Zeolite-encapsulated cobalt salophen complexes as efficient oxygen-activating catalysts in palladium-catalyzed aerobic 1,4-oxidation of 1,3-dienes

Jens Wöltinger, Jan E. Bäckvall, Ágnes Zsigmond

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Abstract

Different cobalt salophen catalysts 1, 2, 3, and 4 were prepared and studied as oxygen-activating agents in the palladium - quinone catalyzed aerobic oxidation of 1,3-dienes. These cobalt salophen catalysts were also encapsulated into the supercage of zeolite Y by the template synthesis method (ship-in-the-bottle technique). The cobalt salophen catalyst 2 from 3,5-di-tert-butylsalicylaldehyde and 1,2-diamino-benzene was found to be more active than the unsubstituted parent cobalt salophen and the zeolite-encapsulated variant 2-ZeY showed remarkably high activity. With this catalyst, palladium-catalyzed aerobic oxidation of 1,3-cyclohexadiene afforded 1,4-diacetoxy-2-cyclohexene in high yield (95%) at room temperature within three hours. It was demonstrated that the zeolite-encapsulated catalyst 2-ZeY can be isolated and reused several times and still show good conversion in the third run.

Original languageEnglish
Pages (from-to)1460-1467
Number of pages8
JournalChemistry - A European Journal
Volume5
Issue number5
Publication statusPublished - Dec 1 1999

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Keywords

  • Cobalt
  • Electron transfer
  • Oxidations
  • Palladium
  • Zeolites

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Organic Chemistry

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