SYNTHESIS, CHARACTERIZATION AND HETEROGENEOUS CATALYSIS OF CERIUM METAL ORGANIC FRAMEWORKS (Ce- UiO-66) AND ITS INORGANIC HYBRIDS ON KNOVENAGEL CONDENSATION

Abstract

Heterogeneous catalysis is one of the most explored applications of metal-organic frameworks. Metal organic frameworks (MOFs) as exciting types of organic/inorganic hybrid materials have attracted great focus of scientists in the last two decades. The objective of this study was to synthesize Ce-UiO-66 and its inorganic hybrids (CdS/Ce-UiO-66/Ag3PO4) and evaluate its performance as a heterogeneous catalyst considering Knovenagel condensation. All the materials in this work were prepared via Co-precipitation and hydrothermal synthesis method and characterized by X-ray powder diffraction (XRD) and scanning electron microscope (SEM) hyphenated with energy dispersive x-ray (EDX). The synthesized organic product was characterized by 1H-NMR and 13C-NMR spectroscopy. Catalytic proficiency of Ce-UiO-66 and its inorganic hybrids in the Knoevengel condensation reaction for various aldehyde substrates and malononitrile was investigated under optimized reaction condition; reaction time, catalytic activity and reaction yield in aqueous media. The yield of the target product over the investigated catalysts in Knoevenagel condensation of benzaldehyde and malononitile was 88 % when T3 was used as catalyst. The catalytic system has also been tested for various aromatic aldehydes, the conversions easily reaching 88 % when electron withdrawing groups were there and decreased for electron donating groups and for bulky aldehyde substrates at room temperature. Furthermore, the catalyst was reused more than three times without significant loss of its catalytic efficiency.