Liquid-liquid equilibrium of acetic acid – ethanol – ethyl acetate – water quaternary system: Data review and new results at 323.15 K and 333.15 K

Fluid Phase Equilibria 503 (2020) 112321

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Fluid Phase Equilibria j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / fl u i d

Liquid-liquid equilibrium of acetic acid e ethanol e ethyl acetate e water quaternary system: Data review and new results at 323.15 K and 333.15 K Maya Trofimova a, Alexey Sadaev a, Artemiy Samarov a, Alexandra Golikova a, Nikita Tsvetov a, b, Maria Toikka a, *, Alexander Toikka a a

Saint Petersburg State University, Department of Chemical Thermodynamics and Kinetics, Universitetskiy prospect 26, Peterhof, St. Petersburg, 198504, Russia Tananaev Institute of Rare Element and Mineral Chemistry and Technology, Kola Research Center Russian Academy of Sciences, Murmansk region, Apatity, Academic town, 26a, 184209, Russia

b

a r t i c l e i n f o

a b s t r a c t

Article history: Received 6 June 2019 Received in revised form 11 September 2019 Accepted 11 September 2019 Available online 14 September 2019

A brief review of data on solubility and liquid-liquid equilibrium (LLE) in the acetic acid e ethanol e ethyl acetate e water system is presented. A new set of experimental data on solubility, LLE, and critical phases in this quaternary system, ternary subsystems (acetic acid e ethyl acetate e water, ethanol e ethyl acetate e water) and binary subsystem ethyl acetate e water are presented for 323.15 K and 333.15 K at atmospheric pressure. The gas chromatography and the cloud point technique were used to obtain experimental data. Binodal curves, surfaces, and critical manifolds are presented including 3D phase diagrams in composition tetrahedron. Experimental LLE data were correlated using the NRTL model. © 2019 Elsevier B.V. All rights reserved.

Keywords: Solubility Liquid-liquid equilibrium Critical state Quaternary system Ethyl acetate

1. Introduction It is evident that nowadays data on fluid phase equilibrium and mixing properties are of significant interest for both applied and fundamental purposes (industrial equipment optimization, manufacturing process modelling, estimation of parameters and efficiency of synthesis process, etc.). Most recent research works include the study of multicomponent systems with chemical reactions. The data on reactive systems are of special application interest, first of all for the reactive distillation design [1e3]. According to our analysis of the literature data on phase and chemical equilibrium in reactive mixtures, most investigations deal with the systems with esterification [4]. The data on these mixtures are useful for the production of esters, which are important organic solvents. On the other hand, these studies relate to the synthesis of alcohols from plant raw materials. The various common usages of alcohols are well-known (pharmaceutical, food, chemical

* Corresponding author. E-mail address: [email protected] (M. Toikka). https://doi.org/10.1016/j.fluid.2019.112321 0378-3812/© 2019 Elsevier B.V. All rights reserved.

industries, etc.). Moreover, these results are also necessary in the production of biofuels. Organization of production of the first- and second-generation biofuels requires an overestimated amount of raw materials. Accordingly, the rational design of biofuel production requires the involvement of scientific methods, taking into account thermodynamic and kinetic features of the systems and processes. In this paper, we consider the system with the ethyl acetate synthesis reaction that is one of the most important objects of the esters production technology. This work is a continuation of our previous studies of acid ‒ alcohol ‒ ester ‒ water systems where we obtained new data sets on solubility, LLE, and critical states in the acetic acid-ethanol-ethyl acetate-water system. Additionally, we determined the location of the polythermal critical surface in the concentration space of the quaternary system. Ethanol (bioethanol) often appears as a fuel or an additive to gasoline [5e10]. As concerns ethyl acetate, it is a product of esterification from acetic acid and ethanol, for example, via the reactive distillation process [11]. The products of esterification are ethyl acetate and water, which are partially miscible. Therefore, the resulting reaction mixture containing ethyl acetate, water, ethanol,

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and acetic acid can also form a heterogeneous solution. Usually these final solutions include initial reagents (acetic acid and ethanol) at low concentrations, but one cannot neglect their content in the industrial process design. In this regard, the data on solubility and LLE in the acetic acid ‒ ethanol ‒ ethyl acetate ‒ water system are required for the organization of synthesis, purification, and recovery of ethyl acetate. In addition, the preparation of pure anhydrous ethyl acetate (target product) from its mixtures includes the stage of aqueous extraction of ethanol, so the data on the ethanol e ethyl acetate e water ternary system are also of considerable industrial importance. Besides, ethyl acetate is used as a solvent for the extraction of acetic acid from dilute aqueous solutions resulting from fermentation processes and from spent or recycle solutions. Thus the data on the mutual solubility in system acetic acid e ethyl acetate e water and on distribution of acetic acid between water and a solvent are essential for the extraction process design. Beforehand we analyzed the available literature data on solubility and LLE in the acetic acid e ethanol e water e ethyl acetate system in numerous investigations for more than a hundred years. During this period, researchers accumulated a substantial array of experimental and calculated data. In particular, the data on solubility in the ethyl acetate e water binary subsystem cover the wide temperature range of 273.15e363.15 K. We refer briefly to only those works that include the experimental results on the solubility and LLE in the acetic acid e ethanol e ethyl acetate e water system and some subsystems [12e42,48] (Table 1). The earliest experimental investigation of the binodal curve, plait point, and tie-lines in the ethanol e ethyl acetate e water system is the work of Bonner [16], which contains the data obtained by titration and volumetry at 273.15 K. Griswold et al. [33] presented the data on liquid phase equilibria for the ethanol e ethyl acetate e water system at the temperature range 281.50e351.30 K; there are also solubility isotherms, binodal curves, and tie-lines. The paper of Pai and Rao [34] refers to the study of the salt effect influence on LLE in the ethanol e ethyl acetate e water system in the presence of potassium acetate and sodium acetate; it includes also the comparison of solubility with LLE data for the case of the absence of the salt at 303.15 K. Mertl [19] measured solubility and LLE in the ethanol e ethyl acetate e water system at 293.15 K, 313.15 K, 328.15 K and 343.15 K; they constructed phase diagrams for all experimental temperatures. The paper of Van Zandijcke and Verhoeye [35] comprises isobaric LLE data determined at the boiling point (343.45e351.75 K)

