Bio-assisted synthesized Ag(0) nanoparticles stabilized on hybrid of sepiolite and chitin: efficient catalytic system for xanthene synthesis

Abstract

In this work, with the use of two natural compounds, chitin and sepiolite clay, a novel covalent hybrid is fabricated and applied as a support for the stabilization of silver nanoparticles with the aid of Kombucha extract as a natural reducing agent. The resultant catalytic system, Ag@Sep-N–CH, was characterized via XRD, TEM, FTIR, ICP, SEM, TGA, UV–Vis and BET. It was found that fine Ag(0) nanoparticles with mean diameter of 6.1 ± 1.8 nm were formed on the support and the specific surface area of the catalyst was 130 m2 g−1. The study of the catalytic performance of Ag@Sep-N–CH for catalyzing synthesis of xanthenes in aqueous media under mild reaction condition confirmed that Ag@Sep-N–CH exhibited high catalytic activity and could promote the reaction of various substrates to furnish the corresponding products in high yields. Moreover, the contribution of both chitin and sepiolite to the catalysis has been affirmed. It was found that hybridization of these two components led to synergistic effects and consequently improved the observed catalytic activity. Notably, the catalyst was recyclable up to several reaction runs.

Clay-Supported Metal Oxide Nanoparticles in Catalytic Advanced Oxidation Processes: A Review

“…The same scheme was also performed for the dispersion of Ni NPs in montmorillonite [ 156 ] and Pd NPs [ 157 ]. The in situ metal nanoparticle dispersion was actually similar to the ion-exchange method, but the certain amount of metal was chosen without consideration of cationic equilibrium [ 158 , 159 , 160 ]. The dispersion of Au NPs into attapulgite is an example where Au NPs are prepared by the most commonly published method—Frens.…”

“…The solution is then dispersed into clay suspension to produce the nanocomposite. The greenness of using plant extract as a bio-reductor as a replacement for common reductors such as NaBH 4 and other corrosive chemicals is the main consideration for the popularity of this method [ 158 , 164 ]. In addition to the reductor for NPs formation, the secondary metabolites from the plant extracts play roles in maintaining the stability of the nanoparticles.…”

The preparation of polyvinyl imidazole-functionalized magnetic biochar decorated by silver nanoparticles as an efficient catalyst for the synthesis of spiro-2-Amino-4H-pyran compounds

“…Silver nanoparticles are one of the most used metal nanoparticles, and can catalyze some organic transformations. To produce silver nanoparticles, the salt is usually reduced using various reducing agents, such as hydrazine hydrate 8 , 9 . The most advantage is that an expansive amount of nanoparticle material can be produced.…”

A sustainable gateway to access 1,8-dioxo-octahydroxanthene scaffoldsviaa surface-engineered halloysite-based magnetically responsive catalyst

“…Also, a variety of catalysts, such as silica sulphuric acid, CaCl 2 , Fe 3+ −montmorillonite, and Zr(DP) 2 , have been employed for the synthesis of 1,8-dioxo-octahydroxanthene derivatives. 38–47 Though many of the aforesaid reported protocols have certain merits of their own, they still suffer from some intrinsic drawbacks, such as lesser yields, prolonged reaction times, high catalyst loading, use of toxic solvent, non-recyclability or expensive catalysts, or harsh reaction conditions. To overcome these issues, chemists are diverting their attention towards more facile and straightforward strategies that encompass a substantial decrease in reaction times, easy work-up and increased yields that match well with the goals of sustainable and green chemistry.…”