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:
May. 13, 2008
Filed:
May. 21, 2004
Sebastian Storck, Mannheim, DE;
Jürgen Zühlke, Speyer, DE;
Samuel Neto, Dresden, DE;
Frank Rosowski, Mannheim, DE;
Sebastian Storck, Mannheim, DE;
Jürgen Zühlke, Speyer, DE;
Samuel Neto, Dresden, DE;
Frank Rosowski, Mannheim, DE;
BASF Aktiengesellschaft, Ludwigshafen, DE;
Abstract
A description is given of a process for preparing aldehydes, carboxylic acids and/or carboxylic anhydrides, in particular phthalic anhydride, in which a gaseous stream comprising an aromatic hydrocarbon and molecular oxygen is passed at elevated temperature over a bed of a first catalyst and a bed which is made up of a second catalyst having a higher activity than the first catalyst and is located downstream of the first catalyst in the flow direction of the gaseous stream, wherein the catalytically active composition of the first catalyst comprises at least vanadium oxide, titanium dioxide and antimony oxide and the ratio of vanadium, calculated as VO, to antimony, calculated as SbO, in the first catalyst is from 3.5:1 to 5:1. The source of antimony oxide used for the first catalyst is preferably particulate antimony trioxide having a mean particle size of from 0.5 to 5 μm. The process allows the desired oxidation products to be obtained in high yield over longer periods of time.