Electrochemical Hydroxylation of Arenes Catalyzed by a Keggin Polyoxometalate with a Cobalt(IV) Heteroatom

Alexander M. Khenkin, Miriam Somekh, Raanan Carmieli, Ronny Neumann

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

The sustainable, selective direct hydroxylation of arenes, such as benzene to phenol, is an important research challenge. An electrocatalytic transformation using formic acid to oxidize benzene and its halogenated derivatives to selectively yield aryl formates, which are easily hydrolyzed by water to yield the corresponding phenols, is presented. The formylation reaction occurs on a Pt anode in the presence of [CoIIIW12O40]5− as a catalyst and lithium formate as an electrolyte via formation of a formyloxyl radical as the reactive species, which was trapped by a BMPO spin trap and identified by EPR. Hydrogen was formed at the Pt cathode. The sum transformation is ArH+H2O→ArOH+H2. Non-optimized reaction conditions showed a Faradaic efficiency of 75 % and selective formation of the mono-oxidized product in a 35 % yield. Decomposition of formic acid into CO2 and H2 is a side-reaction.

Original languageEnglish
Pages (from-to)5403-5407
Number of pages5
JournalAngewandte Chemie - International Edition
Volume57
Issue number19
DOIs
Publication statusPublished - May 4 2018

Keywords

  • C−H bond activation
  • electrocatalysis
  • oxidation
  • polyoxometalate
  • radicals

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

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