Selective side-chain oxidation of alkyl aromatic compounds catalyzed by cerium modified silver catalysts

Journal article

Authors / Editors

Andersen, Jens

Research Areas

No matching items found.

Publication Details

Author list: Beier MJ, Schimmoeller B, Hansen TW, Andersen JET, Pratsinis SE, Grunwaldt JD

Publisher: Elsevier

Place: AMSTERDAM

Publication year: 2010

Journal: Journal of Molecular Catalysis A: Chemical (1381-1169)

Journal acronym: J MOL CATAL A-CHEM

Volume number: 331

Issue number: 1-2

Start page: 40

End page: 49

Number of pages: 10

ISSN: 1381-1169

eISSN: 1873-314X

Languages: English-Great Britain (EN-GB)

View in Web of Science | View on publisher site | View citing articles in Web of Science

Abstract

Silver supported on silica effectively catalyzes the aerobic side-chain oxidation of alkyl aromatic compounds under solvent-free conditions. Toluene, p-xylene, ethylbenzene and cumene were investigated as model substrates. Typically, the reaction was performed at ambient pressure; only for toluene an elevated pressure was required. Carboxylic acids, such as benzoic acid or p-toluic acid, additionally increased the reaction rate while CeO2 could act both as a promoter and an inhibitor depending on the substrate and the reaction conditions. Silver catalysts were prepared both by standard impregnation and Flame spray pyrolysis. Addition of a Ce precursor to the FSP catalyst resulted in significantly smaller silver particles. Ce-doped FSP catalysts in general exhibited a superior catalytic performance with TONs up to 2000 except for cumene oxidation that appeared to proceed mainly by homogeneous catalysis. In addition, Flame-made catalysts were more stable against silver leaching compared to the impregnated catalysts. The structure of the silver catalysts was studied in detail both by X-ray absorption spectroscopy and transmission electron microscopy suggesting metallic silver to be required for catalytic activity. Catalytic studies point to a radical mechanism which differs depending on the type of substrate. (C) 2010 Elsevier B.V. All rights reserved.

Keywords

Flame spray pyrolysis, Homogeneous vs. heterogeneous catalysis, p-Xylene, Selective aerobic oxidation, Silver catalysis

Documents