Reactive system (acetic acid-n-butanol-butyl acetate-water, in liquid phase, 0.76 Bar pressure) adsorption on a cationic exchange resin (Bayer Lewatit K-2431) was studied in this work. Solid particle size distribution was verified and low dispersion was noticed with 86% of total mass between 20 and 30 mesh. The dried solid showed a binodal distribution with 40% above 25 mesh and 45% between 25 and 45 mesh. Resin swelling assays were carried out on pure components and non-reactive binary mixtures and increased matrix volume was observed (2.2 to 3 times higher). Selective adsorption on the reactive system was observed in the sequence: water > n-butanol acid > acetate. Both ideal and non-ideal models were tested for calculating adsorption using a composite isotherm, demonstrating these models’ weakness in representing adsorption on ionic polymer matrices. Calorimetric characterisation assays were carried out on swelled catalyst and a change in solid structure caused by thermal treatment was recognised using infrared scanning.