Patents Assigned to Nippon Shokubai Kagaku Ogyo Co., Ltd.
  • Patent number: 5248819
    Abstract: In the production of methacrylic acid by the vapor phase catalytic oxidation of isobutylene, t-butanol, methacrolein isobutyl aldehyde or isobutyric acid, or mixture thereof, the reaction product gas is condensed by contact with an aqueous phase containing methacrylic acid and acetic acid thereby forming an aqueous solution of methacrylic acid and a gas phase containing methacrolein and methacrylic acid. The aqueous solution of methacrylic acid is extracted with a saturated hydrocarbon solvent containing from 6-9 carbon atoms. The methacrylic acid is extracted into the solvent phase and an aqueous phase containing acetic acid is also formed. Methacrolein is recovered from the gas containing methacrolein and methacrylic acid by contacting the gas with an aqueous phase containing methacrylic acid and acetic acid. An aqueous phase containing methacrylic acid, acetic acid and methacrolein is formed in the methacrolein recovery step.
    Type: Grant
    Filed: October 3, 1991
    Date of Patent: September 28, 1993
    Assignee: Nippon Shokubai Kagaku Ogyo Co., Ltd.
    Inventors: Syoichi Matsumoto, Masatoshi Ueoka, Yosuke Ogata, Hiroshi Yoshida, Masao Baba