Immobilized molybdenum acetylacetonate complex on montmorillonite K-10 as catalyst for epoxidation of vegetable oils

Heterogeneous catalyst was obtained by the direct immobilization of molybdenum compound on montmorillonite K10 clay. The resultant solid was characterized by inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray diffractometry (XRD), scanning electron microscopy coupled in a energy dispersive X-ray spectrometer (SEM-EDS), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Brunauer–Emmett–Teller and Barret–Joyner–Halenda isotherms (BET/BJH), ultraviolet–visible diffuse reflectance spectroscopy (UV–vis-DRS) and Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR). The catalyst was tested for the epoxidation of both soybean and castor oils, using tert-butyl hydroperoxide (TBHP) as oxidizing agent. After the first use, the immobilized catalyst showed an enhanced activity and also catalytic stability in recycling experiments. The best results for epoxidation reactions concerning castor oil were observed under conditions of 80 °C for 24 h (100% conversion and 75% selectivity) and catalytic reuse.

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► In this work, molybdenum (VI) complex was immobilized onto montmorillonite clay.
► The catalyst was tested for the epoxidation of both soybean and castor oils.
► The catalyst showed high performance for epoxidation reactions of vegetable oils.
► After the first use, the catalyst showed an enhanced activity in recycling experiments.
► The best results for epoxidation reactions were obtained for castor oil.