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Vapor–liquid equilibria in the poly(acrylic acid) + water system containing lower concentrations of solute at normal or reduced pressures

Vapor–liquid equilibria have been determined in the systems composed of polyacrylic acid (PAA) [Aldrich ; MW = 240000 ; d = 1.15, 25% aqueous solution] with water by ebulliometric total pressure measurement method. Experiments have been carried out isothermally at 353.15, 363.15 and 373.15 K, i.e. below normal boiling point of water and up to the highest polymer concentrations, which allowed a reliable determination of boiling point of the mixture. For this purpose, the micro-ebulliometer has been used which has been developed and tested earlier [1]. The measured data were correlated with the UNIQUAC equation analogously as in the Polymer Solution Data Collection [2], and compared with data by Arce et. al. [3] measured using the different experimental technique. Values predicted by two group contribution models, namely the Entropic–FV [4] and the GC–Flory [5] models are underestimated in comparison with experimental data. References: [1] J. Pavlíček, G. Bogdanić, I. Wichterle, Fluid Phase Equilib. 2010, 297, 142–148. [2] Hao, W. ; Elbro, H. S. ; Alessi P. Polymer Solution Data Collection. 1: Vapor–Liquid Equilibrium, Chemistry Data Series XVI, Part 1, DECHEMA: Frankfurt/M., 1992. [3] A. Arce, F. Fornasiero, O. Rodrigues, C. R. Radke, J.M. Prausnitz, Phys. Chem. Chem. Phys. 2004, 6, 103-108. [4] G.M. Kontogeorgis, A. Fredenslund, D.P. Tassios, Ind. Eng. Chem. Res. 1993, 32, 362–372. [5] G. Bogdanić, A. Fredenslund, Ind. Eng. Chem. Res. 1994, 33, 1331–1340.

vapor–liquid equilibria; experimental data; poly(acrylic acid) + water system

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