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:
Jun. 25, 2002
Filed:
Apr. 24, 2000
Nippon Shokubai Co, Ltd, Osaka, JP;
Abstract
A process for vapor phase catalytic oxidation of methacrolein to produce methacrylic acid at high yield and with stability over a prolonged period is provided. The process is characterized, in the occasion of producing methacrylic acid by vapor phase catalytic oxidation of methacrolein using a fixed bed shell-and-tube reactor, in that (1) the catalyst layer in each reaction tube is divided into at least two layers in the axial direction of the tube to provide plural reaction zones, and (2) each of the reaction zones is filled with the catalyst in such a manner that the amount of the catalytically active component per unit volume of the reaction tube decreases from the gas inlet portion toward the gas outlet portion.