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. 10, 2009
Filed:
Mar. 02, 2006
Christian Guckel, Paramus, NJ (US);
Harald Dialer, Munich, DE;
Marvin Estenfelder, Karlsruhe, DE;
Werner Pitschi, Bruckmuhl, DE;
Christian Guckel, Paramus, NJ (US);
Harald Dialer, Munich, DE;
Marvin Estenfelder, Karlsruhe, DE;
Werner Pitschi, Bruckmuhl, DE;
Süd-Chemie AG, München, DE;
Abstract
The present invention relates to the use of a catalyst comprising at least one first catalyst zone located towards the gas inlet, a second catalyst zone located closer to the gas outlet and a third catalyst zone located even closer to or at the gas outlet for the preparation of phthalic anhydride by gas-phase oxidation of o-xylene and/or naphthalene, with the catalyst zones preferably each having an active composition comprising TiO, characterized in that the catalyst activity of the first catalyst zone is higher than the catalyst activity of the second catalyst zone. Furthermore, a preferred process for the preparation of phthalic anhydride is described.