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:
Nov. 01, 2005
Filed:
Mar. 09, 2003
Hiromi Yunoki, Himeji, JP;
Hiromi Yunoki, Himeji, JP;
Nippon Shokubai Co., Ltd., Osaka, JP;
Abstract
The present invention provides a process in which, when an unsaturated aldehyde and/or an unsaturated carboxylic acid are produced by carrying out a catalytic gas phase oxidation reaction by using a fixed-bed multitubular reactor which is packed with a molybdenum-containing catalyst, the deterioration of the catalyst as located at a hot spot portion can be suppressed; so that the reaction can be continued for a long time while a high yield is maintained, regardless of where the hot spot portion occurs and also even if the concentration of a raw gas is high. An oxide and/or a complex oxide including molybdenum, bismuth, and iron as essential components are used as the catalysts, and the inside of each reaction tube of the fixed-bed multitubular reactor is divided in a tubular axial direction to thus arrange at least two reaction zones, and then these reaction zones are packed with the catalysts in such a manner that the ratio R of the apparent density of the catalyst to the true density of the catalyst (apparent density of catalyst/true density of catalyst) in each reaction zone differs from that in another reaction zone.