Patents by Inventor Herbert Mauser

Herbert Mauser 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 preparation of azo dyes
    Patent number: 5606034
    Abstract: The invention discloses a process for the preparation of azo dyes using an aminodiphenylamine as diazo component. The process comprises reacting the amine, an alkali metal nitrite and a mineral acid continuously in the temperature range from 35.degree. to 65.degree. C. to give the diazo compound, using a 3 to 15% excess of alkali metal nitrite, and thereafter coupling the diazo compound to a coupling component. Azo dyes of superior quality constancy and in high yield are obtained by the novel process.
    Type: Grant
    Filed: February 16, 1995
    Date of Patent: February 25, 1997
    Assignee: Ciba-Geigy Corporation
    Inventors: Horst Langfeld, Karl-Friedrich Haarburger, Herbert Mauser