Patents by Inventor Norio Nagano

Norio Nagano 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).

  • Method of preparing a fluorene derivative and the method of purifying thereof
    Patent number: 5629456
    Abstract: A fluorene derivative of high purity is produced by reacting fluorenone with phenoxyethanol in the presence of a sulfuric acid-thiol catalyst system, dissolving the reaction mixture in a lower aliphatic alcohol and adding water to the resulting solution for precipitation of 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene [fluorene derivative]. A fluorene derivative of still higher purity is obtained by recrystallization from a lower aliphatic alcohol.In accordance with this invention, a fluorene derivative can be produced advantageously on a commercial scale without incurring any appreciable loss of fluorenone, in good yield, with high efficiency and in a reduced production time.
    Type: Grant
    Filed: December 7, 1994
    Date of Patent: May 13, 1997
    Assignee: Osaka Gas Company Limited
    Inventors: Mitsuaki Yamada, Katsuhide Okimi, Katsuyuki Takahashi, Norio Nagano