Oxidant free dehydrogenation of alcohols using chitosan/polyacrylamide entrapped Ag nanoparticles

Abstract

Silver nanoparticles encaged in a nanoporous chitosan/ polyacrylamide interpenetrating polymer network (Ag@IPN) were synthesized and characterized by various techniques such as Fourier Transform Infra Red (FTIR), X-ray Diffraction (XRD), Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDX), Transmission Electron Microscopy (TEM), Thermogravimetric Analysis (TGA) and ICP-AES. This material exhibits good catalytic activity for the oxidant free dehydrogenation of alcohols to the corresponding carbonyl compounds. The reusability of Ag@IPN for this reaction was compared with a chitosan-silver complex under the same reaction conditions. It was found that encaging silver nanoparticles in interpenetrating polymer networks (IPN) has improved their stability by avoiding leaching and aggregation.

Silver nanoparticles immobilized onto poly(4‐vinylpyridine)‐functionalized magnetic nanoparticles: A robust magnetically recyclable catalyst for oxidant‐free alcohol dehydrogenation

“…Also, O 2 ‐sensetive functional groups in the primary and secondary alcohols do not change in the oxidant‐free dehydrogenation of alcohols. In recent years, several homogeneous and heterogeneous catalysts have been designed and synthesized for oxidant‐free or acceptor‐free oxidation of alcohols . However, the designing of highly recyclable heterogeneous systems still remains a significant challenge for oxidant‐free dehydrogenation of alcohols.…”

Dehydrogenation of Alcohols over Alumina‐Supported Silver Catalysts: The Role of Oxygen in Hydrogen Formation

“…Hence, in this work, we investigated the release of hydrogen by alcohol dehydrogenation in open and closed systems. We chose Ag as the catalyst as it is known to be active in alcohol dehydrogenation . Furthermore, the interaction of oxygen with Ag has been well studied as Ag is an industrially important catalyst for the production of ethylene oxide from ethylene and formaldehyde from methanol …”

“…Similarly,s upported Ag was reported to catalyzeg as-and liquid-phase alcohol oxidation with high yields of the carbonyl compounds. [30][31][32][33][34][35][36] In recent years, the acceptorless or oxidant-free dehydrogenation of alcohols (Scheme 1, route b) has attracted considerable interesta st he generation of hydrogen from bioalcohols could be utilized in fuel cells as ac arbon-neutral means of locomotion.A dditionally,t he absence of oxygen is aw orthwhile safety consideration. However,f rom at hermodynamics point of view,o xidant-free dehydrogenation reactions are energetically uphill with ap ositive enthalpy of reaction.…”

“…Despite the unfavorable energetics, there are many reports of apparently acceptorless dehydrogenation at lowt emperatures of 78-155 8C. [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51] In many studies, only the disappearance of the alcohol and the formation of the carbonyl product were followed, but in some investigations,t he reactionp roceeded in ac losed system in which the evolution of gaseous hydrogen wasf ollowed by gas burettem easurement or by intermittent sampling of the head space and analysis by GC or MS. [41-43, 45, 46] The high activity of the catalyst, the action of special ligands that push the reactioni no ne direction, as upport…”

Ag‐nanoparticle embedded p(AA) hydrogel as an efficient green heterogeneous Nano‐catalyst for oxidation and reduction of organic compounds

“…3.4 | Comparison with other reported catalytic system Table 3 provides a comparison of the NP reduction results obtained (k app and E a ) for our present catalytic system with those reported in the literatures. [43][44][45][46][47][48][49][50][51] Also, oxidation of benzyl alcohol under heterogeneous conditions over a variety of catalysts has been studied [52][53][54][55][56][57] ( Table 4). From Table 3 and 4, it is seen that p(AA)-Ag showed higher catalytic activity over reported catalysts.…”