Patents by Inventor Shigefumi Tokumasu

Shigefumi Tokumasu 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: 6960698
    Abstract: A method for treating tar separated from a liquid containing an aromatic hydroxybenzene obtained by acidolysis of a liquid containing an aromatic hydroperoxide, which comprises dissolving the tar with an alkaline aqueous solution.
    Type: Grant
    Filed: March 20, 2003
    Date of Patent: November 1, 2005
    Assignee: Sumitomo Chemical Compnay, Limted
    Inventors: Mamoru Seino, Shigefumi Tokumasu
  • Publication number: 20030183557
    Abstract: A method for treating tar separated from a liquid containing an aromatic hydroxybenzene obtained by acidolysis of a liquid containing an aromatic hydroperoxide, which comprises dissolving the tar with an alkaline aqueous solution.
    Type: Application
    Filed: March 20, 2003
    Publication date: October 2, 2003
    Applicant: SUMITOMO CHEMICAL COMPANY, LIMITED
    Inventors: Mamoru Seino, Shigefumi Tokumasu
  • Patent number: 6423876
    Abstract: There is provided a process for producing dihydroxybenzene, which comprises the steps of: (1) oxidizing diisopropylbenzene to obtain a reaction mixture containing di(2-dihydroperoxy-2-propyl)benzene; (2) cleaving di(2-dihydroperoxy-2-propyl)benzene in the reaction mixture to obtain a mixture containing crude dihydroxybenzene; (3) distilling the mixture containing crude dihydroxybenzene to obtain a fraction containing acetone from a low boiling side, and a fraction containing dihydroxybenzene from a high boiling side; (4) distilling the fraction containing dihydroxybenzene obtained in the above-mentioned step (3) to obtain a fraction containing dihydroxybenzene from a low boiling side, and a fraction containing heavy material from a high boiling side; and (5) mixing the fraction containing dihydroxybenzene obtained in the above-mentioned step (4) with water, and contacting the resulting mixture with an extraction solvent, followed by separating into an aqueous layer containing dihydroxybenzene and an oily
    Type: Grant
    Filed: February 5, 2002
    Date of Patent: July 23, 2002
    Assignee: Sumitomo Chemical Company, Limited
    Inventor: Shigefumi Tokumasu
  • Patent number: 5962747
    Abstract: A process for producing 1,3-di-(2-hydroperoxy-2-propyl)benzene comprising an oxidizing step, an extracting step with an aqueous solution and a recycling step wherein the accumulated equilibrium concentration of 1,3-di-(2-hydroxy-2-propyl)benzene in the circulating oil obtained by an extracting step with an aqueous solution is 4.2% by weight or less. The process enables to avoid inconveniences like occlusion of inside space of an apparatus and failure of detection of measuring machines and allows continuous safe operation.
    Type: Grant
    Filed: October 23, 1997
    Date of Patent: October 5, 1999
    Assignee: Sumitomo Chemical Co., Ltd.
    Inventors: Shigefumi Tokumasu, Hideo Ohki, Toshikazu Ohmae
  • Patent number: 5959155
    Abstract: A process for extraction of hydroperoxides wherein 1,3-di-(2-hydroperoxy-2-propyl)benzene and 3-(2-hydroxy-2-propyl)-1-(2-hydroperoxy-2-propyl)benzene are extracted from a raw solution comprising 1,3-di-(2-hydroperoxy-2-propyl)benzene, 3-(2-hydroxy-2-propyl)-1-(2-hydroperoxy-2-propyl)benzene and an aqueous sodium hydroxide solution, said process using methyl isobutyl ketone containing not more than 10 ppm by weight of a phenol or phenols as a solvent for extraction.
    Type: Grant
    Filed: December 10, 1997
    Date of Patent: September 28, 1999
    Assignee: Sumitomo Chemical Company, Limited
    Inventors: Toshikazu Ohmae, Shigefumi Tokumasu, Hideo Ohki
  • Patent number: 5138109
    Abstract: A halogenated alkyl of the formula: ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3 are the same or different and each is a lower alkyl group, X is chlorine atom or a bromine atom and Y is a hydrogen atom or a halogen atom is prepared in high conversion and high selectivity by reacting a tertiary halogenated alkyl of the formula: ##STR2## wherein R.sub.1, R.sub.2, R.sub.3 and X are the same as defined above with an ethylene derivative of the formula:CH.sub.2 .dbd.CH--Y (III)wherein Y is the same as defined above in the presence of a liquid catalyst comprising aluminum chloride and an alkylbenzene of the formula: ##STR3## wherein R.sub.4, R.sub.5 and R.sub.6 are the same or different and each is a lower alkyl group or a hydrogen atom provided that at least one of them is a lower alkyl group.
    Type: Grant
    Filed: November 4, 1991
    Date of Patent: August 11, 1992
    Assignee: Sumitomo Chemical Company, Ltd.
    Inventors: Michio Yamamoto, Masaru Ishino, Motoo Hazama, Shigefumi Tokumasu