Autores: Hazarika, S; Borah, G

Article; Early Access.
Appl. Organomet. Chem.. vol: . page: 0268-2605.
Fecha: . .
Doi: 10.1002/aoc.6864.

The silica-supported cobalt ferrite spinel nanocatalyst has been successfully synthesized by the coprecipitation method and extensively characterized by FTIR, XRD, SEM-EDX, TEM, BET, VSM, XPS, TGA, and ICP-AES analysis. The bands observed at 3435 cm(-1) (nu (OH) of Si-OH) and 1637 cm(-1) (gamma (OH) of Si-OH) in the FTIR spectrum of the as-synthesized nanocatalyst unambiguously tell the presence of silica support. Moreover, a very weak intensity and a medium intensity peak at 683 cm(-1) and 463 cm(-1) suggested intrinsic stretching vibrations of Fe-O and Co-O of cobalt ferrite, respectively. The XRD pattern confirms the formation of CoFe2O4 spinel. The average crystallite size was found to be 5.4 nm as calculated by using the Debye-Scherrer equation based on the (220) plane while the average particle size was found to be 5.08 nm from TEM analysis. The crystalline nature of the nanocomposite was confirmed by the SAED pattern. The successful incorporation of CoFe2O4 on the surface of silica was established by the BET surface area measurements. The silica-supported cobalt ferrite nanocatalyst has been explored as a heterogeneous multifunctional catalyst for hydration of nitriles and oxidative decarboxylation of phenylacetic acids as well under mild reaction conditions with moderate to excellent isolated yield of the desired products (60-99%). The catalyst was magnetically recoverable within a time frame of similar to 90 s and reusable up to the fifth catalytic cycle without profound loss of activity. A magnetic hysteresis study was performed to elucidate the magnetic behavior of the catalyst. The saturation magnetization value of 39.785 emu/g with a coercivity value of 110.87 Oe and saturation remanence value of 5.185 emu/g clearly indicated the presence of a ferromagnetic component in the material..