Salt effect on liquid-liquid equilibrium of water plus 1-butanol plus acetone system: experimental determination and thermodynamic modeling

Liquid-liquid equilibrium data for the quaternary systems (water + 1-butano l + acetone + sodium chloride) and (water + 1-butanol + acetone + sodium ac etate) were measured at 20 and 40 degreesC. The results were compared with experimental liquid-liquid equilibrium data for the ternary, salt-free syst ems, both from literature and determined in this work. In this way, the sal t effect could be, evaluated. Ternary liquid-liquid equilibrium data for th e salt-free system water + acetone + 1-butanol were also determined and fou nd in good agreement with reported data from literature. The experimental d ata were correlated with the NRTL activity coefficient model. New thermodyn amic interaction parameters were estimated with the Simplex method and the Maximum Likelihood principle, using binary water + 1-butanol liquid-liquid equilibrium data from literature, ternary water + acetone + 1-butanol, both from literature and determined in this work, and quaternary water + aceton e + 1 -butanol + salt, determined in this work. The results are very satisf actory in accordance with root mean square deviations between experimental and calculated compositions of both equilibrium phases, that are always bel ow 1.2%. (C) 2001 Elsevier Science B.V. All rights reserved.