Patents by Inventor Fumio Ohi

Fumio Ohi 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 and purifying p-phenylenediamine
    Patent number: 4191708
    Abstract: Highly pure p-phenylenediamine can advantageously be prepared on a commercial scale by separating and removing o-aminoazobenzene produced as a by-product in the step of producing p-aminoazobenzene, from the product mixture before p-aminoazobenzene is reduced in a process for preparing p-phenylenediamine which comprises preparing p-aminoazobenzene from aniline by way of diazoaminobenzene and then reducing p-aminoazobenzene.
    Type: Grant
    Filed: January 10, 1978
    Date of Patent: March 4, 1980
    Assignee: Sumitomo Chemical Company, Limited
    Inventors: Hiromichi Okabe, Kiyomi Kishimoto, Fumio Ohi