Jacobsen catalyst immobilized on chitosan membrane as interface catalyst in organic/aqueous system for alkene oxidation

The Jacobsen catalyst, Mn(salen), was immobilized in chitosan membrane. The obtained Mn(salen)-Chit was characterized by thermogravimetric analysis (TG), differential thermal analysis (DTA), differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR), degree of N-acetylation by 1H NMR, and UV–vis spectroscopy. The UV–vis absorption spectrum of the encapsulated catalyst displayed the typical bands of the Jacobsen catalyst, and the FT-IR presented an absorption band characteristic of the imines present in the Jacobsen catalyst. The chitosan membranes were available, in a biphasic system, as a catalytic barrier between two different phases: an organic substrate phase (cyclooctene or styrene) and an aqueous solution of either m-CPBA, t-BuOOH or H2O2, and dismissing the need for phase transfer agents and leading to better product yields compared with the catalyst in homogeneous medium. This new catalyst did not leach from the support and was reused many times, leading to high turnover frequencies.

Graphical abstractThe Jacobsen catalyst was immobilized in chitosan membrane and characterized by different techniques. The new catalyst was used in a biphasic system, as a catalytic barrier between two different phases: an organic substrate phase and an aqueous solution of oxidants, dismissing the need for phase transfer agents, and leading to better product yields compared with the catalyst in homogeneous medium.Figure optionsDownload full-size imageDownload as PowerPoint slide