Patents by Inventor Volker Hautzel

Volker Hautzel 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: 5312976
    Abstract: 2-Hydroxy-naphthalene-6-carboxylic acid or its dipotassium salt is obtained in a good yield and purity without substantial formation of the isomeric compound 2-naphthol-3-carboxylic acid by reacting potassium .beta.-naphtholate with potassium carbonate in the presence of carbon monoxide at a temperature above 260.degree. C. in potassium formate as the solvent.
    Type: Grant
    Filed: July 31, 1992
    Date of Patent: May 17, 1994
    Assignee: Hoechst Aktiengesellschaft
    Inventors: Volker Hautzel, Siegbert Rittner
  • Patent number: 5136083
    Abstract: The present invention relates to a process for the purification of 4-acetoxystyrene from a crude product mixture comprising 4-acetoxystyrene and typically 5 or more contaminants in substantial amount.The crude product mixture is purified by melt crystallization by cooling the mixture to a temperature ranging from about +8.degree. C. to about -50.degree. C., whereby at least a first portion of the mixture is crystallized; removing the liquid remaining from contact with the crystallized first portion of the mixture; and, subsequently slowly heating the crystallized first portion, while simultaneously removing liquid which forms due to the heating, whereby impurities contained in the liquid which forms are removed from the crystallized first portion.Surprisingly, despite the large number of contaminants present, and use of the process to purify crude product mixtures containing as little as 50% by weight 4-acetoxystyrene, purities as high as 99.
    Type: Grant
    Filed: August 30, 1990
    Date of Patent: August 4, 1992
    Assignee: Hoechst Celanese Corporation
    Inventors: Jack Chosnek, George E. Beck, Donna L. Keene, Siegbert Rittner, Volker Hautzel