CHEMISTRY OF CRYSTALLINE ALUMINOSILICATES .7. THERMAL DECOMPOSITION PRODUCTS OF AMMONIUM ZEOLITE Y

Two distinct products can be obtained on the thermal decomposition of ammonium zeolite Y at 760 torr and 500 °. The geometry of the zeolite bed during calcination determines the nature of the product. Where the geometry permits rapid removal of ammonia from the bed, the expected hydrogen zeolite is obtained. Bed geometries that impede removal of ammonia from the bed yield an ultrastable product. This material contains cationic aluminum; the cations are derived from a portion of the tetrahedrally coordinated aluminum ions which were initially part of the zeolitic framework. A mechanism is proposed to explain this transition of the aluminum ions. © 1969.