Nuclear magnetic resonance studies of hydroxyl groups in decationated zeolites Y

Abstract

A detailed study by stationary nmr techniques has been made on the influence of decationation and of the pretreatment temperature on line width, second moment, line shape, and intensity of proton resonance signals caused by structural OH-groups in a series of decationated zeolites type Y. Line shape analysis shows that the hydroxyl groups mainly exist in pairs with an inner proton-proton distance of about 3.7 Å. A study of the temperature dependence of the proton line width points to two sorts of hydroxyls of different correlation times attributed to different thermal stabilities.