Modified UiO-66-NH2 metal–organic frameworks (MOFs) with Melamine for Knoevenagel condensation

In recent years, metal-organic frameworks (MOFs) have attracted considerable attention due to their special characteristics such as hybrid compositions, diverse networks, tunable porosity and tailorable surfaces [1, 2]. The application of MOFs as porous heterogeneous catalysts alternative or complementary to microporous zeolites is especially interesting, since the pore size and chemical functionality of MOFs can be modulated within a wider range [3,4].In this work, Zr-based MOFs,UiO-66-NH2, was used for post-synthesis by melamine(UiO-66-NH2-Mlm) (Fig. 1) to provide higher content of primary amine for Knoevenagel reaction. The modified MOFs were characterized with XRD, FT-IR, TEM, SEM, BET, TGA, XPS. The effective parameters in Knoevenagel reaction such as catalyst type, amount, and solvent type were investigated. The modified MOFs exhibited excellent catalyst activities in heterogeneous phase due to their large surface area and porosity.