Catalytic hydrogenation of tertiary amides at low temperatures and pressures using bimetallic Pt/Re-based catalysts

• Published in: Journal of catalysis 2011-10, Vol.283 (1), p.89-97
• Main Authors: Burch, R., Paun, C., Cao, X.-M., Crawford, P., Goodrich, P., Hardacre, C., Hu, P., McLaughlin, L., Sá, J., Thompson, J.M.
• Format: Article
• Language: English
• Subjects: adsorption; Amide; amides; Bimetallic; Catalysis; catalysts; Catalytic oxidation; Chemistry; DFT; Exact sciences and technology; General and physical chemistry; hydrogenation; Metals; oxygen; Platinum; Pressure; Rhenium; Surface physical chemistry; temperature; Temperature effects; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Titania; titanium dioxide
• ISSN: 0021-9517; 1090-2694
• DOI: 10.1016/j.jcat.2011.07.007

A bimetallic Pt–Re catalyst can facilitate the hydrogenation of N-methylpyrrolidin-2-one to N-methylpyrrolidine to high conversion at low temperature and pressure. Catalyst preparation, characterisation and kinetic analysis combined with DFT calculations have shown that the role of rhenium is to activate the carbonyl bond, whilst that of the platinum is as a hydrogenation catalyst, removing intermediates from the surface of the catalyst. [Display omitted] ► Bimetallic Pt–Re catalysts facilitate hydrogenation of amides under mild conditions. ► Characterisation, kinetic analysis and DFT calculations show the role of each metal. ► Re activates the carbonyl bond, Pt hydrogenates intermediates, cleaning the catalyst. Hydrogenation of tertiary amides, in particular, N-methylpyrrolidin-2-one, can be efficiently facilitated by a TiO 2-supported bimetallic Pt/Re catalyst at low temperatures and pressures. Characterisation of the catalysts and kinetic tests have shown that the close interaction between the Re and Pt is crucial to the high activity observed. DFT calculations were used to examine a range of metal combinations and show that the role of the uncoordinated Re is to activate the C O and that of the Pt is as a hydrogenation catalyst, removing intermediates from the catalyst surface. The rate enhancement observed on the TiO 2 support is thought to be due to the presence of oxygen vacancies allowing adsorption and weakening of the C O bond.