جستجوی مقالات مرتبط با کلیدواژه "cofe2o4" در نشریات گروه "شیمی"

A green and effective method for the synthesis of benzylidene malononitrile derivatives via condensation of different aldehyde and malononitrile in the presence of Acetoguanamine supported on CoFe2O4 magnetic nanoparticles coated by silica gel as a new catalyst at room temperature with ethanol and water solvent was reported. The simple separation of products from the reaction mixture, the improvement of product yields, the short reaction time, and the use of solvents that have relatively less environmental pollution, the easy reaction method, the recoverable and reusable catalysts are the advantages of this method. The 6-methyl-1,3,5-triazine-2,4-diamine supported on CoFe2O4 magnetic nanoparticles coated by silica gel could be recycled five times without significant loss of its catalytic activity. All products were characterized by spectral data and by comparison with authentic samples reported in the literature.

Currently, the need for more efficient materials that work in the visible light spectrum for water treatment has been increasing. A CoFe2O4/CuO nanocomposite was successfully synthesized by co-precipitation method. The obtained nanocomposite was characterized by XRD, DRS, FT-IR and FESEM. X-ray diffraction data showed that the obtained nanoparticle was composed of CoFe2O4 and CuO with average crystal size of 36nm. The optical absorption spectrum of the CuO/CoFe2O4 nanocomposite displayed a band gap of 2.75 eV. The materials showed photocatalytic activity due to the presence of Cu, associated with the magnetic activity of CoFe2O4, which is useful for the separation and recovery of the photocatalyst after use in an oxidative process. Photocatalytic activity was studied by degradation of methylene blue under visible light. Compared with pure CuO, the CoFe2O4/CuO nanocomposite exhibited improved photodegradation performance (about five more time). To optimize process and obtain a mathematical model, CCD (with three factors at five levels) was used. The optimal conditions were determined where the amount of photocatalyst= 1 g/L, irradiation time= 140 min and the concentration of MB= 15 ppm with optimum degradation efficiency as 84.98%. The synthesized CoFe2O4/CuO nanocomposite can be potentially used as a visible-light responsive magnetically separable photocatalyst.

Magnetic nanoparticles of CoFe2O4 were synthesized through a solid-state procedure in agate mortar and then calcined at high temperatures. The obtained CoFe2O4 nanoferrite was characterized by XRD, SEM, FT-IR and VSM techniques and used as catalyst in the one-pot efficient conversion of different epoxides bearing aryl, allyl and alkyl substituents to the corresponding 1,2-diacetoxy esters with acetic anhydride in oil bath 70 ºC under solvent-free conditions. Synthesis of 1,2-dicetates was carried out within 1-4 h with 77-95 yields. The magnetic nanocatalyst was easily separated using an external magnet and reused several times without any significant loss of catalytic activity or magnetic property.