Suitable Experimentation-Modeling Binomial to Design the Extraction of an Alkanol with Water in Aqueous Ternary Solutions of Ester-Akanol

This work presents an investigation on phase equilibria in partially miscible systems comprised of water, esters, and alkanols. Experimental liquid–liquid equilibria (LLE) were determined for ternaries of water+H_2u–1C_u–1CO₂C_vH_2v+1+C_wH_2w+1(OH) (u = 3,4; v = 2,3; w = 1–4) at 298.15 K and for the four corresponding water+ester binaries, in the temperature interval T = [283–328] K. The results reveal a complex behavior of the ternary LLE. The ester barely dissolves in the aqueous phase, even in the presence of alkanol (x_max,ester^II ≈ 0.15). However, the organic phase contains high quantities of water when the compositions approach the plait point (x_max,water^I ≈ 0.75). Data modeling was carried out with a multiparametric model, obtaining an acceptable correlation with a maximum deviation in the compositions of s_x = 0.031 for the system water(1)+propyl butanoate(2)+propan-1-ol(3). Estimations with COSMO-RS and UNIFAC differed from experimental values in all cases, especially in the systems containing propan-1-ol, since both models predict a nonreal immiscibility at 298.15 K in the binary water+propan-1-ol. Therefore, the simulation of the extractive process using UNIFAC was not adequate.