A convenient green protocol for oxidative esterification of arylaldehydes over Pd NPs decorated polyplex encapsulated Fe₃O₄ microspheres

A mild, competent and eco-friendly protocol has been developed for oxidative esterification of various aldehydes over a post-synthetically modified and Pd fabricated chitosan-starch dual functionalized Fe₃O₄ microspheres as a magnetically isolable heterogeneous and biocompatible nanocatalyst. Molecular O₂ was used as an oxidant in the reaction. A series of aldehydes was directly esterified with MeOH in excellent yields without any pre-activation and involvement of harsh chemicals/conditions. Structural features of the catalyst were assessed through FT-IR, FE-SEM, TEM, EDX, molecular mapping, XRD, VSM and ICP-OES techniques. Due to magnetic core, the catalyst was easily isolated using an external magnet and reused for 8 times in succession, retaining its morphology and catalytic activity.