The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 28, 1993
Filed:
Oct. 03, 1991
Syoichi Matsumoto, Himeji, JP;
Masatoshi Ueoka, Himeji, JP;
Yosuke Ogata, Hyogo, JP;
Hiroshi Yoshida, Toyonaka, JP;
Masao Baba, Himeji, JP;
Nippon Shokubai Kagaku Ogyo Co., Ltd., Osaka, JP;
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. This aqueous phase is contacted with a molecular oxygen containing gas to desorb methacrolein into a gas containing methacrylic acid and methacrolein and also forming an aqueous phase containing methacrylic acid and acetic acid. This aqueous phase is recycled to either or both of the methacrylic acid condensation step and the methacrolein recovery step. Methacrylic acid is recovered from the gas containing methacrylic acid and methacrolein produced in the methacrolein desorption step by mixing this gas with an aqueous phase containing acetic acid recovered from the methacrylic acid extraction step (C). This results in a gas-containing methacrolein which is recycled to the vapor phase reaction.