Heterogeneous an-Henry reactions of aldimes with nitromethane were examined with zeolites as catalysts. Among the zeolite used, H-Y zeolite showed satisfactory catalytic activity for various aldimines, resulting in corresponding beta-nitroamines in good yields. H-Y zeolite also showed the excellent reusability until the 3rd usage without loss of its activity; further, the calcination of deactivated H-Y zeolite allowed it to rejuvenate its catalytic activity. Solid-state C-13 MAS NMR revealed the predominant activation of an aldimine into the H-Y zeolite. (C) 2010 Elsevier B.V. All rights reserved.
Synthesis, Characterization and Catalytic Application of MCM 41 Supported Phenanthrolinium Dibromide Catalyst for Aza-Michael Addition Reaction in Aqueous Medium
MCM-41 immobilized phenanthrolinium dibromide (phen-MCM-Br2) was easily prepared and applied as an efficient heterogeneous catalyst for aza-Michael addition of aromatic amines to α,β-unsaturated nitriles and nitro compounds in water. The catalyst was characterized by CHN, TGA, FT-IR, SEM, EDAX, XRD, BET, and TEM. It could be simply recovered and reused several times without significant loss of catalytic