Electrochemical Strategy for the Simultaneous Production of Cyclohexanone and Benzoquinone by the Reaction of Phenol and Water

Abstract

Cyclohexanone and benzoquinone are important chemicals in chemical and manufacturing industries. The simultaneous production of cyclohexanone and benzoquinone by the reaction of phenol and water is an ideal route for the economical production of the two chemicals. In principle, this can be achieved in an electrochemical reaction system that couples the cathodic reduction of phenol to cyclohexanone and the anodic oxidation of phenol to benzoquinone, which has not been realized. Here, we report the first work on this integration strategy, where nitrogen-doped hierarchically porous carbon (NHPC)-supported NiPt and FeRu designed in this work are very efficient and selective cathode and anode catalysts, affording >99.9% selectivities to both cyclohexanone and benzoquinone. The excellent electrocatalytic performance of the catalysts can be ascribed to the poor absorption capability of the NiPt alloy nanoparticles (NPs) for cyclohexanone and Fe single-atom decorated Ru NPs for benzoquinone, which avoids the excessive reduction and oxidation of the desired products. The reaction pathway is proposed on the basis of control experiments, in which two phenol molecules react with one H 2 O molecule with 100% atom-efficiency. In the scale-up experiment at the 1 g scale, NiPt/NHPC and FeRu/NHPC exhibit excellent durability and stability, which enables this integrated system to afford 645.3 mg of cyclohexanone and 691.7 mg of benzoquinone synchronously in an operating time of 90 h.

Diatomic Pd−Cu Metal‐Phosphorus Sites for Complete N≡N Bond Formation in Photoelectrochemical Nitrate Reduction

“…Compared with traditional bimetallic catalysis at the nanoparticle scale, dual‐atom catalysts have significantly different coordination environments, quantum size effects, and interactions with supports [9] . Converting the bimetallic particles into dual‐atom has significant effects on the adsorption of reactants, the breaking of N−O bond, the transfer of intermediates and the formation of N≡N bond [10] .…”

“…Compared with traditional bimetallic catalysis at the nanoparticle scale, dual-atom catalysts have significantly different coordination environments, quantum size effects, and interactions with supports. [9] Converting the bimetallic particles into dual-atom has significant effects on the adsorption of reactants, the breaking of NÀ O bond, the transfer of intermediates and the formation of N�N bond. [10] However, the electron hybridization and polarization between metal atoms and supports often lead to the high valence state of metal atoms, which limits its application in the catalytic reduction reaction.…”

Hydrogen Peroxide Assisted Electrooxidation of Benzene to Phenol over Bifunctional Ni–(O–C2)4 Sites

“…The peaks at around 858.8 and 880.7 cm −1 were attributed to the OH bending mode of H 2 O 2 , and the weak peak situated at around 1000 cm −1 was assigned to the vibration of benzene ring. [ 11 , 35 ] When the anodic potential was applied, the Raman peak intensity at around 1000 cm −1 enhanced obviously, due to the enhanced vibration and activation of benzene ring on Ni–O–C surface, meaning its effective activation with the applied potential. We further investigated the electrochemical oxidation of benzene to phenol at 1.5 V (vs RHE) for 2 h by the operando Raman measurements.…”

Electrochemical oxidation of phenols in flow: a versatile and scalable access topara-benzoquinones

“…51,52 Recently, a specialized procedure for the simultaneous electrochemical transformation of phenol itself into para-benzoquinone and cyclohexanone on nitrogen-doped hierarchically porous carbon (NHPC)-supported NiPt and FeRu was reported. 53 Nevertheless, to the best of our knowledge, up to this date, no general, synthetically applicable protocol for the direct electrosynthesis of para-benzoquinones from phenols has been disclosed. In order to utilize the unique environmental benign potential of electrochemical synthesis we have developed a scalable flow synthesis that is employable to a broad range of phenols and analogues, applies durable materials and features a recyclable medium to minimizes the waste production.…”