# Traces of Elements in the Electrochemical Reductive Amination of Acetone: Uncovering Bi as Substitute for Pb

## TL;DR

This paper explores using bismuth as a less toxic alternative to lead in a chemical process that makes amines, which are important in pharmaceuticals and materials.

## Contribution

The study introduces bismuth as a novel, low-toxicity mediator for electrochemical reductive amination, replacing lead.

## Key findings

- Only sixth-period p-block elements show activity in the electrochemical conversion of acetone.
- Bismuth enables high amine yields at ambient temperatures with minimal concentrations.
- Bismuth's use offers a sustainable route for synthesizing pharmaceuticals.

## Abstract

Amines are broadly utilized as solvents, pharmaceuticals, herbicides, or materials. A benign synthesis route to produce amines from carbonylic substrates is the electrochemical reductive amination, whereby electrons combined with a green proton source like water serve as formal reducing agent. Surprisingly, investigating various p‐block elements as mediator for the electrochemical conversion of acetone in presence of methylamine revealed that only elements of the sixth period show an activity. Building up on these findings and the general low toxicity of Bi compared to Tl or Pb, the electrochemical hydrogenation of N‐methylpropan‐2‐imine was optimized by studying the effect of Bi concentration, reaction temperature, and cathode material. Thus, this work highlights Bi as innovative mediator for the electrochemical reductive amination, whereby in presence of a few ppm‐amounts of Bi at ambient temperatures high amine yields are achievable.

This study investigates the impact of various p‐block element impurities in the electrochemical reductive amination and reveals with Bi a less toxic alternative for Pb. The utilization of Bi as additive was further optimized by studying the impact of additive concentration, reaction temperature, and cathode material on amine yield, offering new possibilities to synthesize pharmaceuticals sustainably.