Catalytic Performance of [Fe] for Regioselective Ring-opening of Epoxides

In this work, the ring-opening of epoxides was realized using cheap and abundant iron-based catalysts, in which Fe(BF4)(2)center dot 6H(2)O showed the best catalytic effects. The results showed that aldehyde could be obtained with high selectivity in this reaction. The ring-opening of 1,2-epoxyoctane in the presence of 0.01 mmol Fe(BF4)(2)center dot 6H(2)O was applied with 1,4-dioxane as solvent, the yield of octanal was up to 98% with a selectivity of 99%. Gratifyingly, this catalytic system was suitable for a variety of alkyl- and aryl-substituted epoxides. Furthermore, the recycling experiments showed that Fe(BF4)(2)center dot 6H(2)O could maintain excellent catalytic activities when reused for three times, but then deactivated dramatically at the fourth recycle. In order to further understand the reason of catalyst deactivation, Fourier Transform infrared spectoscopy (FTIR), X-ray diffraction (XRD), X-ray fluorescence (XRF) and thermal gravimetric analysis (TGA) were used to analyze the catalyst. It was found that the reason of deactivation was the loss of B and F elements during the reactions, which affected the structure of the catalyst, as well as the coordination ability with epoxides. These findings further proved the mechanism of this reaction and revealed the reason of deactivation, and also provided a theoretical basis for the efficient application of this type of catalysts in homogeneous systems.