Synergistic effect of GO/SrFe12O19 as magnetic hybrid nanocatalyst for regioselective ring-opening of epoxides with amines under eco-friendly conditions

Abstract

Herein, a highly efficient magnetically separable hybrid GO/SrFe₁₂O₁₉ nanocomposite was synthesized via dispersing M-type strontium hexaferrite (SrFe₁₂O₁₉) on graphene oxide (GO) sheets. First, SrFe₁₂O₁₉ nanoparticles (NPs) and GO sheets were prepared via chemical coprecipitation and chemical oxidation of graphite powder, respectively. Chemically reduced GO (rGO) and rGO/SrFe₁₂O₁₉ were also prepared for comparison purposes. Thereafter, the prepared nanostructured materials were explored by XRD, FTIR, FESEM-EDX, BET, and Zetasizer analyses. All the characterizations confirm the nanoscale and the high stability structures of the prepared materials. The prepared hybrid magnetic nanocomposite GO/SrFe₁₂O₁₉ exhibited a high surface area value resulting in a high catalytic activity and selectivity for the epoxide ring-opening with amines in neat water. The use of hybrid GO/SrFe₁₂O₁₉ compared with pure SrFe₁₂O₁₉ and GO sheets is of great interest for using environmentally benign heterogeneous nanocatalysts, for the synthesis of β-amino alcohols, with excellent recyclability under eco-friendly conditions. Moreover, a mechanistic study was performed through density functional theory (DFT) calculations and Parr functions to explain the observed reactivity and selectivity of SrFe-GO catalyst in the epoxide ring-opening reactions.