Patents Assigned to Johoku Chemical Co., Ltd.
  • Patent number: 6495712
    Abstract: A process for production of carboxylic acid aryl esters which comprises reacting a carboxylic acid having at least one carboxyl group with a di- or tri-aryl phosphite compound, in the presence of a basic compound and/or water. The carboxylic acid aryl esters can also be produced by reacting a carboxylic acid or a basic salt thereof with a diaryl phosphite compound.
    Type: Grant
    Filed: July 18, 2001
    Date of Patent: December 17, 2002
    Assignee: Johoku Chemical Co., Ltd.
    Inventors: Toshiyuki Yamauchi, Masuo Omichi, Eisuke Kanagawa, Tomohiro Tanino, Yoshikatsu Osamura
  • Patent number: 5932142
    Abstract: A process for preparing benzotriazolyl-alkylene bisphenol compounds which comprises reacting a 2-hydroxyphenylbenzotriazole and a 2,4-substituted phenol with an aldehyde in the presence of a basic catalyst and an amine compound; benzotriazolyl-alkylene bisphenol compounds obtained by the process; and stabilized organic materials containing the resulting benzotriazolyl-alkylene bisphenol compounds in an amount of 0.01-10 percent by weight. It is possible to prepare the benzotriazolyl-alkylene bisphenol compounds at a high yield, and organic materials can be effectively stabilized with the resulting compounds.
    Type: Grant
    Filed: December 8, 1997
    Date of Patent: August 3, 1999
    Assignee: Johoku Chemical Co., Ltd.
    Inventors: Toshiyuki Yamauchi, Eisuke Kanagawa, Hideo Aoki, Kazuyuki Ishihara
  • Patent number: 5808086
    Abstract: A 2-hydroxyphenylbenzotriazole is reacted with a formaldehyde and an amino alcohol in an organic solvent in the presence of a basic catalyst. It is thereby possible to obtain bis(2-hydroxyphenyl-3-benzotriazole) methanes efficiently and at a high yield.
    Type: Grant
    Filed: July 28, 1997
    Date of Patent: September 15, 1998
    Assignee: Johoku Chemical Co., Ltd.
    Inventors: Naoyuki Sugii, Toshiyuki Yamauchi, Eisuke Kanagawa, Hideo Aoki, Kazuyuki Ishihara
  • Patent number: 5250166
    Abstract: A method of recovering palladium from a palladium-containing aqueous solution by electrolysis is provided. The method comprises the steps of dc-electrolyzing the palladium-containing aqueous solution acidified with nitric acid by using an electrolytic cell equipped with a platinum electrode as a cathode to thereby deposit and collect palladium on the cathode, taking the cathode on which palladium has been deposited and collected out of the electrolytic cell, transferring the palladium-deposited cathode to a recovery vessel containing dilute nitric acid therein, and mechanically shaking the cathode in the recovery vessel to remove and recover palladium from the cathode. An apparatus for carrying out the above-described method is also provided.
    Type: Grant
    Filed: April 22, 1992
    Date of Patent: October 5, 1993
    Assignees: Doryokuro Kakunenryo Kaihatsu Jigyodan, Johoku Chemical Co., Ltd.
    Inventors: Kenji Motojima, Misato Horie, Shin-ichiro Torada