Isobaric vapor-liquid equilibria for methyl ethyl ketone+water+acetic acid system

Isobaric VLE data for (methyl ethyl ketone (MEK)+acetic acid) and (MEK+water+acetic acid) systems were measured at 101.325 kPa by using a improved Rose kettle, and the VEL data for binary systems have passed the thermodynamic consistency test. Considering the association of acetic acid molecules, chemical theory model and Hayden-O'Connell (HOC) model were used to correct the nonideality of vapor phase, while the nonideality of liquid phase was corrected in the calculation of its activity coefficient. NRTL and UNIQUAC modrls were applied to correlate the VLE data for (MEK+acetic acid) system, and the model parameters together with the deviations of temperature and molar fraction in vapor phase were obtained. Two groups of model parameters for (MEK+water) system, five groups for model parameters of (water+acetic acid) system and one group of model parameters for (MEK+acetic acid) system correlated in this work were used to predict the VLE data of the ternary system studied. The optimum combination of model parameters was selected through comparing the predictive deviations of different combinations. The detail of the predictive deviations obtained by using the selected optimum combination are as follows: the average absolute deviation (AAD) for temperature is 0.51°C, the AAD for vapor phase molar fraction of MEK, water and acetic acid are 0.0047, 0.0065 and 0.0067, respectively. So it can be concluded that the above selected model parameters is reliable, and these model parameters can be used as basic thermodynamic data for the design and simulation of the distillation of the (MEK+water+acetic acid) system.