Patents by Inventor Kunihiko Shigematsu

Kunihiko Shigematsu 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 acrylic acid
    Patent number: 6179966
    Abstract: The present invention concerns a method for producing acrylic acid which involves subjecting an acrylic acid-containing aqueous solution obtained by catalytic vapor phase oxidation of propylene and/or acrolein to evaporation whereby an acrylic acid-containing vapor is obtained; and subjecting the acrylic acid-containing vapor to azeotropic dehydration. The present invention offers a number of advantages including a reduce amount of polymer that may adhere to the surface of an azeotropic dehydration column, a low-blowing separation column or an in a high-boiling separation column in a plant for producing acrylic acid. Consequently, the production plant can be operated for a long time without stopping operations.
    Type: Grant
    Filed: November 17, 1998
    Date of Patent: January 30, 2001
    Assignee: Sumitomo Chemical Company, Ltd.
    Inventors: Toyomitsu Shimizu, Osamu Moriya, Kunihiko Shigematsu, Ryuji Matsushita