Palladium Acetate in Polyurea Microcapsules: A Recoverable and Reusable Catalyst for Hydrogenations

Nadine  Bremeyer; Steven V.  Ley; Chandrashekar  Ramarao; Ian M.  Shirley; Stephen C.  Smith

doi:10.1055/s-2002-34862

LETTER

Palladium Acetate in Polyurea Microcapsules: A Recoverable and Reusable Catalyst for Hydrogenations

Nadine Bremeyer^a, Steven V. Ley*^a, Chandrashekar Ramarao^a, Ian. M. Shirley^b, Stephen C. Smith^b
^a Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK
Fax: +44(1223)336442; e-Mail: svl1000@cam.ac.uk;
^b Syngenta, Jealott’s Hill International Research Centre, Bracknell, Berkshire RG42 6EY, UK

Abstract

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Abstract

Polyurea microcapsules containing palladium acetate have been used in a range of catalytic hydrogenation reactions.

Key words

palladium - catalysis - hydrogenations - polyurea - microcapsules

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Referenzen

References

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Samples of Pd EnCat^TMcan be obtained on request from Avecia U. K.

All hydrogenation reactions were carried out using Pd EnCat^TM that had been pre-reduced under H₂ (50 bar) for two days. This pre-reduction is required for high activity and reduced reaction times.

The reduction of 4-nitrotoluene (entry 6, method A) to p-toluidine using Pd/C was complete in 1 h. Using Pd/C under the same conditions used for entry 14 resulted in the reduction and complete removal of the benzyloxy group.

The veracity of this statement has not been established on reaction scales greater than those commonly employed in research laboratories.