Influence of chromium cations on properties of stabilized and non-stabilized forms of Y-zeolites

Abstract

Differences in the behaviour of the non-stabilized form and of stabilized forms of the Y-type zeolite with Cr3+ in the interaction with ethylene were investigated. While with the stabilized forms the polymerization of ethylene takes place with initial rates r0 = 9-12 . 10-2 g(C2H4)g-1 (zeolite) min-1, the initial rate of polymerization with the non-stabilized zeolite containing Cr3+ is by two orders of magnitude lower. In the infrared spectra of OH stretching vibrations of the zeolites with Cr3+ cations two new bands were found at 3 660 and 3 550 cm-1, in comparison with the initial samples. These bands were ascribed to hydroxocomplexes of chromium.