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

A novel hybrid material was prepared by the direct growth technique starting from metal-organic framework HKUST-1 (Cu-3(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 HKUST1-@MMS hybrid, it was examined as a heterogeneous catalyst with Lewis and Brunsted acid sites in demanding organic transformations widely used for fine chemicals production, i.e. in the Friedlander 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.