Selective Methane Oxidation by Heterogenized Iridium Catalysts
Haoyi Li, Muchun Fei, Jennifer L. Troiano, Lu Ma, Xingxu Yan, Peter Tieu, Yucheng Yuan, Yuhan Zhang, Tianying Liu, Xiaoqing Pan, Gary W. Brudvig, Dunwei Wang
Abstract
Oxidative methane (CH 4 ) carbonylation promises a direct route to the synthesis of value-added oxygenates such as acetic acid (CH 3 COOH). Here, we report a strategy to realize oxidative CH 4 carbonylation through immobilized Ir complexes on an oxide support. Our immobilization approach not only enables direct CH 4 activation but also allows for easy separation and reutilization of the catalyst. Furthermore, we show that a key step, methyl migration, that forms a C–C bond, is sensitive to the electrophilicity of carbonyl, which can be tuned by a gentle reduction to the Ir centers. While the as-prepared catalyst that mainly featured Ir(IV) preferred CH 3 COOH production, a reduced catalyst featuring predominantly Ir(III) led to a significant increase of CH 3 OH production at the expense of the reduced yield of CH 3 COOH.