Potential-tuned selective electrosynthesis of azoxy-, azo- and amino-aromatics over a CoP nanosheet cathode

Abstract

Azoxy-, azo- and amino-aromatics are among the most widely used building blocks in materials science pharmaceuticals and synthetic chemistry, but their controllable and green synthesis has not yet been well established. Herein, a facile potential-tuned electrosynthesis of azoxy-, azo- and amino-aromatics via aqueous selective reduction of nitroarene feedstocks over a CoP nanosheet cathode is developed. A series of azoxy-, azo- and amino-compounds with excellent selectivity, good functional group tolerance and high yields are produced by applying different bias input. The synthetically significant and challenging asymmetric azoxy-aromatics can be controllably synthesized in moderate to good yields. The use of water as the hydrogen source makes this strategy remarkably fascinating and promising. In addition, deuterated aromatic amines with a high deuterium content can be readily obtained by using D2O. By pairing with anodic oxidation of aliphatic amines to nitriles, synthetically useful building blocks can be simultaneously produced in a CoP||Ni2P two-electrode electrolyzer. Only 1.25 V is required to achieve a current density of 20 mA cm−2, which is much lower than that of overall water splitting (1.70 V). The paired oxidation and reduction reactions can also be driven using a 1.5 V battery to synthesize nitrile and azoxybenzene with good yields and selectivity, further emphasizing the flexibility and controllability of our method. This work paves the way for a promising approach to the green synthesis of valuable chemicals through potential-controlled electrosynthesis.

Co P@NiCo-LDH heteronanosheet arrays as efficient bifunctional electrocatalysts for co-generation of value-added formate and hydrogen with less-energy consumption

“…Recently, an efficient strategy has been developed to replace OER by thermodynamic favorable anodic oxidation reaction in water since it can be integrated with HER to generate H 2 with less electrical energy consumption [6-8 , 13] . To realize the coelectrolysis, some reduced agents and organics substrate molecules have been used to optimizing the aqueous electrolyte, such as: urea [18 , 19] , hydrazine [20 , 21] , ammonia [22][23][24] , alcohols [25][26][27][28][29][30][31] , furfural [7 , 13 , 32 , 33] , biomass-derived intermediate compounds [34 , 35] , etc. Comparing to the traditional water electrolysis with HER and OER, these co-electrolysis reactions could significantly decrease operating voltage to produce hydrogen.…”

Unveiling the Activity Origin of a Copper‐based Electrocatalyst for Selective Nitrate Reduction to Ammonia

“…The model showed the electron density of Cu in Cu/Cu 2 O NWAs minus the electron density of Cu in pure Cu NWAs, and the extra electronic cloud was the yellow part. Thus, it can be deduced that high electronic density of Cu induced the decrease of reaction barrier and suppresses the competitive H 2 production, [42][43][44][45][46] leading to high conversion rate, Faradaic efficiency, and selectivity of Cu/Cu 2 O for NRA.…”

Electrocatalytic Deuteration of Halides with D2O as the Deuterium Source over a Copper Nanowire Arrays Cathode

“…Recently, the electrochemical transformation has emerged as a powerful and green tool in synthetic chemistry . The high tunability by the applied potential or current makes it very suitable for various redox reactions . Among the transformations, the electrochemical reduction reactions are regarded as the most promising, including electrocatalytic water splitting, carbon dioxide reduction reaction, or nitrogen reduction reaction .…”