Oxidative coupling of primary amines to imines under base-free and additive-free conditions over AuNPs/SBA-NH2 nanocatalyst

A 4-12 nm sized AuNPs/SBA-NH 2 catalyst has been synthesized by post-synthetic functionalization of SBA-15 with propylamine followed by the deposition of Au 3+ using AuCl 3 as a gold precursor and the reduction of Au 3+ to metallic Au using NaBH 4 as a reducing agent. The structural and textural characteristics of the AuNPs/SBA-NH 2 catalyst have been authenticated by XRD and N 2 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-NH 2 catalyst has been determined using the SEM technique. The AuNPs/SBA-NH 2 catalyst is capable of catalyzing the oxidative coupling of amines to imines effectively with a green O 2 oxidant at atmospheric pressure under base-free and additive-free conditions. Oxidative coupling of benzylamines to N -benzylbenzylimines under base- and additive-free conditions is achieved over AuNPs/SBA-NH 2 . Facile preparation, high activity, ease of separation and good reusability are the credentials of AuNPs/SBA-NH 2 catalyst.