Alcohol‐Activated Vanadium‐Containing Polyoxometalate Complexes in Homogeneous Glucose Oxidation Identified with <sup>51</sup>V‐NMR and EPR Spectroscopy
Stefanie Wesinger, Matthias Mendt, Jakob Albert
Abstract
Abstract Alcoholic solvents, especially methanol, show an activating affect for heteropolyacids in homogenously catalysed glucose transformation reactions. In detail, they manipulate the polyoxometalate‐based catalyst in a way that thermodynamically favoured total oxidation to CO 2 can be completely supressed. This allows a nearly 100 % carbon efficiency in the transformation reaction of glucose to methyl formate in methanolic solution at mild reaction conditions of 90 °C and 20 bar oxygen pressure. By using powerful spectroscopic tools like 51 V‐NMR and continuous wave EPR we could unambiguously prove that the vanadate‐methanol‐complex[VO(OMe) 3 ] n is responsible for the selectivity shift in methanolic solution compared to the aqueous reference system.