Nanocomposites and Nanomaterials

Hierarchical zeolites as potential catalyst for Bayer-Villiger oxidations for cyclic ketones using H2O2  
M.M. Kurmach, P.S. Yaremov, K.V. Valihura, O.V.Shvets
 Department of Porous Substances and Materials 
L.V.Pisarzhevskiy Institute of Physical Chemistry of the NAS of Ukraine,                  31 ,Nauky Ave., Kyiv 03028, Ukraine. E-mail:mazinator3710@ukr.net

Bayer-Villiger oxidation process is well known industrial organic process with industrial use, especially, in production of naylone-666 using cyclohexanone as starting material. Although different homoheneous peroxyacids are used as industrial catalysts used, development of new heterogeneous catalysts for Bayer-Villiger oxidations still important role. It is known, that Sn-containing zeolites provide high efficiency in oxidation of some ketones [1], although their activity in process using bulk ketones decreases.   Hierarchical zeolites are promising catalysts for a variety of catalytic process including bulk substrates due to their developed external surface and, consequently, high concentration of active sites available for them. 
Fe-, Sn-, Zr- and Al-containing hierarchical zeolites were obtained using different Gemini-type surfactants as structure-directing agents (SDA) [2]. Significant decrease in particle size allow to increase values of external surface area and mesopore volume values of which achieved up to 400 m2·g–1 and                  1,0 cm3·g–1, consequently. Zeolites possessed a high concentration of Brønsted (BAS) and Lewis acid sites (LAS) (50 – 200 µmole·g–1) available for bulk molecules.
Catalytic properties of Al-, Sn- and Zr-containing hierarchical zeolites were evaluated in oxidation of cyclic ketones with H2O2 as oxidant to ε-caprolactone.  Zr-MTW and AlZr-BEA provide high conversion (up to 65%) of cyclohexanone as well as high selectivity towards desired ε-Caprolactone (up to 90%).

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2.	Choi, M.;  Na, K.;  Kim, J.;  Sakamoto, Y.;  Terasaki, O.; Ryoo, R., Stable single-unit-cell nanosheets of zeolite MFI as active and long-lived catalysts.// Nature. –  2009. – 461, 7261. – P. 246-9