Patents by Inventor Yoshiro Ashina

Yoshiro Ashina 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 for maintaining the activity of zeolite catalysts
    Patent number: 5068442
    Abstract: There is provided a method for maintaining the activity of a zeolite catalyst in the catalytic production of methylamines from methanol and ammonia using a zeolite catalyst as at least one of catalysts applied, which comprises controlling the amount of aldehyde compounds as impurities flowing into a zeolite catalyst layer to about 0.15 g/hr.kg-cat. or lower, as calculated in terms of formaldehyde.
    Type: Grant
    Filed: May 17, 1989
    Date of Patent: November 26, 1991
    Assignee: Nitto Kagaku Kogyo Kabushiki Kaisha
    Inventors: Yoshiro Ashina, Takeyuki Fujita, Kiyonobu Niwa, Takeshi Inagaki, Yuko Nikaido
  • Process for producing dimethylamine in preference to mono- and trimethylamines by gas phase catalytic reaction of ammonia with methanol
    Patent number: 4582936
    Abstract: A process for the selective production of dimethylamine in preference to mono- and trimethylamines by a catalytic vapor phase reaction of ammonia and methanol over a zeolite selected from mordenite, clinoptilolite and erionite is disclosed, wherein the improvement is characterized by the fact that the zeolite used has been contacted with steam at a temperature of 250.degree. to 700.degree. C.
    Type: Grant
    Filed: June 6, 1984
    Date of Patent: April 15, 1986
    Assignee: Nitto Kagaku Kogyo Kabushiki Kaisha
    Inventors: Yoshiro Ashina, Takeyuki Fujita, Michio Fukatsu, Junsuke Yagi
  • Process for producing dimethylamine in preference to mono- or trimethylamine by vapor-phase catalytic reaction of methanol and ammonia
    Patent number: 4578516
    Abstract: Catalytic production of dimethylamine in preference to mono- and trimethylamine over a mordenite catalyst is disclosed, which mordenite is characterized by its alkali metal content.
    Type: Grant
    Filed: May 7, 1984
    Date of Patent: March 25, 1986
    Assignee: Nitto Kagaku Kogyu Kabushiki Kaisha
    Inventors: Yoshiro Ashina, Takeyuki Fujita, Michio Fukatsu, Junsuke Yagi
  • Process for producing methylamines
    Patent number: 4485261
    Abstract: Methylamines rich in dimethylamine are produced through two-step reaction of ammonia and methanol in which two types of catalysts are used and the methylamine mixture produced is recycled to the first step reaction.
    Type: Grant
    Filed: April 9, 1982
    Date of Patent: November 27, 1984
    Assignee: Nitto Kagaku Kogyo Kabushiki Kaisha
    Inventors: Yoshiro Ashina, Michio Fukatsu