Functionalized chitosan polymerized with cyclodextrin decorated ionic liquid: Metal free and biocompatible catalyst for chemical transformations.

A novel metal -free triple composite that benefits from the chemistry of chitosan, β-cyclodextrin and ionic liquid has been prepared through polymerization of vinyl functionalized chitosan and cyclodextrin decorated ionic liquid. The resulting compound, CS-CD-IL, was characterized and successfully applied as a heterogeneous catalyst for promoting Knoevenagel condensation reaction under mild reaction condition in aqueous media. It was believed that the presence of cyclodextrin in the structure of the catalyst could facilitate the reaction in aqueous media through transferring the hydrophobic substrate in the vicinity of the catalytic sites. Chitosan and ionic liquid, on the other hand, could activate the substrates via two pathways. The effects of the reaction variables as well as the recyclability of the catalyst were also investigated. The results confirmed high recyclability of the catalyst up to six reaction runs. Notably, the developed catalyst was versatile and could promote similar condensation reactions to furnish more complex chemicals such as Xanthane.