FCC Catalysts: Cu(II)-Exchanged USY-Type. Stability, Dealumination, and Acid Sites after Thermal and Hydrothermal Treatment before and after Vanadium Impregnation
FCC Catalysts: Cu(II)-Exchanged USY-Type. Stability, Dealumination, and Acid Sites after Thermal and Hydrothermal Treatment before and after Vanadium Impregnation
(EN)
Tsiatouras, V. A.
(EN)
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας
(EL)
Tsiatouras, V. A.
(EN)
NaH-USY, H-USY, and Cu(II)-exchanged NaH-USY samples prepared were studied for ion-exchange mass balance, framework aluminum microenvironments (FAI-MEs), and number and strength of acid sites (AS) generated by the increase of the Cu(Il)-exchange after thermal treatment (500 degrees C) and lost under hydrothermal treatment conditions in the presence and in the absence of V species. From the data obtained, conclusions were drawn that (a) the nature and number of Cu(II) species exchanged enter FAI-MEs which can compensate their charge, (b) the strength and number of generated AS in CuNaH-USY samples after thermal treatment is related to the nature and number of Cu(Il) species accommodated in the corresponding FAI-MEs, (c) the AS lost during the hydrothermal treatment depend on the nature of counterion involved, and (d) in the presence of V species, an extra loss, restricted to strong AS, takes place. Differences of lost AS and structure - stability during hydrothermal treatment in the presence and absence of V species give evidence of V catalytic action and support the implication of the nature of counterion species for the degree of structure breakdown. These findings lead to the proposed reaction pathway for the chemistry of V detrimental effect.
(EN)
