Method for producing acid phthalic anhydride and an appropriate shell catalyst containing titanium-vanadium-cesium

US6458970B1 · kind B1 · utility

Assignee

• BASF SE

Inventors

• Gerhard Hefele · Wasserburg am Inn, DE
• Otto Kratzer · Frankenthal (Pfalz), DE
• Walter Scheidmeir · Schifferstadt, DE
• Bernhard Ulrich · Port Aransas, US

Key dates

• Filing date: Aug 26, 1999
• Grant date: Oct 1, 2002
• Expiry date: Aug 26, 2019

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C51/313
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

In a process for preparing phthalic anhydride by catalytic gas-phase oxidation of o-xylene or naphthalene or o-xylene/naphthalene mixtures with a gas comprising molecular oxygen over a coated catalyst comprising an inert, nonporous support material on which a catalytically active composition comprising titanium dioxide and vanadium pentoxide is applied in layer form, a catalyst whose catalytically active composition comprises from 3 to 6% by weight of vanadium pentoxide, calculated as V2O5, from 0.3 to 0.5% by weight of a cesium compound, calculated as Cs, and the remainder to 100% by weight of titanium dioxide in the anatase modification is used in the presence or absence of a coated catalyst, differing therefrom, for the catalytic gas-phase oxidation of o-xylene or naphthalene or o-xylene/naphthalene mixtures and, in the presence of such a second catalyst, the latter is used in a combined bed with the catalyst of the above composition in the reactor.