Abstract
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•Preparation and characterization of aminopropylsilane–GO (NH2-GO) is reported.•Vanadium complex incorporated Schiff base ligand (catalyst) was synthesized.•Catalyst is used for epoxidation of alkenes using NaHCO3/H2O2 system.•Catalyst show good catalytic activity (98 %) in the oxidation of olefins to epoxides.•The catalyst shows high durability and selectivity.
Catalysts are of great importance in the petrochemical industry, so the design and synthesis of heterogeneous catalysts for this purpose is the most important field in catalysts. In this context, 3-aminopropyltriethoxysilane was grafted into graphene oxide via the condensation reaction, and then the amine terminal groups were utilized to produce azomethine (–C = N–) group using the 3-formyl 4-hydroxy benzoic acid compound. The post-modification approach was used to fabricate the novel vanadium (IV) Schiff-base complex. Characterization was carried out to achieve chemical composition and physical properties such as Raman spectroscopy, FTIR, XRD, XPS, elementary analysis, TGA, FESEM-EDX, AFM, HRTEM, and nitrogen sorption have been performed to realize the grafting vanadium (IV) Schiff base complex on GO. The value of the prepared material as a catalyst was examined for the epoxidation of cyclohexene, cyclooctene, 1-octene, styrene, allyl bromide, and ally alcohol, and styrene. Also, the impact of pH, time, temperature, and catalyst dose was observed. The results showed that the novel catalyst for the epoxidation reaction showed distinct catalytic efficiency. Besides, owing to the strong interaction between the V(IV) ions and chelating moieties in GO, the novel catalyst showed outstanding recycling effectiveness after being used for six subsequent cycles.