Patents by Inventor Stefan Westernacher

Stefan Westernacher 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).

  • Method for producing and purifying 3-(4-Hydroxyphenyl)-1, 1,3-trimethylindan-5-ol
    Patent number: 6268538
    Abstract: A process is disclosed for the preparation and purification of 3-(4-hydroxyphenyl)-1,1,3-trimethylindan-5-ol. Accordingly, isopropenylphenol, its dimers or oligomers undergo isomerization in the presence of an acid catalyst, crude 3-(4-hydroxyphenyl)-1,1,3-trimethylindan-5-ol is isolated from the reaction mixture and purified by distillation.
    Type: Grant
    Filed: January 24, 2000
    Date of Patent: July 31, 2001
    Assignee: Bayer Aktiengesellschaft
    Inventors: Stefan Westernacher, Claudia Laukötter, Jürgen Stebani, Gerhard Fennhoff
  • Method for preparing and purifying 3-(4-hydroxyphenyl)-1,1,3-trimethylindan-5-ol
    Patent number: 6235945
    Abstract: A process is disclosed for the preparation and purification of 3-(4-hydroxyphenyl)-1,1,3-trimethylindan-5-ol. Accordingly, isopropenylphenol, its dimers or oligomers undergo isomerization in the presence of an acid catalyst, the reaction mixture is optionally neutralized by adding a base and 3-(4-hydroxyphenyly)-1,1,3-trimethylindan-5-ol is isolated from the reaction mixture by fractional distillation.
    Type: Grant
    Filed: December 21, 1999
    Date of Patent: May 22, 2001
    Assignee: Bayer Aktiengesellschaft
    Inventor: Stefan Westernacher
  • Method for producing and purifying 3-(3-hydroxyphenyl)-1,1,3-trimethylindan-5-ol
    Patent number: 6225512
    Abstract: A process is disclosed for the preparation and purification of 3-(4-hydroxyphenyl)-1,1,3-trimethylindan-5-ol. Accordingly, isopropenylphenol, its dimers or oligomers undergo isomerization in the presence of an acid catalyst, the reaction mixture is optionally neutralized by adding a base and 3-(4-hydroxyphenyl)-1,1,3-trimethylindan-5-ol is isolated by recrystallization.
    Type: Grant
    Filed: February 14, 2000
    Date of Patent: May 1, 2001
    Assignee: Bayer Aktiengesellschaft
    Inventors: Stefan Westernacher, Franz Kosik, Wolfgang Calaminus, Wilfried Haese
  • Copolycarbonates with an indane bisphenol base
    Patent number: 6218502
    Abstract: A copolycarbonate having glass transition temperature not higher than 160° C. and a rheooptic constant not higher than 4 is disclosed. Containing structural units conforming to wherein the radicals R1 each independently denotes a C1-12-alkyl radical or a halogen atom and n is 0 to 3, the copolycarbonate is suitable for the preparation of lenses and optical mass storage means.
    Type: Grant
    Filed: February 28, 2000
    Date of Patent: April 17, 2001
    Assignee: Bayer Aktiengesellschaft
    Inventors: Stefan Westernacher, Annett König, Jürgen Stebani, Friedrich-Karl Bruder, Wilfried Haese