for liquid mixtures ethanol e ethyl acetate e water; additionally they calculated the location of the binodal curve and tie-lines, compared the results of experiment and modelling, application of NRTL method for the prediction of ternary LLE data showed good results. The work of Lee and co-authors [36] reports phase equilibrium in ternary mixtures of ethanol, ethyl acetate, and water including vapor-liquid-liquid equilibrium (VLLE) at 343.8e344.4 K and atmospheric pressure. They used gas chromatography (GC) for LLE determination. UNIQUAC, NRTL, and modified Wilson models were used for the ternary LLE prediction. Graphical comparison of calculated and experimental data is presented. The modified Wilson model appeared to be superior to the UNIQUAC and NRTL models in estimating ternary LLE. Arce et al. [37] determined the LLE data in the ethanol e ethyl acetate e water system at 298.15 K, 308.15 K, and 318.15 K. The experimental data were correlated by the NRTL and UNIQUAC equations. Binodal curves were determined by the cloud point technique, tie-lines were obtained by GC. All experimental data were presented on phase diagrams. It appeared that changing temperature barely affects the area of the heterogeneous region. Gomis et al. [38] studied isobaric (101.3 kPa) VLLE in the ethanol e ethyl acetate e water system at 343.35e343.95 K using a circulation setup with ultrasonic homogenizer designed by the authors. The experimental VLLE data were compared with the data obtained in [19,35,36]. VLLE diagram plots compared with LLE data showed that Gomis’ data were in agreement with those of Refs. [19,36], however there are significant differences with the results of [35]. Lin et al. [39] presents experimental investigation of LLE for ternary system ethanol e ethyl acetate e water and for quaternary systems including auxiliary agent (a hydrophilic agent or an electrolyte) in order to measure the enhancement of the heterogeneity region at temperatures 283.15 K, 298.15 K, and 313.15 K at atmospheric pressure. The compositions were determined using GC. The authors built a phase diagram with experimental tie-lines for the ethanol e ethyl acetate e water system at a single temperature (313.15 K). They used the NRTL model to correlate LLE data; the model reasonably reproduced LLE phase envelope. Resa et al. [40] experimentally studied LLE for ternary ethanol e ethyl acetate e water mixtures at 298.15 K, 308.15 K, and 318.15 K. The authors measured the densities and the refractive indices of equilibrium phases, which they used then to compute equilibrium compositions. They used the UNIQUAC equation to correlate experimental tie-lines and the UNIFAC method to predict the immiscibility region (the LLE borderline). They presented plots of experimental and calculated heterogeneous regions and tie-lines

Table 1 Works on the experimental study of solubility in the acetic acid e ethanol e ethyl acetate e water system at 273.15e363.15 K. T, K

References ethyl acetate e water

ethanol e ethyl acetate e water

273.15 283.15 293.15 298.15 303.15 308.15 313.15 318.15 323.15 328.15 333.15 343.15 353.15 363.15

[12,16,28e30] [12,13,15,26e31,42] [12,17e19,26e33,41,48] [12,14,18e20,26e33,39,42] [12,14,18e22,24e29,31e34] [13,14,37,40] [13,14,18e20,25e33,42] [13,14,37,40] [13e15,27,28,30e33] [13,14,19] [13,14,23,30,31,33] [13,19,22,30,31,33,35,36,38] [31] [31]

[16] [39] [19,33,48] [33,37,39,40] [25,33,34] [37,40] [19,25,33,39] [37,40] [33] [19] [33] [19,33,35,36,38]

acetic acid e ethyl acetate e water [42] [41,48] [42] [24,25] [25,42]

acetic acid e ethanol e ethyl acetate e water

[48] [25] [25]

M. Trofimova et al. / Fluid Phase Equilibria 503 (2020) 112321

for each experimental temperature. The paper of Sohoni and Warhadpande [24] contains the data on the binodal curve of the ternary acetic acid e ethyl acetate e water system at 303.15 K. The plait point was determined graphically by interpolating the data for tie-lines and the binodal curve. Ratkovics et al. [41] report the results of the experimental study of LLE for the ternary acetic acid e ethyl acetate e water mixture at 293.15 K. Compositions of the ternary equilibrium mixtures were determined by GC. The experimental results were compared with those calculated by UNIQUAC, UNIFAC, and NRTL models. Both UNIQUAC and NRTL equations correlated the results quite well, but UNIFAC predicted larger two-phase region than that observed experimentally. Ternary phase diagram comparing predicted and experimental values was plotted. Colombo et al. [42] studied LLE in the acetic acid e ethyl acetate e water system at 283.15 K, 298.15 K, and 313.15 K. Compositions of equilibrium phases were measured by titration. Phase diagrams presenting experimental and calculated data were constructed for all temperatures. The authors used the experimental results to test the capability of various equilibrium models to correlate these data. Both NRTL and UNIQUAC were almost equally good in correlating the equilibrium compositions with standard deviation values lower than 1%. An analysis of the literature shows that currently there are many results on solubility studies in the binary subsystems, as well as in the ternary subsystems, but for the quaternary system, the information on solubility and LLE is limited in comparison with the vapor-liquid equilibrium (VLE) data in the case of chemical reaction equilibrium (CE). For example, Bernatova, Aim, and Wichterle presented the data on VLE for chemically equilibrium states in the acetic acid e ethanol e ethyl acetate e water system at 348.15 K [43]. Other similar works were carried out by Kang et al. [44] and Calvar et al. [45] at atmospheric pressure. Due to the industrial importance of reactive distillation the main direction of the investigation of phase equilibrium in the system with ethyl acetate synthesis reaction was aimed at studying simultaneous VLE and CE. We should mention that CE in this system appears in the homogeneous region; therefore, one did not study LLE. Some data on LLE were obtained by model calculation, see, e.g. [46]. We should also mention that the compositions of critical states of LLE appear in just few works. Some other references are presented in our review papers [4,47]. Basically, experimental information on the quaternary liquid acetic acid e ethanol e ethyl acetate e water mixture (solubility, LLE, critical phases and chemical equilibrium) is presented in our earlier papers [25,48e50]. On the base of the above information we have studied solubility and LLE in the acetic acid e ethanol e ethyl acetate e water system at 323.15 K and 333.15 K that are closer to the reactive distillation conditions. Additionally we present the data on critical states of

