Chinese Journal of Catalysis ›› 2011, Vol. 32 ›› Issue (9): 1446-1451.DOI: 10.1016/S1872-2067(10)60254-9

• Research Briefing • Previous Articles     Next Articles

2,2,6,6-Tetramethylpiperidine-1-Oxyl-Promoted Hydroxylation of Benzene to Phenol over a Vanadium-Based Catalyst Using Molecular Oxygen

CHEN Jiaqi1,2, GAO Shuang1,*, LI Jun1, LÜ Ying1   

  1. 1Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China; 2Graduate School of the Chinese Academy of Sciences, Beijing 100049, China
  • Received:2011-05-28 Revised:2011-07-07 Online:2011-09-09 Published:2015-01-24

Abstract: Rapid benzene hydroxylation was achieved using a reaction system that consisted of a vanadium-based catalyst, ascorbic acid, and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) with molecular oxygen as the oxidant. The hydroxyl radicals that form by a Fenton-type process attack the benzene ring to produce a hydroxycyclohexadienyl radical. The hydroxyl hydrogen is then abstracted quickly in the presence of TEMPO and phenol forms by the transfer of a hydrogen atom from the benzene ring to oxygen. Over the [(CH3)4N]4-PMo11VO40 catalyst the phenol yield reached 8.3% with a selectivity of 95% in 1 h while trace amounts of phenol were obtained in the normal system without TEMPO.

Key words: 2,2,6,6-tetramethylpiperidine-1-oxyl, vanadium, benzene, hydroxylation, phenol, molecular oxygen