Direct potentiometry of residual water in sulpholane using the proton isoconcentration technique

Abstract

Direct potentiometry of the system sulpholane-0–1%m/m water-10^–3 mol dm^–3 perchloric acid in glacial acetic acid, using a combination pH glass electrode and a calomel reference electrode with saturated lithium chloride in sulpholane as the filling electrolyte, shows a systematic and large change in potential with variation in the water concentration. This technique allows a fast and accurate determination of residual water in binary sulpholane-water mixtures.