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LLE. The work continues our research of phase behavior and critical states in the system with the ethyl acetate synthesis reaction [25,48e50]. In these studies we obtained detailed experimental data on solubility, LLE, critical states, and excess enthalpies [25,48,49] for this system and its ternary subsystems ethanol e ethyl acetate e water and acetic acid e ethyl acetate e water at 293.15 K, 303.15 K and 313.15 K (atmospheric pressure). Paper [50] contains the only information about chemical equilibrium at 303.15 K, 313.15 K, and 323.15 K. Binodal surfaces, binodal curves, tie-lines, and critical manifolds were plotted in concentration spaces (composition triangle and tetrahedron). Additionally, we compared experimental LLE data with the values calculated by the UNIFAC and NRTL models, and found out that the experimental and calculated data are in good agreement. In conclusion we must note that the data on solubility and the knowledge of diagrams of state of multicomponent reacting systems, in particular, mixtures with ester synthesis reactions in a wide temperature range not only serve to replenish the fundamental database. This knowledge also makes it possible to vary parameters of the process of synthesis depending on the requirements and equipment of a particular manufacturer. 2. Experimental 2.1. Materials Ethanol (reagent grade, Vekton) and ethyl acetate (reagent grade, Vekton) were previously dried using molecular sieves (synthetic zeolite) and after that purified by rectification columns; water was distilled twice. Acetic acid (reagent grade, Vekton) was taken without previous purification. Refractive index measurements were performed with IRF 454 BM refractometer (Russia) at 101.3 kPa (±1 kPa) and 293.15 K and provided with the temperature controlled to within ±0.05 K by circulating thermostated water through it (uncertainty is estimated as 0.0002). The temperatures of boiling points of substances were determined by ebulliometer with an accuracy of ±0.05 K. Purity of reactants was tested by GC. Physical characteristics of pure ethanol, ethyl acetate, water, and acetic acid such as boiling points and refraction indices showed good agreement(Table 2) with the data reported by National Institute of Standards and Technology (NIST) [51]. 2.2. Solubility and critical points determination To study solubility and determine compositions of critical points in the acetic acid ‒ ethanol ‒ ethyl acetate ‒ water system and in its ternary subsystems acetic acid ‒ ethyl acetate ‒ water and ethanol ‒ ethyl acetate ‒ water cloud point technique was applied. The following method of sample preparation was used: initial binary (ethanol ‒ ethyl acetate or acetic acid ‒ ethyl acetate) and

Table 2 Purities of the reagents. Substance

Ethyl acetate Acetic acid Ethanol Water a b c d e

Purification method

molecular sieves, rectification molecular sieves, rectification double distillation

Boiling temperaturea, T, K (at 101.3 kPa)

Refractive indexb, n293.15 d (at 101.3 kPa)

Purity, mole fractionc (GC)

Exp.

Ref. [51]

Exp.

Ref. [51]

initial

final

350.00 390.90 351.75 373.15

350.15 391.25 352.20 373.16

1.3700 1.3695 1.3608 1.3330

1.3720 1.3720 1.3614 1.3330

0.992 0.996d 0.960 0.999

0.995 0.996d 0.980e 0.999

Standard uncertainties of boiling temperatures u(T) ¼ 0.05, u(P) ¼ 0.5 kPa. Standard uncertainties of refractive indices u(n293.15 ) ¼ 0.0002, u(T) ¼ 0.05, u(P) ¼ 1 kPa. d Standard uncertainties u(mole fraction) ¼ 0.002. As reported by the supplier in accordance with certificate of analysis. Ethanol sample contains 0.020 mol fraction of water.

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M. Trofimova et al. / Fluid Phase Equilibria 503 (2020) 112321

Fig. 1. Schematic view of the experimental setup for isothermal titration: 1 - thermostat, 2 - thermostatically controlled cell, 3 - syringe, 4 - magnetic stirrer, 5 - tripod with foot, ring and sleeve, a - individual substance (titrant), b - titrated mixture.

ternary (acetic acid ‒ ethanol ‒ ethyl acetate) homogeneous solutions of known in advance composition were prepared in a thermostated glass flask (10 ml) by gravimetric method with accuracy of 0.001 g (Fig. 1). The compositions of initial mixtures were fixed in such a way that experimental points of the compositions were set regularly on binodal curves and on binodal surfaces. The number of solubility points in the near-critical region is greater, due to the need to get a single point corresponding to the critical state. Initial ternary mixtures for titration were prepared in such a way that the ratio of the mole fractions of acetic acid and ethanol had a fixed value (4:1, 2:1, 1:1, 1:2, and 1:4) to provide ordered and uniform arrangement of experimental points of compositions for the quaternary system on the 3D diagram of state. Such compositions of the experimental points correspond to five cutting planes of the concentration tetrahedron and give an opportunity to visualize optimally the form of the binodal surface of the quaternary acetic acid ‒ ethanol ‒ ethyl acetate ‒ water system. Titration of initial solutions with bidistilled water was carried out with continuous stirring by a magnetic stirrer. Syringe (2 ml) was used to add water to the titrated mixture. In order to avoid loss of volatile components (ethanol, ethyl acetate) during titration, the thermostated flask was tightly closed with a rubber stopper, which was easily punctured with the syringe (Fig. 1). The exact amount of water used for titration of each experimental solution was estimated gravimetrically as the difference between the mass of the syringe before titration and at the end of the process. Titration accuracy was 0.02 ml. The final points of titration corresponding to the binodal curves and to the binodal surface were determined visually at the moment when the titrated mixture became turbid, i.e., at the moment of solution splitting into two phases. The fixation of the critical points of solubility was performed visually during the examination of color change of the titrated solutions. The state of the solution, at which turbidity persisted for at least 2 min at a given temperature, was accepted as the final point of titration. It should be noted that reaching the critical point can be easily fixed visually due to the phenomenon of opalescence. In the case of the acetic acid e ethanol ‒ ethyl acetate ‒ water system pale blue opalescence appears in a titrated solution in the near critical region and directly at the critical point completely clear solution is transforming instantly into emulsion; opalescence at this moment

