Activity of Alkaline Earth-Modified Mesoporous Molecular Sieves

Catalytic Activity of Alkaline Earth-Modified Mesoporous Molecular Sieves 

In the last decade, the mesoporous molecular sieve MCM-41 has been developed (2S2) and applied as a catalyst to many acid-catalyzed reactions (2SS). However, until now, comparatively few investigations of mesoporous molecular sieves as base catalysts have been reported (169,211-214,234,235). For example, sodium- and cesium-exchanged mesoporous MCM-41 were shown to be mildly selective, water-stable, recyclable catalysts for the base-catalyzed Knoevenagel condensation, and mesoporous MCM-41 containing intraporous cesium oxide particles prepared by impregnation with aqueous cesium acetate and subsequent calcination was found to have strong-base activity for the Michael addition (211,213) and rearrangement of co-phenylalkanals to phenyl alkyl ketones (212). 

In addition to the results presented above, Jaenicke et al. (234) compared the activities of K2O, BaO, and K20/La203 incorporated in MCM-41 for the same reaction at 433 K with a benzaldehyde/heptanal molar ratio of 1.5. They found 

Cross-aldol Condensation of Benzaldehyde with Heptanal on Basic Catalysts (236) 

Catalyst BET surface area (m /g) Base amount (mmol of COfg) Conversion (%) after 2h Selectivity to jasminaldehyde (%) 

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