A new non-cinchona chiral modifier immobilized on Pt/SiO2 catalysts for enantioselective heterogeneous hydrogenation

Cristian H. Campos, Cecilia C. Torres, Ariel Leyton, Julio Belmar, Claudio Mella, Paula Osorio-Vargas, Doris Ruiz, José L.G. Fierro, Patricio Reyes

Resultado de la investigación: Contribución a una revistaArtículo

4 Citas (Scopus)

Resumen

Pt heterogeneous catalysts were prepared by the covalent immobilization of (4′R,5′S)-4′,5′-dihydro-4′,5′-diphenyl-2-(6-cyanopyridyl)imidazoline (PyIm) as the asymmetric modifier. These novel series of catalysts were studied in the 1-phenyl-1,2-propanodione (PPD) hydrogenation. The effects of the PyIm surface concentration, hydrogen pressure, solvent nature and recycles on the reaction were studied. These modified catalysts represent the first effective immobilized chiral non-Cinchona-type modifier of Pt for the enantioselective hydrogenation. The enantio-differentiation was attributed to the substrate-modifier interactions involving hydrogen bonding between the keto-carbonyl O atom and the NH moiety PyIm. The results confirmed that the variations in the H2 pressure and the solvent affect the activity and the enantioselectivity due to the substrate adsorption on the active sites of the metal. Additionally, this heterogeneous catalyst can be conveniently reused at least five times without loss of its catalytic efficiency, but the enantioselectivity decreased, which may be due to the leaching of the modifier.

Idioma originalInglés
Páginas (desde-hasta)76-87
Número de páginas12
PublicaciónApplied Catalysis A: General
Volumen498
DOI
EstadoPublicada - 5 jun 2015

Áreas temáticas de ASJC Scopus

  • Catálisis
  • Química de procesos y tecnología

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