is the most intensive [25,48,52,53]. These interesting properties are due to the density increase and concentration fluctuations leading to the occurrence of the anomalous scattering of light, X-rays, and neutrons, strong sound absorption, a change in the nature of Brownian motion, viscosity anomalies, thermal conductivity, etc. [52,53]. Similar phenomena were observed for other systems, which also include acid, alcohol, ester, and water [54e56]. To prove the reliability of the data we additionally applied the Coolledge method [57,58]. Since we had to take into account the volume of mixtures (about 10 ml) and the volume of titrant (0.02 ml), the accuracy of composition determination was limited to 0.001 mol fractions. With other factors that affect the accuracy (purity of substances, thermostatic control uncertainty) the maximum deviations of experimental data was appreciable to be 0.005 mol fraction of the component in solubility and critical points determination using the cloud point technique. It is worth pointing out that the esterification of acetic acid by ethanol and the chemical reaction of hydrolysis of ethyl acetate have no influence on the compositions of experimental mixtures due to their low rates in the absence of a catalyst, thus there was no shift of each component concentration during the experiment, which we proved using GC. 2.3. LLE determination To obtain LLE data by GC we used the following approach to sample preparation. Binary (ethyl acetate ‒ water), ternary (acetic acid ‒ ethyl acetate ‒ water, ethanol ‒ ethyl acetate ‒ water), and quaternary (acetic acid ‒ ethanol ‒ ethyl acetate ‒ water) initially heterogeneous mixtures were prepared in chromatographic vials (5 ml) using the gravimetric method with the accuracy of 0.001 g. Then the sealed vials were shaken up and held in liquid thermostat at a given temperature until phase equilibrium was reached. We assumed that the phase equilibrium appeared when the full distribution of liquid phases occurred. Equilibration time was on the average 10 min at both temperatures. As in the case of solubility research, the initial quaternary solutions were prepared with definite ratios of the mole fractions of acetic acid and ethanol (2:1, 5:3, 1:1, 3:5 and 1:2) for ordered arrangement of the experimental tielines of LLE in the concentration space (tetrahedron). After LLE was established, the samples of each liquid phase were taken by the chromatographic syringe (Hamilton, USA, 1 ml) previously heated to avoid splitting of the samples and were analyzed using the Chromatec Crystal 5000.2 gas chromatograph (Russia). Analysis of each phase was carried out three times. Chromatographic conditions were as follows: Porapac R packed column (1 m  3 mm i. d.), helium was a carrier gas with the flow rate of 30 ml/min, operating temperatures of vaporizing injector, column, and thermal conductivity detector were 503.15 K, 443.15 K, and 513.15 K, respectively. The chromatographic column was calibrated by the method of internal normalization using ethanol as a linking component (because of its unlimited miscibility with all other components). Uncertainty of the LLE determination using GC is 0.002 mol fraction on the average. 3. LLE modelling To correlate the experimental data, we chose the NRTL model [59] that was previously successfully used to simulate LLE in the carboxylic acid ‒ monohydric alcohol ‒ ester ‒ water systems [25,60,61]. We took the following NRTL equation for activity coefficients in a multicomponent (n-component) liquid system:

M. Trofimova et al. / Fluid Phase Equilibria 503 (2020) 112321

Pm

j¼1 xj tji Gji

lnðgi Þ ¼ Pm

i¼1 xi Gji

tji ¼

þ

m X

Pm

xj Gij r¼1 xr trj Grj tij  P Pm m x G i ij i¼1 i¼1 xi Gij j¼1

!

    gji  gii Dgji ¼ ; Gji ¼ exp  aji tji ; aji ¼ aij ; RT RT

where gji is an energy of interaction between molecule j and molecule i; aji is responsible for the nonrandomness of the solution; x is a mole fraction of the component i or j. The objective function (OF) was an optimization tool to determine NRTL parameters that minimize the composition values; the parameters were estimated using this OF: Standard deviation s was defined as follows:

vffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi 2 2 ffi  uP P  exp exp 4 u n cal þ x  x t k¼1 i¼1 xik  xcal ik ik or ik aq ; sð%Þ ¼ 100 2mn where x is a mole fraction of a component; subscripts i and k denominate components; n is a number of tie-lines, m is a number of components; or, aq e indices of organic and aqueous phases respectively.

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4. Results and discussion 4.1. Experimental Outcome of experimental study of solubility in the acetic acid ‒ ethanol ‒ ethyl acetate ‒ water system and in its ternary subsystems acetic acid ‒ ethyl acetate ‒ water and ethanol ‒ ethyl acetate ‒ water are presented in Tables 3 and 4 (supplementary materials) and Figs. 2e4, 8-10. The compositions of the critical points are shown in Table 3 at 323.15 K and 333.15 K at atmospheric pressure. Figs. 2 and 3 display phase diagrams representing experimental binodal curves for ternary acetic acid ‒ ethyl acetate ‒ water and ethanol ‒ ethyl acetate ‒ water systems. Fig. 4 presents the binodal surface of the quaternary acetic acid ‒ ethanol ‒ ethyl acetate ‒ water system constructed in a 3D concentration space being a rectangular tetrahedron with borders outlined in black. The surface is shown only at one temperature (333.15 K), since it is rather difficult to see significant changes in concentrations at 323.15 K. The diagrams of Fig. 4 demonstrate clearly the form and arrangement of the binodal surface separating homogeneous and heterogeneous areas of compositions in the composition tetrahedron. The surface is an assembly of the solubility curves in ternary subsystems and the quaternary system for certain ratios of the mole

Fig. 2. Phase diagram of the ethanol ‒ ethyl acetate ‒ water system at 323.15 K and 333.15 K: - ‒ points belonging to the solubility curve, △‒‒△ ‒ LLE tie-lines,  ‒ critical point (mole fractions).

