Catalyst, process for its production and its use for preparing vinyl acetate

US6268522A · kind A · utility

Assignee

• Celanese GmbH · US

Inventors

• Alfred Hagemeyer · Sunnyvale, US
• Uwe Dingerdissen · Seeheim-Jugenheim, DE
• Klaus Kuhlein · Kelkheim, DE
• Johannes Heitz · Glückstadt, DE
• Dieter Bauerle · Orth an der Donau, AT

Key dates

• Filing date: Jun 3, 1998
• Grant date: Jul 31, 2001
• Expiry date: Jun 3, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C67/055
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

The invention relates to a process for producing supported shell catalysts comprising noble metals by UV photoreduction of noble metal salt precursors fixed to a support. For this purpose, the shaped supported body is impregnated with suitable noble metal salts which are then reduced to the metals in a zone close to the surface by means of UV radiation, preferably in the absence of a chemical reducing agent. The metal salts in the interior of the pellets which have not been irradiated and therefore have not been reduced are extracted using a solvent. The noble metal shell catalysts produced in this way can be used for many heterogeneously catalyzed reactions such as hydrogenations and oxidations. According to the invention, Pd/Au shell catalysts on porous ceramic supports, e.g. SiO.sub.2 shaped bodies, produced by this process can be used in the synthesis of vinyl acetate.