Solid-State Ion Exchange - Phenomenon and Mechanism

Highly exchanged MeI-Y (MeI = Li, Na, K, Rb, Cs) as well as La-Y zeolites were prepared through solid-state ion exchange between NH4-Y (98%) and the respective chlorides. It was shown that, except for the case of Li-Y, both low- temperature and high-temperature exchange processes occurred. With the system MeICl/NH4-Y the high-temperature reaction seemed to proceed more easily the lower the lattice energy of the alkaline chloride. In La-Y, the bare La3+ ions introduced via solid-state ion exchange were catalytically inactive. However, La-Y obtained via solid-state ion exchange was rendered an active catalyst for both ethylbenzene disproportionation and n-decane cracking after a brief contact with traces of water vapor. For the solid-state reaction itself, the presence of water is not a prerequisite