Patents by Inventor Yoshiyuki Sumi

Yoshiyuki Sumi 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).

  • Process for preparing an aqueous slurry of terephthalic acid
    Patent number: 5557009
    Abstract: A process for preparing an aqueous slurry of terephthalic acid, which comprises oxidizing p-xylene with molecular oxygen in a liquid phase in an acetic acid solvent in the presence of a catalyst, to obtain an acetic acid slurry of terephthalic acid, separating terephthalic acid crystals from the acetic acid slurry, washing the terephthalic acid crystals containing acetic acid, with p-xylene or an acetic acid ester, and then mixing water thereto.
    Type: Grant
    Filed: October 31, 1995
    Date of Patent: September 17, 1996
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Yoshiaki Izumisawa, Yoshiyuki Sumi, Takayuki Isogai
  • Process for producing highly pure terephthalic acid
    Patent number: 5420344
    Abstract: A process for producing highly pure terephthalic acid, which comprises heating and dissolving crude terephthalic acid in water, and purifying it by contacting the aqueous solution with hydrogen at a temperature of from 260.degree. to 320.degree. C. in the presence of a platinum group metal catalyst, wherein the purification is initiated within three minutes after the aqueous solution under heating reaches a temperature of 250.degree. C.
    Type: Grant
    Filed: October 13, 1993
    Date of Patent: May 30, 1995
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Yoshiaki Izumisawa, Tsukasa Kawahara, Yoshiyuki Sumi, Takehiko Baba, Yoshio Ishinaga, Katsuhiko Fukui, Hironori Ohgi