dealuminated Y zeolite
Springer Online Journal Archives 1860-2000
Chemistry and Pharmacology
Abstract The solid-state ion exchange of Rh chloride with highly dealuminated Y zeolite has been studied by in situ FTIR spectroscopy. Thermal treatment in vacuum and calcination in oxygen up to 600°C results in an exchange limited to ca. 25% at temperatures higher than 400°C. The ion exchange can be performed much more effectively (over 50%) and at lower temperatures (100–150°C) in the presence of CO in the gas phase. A linear correlation has been found between the formation of well-defined Rh(CO) 2 + species and the simultaneous loss of acid hydroxyl groups for samples treated at different conditions. From these results a model is proposed with the formation of Rh subcarbonyls, the migration of these species to the cation positions of the zeolite and, finally, the formation of the stable well-defined Rh(CO) 2 + species at these positions as essential steps of the ion exchange in the presence of CO.
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