Fig. 3. Phase diagram of the acetic acid ‒ ethyl acetate ‒ water system at 323.15 K and 333.15 K: - ‒ points belonging to the solubility curve, △‒‒△ ‒ LLE tie-lines,  ‒ critical point (mole fractions).

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M. Trofimova et al. / Fluid Phase Equilibria 503 (2020) 112321

Fig. 4. Solubility surface from two points of view for the acetic acid e ethanol e ethyl acetate e water system at 333.15 K: CdC ‒ solubility data, fractions). The gray area of space at the base of the tetrahedron is the projection of the surface.

‒ critical curve (mole

Fig. 5. Tie-lines of the acetic acid e ethanol e ethyl acetate e water system at 333.15 K from two points of view; CeC e experimental tie-lines (mole fractions).

fractions of acetic acid and ethanol (4:1, 2:1, 1:1, 1:2, and 1:4). It is located inside the composition tetrahedron in a certain way. It passes near the edge of the binary subsystem with limited ethyl acetate ‒ water miscibility and ends up on two faces of the tetrahedron corresponding to the ternary acetic acid ‒ ethyl acetate ‒ water and ethanol ‒ ethyl acetate ‒ water subsystems. The area of immiscibility covers a relatively small volume of the composition tetrahedron; the total content of acid and alcohol on the binodal surface is 0.163 and 0.153 mol fraction at 323.15 K and 333.15 K accordingly. We have to note that the general view of the binodal surface of the investigated system persists within the temperature range 273.15e333.15 K [25,48]. Such form of the solubility surface is typical for some other carboxylic acid ‒ monohydric alcohol ‒ ester ‒ water systems [54,60e63]. Tables 4 and 5 show experimental LLE data. Figs. 2, 3 and 5 show tie-lines of LLE in the acetic acid ‒ ethanol ‒ ethyl acetate ‒ water system and in its binary ethyl acetate ‒ water and ternary acetic acid ‒ ethyl acetate ‒ water and ethanol ‒ ethyl acetate ‒ water subsystems. Fig. 5 reflects the results of the phase equilibrium study at 333.15 K. In general, LLE data obtained by GC match closely and complete the data on solubility obtained by the method of cloud point; all tie-lines substantially coincide with corresponding binodal curves or surfaces to a considerable degree.

The previously obtained experimental data on the solubility and LLE in the acetic acid ‒ ethanol ‒ ethyl acetate ‒ water system at lower temperatures (293.15 K, 303.51 K, and 313.15 K) [25,48] make it possible to retrace the temperature evolution of phase behavior of the system under study for the temperature range 293.15e333.15 K. Fig. 6 enables one to analyze LLE for binary subsystems. From this diagram it is clearly seen that with increasing temperature the composition of the ester shifts towards lower concentrations for both aqueous and organic phases. In general, the temperature increase in the range from 293.15 K to 333.15 K weakly affects the increase of solubility in binary ethyl acetate e water system. Fig. 7 presents the information on LLE and solubility for the same binary system at 323.15 K, 333.15 K, and close temperatures in comparison with the results of other authors [13,14,26e28,30e32]. From this diagram one can conclude that for the aqueous phase the spread of values is not large - no more than 0.005 mol fractions. On the contrary, in the organic phase all available data on solubility and LLE are quite different. It should be noted that all the values given in Fig. 7 are recommended by Getzen, Hefter, and Maczynski in “Solubility data series: Esters with Water. Part 1: Esters 2-C to 6C” [64]. As an illustration, Fig. 8 presents comparative phase diagrams

M. Trofimova et al. / Fluid Phase Equilibria 503 (2020) 112321

7

Fig. 6. An evolution of LLE data (mole fractions, atmospheric pressure) for the binary ethyl acetate e water system with temperature [25, 48, this work].

Fig. 7. The comparison of experimental LLE and solubility data with literature results for binary ethyl acetate e water system at the temperatures close to 323.15 K and 333.15 K (mole fractions, atmospheric pressure).

Fig. 8. Temperature evolution of the phase diagram of the acetic acid e ethyl acetate e water and ethanol ‒ ethyl acetate ‒ water systems at 293.15e333.15 K (mole fractions): ‒ points of solubility belonging to the binodal curve at 293.15 K [48], e tie-lines at 293.15 K [48], ‒ points of solubility belonging to the binodal curve at 333.15 K, e tielines at 333.15 K.

8

M. Trofimova et al. / Fluid Phase Equilibria 503 (2020) 112321 Table 4 LLE data (mole fractions) for ternary subsystems of the acetic acid (1) ‒ ethanol (2) ‒ ethyl acetate (3) ‒ water (4) quaternary system at 323.15 K and 333.15 K, p ¼ 101.3 kPaa. aqueous phase x1

x2

x3

x1

x2

x3

323.15 K

0 0 0 0 0 0 0.020 0.040 0.053 0.070 0.083 0

0.019 0.038 0.048 0.058 0.074 0.091 0 0 0 0 0 0

0.022 0.031 0.044 0.054 0.066 0.090 0.022 0.036 0.047 0.066 0.090 0.013

0 0 0 0 0 0 0.033 0.064 0.099 0.114 0.118 0

0.051 0.094 0.120 0.140 0.155 0.160 0 0 0 0 0 0

0.674 0.575 0.507 0.426 0.332 0.279 0.687 0.587 0.453 0.347 0.234 0.768

333.15 K

0 0 0 0 0 0.019 0.038 0.052 0.067 0

0.017 0.042 0.059 0.076 0.089 0 0 0 0 0

0.024 0.035 0.049 0.064 0.085 0.021 0.038 0.054 0.066 0.013

0 0 0 0 0 0.028 0.063 0.091 0.109 0

0.032 0.091 0.131 0.145 0.154 0 0 0 0 0

0.697 0.585 0.489 0.394 0.284 0.691 0.600 0.496 0.393 0.755

Fig. 9. The comparison of experimental LLE and solubility data with literature results for the ternary acetic acid ‒ ethyl acetate ‒ water system at different temperatures (mole fractions, atmospheric pressure): e 283 K [42], e 293.15 K [41], e 298 K [42], B e 303.15 K [24], e 313 K [42], - e 323.15 K (this work), , e 333.15 K (this work).

