Preparation and characterization of a new bis-layered supported ionic liquid catalyst (SILCA) with an unprecedented activity in the Heck reaction

A1 Originalartikel i en vetenskaplig tidskrift (referentgranskad)


Interna författare/redaktörer


Publikationens författare: Nemanja Vucetic, Pasi Virtanen, Ayat Nuri, Ida Mattsson, Atte Aho, Jyri-Pekka Mikkola, Tapio Salmi
Publiceringsår: 2019
Tidskrift: Journal of Catalysis
Tidskriftsakronym: J. Catal.
Volym: 371
Artikelns första sida, sidnummer: 35
Artikelns sista sida, sidnummer: 46
eISSN: 1090-2694


Abstrakt

A new bis-layered supported ionic liquid catalyst (SILCA) loaded with palladium was designed and successfully applied for the Heck reaction of iodobenzene and methyl acrylate. The silica modified catalyst consisting of the first ionic liquid layer – covalently anchored imidazolium bromide – on which the second layer, made of pyridine-carboxylic acid balanced with tetramethylguanidinium cation was attached, resulted in a catalyst with high activity. High turnover frequencies of 22,000 h−1 were achieved in reactions with a low palladium loading as 0.009 mol %. Lower TOFs, indicating on palladium dimerization was detected when higher amounts were used. The TMG cation had a purpose to recapture and stabilize the Pd nanoparticles thus followed a release and catch mechanism. In order to get a full understanding of the catalyst structure and behaviour, the catalyst was characterized by means of nitrogen physisorption, thermal gravimetric analysis, infrared spectroscopy, scanning electron and transmission electron microscopes, solid-state NMR, X-ray photoelectron spectroscopy and inductively coupled plasma spectroscopy. The catalyst preserved good activity in five cycles.


Nyckelord

Chemical Engineering

Senast uppdaterad 2020-14-07 vid 05:51