Preparation of novel hybrid catalyst with an hierarchical micro-/mesoporous structure by direct growth of the HKUST-1 nanoparticles inside mesoporous silica matrix (MMS)

Abstract

Abstract A novel hybrid material was prepared by the direct growth technique starting from metal-organic framework HKUST-1 (Cu3(BTC)2, BTC = benzene-1,3,5-tricarboxylate) and mesoporous silica matrix (MMS). MMS acts as a structure-directing agent, which assists to the formation of very small HKUST-1 nanoparticles (4–8 nm) are dispersed homogeneously in the silica matrix. To evaluate the field of the potential exploitation of HKUST-1@MMS hybrid, it was examined as a heterogeneous catalyst with Lewis and Bronsted acid sites in demanding organic transformations widely used for fine chemicals production, i.e. in the Friedlӓnder reaction between 2-amino-5-chlorobenzophenone and acetylacetone and Henry reaction (nitroaldol condensation) between nitromethane and 4-nitrobenzaldehyde. The cooperative effect between Lewis acid sites as Cu2+ ions in the HKUST-1 framework and acid sites of MMs silica in the HKUST-1@MMS catalytic material relevant to the Henry reaction between 4-nitrobenzaldehyde and nitromethane was found for the first time. According to adsorption tests, the novel hybrid features an hierarchical micro-/mesoporous structure and can also find application as an adsorbent with molecular-sieving properties.