Boosting electrocatalytic oxidation of heterocyclic alcohols with low
usage aminoxyl radicals via MOF-derived NiOOH
Abstract
Aminoxyl-mediated electrocatalysis offers a sustainable approach for the
oxidation of alcohols to carboxylic acids. However, the high dosage of
aminoxyl radicals and the limiting current density hinder the
practicality of industrial application. Herein, a nickel-based
electrocatalyst (Ni-tpdc) was synthesized on a three-dimensional porous
graphite felt substrate. Taking advantage of the synergistic effect of
the electrochemically activated Ni-tpdc/GF electrocatalyst with
4-acetamido-TEMPO, the yield of 4-pyridinecarboxylic acid was up to 99%
with only 1 mol% ACT. A series of in situ measurements showed that
NiOOH enhanced the activity of the intrinsic electrocatalyst.
Additionally, the synergistic system was extended to the oxidation of
various heterocyclic alcohols. The scale-up synthesis of chiral acid
(LEV-CO 2H) was achieved in an improved electrolyzer
with a yield of 95.4%, enantiomeric retention of 99.2%, and space-time
yield of 34.12 kg/(m 3·h). The practicality and
effectiveness of this synergistic electrocatalytic strategy in practical
electrosynthesis was further demonstrated.