Patents by Inventor Katsuju Watanabe

Katsuju Watanabe 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 of purifying 2,4-xylenol
    Patent number: 4851590
    Abstract: 2,4-Xylenol can be obtained in high yield and high purity from a crude 2,4-xylenol isomer mixture containing 2,5-xylenol by selectively reacting the 2,5-xylenol with an aldehyde in the presence of an aromatic sulfonic acid, thereby converting the 2,5-xylenol into a xylenol-aldehyde condensate and, subsequently, separating the 2,4-xylenol, e.g., by distillation.
    Type: Grant
    Filed: May 27, 1988
    Date of Patent: July 25, 1989
    Assignee: Mitsui Toatsu Chemicals, Inc.
    Inventors: Tohru Miura, Katsuju Watanabe, Hitoshi Nakayama, Masayuki Furuya, Teruyuki Nagata