Highly Efficient Etherification and Oxidation of Aromatic Alcohols Using Supported and Unsupported Phosphorus Pentoxide as a Heterogeneous Reagent

Abstract

A highly efficient procedure for etherification and oxidation of aromatic alcohol is described using unsupported and supported P₂O₅ on alumina and/or silica gel. The silica gel and alumina proved to be the most suitable support among the supports examined in our experiments. It was illustrated that the etherification and oxidative performance in reactions depend largely upon variables including reaction temperature, the nature of the P₂O₅ used (supported or unsupported P₂O₅), and whether solvent-free conditions are applied. It was shown that P₂O₅ not only can convert the aromatic alcohols into corresponding ethers and/or aldehyde and ketone but also can convert aromatic ethers into aldehyde or ketone via oxidative cleavage. Finally, quantum mechanical calculations were performed to rationalized these events, and it was indicated that aldehyde and ketone are more favorable products on the basis of the heat of formation (ΔH_f).

Keywords:

• Alumina
• aromatic alcohol
• etherification
• oxidation
• P₂O₅
• silica gel

ACKNOWLEDGMENT

The authors acknowledge to Bu-Ali Sina University Research Council and Center of Excellence in Development of Chemical Methods (CEDCM) for support of this work.

Notes

^a Tedious workup procedures.

^a Anhydrous solvent.

^b No reaction after 12 h.

^a Anhydrous Solvent.

^a No Reaction.

^a Isolated yield.