Electrochemical studies of the adsorption of propargyl alcohol on a smooth platinum electrode in acid medium

Abstract

The electrooxidation of the intermediate species produced by the adsorption of propargyl alcohol on a smooth platinum electrode has been studied in 0.5 M H2SO4 medium. At 25°C, the maximum amount of adsorbed intermediates was observed for Eads=0.2 V/rhe and the alcohol re-adsorption was avoided using a sweep rate ranging from 3 to 10 V s-1. The adsorption process is well described by a Temkin isotherm, with an interaction factor, f≈16, and an adsorption energy Δadso≈-49 kJ mol-1. The experimental data shown that the electrooxidation of propargyl alcohol proceeds through a reaction pathway involving an initial monoelectronic transfer step. In the temperature range from 20 to 80°C, the apparent activation energy for the electrooxidation of the adsorbed intermediates resulting from propargyl alcohol was determined, ΔHa*≈12 kJ mol-1. © 1989.