Nanocomposites and nanomaterials

Catalytic properties of nanocomposites based on metal oxides and hierarchical zeolites (0D, 1D or 2D) in fine chemical synthesis reaction
Shvets O.V., Kurmach M.M., Konysheva K.M.
Department of porous substances and materials, Institute of Physical Chemistry of the NAS of Ukraine. Prospect Nauki, 31, Kyiv-03028, Ukraine. 
E-mail: alexshvets@ukr.net

Hierarchical zeolites were obtained using Gemini-type surfactants as structure-directing agents (SDA). Zeolite BEA, MTW and MOR nanosheets, MTW and MOR nanoneedles and BEA and MTW nanosponges were obtained using different SDA molecules [1]. A significant narrowing in the particle size of hierarchical zeolites increases the value of the specific external surface and mesopore volume compared with the "traditional" analogues, reaching values ​​of 700 m2·g–1 and 1.4 cm3·g–1, respectively. High availability of active centers for bulk molecules were reached for these materials (up to 85%) [2].
The type and concentration of isomorphically incorporated elements in the zeolite framework determines the ratio of the Lewis and Brønsted acid centers concentrations of the and the catalytic properties of the synthesized materials. In particular, Ga- and B-containing hierarchical zeolites are characterized by high selectivity in 2-bromindenol dehydration processes (yield of target product was greater than 96%), while Al-containing are more selective in processes involving 2-bromindenol derivatives. Due to the presence of strong acid centers Al-containing hierarchical zeolites are characterized by high activity in the processes of obtaining diethoxyethane and other acetals, the synthesis of coumarins by the Pechman reaction. Nickel-doped hierarchical Al-MFI and Al-MOR exhibit high selectivity for 2,2- and 2,3-dimethylbutane in the n-hexane hydroisomerization process. Cs, Mg, Zn, Ti-containing hierarchical zeolites are effective catalysts for the production of bulk 2-aminothiophenes by the Gevald process. High activity of Cu-dopped hierarchical zeolites (Cu/Zr-MTW) in the conversion of ethanol into 1,3-butadiene by the Lebedev process was revealed. Selectivity for 1,3-butadiene for the best samples reaches 81% at ethanol conversion of 61%.

1.	Shvets O.V., Konysheva K.M., Shamzhy M.V., et all. // Catalysis Today – 2019.- P. 115–122.
2.	Konysheva K.M., Yaremov P.S., Chernenko Zh.V., Filonenko S.M., Shvets O.V. // Theoret. Exper. Chem. – 2017.-53.-P. 410-415.