In this research, Keggin-type polyoxometalate, H5PMoV2O40 (denoted as PMoV) was immobilized on modified NiFe2O4 nanoparticles to produce a magnetically separable catalyst. This catalyst was characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), cyclic voltummetry (CV), energy dispersive X-ray (EDX) and UV-vis diffuse reflectance spectroscopy (UV-DRS). The catalytic activity of synthesized catalyst in oxidation of dibenzothiophene (DBT) to dibenzothiophene sulfone (DBTO2) was investigated using H2O2 as an oxidant and acetonitrile as an extractant. The catalyst could be readily separated from the catalytic system using the magnetic field; and loss of activity was negligible when the catalyst was recovered in five consecutive runs. The effects of main process variables including H2O2 amount (mmol), reaction temperature (°C) and reaction time (min) were analyzed by response surface methodology (RSM) based on the central composite design (CCD). The optimal condition for conversion of DBT was found to be H2O2 2.8 mmol, reaction temperature 42°C and reaction time 57 min for 0.1 g of catalyst dosage. The conversion of DBT to DBTO2 under optimized conditions was 85.9 %. Moreover, the dibenzothiophene sulfone product was characterized by NMR, FT-IR, Mass and GC analysis. پرونده مقاله

An efficient and green protocol for the synthesis of pyrazoles derivatives by one-pot reaction of different 1,3-dicarbonyl compounds with hydrazines/hydrazides has been developed using nano-sulfated zirconia, nano-structured ZnO, nano-g-alumina and nano-ZSM-5 zeolites, as the catalyst. The optical properties of the nano-structured catalysts and organic molecules were studied. The advantages of methods are short reaction times and milder conditions, easy work-up and purification of products by non-chromatographic methods. The catalysts can be recovered for subsequent reactions and reused without any appreciable loss of efficiency. پرونده مقاله