Synthesis, Characterization, and Catalytic Activity of Pd(II) Salen-Functionalized Mesoporous Silica

Abstract

Salen ligand synthesized from 2-hydroxybenzaldehyde and 2-hydroxy-1-naphthaldehyde was used as a palladium chelating ligand for the immobilization of the catalytic site. Mesoporous silica supported palladium catalysts were prepared by immobilizing Pd(OAc) 2 onto a mesoporous silica gel through the coordination of the imine-functionalized mesoporous silica gel. The prepared catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), inductivity couple plasma (ICP), nitrogen adsorption-desorption, and Fourier transform infrared (FT-IR) spectroscopy. The solid catalysts showed higher activity for the hydroamination of C-(tetra-O-acetyl--D-galactopyranosyl)allene with aromatic amines compared with the corresponding homogenous catalyst. The heterogeneous catalytic system can be easily recovered by simple filtration and reused for up to five cycles with no significant loss of catalytic activity.

Investigation of palladium catalysts in mesoporous silica support for CO oxidation and CO2 adsorption

“…Catalytic Pd can exist in two stable phases (PdO or Pd 0 ) depending on the oxygen concentration and reaction temperature, which enables a wide operating temperature range [ 13 ]. However, the properties of Pd catalysts are highly influenced by preparation conditions, the type and chemical nature of the support, and Pd particle dispersion within the support [ [14] , [15] , [16] ].…”

CO Oxidation Efficiency and Hysteresis Behavior over Mesoporous Pd/SiO2 Catalyst

“…In recent years, "metal oxide supported palladium catalysts" have been studied in detail due to their high intrinsic activity, lower cost, metal-support interaction, and other non-linear dynamic behaviors, which are beneficial for CO oxidation [2,3]. The properties of Pd catalysts are affected by types of support, preparation conditions, and the dispersion of the Pd particles [4]. Support materials are a crucial factor in the catalytic behavior of Pd toward CO oxidation where the synergistic effect between Pd and the support depends on the nature of support (i.e., reducible vs. non-reducible) [5].…”