Electrochemical reduction of acetonitrile to ethylamine

Rong Xia,Feng Jiao,Dong Tian,Bjorn Hasa,Shyam Kattel,Jingguang G Chen,Xinbin Ma,Haeun Shin

doi:10.1038/s41467-021-22291-0

Abstract

Electrifying chemical manufacturing using renewable energy is an attractive approach to reduce the dependence on fossil energy sources in chemical industries. Primary amines are important organic building blocks; however, the synthesis is often hindered by the poor selectivity because of the formation of secondary and tertiary amine byproducts. Herein, we report an electrocatalytic route to produce ethylamine selectively through an electroreduction of acetonitrile at ambient temperature and pressure. Among all the electrocatalysts, Cu nanoparticles exhibit the highest ethylamine Faradaic efficiency (~96%) at −0.29 V versus reversible hydrogen electrode. Under optimal conditions, we achieve an ethylamine partial current density of 846 mA cm−2. A 20-hour stable performance is demonstrated on Cu at 100 mA cm−2 with an 86% ethylamine Faradaic efficiency. Moreover, the reaction mechanism is investigated by computational study, which suggests the high ethylamine selectivity on Cu is due to the moderate binding affinity for the reaction intermediates.

Highlights

Electrifying chemical manufacturing using renewable energy is an attractive approach to reduce the dependence on fossil energy sources in chemical industries
The online electrochemical differential flow electrolyzer mass spectrometry (FEMS) is employed for the time-resolved detection of the product and density functional theory (DFT) calculation is applied for further understanding of the reaction mechanism
The maximum ethylamine Faradaic efficiency (FE) together with the corresponding H2 FE of each catalyst is summarized in Fig. 2a

Summary

Introduction

Electrifying chemical manufacturing using renewable energy is an attractive approach to reduce the dependence on fossil energy sources in chemical industries. The maximum production rate of ethylamine on Cu was 3.135 mmol cm−2 h−1 (Supplementary Fig. 3), which was approximately three times as Ni and Pd, and 31 times as Pt. Another important observation is that neither diethylamine nor triethylamine was detected over all the catalysts by NMR, they are major byproducts in the thermocatalytic nitrile hydrogenation reaction, suggesting that electroreduction of acetonitrile is a highly selective approach to produce primary amine from its corresponding nitrile.

Results

Conclusion