Efficient and recyclable gold nanoparticles as catalysts for the cleaner production of 4-morpholinoanilines used as pharmaceutical building blocks

摘要: Abstract Gold nanoparticles (Au-NPs) stabilized with PEGylated Poly(amidoamine) (PEG-PAMAM) dendrimers were successfully prepared in mild aqueous conditions; they evaluated as efficient and recyclable catalysts for the cleaner reduction of 4-morpholinonitrobenzenes (MNBs) to 4-morpholinoanilines (MANs), which have pharmaceutical significance. Transmission electron microscopy, UV–visible spectroscopy, X-ray photoelectron dynamic light scattering experiments performed confirm formation stable Au-NPs aggregates, mean particles sizes 1.6–4.0 nm. Catalytic reactions conducted at room temperature using sodium borohydride a reducing agent instead hydrazine, representing significant progress toward more environmentally friendly catalytic methods. The showed high efficiency MNBs MANs, achieved maximum conversion rates >98% less than 4 min, no byproduct was detected. Pseudo-first order rate constants 0.78–1.32 s−1 obtained turnover number 964, is 2.4-fold higher that best catalyst MNB reported literature. PEG-PAMAM-Au catalyst, recovered via dialysis, remained active after 7 consecutive cycles, negligible metal leaching. This system exhibited enhanced activity substituted derivatives, are used building blocks chemical industry. Thus, our results provide valuable, practical, green method by aromatic amines relevance can be gold-based catalysts.