Mn-analcime: Synthesis, characterization and application to cyclohexene oxidation

• We report an easy way to prepare analcime containing Mn in the zeolite framework.
• The use of MnCO3 is a key factor to obtain Mn-analcime.
• Both Mn(IV) and Mn(III) are present in Mn-analcime with Mn(IV)/Mn(III) molar ratio = 4.
• The material is active in oxidation catalysis.
• The incorporation of Mn into the zeolite framework avoids leaching.

The hydrothermal synthesis of Mn-analcime was performed by mixing manganese(II) carbonate, silicic acid and aluminum nitrate in a basic medium in the 120–175 °C temperature range for 6–72 h. Different Mn/Al ratios were used. The obtained samples were characterized by powder XRD, N2 physical adsorption analysis, TGA/DTA, transmission electron microscopy, elemental analysis, IR, XPS, EPR and 29Si and 27Al MAS-NMR spectroscopies. Manganese is probably mostly in the +IV oxidation state and partly substitutes silicon in the zeolite framework. The catalytic properties of Mn-analcime were evaluated in the cyclohexene oxidation reaction and highlight an interesting activity of this material, together with a good recyclability, which make it a promising catalyst for selective oxidation reactions.

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