Nanocrystalline sodalite: Preparation and application to epoxidation of 2-cyclohexen-1-one with hydrogen peroxide

In this study, we have synthesized nanocrystalline sodalite and investigated its activity for the epoxidation of alpha,beta-unsaturated ketone with hydrogen peroxide. Nanocrystalline sodalite was prepared by hydrothermal synthesis using sodium metasilicate (Na2SiO3 center dot 9H(2)O), sodium aluminate (NaAlO2), and sodium chloride at 423 K. The obtained samples were characterized by X-ray diffraction, the Brunauer-Emmet-Teller (BET) method using nitrogen adsorption isotherms, scanning electron microscopy (SEM), and energy dispersive X-ray analysis. The maximum BET surface area of the nanocrystalline sodalite prepared in this study was 73 m(2) g(-1), and the average crystallite diameter of the sample was determined to be 47 nm by SEM. Nanocrystalline sodalite was found to promote the epoxidation of 2-cyclohexen-1-one with hydrogen peroxide. Epoxidation was observed to proceed mainly in the liquid phase and not on the surface of the nanocrystalline sodalite, and nanocrystalline sodalite was found to play a role in the pH adjustment of the liquid phase, which was required for the reaction to proceed. Further, nanocrystalline sodalite could be easily recovered by filtration after the epoxidation of 2-cyclohexen-1-one and used repeatedly for the reaction. (C) 2012 Elsevier B.V. All rights reserved.