Electroreduction of buta-1,2-diene on a platinum electrode in sulphuric acid solution

Abstract

The electroreduction of buta-1,2-diene on a platinized platinum electrode in 0.5 mol dm^–3 H₂SO₄ or D₂SO₄ solution has been studied at room temperature.

The reactant is reduced with a current efficiency of ca. 100% in a potential region of 220 > ϕ/mV (RHE) > ca. 100 and the main product is butane at ϕ < ca. 100 mV and cis-but-2-ene at ϕ > ca. 200 mV, respectively. The average deuterium atom number in butane decrease sharply from 6.3–6.6 to 3.9 when hydrogen starts to codeposit (ϕ< ca. 100 mV), while those of the butenes are 2–3 over the whole potential region studied, 0 < ϕ/mV < 220.

These results are interpreted by taking into account the different orientation of the orbitals of two adjacent π-bonds in buta-1,2-diene on the electrode surface.