New bio-nanocomposites based on iron oxides and polysaccharides applied to oxidation and alkylation reactions

How the Chemical Properties of Polysaccharides Make It Possible to Design Various Types of Organic-Inorganic Composites for Catalytic Applications

Recently, the use of plant-origin materials has become especially important due to the aggravation of environmental problems and the shortage and high cost of synthetic materials. One of the potential candidates among natural organic compounds is polysaccharides, characterized by a number of advantages over synthetic polymers. In recent years, natural polysaccharides have been used to design composite catalysts for various organic syntheses. This review is devoted to the current state of application of polysaccharides (chitosan, starch, pectin, cellulose, and hydroxyethylcellulose) and composites based on their catalysis. The article is divided into four main sections based on the type of polysaccharide: (1) chitosan-based nanocomposites; (2) pectin-based nanocomposites; (3) cellulose (hydroxyethylcellulose)-based nanocomposites; and (4) starch-based nanocomposites. Each section describes and summarizes recent studies on the preparation and application of polysaccharide-containing composites in various chemical transformations. It is shown that by modifying polysaccharides, polymers with special properties can be obtained, thus expanding the range of biocomposites for catalytic applications.

Pluronic F127-assisted partial decomposition of ammonium phosphomolybdate and its application as an efficient and recyclable catalyst for the alkylation of toluene with benzyl alcohol

The thermal decomposition of ammonium phosphomolybdate was adjusted by F127 to obtain an efficient and recyclable catalyst for liquid-phase alkylation.

Insight into 6-aminopenicillanic acid structure and study of the quantum mechanical calculations of the acid–base site on γ-Fe2O3@SiO2 core–shell nanocomposites and as efficient catalysts in multicomponent reactions

Magnetic 6-APA/γ-Fe₂O₃@Sio₂ nanocomposites have been developed by exploiting the potential of the acid–base bifunctional system to study the quantum mechanistic calculations.

Versatile Sulfathiazole-Functionalized Magnetic Nanoparticles as Catalyst in Oxidation and Alkylation Reactions

Catalyst design and surface modifications of magnetic nanoparticles have become attractive strategies in order to optimize catalyzed organic reactions for industrial applications. In this work, silica-coated magnetic nanoparticles with a core-shell type structure were prepared. The obtained material was successfully functionalized with sulfathiazole groups, which can enhance its catalytic features. The material was fully characterized, using a multi-technique approach. The catalytic performance of the as-synthesized material was evaluated in 1) the oxidation of benzyl alcohol to benzaldehyde and 2) the microwave-assisted alkylation of toluene with benzyl chloride. Remarkable conversion and selectivity were obtained for both reactions and a clear improvement of the catalytic properties was observed in comparison with unmodified γ-Fe2O3/SiO2 and γ-Fe2O3. Noticeably, the catalyst displayed outstanding magnetic characteristics which facilitated its recovery and reusability.

Mechanochemically Synthesized Supported Magnetic Fe-Nanoparticles as Catalysts for Efficient Vanillin Production

Magnetically separable nanocatalysts were synthesized by incorporating ironnanoparticles on a mesoporous aluminosilicate (Al-SBA-15) through a mechanochemical grindingpathway in a single step. Noticeably, magnetic features were achieved by employing biomass wasteas a carbon source, which additionally may confer high oxygen functionalities to the resultingmaterial. The resulting catalysts were characterized using X-ray diffraction, X-ray photoelectronspectroscopy, transmission electron microscopy, scanning electron microscopy, porosimetry, andmagnetic susceptibility. The magnetic nanocatalysts were tested in the selective oxidative cleavagereaction of isoeugenol and vanillyl alcohol to vanillin. As a result, the magnetic nanocatalystsdemonstrated high catalytic activity, chemical stability, and enormous separation/reusabilityqualities. The origin of catalytic properties and its relationship with the iron oxide precursor wereanalyzed in terms of the chemical, morphological, and structural properties of the samples. Suchanalysis allows, thus, to highlight the superficial concentration of the iron entities and the interactionwith Al as key factors to obtain a good catalytic response.