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. 22, 2009
Filed:
Aug. 29, 2007
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;
Sud-Chemie AG, Munich, DE;
Abstract
The present invention relates to processes for improving or optimizing a catalyst for the preparation of phthalic anhydride by gas-phase oxidation of o-xylene and/or naphthalene, which comprises the following steps: a) provision of a starting catalyst (C) comprising at least one first catalyst zone located towards the gas inlet and a second catalyst zone located closer to the gas outlet, with the catalyst zones preferably each having an active composition comprising TiO; b) replacement of part of the first catalyst zone by an upstream zone of a catalyst having a higher activity than the first catalyst zone in order to provide an improved catalyst. Furthermore, an improved catalyst obtainable by this process is described.