Method for producing phthalic anhydride by means of catalytic vapor-phase oxidation of o-xylol/naphthalene mixtures

US6362345B1 · kind B1 · utility

Assignee

• BASF SE

Inventors

• Thomas Heidemann · Viernheim, DE
• Heiko Arnold · Mannheim, DE
• Gerhard Hefele · Wasserburg am Inn, DE
• Herbert Wanjek · Frankenthal (Pfalz), DE

Key dates

• Filing date: Nov 15, 2000
• Grant date: Mar 26, 2002
• Expiry date: Nov 15, 2020

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/naphthalene mixtures by molecular oxygen, use is made of a catalyst I in a first zone on the gas inlet side which makes up from 25 to 75 percent by volume of the total catalyst volume, comprising, in each case based on the catalytically active composition, from 1 to 10% by weight of vanadium oxide (calculated as V205), from 1 to 10% by weight of antimony oxide (calculated as Sb203) and from 80 to 98% by weight of titanium dioxide of the anatase type having a BET surface area of from 13 to 28 m2/g and also from 0.05 to 1% by weight of cesium (calculated as Cs) applied to a steatite support and a catalyst II in a second zone which makes up the remaining 75 to 25 percent by volume of the total catalyst volume, comprising, in each case based on the catalytically active composition, from 1 to 10% by weight of vanadium oxide (calculated as V205), from 1 to 10% by weight of antimony oxide (calculated as Sb203) and from 80 to 98% by weight of titanium dioxide of the anatase type having a BET surface area of from 13 to 28 m2/g and from 0.01 to 1% by weight of phosphorus oxide (calculated as P) and als…