friedrich Engelhardt, Herbert Wille, Wolf Weidemuller, Artur Meyer
  • Process for isolating sulphur dyestuffs from aqueous crude melts containing sodium polysulphide
    Patent number: 4309178
    Abstract: In the processs for isolating solid sulphur dyestuffs from crude sulphur dyestuff melts, the improvement comprises adding 10.sup.-4 to 1% by weight, relative to the amount of dyestuff, of an organic flocculating auxiliary to the crude dyestuff melt to produce a filterable dyestuff precipitate and then separating said precipitate.
    Type: Grant
    Filed: October 17, 1980
    Date of Patent: January 5, 1982
    Assignee: Cassella Aktiengesellschaft
    Inventors: Georg Daniek, Artur Meyer, Wolf Weidemuller