Measurement of the acidity function H0 of sulfo cation exchangers by the indicator method

Abstract

1. A method of the measurement of the acidity function H0 of sulfo cation exchangers was proposed. It was based on their absorption of an indicator base from an aqueous solution taking into account the activity coefficient of its unionized form (fB) in the phase of the sulfo cation exchanger. This is measured in an aqueous solution of p-toluenesulfonic acid with the same molar ratio of the sulfo groups to water as in the swollen sulfo cation exchanger. 2. The fB values of o-nitroaniline in aqueous solutions of p-toluenesulfonic acid (up to 53%) were measured at 25°C. 3. The H0 values of styrene-divinylbenzene sulfo cation exchangers of the gel type KRS-1, KRS-3, KRS-6, KRS-10, and KRS-12 and the large-pore types KU-23-15/100 and KU-23-30/ 100 were measured at 25°C.