Heterogeneous Hybrid Nanocomposite Based on Chitosan/Magnesia Hybrid Films: Ecofriendly and Recyclable Solid Catalysts for Organic Reactions

Abstract

Chitosan/magnesia hybrid films (CS-Mg) have been prepared via sol-gel process and employed as heterogeneous catalysts. An in situ generation of a magnesia network in the chitosan matrix was performed through hydrolysis/condensation reactions of magnesium ethoxide. The synthesized hybrid films were characterized using various analytical techniques, such as X-ray photo-electron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The hybrid films display excellent catalytic activities in Michael and Knoevenagel reactions via one pot or solvent-free approaches under microwave irradiation conditions. Chitosan/magnesia hybrid films, catalysed pyrimidine, benzochromene, coumarin and arylidene-malononitriles derivatives formation reactions occurred with highly efficient yields of 97%, 92%, 86% and 95% respectively. Due to the fact that the films are durable and insoluble in common organic solvents, they were easily separated and can be recycled up to five times without a considerable loss of their catalytic activity.

Chitosan-Strontium Oxide Nanocomposite: Preparation, Characterization, and Catalytic Potency in Thiadiazoles Synthesis

“…Structural lineaments of the unmodified chitosan (A), and chitosan-strontium oxide composites with 10 wt.% (B), were explored by measuring X-ray diffraction technique as seen below in Figure 5 . In Figure 5 A, the usual peak of chitosan appeared at 2θ (16–22°), which in agreement with the literature values of the hydrated crystalline structure of chitosan [ 25 , 26 ]. In Figure 5 B, the XRD pattern showed the same characteristic peak of chitosan but with slight depression as result of the coordination between strontium oxide molecules and chitosan chain.…”

“…Modified microwave aided solution casting was used to synthesize chitosan-Strontium (CS/SrO) nanocomposite films [ 25 , 26 , 27 ]. Dissolving medium molecular weight chitosan in a 2 percent ( w / v ) aqueous acetic acid solution for 48 h at room temperature yielded a 2 wt.% chitosan solution.…”

Use of a bioresource nanocomposite as a heterogeneous base catalyst for the green synthesis of novel bioactive pyrazoles: antibacterial evaluation using molecular docking

“…Polymeric nanocomposites have been used for base-catalyzed reactions. [5][6][7] Chitosan (CS) possesses excellent properties: it is biodegradable, non-toxic and insoluble in most solvents. Despite these advantages, chitosan is unable to form a film or membrane, as it forms a gel when cast.…”

Chitosan Capped Copper Oxide Nanocomposite: Efficient, Recyclable, Heterogeneous Base Catalyst for Synthesis of Nitroolefins

“…Due to their unique features and vast range of applications as potent catalytic agents in various organic transformations, nano catalysis has attracted the interest of many researchers [1][2][3]. Nano catalysts have emerged as a low-cost, long-term alternative to hazardous commercial catalysts since they contain nanosized particles with a large, exposed surface area, which increases catalytic activity and regioselectivity in a variety of chemical processes [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19].…”

“…For the above-mentioned reasons, and because of their vast range of applications in numerous disciplines, many efforts have been made to synthesize new hybrid materials, including metal oxide nanoparticles. In particular, these hybrid nanocomposites confer a considerable synergistic effect, as compared to their constituents, that increases their potential use in many applications, especially in the field of heterogenous catalysis [14][15][16][17][18][19][20][21]. Solid catalysts have unique characteristics such as a large surface area, a high atom economy, and the ability to be easily removed from the product, recovered, and reused multiple times without losing catalytic activity.…”