ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

In situ synthesis of bimetallic γ-Fe₂O₃/Cu nanoparticles over pectin hydrogel obtained from biomass resource (orange peel) as a reusable green catalyst for oxidation and C-S cross-coupling reactions

Nasrin Yarmohammadi, Mohammad Ghadermazi, Zohreh Derikvand, and Roya Mozafari

Department of Chemistry, University of Kurdistan, Sanandaj, Iran

E-mail: mghadermazi@yahoo.com

Received: 10 December 2021  Accepted: 7 March 2022

Abstract:

The incorporation of nanoparticles into the hydrogel matrix empowers the development of innovative catalytic materials with improved properties. Pectin is a heteropolysaccharide containing a large number of hydroxyl, carbonyl, and carboxylic acid functional groups that were selected as suitable support. Then, in the presence of calcium chloride pectin hydrogel was prepared by physical cross-linking. After that, the iron and copper nanoparticles were loaded on their surface and used as an efficient and biodegradable catalyst. The synthesized bimetallic nanocatalyst was characterized via FESEM, VSM, TGA, ICP, XRD, EDX, BET, TEM, and FT-IR techniques. The morphology and structure studies revealed that pectin matrix hydrogel can efficiently load nanoparticles and also prevent the agglomeration of nanoparticles. Catalytic performances of γ-Fe₂O₃/Cu@HPECGs nanocomposite were investigated in the oxidative coupling of thiols to disulfides in the presence of hydrogen peroxide (H₂O₂) as a green oxidant. In addition, γ-Fe₂O₃/Cu@HPECGs nanocatalyst can synthesize symmetric sulfides in a one-pot method with thiourea as the sulfur source under mild conditions. In comparison to pure iron nanoparticles, the addition of Cu nanoparticles increased the catalytic efficiency. These procedures provide applicable strategies with yields as high as 90% and high selectivity. This bimetallic catalyst can be recycled nine times without changing its structure, activity, and selectivity.

Graphical abstract

Keywords: Pectin; Hydrogel; Heterogeneous catalyst; Nanocomposite; Disulfide; Symmetrical sulfide

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02174-4

Chemical Papers 76 (7) 4289–4307 (2022)