Immobilized 4-methyl-2,6-diformyl phenol complexes on a zeolite: Characterization and catalytic applications in esterification, Diels–Alder and aldol condensation

Abstract

Development of simple and reliable protocols for the immobilization of catalytically active species is an important aspect of the field of hybrid nanomaterials. We have attempted (succeeded) to entrap aldehyde species on the surface of micron-sized zeolite particles functionalized with amine groups. Thus, we have demonstrated that 4-methyl-2,6-diformyl phenol bound at high surface coverage on 3-aminopropyltrimethoxysilane (3-APTS)-functionalized NaY zeolites generates excellent heterogeneous catalysts for organic transformation reactions. The assembly of Schiff base compound on the zeolite surface occurs via an interaction of 4-methyl-2,6-diformyl phenol with the amine groups present in 3-APTS leading to a new class of catalyst. The synthesized catalysts were characterized by DRS, FTIR, TGA, XRD, BET, PL and ICP-OES. The Ni and Cu complexes grafted on amino functionalized zeolite are efficient catalysts for esterification, Diels–Alder and aldol condensation at ambient conditions. In all these reactions, the modified zeolite showed higher yield and selectivity.