Patents by Inventor Kiyoshi Kumaki

Kiyoshi Kumaki 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 production of 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene
    Patent number: 6326522
    Abstract: The invention provides a process for production of 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene which comprises: reacting 1,3-di(2-hydroxy-2-propyl)benzene with phenol in an amount of 4-6 times in mols the amount of the 1,3-di(2-hydroxy-2-propyl)benzene in the presence of an acid catalyst at a temperature of 10-55° C. thereby crystallizing adducts formed of phenol and the resulting 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene so that the reaction is effected in a slurry, and then recovering 1,3-di(2-p-hydroxyphenyl-2-propyl)benzene from the adduct.
    Type: Grant
    Filed: June 13, 2000
    Date of Patent: December 4, 2001
    Assignee: Honshu Chemical Industry Co. Ltd.
    Inventors: Toru Nakaguchi, Takafumi Tsujigami, Kenji Ekawa, Kenzo Tsujimoto, Kiyoshi Kumaki