Gel entrapped ZnO nanorods: An efficient and sustainable catalyst for the Claisen-Schmidt condensation reaction in aqueous hydrotropic media

A new strategy is reported for enhancing the catalytic activity of nanoparticles for the sustainable development of organic transformations. Gel entrapped zinc oxide nanorods (GE-ZnO NRs) have been prepared and analyzed by FT-IR, XRD, TG, SEM, and EDX. Catalytic activity of ZnO NRs entrapped in gel was explored through the CSC reaction of aldehydes and acetophenone at room temperature in the hydrotropic aqueous medium. The catalyst was isolated by a centrifugation-free easy filtration process and re-used more than four times without any substantial loss in its catalytic activity. Use of low-cost biodegradable natural material, centrifugation-free separation of catalyst and isolation of the product without column chromatography are the attractive points of this sustainable approach.

Automated summary

A new strategy for improving the catalytic activity of nanoparticles in organic transformations has been reported. Gel-entrapped zinc oxide nanorods (GE-ZnO NRs) were prepared and characterized by various techniques. The catalytic activity of GE-ZnO NRs was investigated in the CSC reaction of aldehydes and acetophenone in an aqueous medium at room temperature. The catalyst was easily separated from the reaction mixture using a centrifugation-free filtration process and could be reused multiple times without significant loss in activity. The use of low-cost biodegradable materials, centrifugation-free separation, and isolation of the product without column chromatography are noteworthy features of this sustainable approach.