Abstract
Electrocatalytic deuteron-dechlorination of trichloroacetic acid (TCAA) in D(2)O provides a green route to synthesize commercial acetic-d(3) acid-d (AA-d(4)). Synthesizing AA-d(4) with a high Faradaic efficiency (FE) and reaction rate is highly challenging because of the difficult C-Cl bond deuteration of the 2-monochloroacetic-2,2-d(2) acid-d (MCAA-d(3)) intermediate. Here, a quaternary ammonium salt surfactant-modified low-coordination copper electrocatalyst is designed, achieving TCAA-to-AA-d(4) with a 91% selectivity, 91% FE and 0.59 mmol h(-1) reaction rate at -100 mA cm(-2). Mechanistic and kinetic studies reveal that the surfactant enhances the adsorption of MCAA-d(3) through electrostatic forces and increases the electron deficiency of Cu(δ+) sites, which accelerates electron transfer and promotes C-Cl bond activation, increasing the AA-d(4) selectivity. Surfactant-induced low D(2)O coverage suppresses D(2) formation, improving the FE. AA-d(4) electrosynthesis (1.84 g) with a 30 mmol h(-1) reaction rate and 65% FE at 600 mA cm(-2) and deuterated drug applications demonstrate promising potential.