TEMPO-Ru-BEA Composite Material for the Selective Oxidation of Alcohols to Aldehydes

The selective aerobic oxidation of alcohols to aldehydes is an important industrial challenge due to the easy further overoxidation of these products to acids and esters. The most common industrial methods require organic radicals such as 2,2,6,6,-tetramethylpiperidine-1-oxyl (TEMPO) for the selective conversion of alcohols to carbonyl compounds with the formation of TEMPOH, which can be regenerated back to TEMPO by oxygen over metal complexes. The high cost and difficulties related to the separation of complexes prompted us to develop heterogeneous catalysts by coordinating TEMPO over acid sites in zeolite BEA with encapsulated RuO2 nanoparticles. The catalyst demonstrates excellent activity, selectivity, and stability for the oxidation of alcohols to aldehydes. The analysis of the reaction mechanism confirms the activation of alcohols by TEMPO and the subsequent regeneration of TEMPOH by RuO2.