Memory effect of hydrotalcites and its impact on cyanoethylation reaction

The aim of this work is to study the changes of hydrotalcites structure when is subjected to gradual multiple calcination/hydration treatments in the presence of water or alkaline solution with the same composition like in co-precipitation step and then to analyze its influence on the catalytic activity in the cyanoethylation reaction between ethanol and acrylonitrile with the main product being beta-ethoxypropionitrile according to these treatment. The samples were characterized by elemental analysis, XRD, DRIFT, CO2-TPD.

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► Memory effect by means of alkaline solution extract aluminum from hydrotalcite-type structure.
► After several hydration/calcination cycles the Mg and Al cations migrate to stable MgAl2O4 spinel.
► Replacing of carbonic anions from interlayer with hydroxyl groups lead to a pronounced basic character of catalysts.
► The activity of samples in cyanoethylation reaction depends mostly by basicity of samples.