Fig. 10. The comparison of experimental LLE and solubility data with literature results for the ternary ethanol ‒ ethyl acetate ‒ water system at different temperatures (mole fractions, atmospheric pressure): B e 273.15 K [16], e 283.15 K [39], e 293.15 K [19], e 298.15 K [39], e 313.15 K [19], e 313.15 K [39], - e 323.15 K (this work), e 328.15 K [19], , e 333.15 K (this work), e 343.15 K [19].

being binodal curves of the ternary acetic acid ‒ ethyl acetate ‒ water and ethanol ‒ ethyl acetate ‒ water subsystems since they are easier for visual perception than comparative spatial phase diagrams representing binodal surfaces. Analysis of temperature evolution of experimental data on phase diagrams shows that solubility in the acetic acid e ethanol e ethyl acetate e water system increases with temperature. Comparative analysis shows that the heterogeneous region reduces by an average of 15% with temperature increasing from 293.15 K [48] to 333.15 K. Fig. 9 presents the comparison of the results obtained in this work for ternary acetic acid ‒ ethyl acetate ‒ water system with the data available in the literature on an enlarged scale. The analysis shows a good consistency of all the data (Fig. 9), except for the results obtained in [24]. In general, the solubility region decreases with increasing temperature. In comparative analysis of the data for ternary ethanol ‒ ethyl acetate ‒ water system (Fig. 10) it was found that all the data are in sufficient correlation except for the results from [16] at 273.15 K. It was determined experimentally that the ternary acetic acid ‒ ethyl acetate ‒ water and ethanol ‒ ethyl acetate ‒ water

organic phase

a

Standard uncertainties u(x) ¼ 0.002, u(P) ¼ 1.5 kPa, u(T) ¼ 0.05 K.

subsystems have one critical point and the quaternary acetic acid ‒ ethanol ‒ ethyl acetate ‒ water system has a critical curve formed by an assemblage of critical points; the course of this curve can be demonstrated on the spatial phase diagram [25,48]. Experimental data on compositions of critical points in the system acetic acid ‒ ethanol ‒ ethyl acetate ‒ water and its subsystems at 323.15 K and 333.15 K are listed in Table 3 and presented on phase diagrams in Figs. 2e4 and 11. It seems interesting to combine the previously obtained results on critical states in the quaternary system for 293.15 K [48], 303.15 K [25], and 313.15 K [25] with the data on critical points of this system obtained in the present work (Fig. 11). Combining the experimental results from the papers [25,48] with the data of the present work permits us to construct the polythermal critical surface of the acetic acid ‒ ethanol ‒ ethyl acetate ‒ water system for the temperature range 293.15e333.15 K, which consists of a series of critical curves for five temperatures (Fig. 11). We must emphasize that such experimental outcome is of rare occurrence in academic literature, thus it is interesting to consider the topology of critical manifolds of a multicomponent system at least in a quality manner. According to Fig. 11, we can enumerate the following peculiarities of the critical surface of the

Table 3 Experimental data on visually determined critical points (mole fractions) for the acetic acid (1) ‒ ethanol (2) ‒ ethyl acetate (3) ‒ water (4) system at 323.15 K and 333.15 K, p ¼ 101.3 kPaa. mole fractions ratio of acetic acid and ethanol

323.15 K x1

x2

x3

х4

x1

x2

x3

х4

‒ 4:1 2:1 1:1 1:2 1:4 ‒

0.115 0.090 0.076 0.060 0.037 0.022 0.000

0.000 0.029 0.049 0.078 0.096 0.113 0.138

0.172 0.170 0.175 0.176 0.168 0.167 0.157

0.713 0.711 0.700 0.686 0.698 0.698 0.705

0.111 0.080 0.070 0.055 0.036 0.021 0.000

0.000 0.026 0.046 0.071 0.094 0.111 0.136

0.187 0.183 0.190 0.192 0.188 0.183 0.171

0.702 0.711 0.694 0.682 0.682 0.685 0.693

a

Standard uncertainties u(x) ¼ 0.005, u(P) ¼ 1.5 kPa, u(T) ¼ 0.05 K.

333.15

M. Trofimova et al. / Fluid Phase Equilibria 503 (2020) 112321

9

Table 5 Experimental LLE data (mole fractions) for the acetic acid (1) ‒ ethanol (2) ‒ ethyl acetate (3) ‒ water (4) system at 323.15 K and 333.15 K, p ¼ 101.3 kPaa. mole fractions ratio of acetic acid and ethanol

323.15 K 4:1

2:1

1:1

1:2

1:4

aqueous phase

organic phase

x1

x2

x3

x2

x1

x3

0.013 0.026 0.035 0.050 0.010 0.017 0.026 0.033 0.038 0.004 0.009 0.018 0.020 0.038 0.005 0.012 0.018 0.027 0.027 0.006 0.011 0.015 0.020 0.018

0.007 0.017 0.018 0.025 0.007 0.017 0.027 0.034 0.041 0.007 0.018 0.020 0.038 0.043 0.019 0.030 0.038 0.052 0.070 0.013 0.027 0.040 0.051 0.064

0.030 0.046 0.064 0.087 0.027 0.042 0.057 0.069 0.088 0.026 0.030 0.032 0.055 0.077 0.032 0.045 0.055 0.083 0.100 0.029 0.041 0.059 0.074 0.086

0.026 0.044 0.061 0.099 0.014 0.031 0.050 0.064 0.066 0.011 0.030 0.051 0.060 0.070 0.007 0.017 0.025 0.040 0.039 0.007 0.013 0.020 0.030 0.024

0.010 0.030 0.040 0.053 0.017 0.038 0.057 0.066 0.069 0.025 0.051 0.060 0.072 0.073 0.025 0.044 0.068 0.090 0.114 0.019 0.045 0.077 0.104 0.130

0.679 0.592 0.502 0.393 0.703 0.620 0.501 0.398 0.263 0.693 0.589 0.512 0.377 0.290 0.700 0.644 0.567 0.457 0.324 0.720 0.663 0.566 0.441 0.312

0.012 0.024 0.032 0.045 0.009 0.016 0.025 0.032 0.004 0.007 0.016 0.015 0.033 0.004 0.011 0.017 0.026 0.026 0.005 0.010 0.014 0.019 0.017

