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One‐pot synthesis of acetamides, benzimidazoles, and benzothiazoles are central reactions for synthesizing pharmaceuticals and fine chemicals. Despite tremendous progress in heterogeneous catalysis, the synthesis of these nitrogen‐containing compounds still remains challenging. Here, we report an efficient, simple, and cost‐effective nitrogen‐doped CeO2‐supported Co single‐atom catalyst (SAC) (Co/N‐CeO2) enabled synthesis of acetamides, benzimidazoles, and benzothiazoles. As far as we know, this is the first to report that SACs catalyze the synthesis of acetamides, benzimidazoles, and benzothiazoles. Detailed spectroscopic characterization revealed the structure of catalytic center. Harnessing the catalytic activity of SACs, the work offers promising routes for future synthesis of heterocycles. [ABSTRACT FROM AUTHOR]

In this work, an efficient, green and retrievable heterogeneous chitosan-supported antimony trichloride catalyst (SbCl3@Chitosan) was synthesized by dispersing antimony trichloride on amine functionalized chitosan modified with methyl salicylate and characterized by using Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Powder X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and ICP-AES analysis. FTIR indicated the various functionalities present in the catalyst such as 3299–3367 cm−1 (N–H and O–H), 2924 and 2874 cm−1 (C–H), 1424 cm−1 (CH2), 1376 cm−1 (CH3), 1151 cm−1 (C–O–C), 1059 and 1020 cm−1 (C–O of chitosan), 1559 cm−1 (C–N), 1653 cm−1 (C = O stretching of amide), 1302 and 1376 cm−1 (Sb–Cl). TGA showed that the catalyst was stable upto 200 °C thereby determining its thermal stability. The characteristic peaks appeared in the powder XRD of the catalyst confirmed the crystal face of antimony. The surface morphology of the catalyst revealed through SEM images exhibited a uniform distribution, and the majority of particles displayed a near-spherical morphology. ICP-AES analysis data revealed the overall content of antimony present in the synthesized catalyst. The catalytic activity of the catalyst was evaluated for the synthesis of 1,2,4,5-tetrasubstituted imidazoles under green reaction conditions. The present method for the synthesis of tetrasubstituted imidazoles has broader significance due to synthesis of various imidazole derivatives in high to excellent yields (83–95%) with short reaction times and high purity under solvent-free conditions with a simple work-up procedure. Moreover, the aforementioned catalyst (SbCl3@Chitosan) could be easily separated from the reaction mixture and reused for five runs without any decline in its catalytic activity. [ABSTRACT FROM AUTHOR]

Copper (II) acetate is covalently anchored onto the surface of chemically modified starch and the resultant heterogeneous catalyst was investigated for the regioselective synthesis of 1,4-disubstituted-1,2,3-triazoles via Huisgen 1,3-dipolar cycloaddition reaction between terminal alkynes, benzyl/allyl/alkyl halides and NaN3 in distilled water at room temperature. Further, starch functionalized copper (II) acetate could be recovered by simple filtration and recycled up to several consecutive runs without loss of significant activity. The catalyst is characterized by FTIR, thermal analysis, XRD, SEM, TEM, and AAS. [ABSTRACT FROM AUTHOR]

Green chemistry has fostered research on recyclable, insoluble and easily separable heterogeneous catalysts. Carbon materials are widely used for renewable energy and environmental studies. Here, we review the synthesis, properties and applications of carbon solid acids in the form of biomass, polymers, and carbon/silica-based catalysts. We show in particular that mesoporosity has a major role in catalysis, notably when bulk materials are transformed into valuable products. [ABSTRACT FROM AUTHOR]

Abstract: Nano palladium(0) supported on cellulose was found to be highly efficient recyclable heterogeneous catalyst for the Suzuki coupling between aryl bromides and phenyl boronic acid in water and aerobic oxidation of benzyl alcohols using air as the source of molecular oxygen in acetonitrile. The Cell-Pd(0) was prepared by stirring commercially available cellulose with Pd(OAc)2 in ethanol at 25°C followed by reduction with hydrazine hydrate, leading finally to nano Pd(0) particles uniformly distributed on surface of cellulose. This catalytic system provides biaryls and polyaryls in excellent yields with very high turn over numbers via Suzuki coupling; and benzaldehyde derivatives in high yields and selectivity by oxidation in air. Cell-Pd(0) was characterized by X-ray diffraction techniques (XRD), thermal analysis (TGA), scanning electron microscope (SEM) and transmission electron microscope (TEM). [Copyright &y& Elsevier]