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 language | English |
|---|---|
| Pages (from-to) | 5403-5407 |
| Number of pages | 5 |
| Journal | Angewandte Chemie - International Edition |
| Volume | 57 |
| Issue number | 19 |
| DOIs | |
| Publication status | Published - May 4 2018 |
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Keywords
- C−H bond activation
- electrocatalysis
- oxidation
- polyoxometalate
- radicals
ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
Cite this
Electrochemical Hydroxylation of Arenes Catalyzed by a Keggin Polyoxometalate with a Cobalt(IV) Heteroatom. / Khenkin, Alexander M.; Somekh, Miriam; Carmieli, Raanan; Neumann, Ronny.
In: Angewandte Chemie - International Edition, Vol. 57, No. 19, 04.05.2018, p. 5403-5407.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Electrochemical Hydroxylation of Arenes Catalyzed by a Keggin Polyoxometalate with a Cobalt(IV) Heteroatom
AU - Khenkin, Alexander M.
AU - Somekh, Miriam
AU - Carmieli, Raanan
AU - Neumann, Ronny
PY - 2018/5/4
Y1 - 2018/5/4
N2 - 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.
AB - 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.
KW - C−H bond activation
KW - electrocatalysis
KW - oxidation
KW - polyoxometalate
KW - radicals
UR - http://www.scopus.com/inward/record.url?scp=85045347216&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85045347216&partnerID=8YFLogxK
U2 - 10.1002/anie.201801372
DO - 10.1002/anie.201801372
M3 - Article
VL - 57
SP - 5403
EP - 5407
JO - Angewandte Chemie - International Edition
JF - Angewandte Chemie - International Edition
SN - 1433-7851
IS - 19
ER -