Reactions of n-butenes on palladium films. Evidence for π-allylic species

Abstract

The contact reactions of all three n-butenes have been investigated on palladium films in the presence of perdeuteropropene or deuterium, using jointly mass spectrometry and microwave spectroscopy.

Conclusive evidence has been found for an allylic mechanism in exchange and double-bond migration.

Part of the exchanged molecules result from dissociative vinylic-type adsorption and isomerization also takes place according to an associative Horiuti–Polanyi mechanism or by direct processes without deuterium incorporation. A proposal was made which correlates the various reaction mechanisms with various types of surface metal atoms, each having a different coordination number.