Oxidative coupling of primary amines to imines under base-free and additive-free conditions over AuNPs/SBA-NH2 nanocatalyst
Abstract
A 4–12 nm sized AuNPs/SBA-NH2 catalyst has been synthesized by post-synthetic functionalization of SBA-15 with propylamine followed by the deposition of Au3+ using AuCl3 as a gold precursor and the reduction of Au3+ to metallic Au using NaBH4 as a reducing agent. The structural and textural characteristics of the AuNPs/SBA-NH2 catalyst have been authenticated by XRD and N2 adsorption techniques. FT-IR spectra validated the functionalized propylamine on the surface of SBA-15. The chemical state of the gold species has been estimated by XPS and XRD techniques. The dispersion and particle size of the Au species have been obtained from CO chemisorption. The particle size of the Au species has also been determined by TEM analysis. The morphology of the AuNPs/SBA-NH2 catalyst has been determined using the SEM technique. The AuNPs/SBA-NH2 catalyst is capable of catalyzing the oxidative coupling of amines to imines effectively with a green O2 oxidant at atmospheric pressure under base-free and additive-free conditions.