Basic Zeolites-Extra-framework Composition

With both alkaline and alkaline earth oxides the order of basicity increases when the size of the cation is increased Na O/NaX K O/KX Rb O/RbX Csfi CsX. However, it seems (at least for MgO) that the entrapped oxides are less basic than the corresponding bulk oxides [49-51]. 

The basicity of zeolite catalysts can be increased even further by occluding 

The samples can be prepared by alkali metal vapor treatment of the zeolite, treatment of the molecular sieve with a solution of the alkali metal in liquid ammonia or in primary amines, treatment of the zeolite with organolithium compounds, or decomposing sodium azide previously impregnated on sodium zeolites [59-62]. 

It should be remarked that for very strong zeolite basic catalysts the presence of CO2 and H2O should be avoided in any stage of preparation and reaction, because these lead to rapid catalyst deactivation. 

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