Patents by Inventor Toyokazu Kitaura

Toyokazu Kitaura 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).

  • Patent number: 6794548
    Abstract: A method for producing 4,4′-biphenol, comprising the steps of: preparing serially arranged reaction bathes for two or more steps; and carrying out a debutylation reaction of 3,3′,5,5′-tetra-t-butyl-4,4′-biphenol sequentially in the presence of an acid catalyst in a reaction solvent by supplying at least one kind of phenols selected from the group consisting of phenol, monoalkylphenols, dialkylphenols, and trialkylphenols, in a proportion of at least 0.5 mole part relative to one mole part of 3,3′,5,5′-tetra-t-butyl-4,4′-biphenol, to each reaction bath as a solvent for addition, wherein the number of carbon atoms of alkyl groups in alkylphenols consisting of the monoalkylphenols, dialkylphenols, and trialkylphenols, is each independently in the range of 1 to 4, and wherein a solvent for addition to a reaction bath for the latter step has a smaller average number of alkyl groups than a solvent for addition to a reaction bath for the former step.
    Type: Grant
    Filed: October 14, 2003
    Date of Patent: September 21, 2004
    Assignee: Honschu Chemical Industry Co., Ltd.
    Inventors: Mikio Kawahara, Toyokazu Kitaura
  • Publication number: 20040147790
    Abstract: A method for producing 4,4′-biphenol, comprising the steps of:
    Type: Application
    Filed: October 14, 2003
    Publication date: July 29, 2004
    Inventors: Mikio Kawahara, Toyokazu Kitaura
  • Patent number: 6313351
    Abstract: The process for producing alicyclic monoketones (hydroxyphenylcyclohexanone derivatives) according to the present invention comprises hydrogenating substituted bisphenols such as bisphenol A in a solvent in the presence of a palladium/alkali metal catalyst in which palladium and an alkali metal are both supported on a carrier to obtain alicyclic monoketones such as 2-(4-oxocyclohexyl)-2-(4-hydroxyphenyl)propane. The process for producing alicyclic diketones according to the present invention comprises hydrogenating substituted bisphenols such as bisphenol A in a solvent in the presence of a palladium/alkali metal catalyst in which palladium and an alkali metal are both supported on a carrier to obtain alicyclic diketones such as 2,2-bis(4-oxocyclohexyl)propane and 4,4′-bicyclohexanone.
    Type: Grant
    Filed: September 2, 1999
    Date of Patent: November 6, 2001
    Assignee: Honshu Chemical Industry Co., Ltd.
    Inventors: Norimoto Kiya, Shinsaku Kawasaki, Kenji Ekawa, Kenji Sugiyama, Toyokazu Kitaura