New and efficient procedure for the oxidation of dioxybenzylic alcohols into aldehydes with Pt and Pd-based catalysts under flow reactor conditions

Selective and efficient catalysts have been developed for the oxidation benzylic alcohols into the respective commercial aldehydes with air. Catalytically active metals (Pt and Pd) retained their activity when immobilized on the modified carbon carrier. To the best of our knowledge, this is the first example of synthesis of vanillin and piperonal from vanillyl and piperonyl alcohols under flow reactor conditions. Based on our evaluation we estimate that if the catalysts retain their activity for ca. 100 h, the yield of vanillin will be over 120/1 kg of the catalyst. Furthermore, we showed that the catalysts can be regenerated via a feasible treatment with basic water followed by acetone.