Epoxidation of olefins catalyzed by manganese(III) salen complexes grafted to porous heterostructured clays

• Tipo: Artigo em Revista Científica Internacional
• Data: 2011

Autores

Iwona Kuzniarska Biernacka (Autor) Outra; Clara Pereira (Autor) FCUP; Ana P Carvalho (Autor) Outra; Joao Pires (Autor) Outra; Cristina Freire (Autor) FCUP

Revista

Título: Applied Clay Science

Vol. 53

Páginas: 195-203

ISSN: 0169-1317

Editora: Elsevier

Indexação

ISI Web of Knowledge - 25 Citações

Scopus - 33 Citações

Classificação Científica

FOS: Ciências da engenharia e tecnologias > Engenharia dos materiais

Outras Informações

ID Authenticus: P-002-NZN

DOI: 10.1016/j.clay.2010.12.017

Abstract (EN): Two chiral manganese(III) salen complexes were immobilized onto functionalized porous clay heterostructures (PCHs). The Jacobsen complex was anchored onto the PCH derivatized with phenoxyl groups (CAT_1) by axial coordination between the metal center and the support. The manganese(III) salen complex containing vinyl functionalities was grafted onto the mercapto-derivatized PCH through the ligand (CAT_2). All the materials were characterized by nitrogen adsorption-desorption isotherms at -196 degrees C, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR); the Mn content of CAT_1 and CAT_2 was determined by atomic absorption spectroscopy (AAS). The heterogeneous catalysts were tested in the asymmetric epoxidation of olefins using m-chloroperoxybenzoic acid (m-CPBA)/N-methylmorpholine-N-oxide (NMO) as the oxygen source, at 0 degrees C in dichloromethane, for two cycles. The catalyst CAT_1 led to almost similar epoxide selectivities and slightly higher enantioselectivities than those obtained with the homogeneous counterpart. Furthermore, in the epoxidation of styrene, it presented higher catalytic performance and stability upon reuse than CAT_2. In contrast, in the alpha-methylstyrene epoxidation. CAT_2 was the most active, selective and stable catalyst.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 9