Activities of Alkaline Earth-Modified Zeolites

Catalytic Activities of Alkaline Earth-Modified Zeolites 

Alkali metal ion-exchanged zeolites and occluded alkali metal oxide zeolites have been investigated extensively and applied as basic catalysts for a variety of organic transformations (1,41,221,222). Zeolites modified with alkaline earth compounds have been applied much less frequently as base catalysts for organic reactions. 

Because BaO/NaX zeolite catalysts exhibited the best performance, further investigations have been carried out recently to characterize the oxidative methylation of toluene catalyzed by BaO-modified X- and Y-zeolites, mordenite, ZSM-5, sil-icalite, and ALPO4-5 (230). The authors found that activity and basicity of BaO-modified zeolites and zeolite-like catalysts depend on both the structural type and composition. Thus, for samples of the same structural type (BaO/NaX zeolite. 

Recently, a combinatorial investigation of alkylation of toluene with methanol to produce styrene with basic zeolites and alkaline earth catalysts was performed (257). The results of tests involving preparation and testing of more than 200 catalysts were modest, and these results emphasize that fine-tuning of the acid and base properties necessary to achieve better alkylation catalysts is not an easy task. 

---

A. Catalytic Activities of Alkaline Earth-Modified Zeolites... 

---