Silica nanosphere-supported palladium(ii) furfural complex as a highly efficient and recyclable catalyst for oxidative amination of aldehydes

Abstract

The present work reports the fabrication of a novel and highly efficient silica nanospheres-based palladium catalyst (SiO2@APTES@Pd-FFR) via immobilization of a palladium complex onto silica nanospheres functionalized with 3-aminopropyltriethoxysilane (APTES), and its catalytic application for the oxidative amination of aldehydes to yield commercially important amides. The structure of the nano-catalyst was confirmed by Solid-state (13)C CPMAS and (29)Si CPMAS NMR spectroscopy, Brunauer-Emmett-Teller (BET) surface area analysis, Fourier transform infrared spectroscopy (FT-IR), Energy dispersive X-ray fluorescence spectroscopy (ED-XRF), Atomic absorption spectroscopy (AAS), Transmission electron microscopy (TEM) and elemental analysis. The nano-catalyst was found to be highly effective for the oxidative amination of aldehydes using hydrogen peroxide as an environmentally benign oxidant to give amides. The effect of various reaction parameters such as temperature, amount of catalyst, reaction time, type of solvent, oxidant used, substrate to oxidant ratio etc. have been demonstrated to achieve high catalytic efficacy. Moreover, this nanostructured catalyst could be recovered with simplicity and reused for several cycles without any significant loss in its catalytic activity. In addition, the stability of the reused nano-catalyst was proved by FT-IR and HRTEM techniques. It is worth noting that the features of mild reaction conditions, simple work-up procedure, high product yield, no use of toxic organic solvents, high turn-over frequency (TOF), and easy recovery and reusability of the present quasi-homogeneous nano-catalyst make this protocol an attractive alternative to the existing catalytic methods for the oxidative amination of aldehydes to furnish industrially important amides.

One‐pot synthesis of (R)‐1‐(pyridin‐4‐yl)ethyl acetate using tandem catalyst prepared by co‐immobilization of palladium and lipase on mesoporous foam: Optimization and kinetic modeling

“…Figure B for Lip/Pd/MCF shows that the loading of palladium gave rise to bands which appear as a single shoulder to the band at 1088 cm −1 . It also shows NH bending and scissoring at 1640 cm −1 which confirms that the lipase is loaded in a microporous structure of MCF . However, the broad peak for moisture at the frequency 3468 cm −1 is seen in both Figure A,B.…”

“…The characteristic spectra of pure MCF at 1088 and 801 cm −1 represent asymmetric stretching band of Si‐O‐Si bond and Si‐O bond due to silica base of MCF (Figure A,B). Figure B for Lip/Pd/MCF shows that the loading of palladium gave rise to bands which appear as a single shoulder to the band at 1088 cm −1 . It also shows NH bending and scissoring at 1640 cm −1 which confirms that the lipase is loaded in a microporous structure of MCF .…”

Development of an electrophoretic method based on nanostructured materials for HbA1c determination

“…The implementation of TMSPBA was evaluated following the procedure described by Sharma, et al. . Boronic acid was exposed on the surface of the silica NPs, capable of interacting in this way with the glyco‐proteins (Fig.…”

Porous and chelated nanostructured multifunctional materials: recoverable and reusable sorbents for extraction of metal ions and catalysts for diverse organic reactions

“…The high activity of this nanocatalyst provided ease in time and cost along with high yield and enhanced dispersion. Since this catalyst provided high turnover frequencies and can be easily reused without loss in its activity, the catalyst proved to be useful for industrial and environmental applications [59].…”