HEAT OF ADSORPTION OF ALKYLDISULFONIC ACIDS ON POLYAMIDE

Abstract

Adsorptions of 1, 2-ethane disulfonic acid (EDSA), 1, 4-butane disulfonic acid (BDSA) and sulfuric acid as the model compounds of dibasic dyes on polyamide were studied by NMR, the adsorption experiment and the flow type microcalorimetry.
The results obtained are as follows:
(1) The adsorption isotherms of alkyldisulfonic acids and sulfuric acid on polyamide were the Langmuir type.
(2) Only one of the two sulfonic acid groups in alkyldisulfonic acids seemed to take part in adsorption.
(3) -Δμ°_I is of alkyldisulfonic acids were larger than that of the corresponding alkylmonosulfonic acids, because of the larger -ΔH°_C•θ=1 and ΔS°_C•I.
(4) ΔS°_C•I and |Δδ| of BDSA were larger than those of EDSA. These are due to the larger contribution of the hydrophorbic hydration in the former.
(5) ΔS°_C•I was positive and decreased with temperature in all cases.