Wells-Dawson heteropoly acid immobilized inside the nanocages of SBA-16 with ship-in-a-bottle method: A new recoverable catalyst for the epoxidation of olefins

• Wells-Dawson type heteropoly acid was immobilized into the nanocages of SBA-16 mesoporous material.
• The pore entrance of the SBA-16 was modified in order to prevent the escape of the heteropoly acid molecules.
• The prepared material acted as active, selective, and reusable catalyst in the epoxidation of olefins with H2O2.

Wells-Dawson structured heteropoly acid (H6P2W18O64) was immobilized into the SBA-16 mesoporous material by ship-in-a-bottle method. The obtained material was characterized by Fourier transform infrared (FT-IR) and inductively coupled plasma-atomic emission (ICP-AES) spectroscopies, X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption–desorption analysis, and thermogravimetric analyses (TGA-DTA). The results indicated that the surface area of SBA-16 support decreased after immobilization of the heteropoly acid and next modification with silylating agent. The prepared material exhibited excellent catalytic performance in the epoxidation of olefins and allylic alcohols in the presence of hydrogen peroxide as green oxidant. The catalyst showed all of the expected advantages of the heterogeneous systems and was shown to be recoverable and reusable several times without major loss of activity.

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