Nanocomposites and nanomaterials

Dimethyl branched isomers in the products of n-hexane hydroisomerization on modified mordenite-containing rock
Voloshyna Yu.G., Pertko O.P., 
Povazhnyi V.A., Patrylak L.K., Yakovenko A.V.
Department of Catalytic Synthesis, V.P Kukhar Institute of Bioorganic Chemistry and Petrochemistry of the NAS of Ukraine. Murmanska Str., 1, Kyiv-02094, Ukraine.
E-mail: yule.v444@gmail.com

Dimethyl branched isomers, having the highest octane numbers among hexane isomers, are the most valuable products of isomerization of the pentane-hexane fraction of oil, so the study of factors determining the selectivity of their formation is topical. In particular, there is no consensus as for the influence on the selectivity of the open areas of zeolite: mesopores, external surface etc. [1,2]. The aim of the work was to determine the influence of the parameters of porous structure of the catalysts based on modified mordenite-containing rock of Transcarpathia on the dimethylbutane (2,2-DMB) formation in n-hexane isomerization. To exclude the possible influence of mesopores as transport pores, the reaction was carried out in micro pulse mode.
The general tendency of decreasing 2,2-DMB selectivity for the samples of different obtaining procedure with an increase in the share of the mesopores prevailing in volume (ø ~2.4 nm) is shown. Consequently, despite the larger critical diameter of molecules, 2,2-DMB is formed more selectively inside zeolite micropores than in mesopores. This is due to steric hindrance to diffusion of reagent molecules in micropores, which prolongs their contact with the active surface and increases the probability of secondary transformations towards 2,2-DMB.
The publication contains the results of research carried out under the grant from the National Research Foundation of Ukraine (Project 2020.01/0042).

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