Prediction of the Partition Coefficient for Acetic Acid in a Two‐Phase System Soybean Oil‐Water

Abstract

An analytical approach for the prediction of the partition coefficient for acetic acid between soybean oil and water, dependent on temperature and composition, has been proposed. The original and three modified UNIFAC models as well as the UNIQUAC model were used to represent the liquid-liquid equilibrium data in the ternary system. To calculate the density of the water and oil phase the COSTALD method was applied. The proposed approach for the prediction of the partition coefficient for acetic acid fit the experimental data well when the UNI-QUAC model was used. The results of the application of the proposed approach to the experimental data for acetic acid partition coefficient taken from the literature were also presented and discussed.

Partitioning of Carboxylic Acid between Oil and Water Phases. Experimental, Correlation, and Prediction

“…3, SO density was calculated as q [kg/m 3 ] = 1,106.9 -0.64T [K], [20]. As shown, the deviation for Rangarajan et al [1] are much larger than for Sinadinović-Fišer and Janković [23]. These results seem to indicate that our experiments are consistent with those of Ref.…”

“…In Table 4, calculated partition coefficients, K c cal , are compared with experimentally determined partition coefficients taken from Refs. [1] and [23]. To obtain K c from K w with Eq.…”

Liquid–Liquid Equilibrium Constant for Acetic Acid in an Epoxidized Soybean Oil–Acetic Acid–Water System

“…Comparison was possible since the experimental conditions used for the system with epoxidized soybean oil are analogous to those used for the system with soybean oil, namely temperatures are the same and mass compositions of the mixtures M1, M2 and M3 are similar to E1, E2 and E3, respectively. The values of the liquid-liquid equilibrium constant for acetic acid in the system with soybean oil, calculated on the basis of experimentally determined partition coefficient data given in Table 1 in the reference [9], are shown in Table 4. Comparison of these values with those given in Table 2 shows that the value of the liquidliquid equilibrium constant for acetic aid in the system epoxidized soybean oil-acetic acid-water is about 1.5 times higher than in the system with soybean oil, what would be expected since the presence of epoxy and hydroxyl groups within the epoxidized soybean oil would increase its polarity relative to soybean oil, which should increase the partitioning of a polar solute such as acetic acid to the oilrich phase.…”

“…The rigorous mathematical model of that system, besides kinetic parameters, comprises the thermodynamic ones, as well as parameters of mass-transfer between the oil and water phase. The simultaneous determination of all parameters by fitting the experimental data for the variation of component concentrations with the reaction time is inconvenient, because it demands a lot of data; incorrect, because of mutually correlated parameters and, in the case of chemical equilibrium constant determination for the reaction of peracid formation, impossible, as this reaction is shifted to the right which is due to constant consumption of peracid in the epoxidation reaction [9]. Because of these reasons, it is more convenient to determine the parameters using data from experiments specified for particular phenomena.…”

“…One of the mathematical model parameters given by Rangarajan et al [4] is the partition coefficient for acetic acid (A) between the oil and water phase that can be calculated from the liquid-liquid phase equilibrium condition and known phase densities. In the previous paper [9] we proposed an approach for the prediction of the partition coefficient for acetic acid between soybean oil and water, dependent on temperature and composition. Since, to the best of our knowledge, no reports have yet appeared about the change of the equilibrium constant for acetic acid, and consequently its partition coefficient, during the epoxidation of soybean oil, in the present work we determined the dependency of the liquid-liquid equilibrium constant for acetic acid (K A ) in the system epoxidized soybean oil (ESO)-acetic acid-water from temperature and composition.…”