Green Synthesis of Silver and Palladium Nanocomposites: A Study of Catalytic Activity towards Etherification Reaction

The work deals with the synthesis of a biomolecule-based monometallic Ag, Pd and bimetallic Ag-Pd nanocomposites and their catalytic activity towards etherification reaction. The as-synthesized nanocomposites were characterized using N2 adsorption-desorption, high-resolution transmission electron microscopy, Fourier transforms infrared spectroscopy, absorption spectroscopy, thermogravimetric analysis, powder X-ray diffraction analysis, X-ray photoelectron spectroscopy and inductively coupled plasma optical emission spectrometry. All three types of the nanocatalysts are based on the formation of a complex between metal and biomolecule, rutin, with association constant (Ka) values of 3833.33 M-1, 606.48 M-1 and 492.36 M-1 for monometallic Ag, Pd and bimetallic AgPd systems, respectively. The nanocomposites showed catalytic activity of towards etherification reactions between different substituted cinnamyl acetate and phenolic compounds under mild and eco-friendly conditions. The values of the products’ yield were of 85-91% with a turnover frequency in a range of 17490-18724 h-1. The best catalyst was shown to be reusable for 4 times without considerable loss in product yield. The catalytic activity of Ag based heterogeneous catalyst towards such O-allylation reaction of phenolic compounds is quite interesting. However, to the best of our knowledge, literature reports based on such reactions using Ag based heterogeneous catalysts are still lacking.