Introducing Structural Diversity: Fe2(MoO4)3 Immobilized in Chitosan Films as an Efficient Catalyst for the Selective Oxidation of Sulfides to Sulfones

Abstract

This work reports how the immobilization of Fe2(MoO4)3 in chitosan films affects the oxidation reaction of sulfide derivatives to sulfates in the dark, resulting in good yields and excellent selectivity. As demonstrated, a variety of substituted sulfides were tolerated even in the presence of oxidative-sensitive functional groups, leading to a regioselective application of the catalyst under mild reaction conditions and guaranteeing its reuse for at least 6 cycles without losing its catalytic performance. Specifically, films containing 1 mg of Fe2(MoO4)3 per ml of chitosan showed a yield and selectivity of 99 %. The key success of the selective oxidation was associated with the presence of the hydroxyl radical, ⋅OH, and the Fe3+/Fe2+ Fenton-like process. As a proof of concept, the selective oxidation of sulfides to the corresponding sulfones was performed to demonstrate the synergistic effect between Fe2(MoO4)3 and chitosan. This work offers a design strategy for efficient catalysts that may extend to other semiconductors and oxidation processes.