Alcohol-Activated Vanadium-Containing Polyoxometalate Complexes in Homogeneous Glucose Oxidation Identified with 51V-NMR and EPR Spectroscopy

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 CO2 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 degrees C and 20 bar oxygen pressure. By using powerful spectroscopic tools like V-51-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.

Automated summary

Alcoholic solvents, especially methanol, activate heteropolyacids in homogeneously catalyzing glucose transformation reactions, resulting in high carbon efficiency. Through spectroscopic tools, it has been proven that the complex in methanolic solution plays a key role in the selectivity shift of the transformation reaction.