Physico-Chemical nanomaterials science
Composites of hierarchical zeolites with basic metal oxides as catalysts for 2-aminotiophenes production by Gewald reaction
Kurmach M.M.1, Konysheva K.M.1, Yaremov P.S.1, Babiy S.B.2, Shvets O.V1, Fetiukhin V.M.2
1 L.V. Pisarzhevskii Institute of Physical Chemistry of the NAS of Ukraine,.  Prospect Nauki 31, Kyiv-03028, Ukraine
E-mail: mazinator3710@ukr.net
2I.F.lab LTD, 
Murmanska str 5, Kyiv-02660, Ukraine

Production of 2-aminothiophenes from ketones, sulfur and malonodinitrile is possible by Gewald reaction, which proceeds in 2 stages (fig.1): the first stage between ketone and malonodinitrile (also known as Knoevenagel reaction) followed by reaction between 2 and sulfur. Basic compounds are widely used as catalyst for this process [1]. Hierarchical zeolites with developed external surface are effective catalysts for transformations including bulk molecules. It is expected that dopped with basic oxides hierarchical zeolites due to high dispersion of oxides particles will be effective catalysts for this process. Cesium forms of hierarchical zeolites obtained by ion exchange, while Mg-, Ti-, Zn-containing zeolites were synthesized by impregnation method. Catalytic properties of the synthesized materials were investigated in the Gewald process of converting cyclohexanone (1) and other cyclic ketones to 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carbonitrile (3) (Fig. 1). Almost quantitative yield of target 2-aminotiophene is achieved for Cs- and Mg-containing hierarchical BEA zeolites due optimal strength and concentration of basic sites.

Fig 1. Scheme of Gevald process of 2-amino-4,5,6,7-tetrahydrobenz[b]tiophene-3-carbonitrile (3) production.

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