FTIR study of the interaction of hydrogen cyanide with alkali-metal ion, silver(I) and nickel (II) ion-exchanged near-faujasite zeolites

Abstract

The uptake of hydrogen cyanide by alkali-metal ion-exchanged near-faujasite zeolites involves Lewis acid binding of hydrogen cyanide by the alkali-metal ions such that the —CN stretch wavenumber depends on the ionic radii. In the case of lithium and sodium ion-exchanged X and Y zeolite there is a significant formation of characteristic Brønsted acid sites resulting from protonation of the zeolite along with formation of cyanide ion by a reversible process. The uptake of hydrogen cyanide by silver(I) ion-exchanged Y zeolite results in the reversible formation of silver cyanide and zeolite Brønsted acidity. Similar treatment of nickel(II)-exchanged zeolite Y involves Lewis acid complexation of hydrogen cyanide at room temperature and irreversible formation of nickel(II) cyanide within the zeolite at elevated temperatures.