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.
|Number of pages||8|
|Journal||Chemistry - A European Journal|
|Publication status||Published - Dec 1 1999|
- Electron transfer
ASJC Scopus subject areas
- Organic Chemistry