Ousmane, M., Perrussel, G., Yan, Z., Clacens, J.-M., De Campo, F. and Pera-Titus, M. 2014. Highly selective direct amination of primary alcohols over a Pd/K-OMS-2 catalyst. Journal of Catalysis 309 , pp. 439-452. 10.1016/j.jcat.2013.10.003 |
Abstract
A new Pd-substituted octahedral molecular sieve (Pd/K-OMS-2) catalyst has been prepared for the direct amination of alcohols with primary amines operating under the borrowing hydrogen mechanism. The catalyst offered full conversion and high selectivity toward N-benzylaniline in the model alkylation reaction of aniline with benzyl alcohol at mild temperature (160 °C) for 3 h with neither production of the tertiary amine nor toluene. Pd/K-OMS-2 performed as a tandem tri-functional catalyst, first oxidizing benzyl alcohol to benzaldehyde, behaving as a Lewis acid for imine formation, and finally reducing the imine to the secondary amine. The catalyst was characterized in depth using BET, XRD, H2-TPR, XPS, FTIR, TEM, TGA/DTG, and ICP-AES / EDX to elucidate the nature of the active sites. The unexpectedly high performance of the Pd/K-OMS-2 catalyst can be ascribed, at least partially, to the in situ generation of a very active, selective and partially recyclable Pd-substituted/supported hausmannite phase (i.e., Pd/Mn3O4) in the early stage of the reaction with a high density of surface oxygen moieties. We argue about a possible role of a Pd(IV)/Pd(II) redox pump for exchanging hydrogen during the amination reaction.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | Chemistry Cardiff Catalysis Institute (CCI) |
Publisher: | Elsevier |
ISSN: | 0021-9517 |
Date of Acceptance: | 7 October 2013 |
Last Modified: | 11 Jan 2021 16:00 |
URI: | https://orca.cardiff.ac.uk/id/eprint/137419 |
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