Polyoxometalates based compounds for green synthesis of aldehydes and ketones

Molecular oxygen within Polyoxometalates (POMs) based compounds are ideal oxidants with high atom economy and its use results in the production of water as the only byproduct. Significant progress has been made in the development of catalytic methods for aerobic alcohol oxidation to have aldehydes and ketones with POMs based compounds. They are alternative to the use of traditional hypervalent iodine catalyst systems which are with molecular oxygen as a terminal oxidant. Further, POMs based catalysts can be applied to catalytic reactions with different modes of energization such as thermocatalysis, photocatalysis and electrocatalysis. This review summarizes the frontier advances in polyoxometalates for catalytic alcohol selective oxidation in thermocatalytic, electrocatalytic, and photocatalytic applications. The three advantages of POM catalysts in terms of performance, economy, and environmental protection are highlighted. These include the use of sol-gel and electrostatic assembly methods to increase the reaction surface area, reduce the use of precious metals, and improve the stability of POMs catalysts. The field of selective alcohol oxidation is advanced. Finally, the challenges of preparing more efficient and “green” catalysts are presented.