0.006 0.015 0.016 0.020 0.006 0.016 0.026 0.033 0.006 0.016 0.017 0.033 0.038 0.018 0.029 0.037 0.051 0.069 0.012 0.026 0.039 0.050 0.063

0.030 0.046 0.064 0.087 0.027 0.042 0.057 0.069 0.026 0.030 0.032 0.055 0.077 0.032 0.045 0.055 0.083 0.100 0.029 0.041 0.059 0.074 0.086

0.024 0.042 0.058 0.094 0.013 0.030 0.049 0.063 0.029 0.049 0.045 0.055 0.065 0.006 0.016 0.024 0.039 0.038 0.006 0.012 0.019 0.029 0.023

0.009 0.028 0.038 0.048 0.016 0.037 0.056 0.067 0.049 0.058 0.055 0.067 0.068 0.024 0.043 0.067 0.089 0.113 0.018 0.044 0.076 0.103 0.129

0.679 0.592 0.502 0.393 0.703 0.620 0.501 0.398 0.693 0.589 0.512 0.377 0.290 0.700 0.644 0.567 0.457 0.324 0.720 0.663 0.566 0.441 0.312

333.15 K 4:1

2:1

1:1

1:2

1:4

a

Standard uncertainties u(x) ¼ 0.002, u(P) ¼ 1.5 kPa, u(T) ¼ 0.05 K.

acetic acid ‒ ethanol ‒ ethyl acetate ‒ water system.  the critical surface is located in the section of the composition tetrahedron enriched with water; the content of ethyl acetate in critical points in general does not exceed 0.192 mol fraction in the temperature range 293.15e333.15 K;  the critical surface emerges from the face of a composition tetrahedron corresponding to the acetic acid e ethyl acetate e water ternary subsystem, and passing through the volume of the tetrahedron goes into the face corresponding to the ethanol e ethyl acetate e water subsystem;  the critical curve shifts in the concentration space by an average of 0.015 mol fractions of ethyl acetate in increments of 10 towards the top of the tetrahedron corresponding to ethyl acetate;

 the form and location of the critical surface of the acetic acid ‒ ethanol ‒ ethyl acetate ‒ water system in the concentration tetrahedron are typical for experimentally defined form and location of the critical surfaces of other systems with esterification; for example, formic acid ‒ ethanol ‒ ethyl formate ‒ water [60], acetic acid ‒ n-propanol ‒ n-propyl acetate ‒ water [61,62], propionic acid e ethanol e ethyl propionate e water [54], and propionic acid e n-propanol e n-propyl acetate e water [63]. All uncertainties were estimated according to the Guide to the expression of uncertainty in measurement (GUM) [65].

10

M. Trofimova et al. / Fluid Phase Equilibria 503 (2020) 112321

and LLE for the acetic acid e ethanol e ethyl acetate e water system at 323.15 K and 333.15 K at atmospheric pressure give a detailed description of the structure of phase diagram in this system. The study of solubility and critical states was performed by the cloud point technique; using obtained data the dispositions of binodal curves, binodal surfaces and critical manifolds are determined and presented in the composition tetrahedron and triangles. The study of LLE was implemented using GC; tie-lines are also presented in the composition triangles and composition tetrahedron. Analysis of temperature evolution of phase diagrams shows that solubility of the acetic acid e ethanol e ethyl acetate e water system increases with temperature. The features of the critical surface under polythermal conditions are discussed in detail. Simulation of LLE was carried out using the NRTL method. The results of LLE modelling closely matched with the experimental data at both temperatures, and standard deviations in general did not exceed 0,41%. The reliability of obtained parameters for thermodynamic consistency was checked by analyzing the GM function in liquid-liquid equilibrium correlation data given in [66]. Fig. 11. The enlarged fragment of the concentration tetrahedron with the critical surface of the acetic acid e ethanol e ethyl acetate e water system at 293.15e333.15 K: ‒ critical curve at 293.15 K [48], ‒ critical curve at 303.15 K [25], ‒ critical curve at 313.15 K [25], ‒ critical curve at 323.15 K, ‒ critical curve at 333.15 K. The gray area of space at the base of the tetrahedron is the projection of the surface.

Table 6 Energy parameters gji obtained by simulation of experimental LLE data of the acetic acid (1) ‒ ethanol (2) e ethyl acetate (3) e water (4) system by the NRTL model, J/ mol. ij

Dgji, J mol1

Dgij, J mol1

aji

323.15 K 1e2 1e3 1e4 2e3 2e4 3e4

313 7986 4167 7550 3690 1596

306 5810 5650 3549 741 9219

0.3 0.3 0.3 0.3 0.3 0.3

Maria Toikka, Maya Trofimova, and Nikita Tsvetov acknowledge the Russian Foundation for Basic Research grant N 18-33-20138 aimed at the support of experimental determination of solubility and phase equilibrium. Artemiy Samarov and Alexander Toikka are grateful to the Russian Foundation for Basic Research (grant N 1903-00375) for the support of the thermodynamic modeling. Alexandra Golikova also acknowledges the Scholarships of President of Russian Federation (SP-2680.2018.1) for the support of research on critical phenomena. Appendix A. Supplementary data Supplementary data to this article can be found online at https://doi.org/10.1016/j.fluid.2019.112321. References

333.15 K 1e2 1e3 1e4 2e3 2e4 3e4

Acknowledgements

400 6336 5563 7802 5588 1651

384 5696 6083 3351 667 8750

0.3 0.3 0.3 0.3 0.3 0.3

4.2. Modelling Table 6 presents parameters estimated using OF. Standard deviation s(NRTL) for the ternary ethanol ‒ ethyl acetate ‒ water and acetic acid ‒ ethyl acetate ‒ water subsystems including the binary ethyl acetate ‒ water mixture does not exceed 0.32% for 323.15 K and 0.41% for 333.15 K; for the quaternary acetic acid ‒ ethanol ‒ ethyl acetate ‒ water it is 0.34% for 323.15 K and 0,34% for 333.15 K. Additionally, we checked the reliability of obtained parameters for thermodynamic consistency [66] for the ternary systems. The corresponding figures are presented in supplementary materials (Figs. 12 and 13). Thus it may be concluded that the results of LLE modelling using NRTL are in a good agreement with the experimental data. 5. Conclusions The set of new experimental data on solubility, critical points

