Patents by Inventor Susumu {overscore (O)}tsuka

Susumu {overscore (O)}tsuka 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: 6476269
    Abstract: A method for producing xylylenediamine by hydrogenating phthalonitrile synthesized through ammoxidation of xylene, wherein phthalonitrile is trapped in an organic solvent (A) by bringing a gas produced through ammoxidation into direct contact with the organic solvent (A), and hydrogenation including adding liquid ammonia to the resultant mixture is carried out without separation of phthalonitrile trapped in the organic solvent (A). Through this method, the phthalonitrile can be readily recovered from the produced gas and at high yield without need for new equipment, and xylylenediamine can be efficiently produced through hydrogenation. Xylylenediamine of high purity can be obtained by subjecting the produced xylylenediamine to extraction by use of an organic solvent (B) and water.
    Type: Grant
    Filed: September 17, 2001
    Date of Patent: November 5, 2002
    Assignee: Mitsubishi Gas Chemical Co. Inc.
    Inventors: Kenichi Nakamura, Susumu {overscore (O)}tsuka, Fumisada Kosuge, Takuji Shitara, Kazuhiko Amakawa