Preparation and characterization of Fe₃O₄@Boehmite core‐shell nanoparticles to support molybdenum or vanadium complexes for catalytic epoxidation of alkenes

Abstract

Fe3O4 core nanoparticles were prepared via a solvothermal process, and then they were covered with a surface hydroxyl‐rich boehmite shell via the hydrothermal‐assisted sol–gel processing of aluminum 2‐propoxide. The outer surface of the boehmite shell was subsequently covalently functionalized with 3‐(tri‐methoxysilyl)‐propylamine or 3‐(tri‐methoxysilyl)‐propyl chloride, and the terminal chlorine groups were treated with imidazole. These compounds were used to support the hexa‐carbonyl molybdenum and oxo‐sulfato vanadium (IV) complexes. The supported catalysts were characterized by the FT‐IR, CHN, ICP, and TEM analysis techniques. They were then used in the epoxidation of cis‐cyclooctene. The catalytic procedures were optimized for different parameters such as the solvent, oxidant, and temperature. The reaction progress was investigated by the gas–liquid chromatography analysis. The catalysts used were simply recovered from the solution by applying a magnet, and recycling the experiments revealed that the heterogeneous nanocatalysts could be repeatedly used for the epoxidation of cis‐cyclooctene. The optimized conditions were also successfully used for the epoxidation of some other alkenes.

Design of a Schiff Base Complex of Copper Coated on Epoxy-Modified Core–Shell MNPs as an Environmentally Friendly and Novel Catalyst for the One-Pot Synthesis of Various Chromene-Annulated Heterocycles

“…The crystalline structure of the Schiff base complex of copper coated on epoxy-modified Fe 3 O 4 @SiO 2 MNPs were measured with the XRD analysis at room temperature (Figure ). As illustrated in Figure , the XRD pattern exhibited reflection peaks at 2θ = 30.17, 35.63, 43.64, 54.04, 57.32, and 63.08°, that are specified to the (220), (311), (400), (422), (511), and (440) crystallographic faces in well in line with the standard XRD pattern of cubic Fe 3 O 4 (JCPDS 88-0866) . These results suggested the acceptable purity of the catalyst.…”

“…As illustrated in Figure 2, the XRD pattern exhibited reflection peaks at 2θ = 30.17, 35.63, 43.64, 54.04, 57.32, and 63.08°, that are specified to the (220), (311), (400), (422), (511), and (440) crystallographic faces in well in line with the standard XRD pattern of cubic Fe 3 O 4 (JCPDS 88-0866). 50 These results suggested the acceptable purity of the catalyst.…”

Pd–Schiff base complex supported on Fe3O4 magnetic nanoparticles: A new and highly efficient reusable catalyst for C–C bond formation in water

“…The XRD pattern of Fe 3 O 4 @Schiff‐base‐Pd is shown in Figure in which the peak positions of 2 θ at 30.17°, 35.5, 43.2°, 53.7°, 57.1° and 62.9° are in agreement with the standard XRD pattern of Fe 3 O 4 nanoparticles . Other peaks at 2 θ values of 39.3°, 45.1° and 66.1° correspond to Pd(0) in Fe 3 O 4 @Schiff‐base‐Pd …”

Grinding Synthesis of 2‐Amino‐4H‐benzo[b]pyran Derivatives Catalyzed By Highly Efficient GPTMS/Guanidine Protected Magnetic Nanoparticles**

“…The XRD pattern of Fe 3 O 4 is depicted in Figure 2a, which displays diffraction patterns consistent with standard JCPDS 88-0866 for pure cubic structure of Fe 3 O 4 . [35] Also, The XRD pattern of Fe 3 O 4 @SiO 2 @GPTMS@guanidine is depicted in Figure 2b sharp peaks of Fe 3 O 4 @SiO 2 @GPTMS@guanidine could be confirmed by the pure phase of the catalyst, which was in accordance with the characteristic peaks of Fe 3 O 4 nanoparticles.…”