Search

A new ZnO@SBA-15 nanocomposite material has been fabricated by an “in situ” generation of ZnO NPs on SBA-15 support. The as-synthesized nanocomposite material was fully characterized with various spectroscopic techniques and their catalytic activity was tested for the synthesis of a diverse range of dihydropyrimidinones (DHPMs) and thione derivatives via Biginelli condensation reaction. The catalytic efficiency of ZnO@SBA-15 nanocomposite was far superior with a remarkably lower catalyst loading and shorter reaction time compared to unsupported ZnO nanoparticles. The catalyst was recycled for minimum of four times without significant loss in its catalytic activity. Moreover, a tentative catalytic cycle for the reaction is also proposed.

The present work reports the synthesis of well dispersed palladium nanoparticles immobilized on an amino functionalized nanoscale metal–organic framework MIL-101(Cr), by using a facile polyol method. The resulting Pd/NH2-MIL-101(Cr) nanocomposite is established to be an active heterogeneous catalyst for oxidative amination of aldehydes under solvent free conditions using hydrogen peroxide as an oxidant. The synthesized Pd/NH2-MIL-101(Cr) is characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, field emission scanning electron microscopy, Brunauer–Emmett–Teller (BET) surface area analysis, Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and atomic absorption spectroscopy (AAS). The catalyst could easily be recovered and recycled without any significant loss of its catalytic activity.

Sulfonic acid-functionalized MIL-101(Cr) was established to be an active heterogeneous catalyst for the one-pot synthesis of 2-amino-4H-chromenes via a three-component condensation reaction between resorcinol, malononitrile and a diverse range of aromatic aldehydes in aqueous medium. Here, sulfonation of the parent MIL-101(Cr) has been carried out through a post synthetic modification (PSM) technique. The resulting MIL-101(Cr)–SO3H has been characterized by employing powder X-ray diffraction, N2 sorption, FESEM, EDS, FT-IR and TGA studies. Furthermore, the catalyst can easily be recovered and recycled without much change in catalytic activity.

In this study, well dispersed gold nanoparticles (Au Nps) were embedded on an amine-functionalized nanoscale metal–organic framework MIL-101(Cr) via a simple solution approach. The resulting Au/NH2-MIL-101(Cr) exhibited a high isoelectric point (IEP) value with Bronsted basic sites that played an important role in determining the size and dispersion of Au Nps onto its matrix. In addition, the uniform nanomorphology of the catalyst provides the advantage of its good dispersion in aqueous media. The synthesized Au/NH2-MIL-101(Cr) catalyst was successfully characterized by different analytical techniques like powder X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller (BET) surface area analysis, Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), zeta potential analysis and atomic absorption spectroscopy (AAS). The catalytic activity of the synthesized material was explored for the epoxidation of styrene using tert-butyl hydroperoxide as oxidant. The catalyst could easily be recovered and recycled up to the fourth catalytic cycle without any significant change in its catalytic activity.