Thermochemistry of hydroxylammonium and hydrazonium zeolites

Abstract

Mordenite and zeolite Y were exchanged with hydroxylammonium and hydrazonium ions. The deammination and dehydroxylation reactions were followed using thermoanalytic, mass spectrometric and infrared techniques. The overall acidity of the decationated zeolites was measured by pyridine adsorption.

Hydrazonium ions in zeolite Y and mordenite react via thermal decomposition, catalytic dehydrogenation and hydrogenolysis reactions. Hydroxylammonium ions are deprotonated and the base is thermally decomposed as in acid or alkaline solutions. A catalytic dehydrogenation reaction is superimposed.

In each case, the NH⁺₄ form is partly obtained and finally the H and dehydroxylated forms of the respective zeolites are formed. The overall acidic properties of the latter two forms are in no way different from a deammoniated-dehydroxylated ammonium zeolite.