Modifying the Electrocatalytic Selectivity of Oxidation Reactions with Ionic Liquids
Tian Yang, Juntao Yang, Xin Deng, Evanie Franz, Lukas Fromm, Nicola Taccardi, Zhi Liu, Andreas Görling, Peter Wasserscheid, Olaf Brummel, Jörg Libuda
Abstract
Abstract The “solid catalyst with ionic liquid layer” (SCILL) is an extremely successful new concept in heterogeneous catalysis. The idea is to boost the selectivity of a catalyst by its modification with an ionic liquid (IL). Here, we show that it is possible to use the same concept in electrocatalysis for the selective transformation of organic compounds. We scrutinize the electrooxidation of 2,3‐butanediol, a reaction which yields two products, singly oxidized acetoin and doubly oxidized diacetyl. When adding the IL (1‐ethyl‐3‐methyl‐imidazolium trifluormethanesulfonate, [C 2 C 1 Im][OTf]), the selectivity for acetoin increases drastically. By in situ spectroscopy, we analyze the underlying mechanism: Specific adsorption of the IL anions suppresses the activation of water for the second oxidation step and, thus, enhances the selectivity for acetoin. Our study demonstrates the great potential of this approach for selective transformation of organic compounds.