Synthesis of deuterated acids and bases using bipolar membranes.

Abstract

Deuterated acids/bases are high-value bulk chemicals used for synthesizing deuterated pharmaceuticals^1,2, modifying optoelectronic materials³ and mediating hydrogen isotope exchange reactions^4,5. However, conventional synthesis methods require harsh reaction conditions with high energy consumption^6,7. Here we propose a versatile platform that takes advantage of heavy water dissociation in bipolar membranes (BPMs) to produce deuterated acids and bases under particularly mild conditions. Specifically, D₂SO₄ (2.75 mol l^-1) and KOD (5.82 mol l^-1), which are comparable with commercial products, were prepared using inexpensive D₂O and K₂SO₄. We find that the deuteron generation rate is approximately 1.25 times greater than that of the protons, which is attributed to less co-ion leakage of D⁺ than H⁺ through the anion-exchange membrane (AEM), lower salt leakage within BPMs in D₂O than in H₂O and lower dehydration barrier of deuterons than proton clusters in the membrane phase. Compared with other contributing factors, salt leakage plays a relatively minor role in the observed H⁺/D⁺ concentration difference. This flexible and robust platform facilitates the synthesis of various deuterium-labelled compounds.