The successful synthesis of biguanide-functionalized mesoporous silica catalysts: Excellent reactivity combined with facile catalyst recyclability

The successful synthesis of a series of novel biguanide-functionalized mesoporous silica (SBA-15 and SiO2) catalysts has been developed. Various amounts of a biguanide; namely metformin, was immobilized onto the silica surface through a covalent attachment and the extents of loading were measured with back titration. The structural and surface characteristics of the prepared catalysts were investigated by various techniques: TEM, SEM, TGA, FT-IR and elemental analysis. Furthermore, the catalytic performance of the prepared catalysts was evaluated in various organic transformations (aldol and nitroaldol coupling and Michael-addition reactions) and they were proved to act as efficient and recoverable catalysts in aqueous solution with excellent reactivity combined with considerable recyclability.

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► Successful report on biguanide-functionalized mesoporous silicas.
► SBA-15/biguanide system as a novel organosuperbase catalyst in green and mild conditions.
► Effective operation of metformin-functionalized mesoporous silicas with feasible recovery.
► The solid organo superbase catalysts possessed excellent stability and recyclability.