[1] K. Sundmacher, A. Kienle (Eds.), Reactive Distillation: Status and Future Directions, Wiley-VCH, Weinheim, 2003. [2] A. Gorak, E. Sorensen (Eds.), Distillation: Fundamentals and Principles, Academic Press, 2014. [3] W.L. Luyben, Ch-Ch Yu, Reactive Distillation Design and Control, Wiley, 2009. [4] A.M. Toikka, A.A. Samarov, M.A. Toikka, Phase and chemical equilibria in multicomponent fluid systems with a chemical reaction, Russ. Chem. Rev. 84 (2015) 378e392, https://doi.org/10.1070/RCR4515. [5] F. Catapano, S. Di Iorio, L. Luise, P. Sementa, B.M. Vaglieco, Influence of ethanol blended and dual fueled with gasoline on soot formation and particulate matter emissions in a small displacement spark ignition engine, Fuel 245 (2019) 253e262, https://doi.org/10.1016/j.fuel.2019.01.173. [6] W.C. Yuan, H.C. Frey, T.C. Wei, N. Rastogi, S. VanderGriend, D. Miller, L. Mattison, Comparison of real-world vehicle fuel use and tailpipe emissions for gasoline-ethanol fuel blends, Fuel 249 (2019) 352e364, https://doi.org/ 10.1016/j.fuel.2019.03.115. [7] F. Pradelle, S.L. Braga, A.R.F.D. Martins, F. Turkovics, R.N.C. Pradelle, Performance and combustion characteristics of a compression ignition engine running on diesel-biodiesel-ethanol (DBE) blends - potential as diesel fuel substitute on an Euro III engine, Renew. Energy 136 (2019) 586e598, https:// doi.org/10.1016/j.renene.2019.01.025. [8] H. Venu, An experimental assessment on the influence of fuel-borne additives on ternary fuel (diesel-biodiesel-ethanol) blends operated in a single cylinder diesel engine, Environ. Sci. Pollut. Res. 26 (2019) 14660e14672, https:// doi.org/10.1007/s11356-019-04739-5. [9] A. Jamrozik, W. Tutak, R. Gnatowska, L. Nowak, Comparative analysis of the combustion stability of diesel-methanol and diesel-ethanol in a dual fuel engine, Energies 12 (2019) 971, https://doi.org/10.3390/en12060971. [10] A.K. Frolkova, V.M. Raeva, Bioethanol dehydration: state of the art, Theor. Found. Chem. Eng. 44 (2010) 545e556, https://doi.org/10.1134/ S0040579510040342. [11] M.A. Santaella, A. Orjuela, P.C. Narvaez, Comparison of different reactive distillation schemes for ethyl acetate production using sustainability indicators, Chem. Eng. Proc. e Process Intensification 96 (2015) 1e13, https://

M. Trofimova et al. / Fluid Phase Equilibria 503 (2020) 112321 doi.org/10.1016/j.cep.2015.07.027. [12] J. Rayman, PhD Thesis, University of Budapest, Budapest, Hungary, 1906. [13] G.B. Hong, M.J. Lee, H. Lin, Multiphase coexistence for mixtures containing water, 2-propanol, and ethyl acetate, Fluid Phase Equilib. 203 (2002) 227e245, https://doi.org/10.1016/S0378-3812(02)00187-5. [14] M.C. Grande, C.M. Marschoff, Liquid-liquid equilibria for water þ benzonitrile þ ethyl acetate or þ butyl acetate, J. Chem. Eng. Data 50 (2005) 1324e1327, https://doi.org/10.1021/je050051h. [15] J.T. Chen, H.Y. Chang, Liquid-liquid equilibria of water þ 2-butanol þ (methyl methacrylate or butyl methacrylate or isobutyl methacrylate) at (288.2 and 318.2) K, J. Chem. Eng. Data 52 (2007) 1950e1954, https://doi.org/10.1021/ je7002572. [16] W.D. Bonner, Experimental determination of binodal curves, plait points, and tie lines, in 50 systems, each consisting of water and two organic liquids, J. Phys. Chem. 14 (1909) 738e789, https://doi.org/10.1021/j150116a004. [17] G.A. Batmanova, M.I. Balashov, A.V. Grishunin, I.G. Savinskaya, L.A. Serafimov, Mutual solubility and liquid-liquid phase equilibrium in three-component systems, Gidroliz. Lesokhim. Prom. 24 (1971) 11e12. [18] A.P. Altshuller, H.E. Everson, The solubility of ethyl acetate in water, J. Am. Chem. Soc. 75 (1953) 1727, https://doi.org/10.1021/ja01103a501. [19] I. Mertl, Liquid-vapour equilibrium. IL. Phase equilibria in the ternary system ethyl acetate-ethanol-water, Collect. Czechoslov. Chem. Commun. 37 (1972) 366e374, https://doi.org/10.1135/cccc19720366. [20] D. Richon, A. Viallard, Water/ester systems. II. Solubility studies, Fluid Phase Equilib. 21 (1985) 279e293, https://doi.org/10.1016/0378-3812(85)87006-0. [21] A. Venkataratnam, R.J. Rao, C.V. Rao, Ternary liquid equilibria, Chem. Eng. Sci. 7 (1957) 102e110, https://doi.org/10.1016/0009-2509(57)80025-6. [22] K. Akita, F. Yoshida, Phase-equilibria in methanol-ethyl acetate-water system, J. Chem. Eng. Data 8 (1963) 484e490, https://doi.org/10.1021/je60019a003. [23] H. Sugi, T. Katayama, Ternary liquid-liquid and miscible binary vapor-liquid equilibrium data for the two systems n-hexane ethanol acetonitrile and water acetonitrile-ethyl acetate, J. Chem. Eng. Jpn. 11 (1978) 167e172, https:// doi.org/10.1252/jcej.11.167. [24] V.R. Sohoni, U.R. Warhadpande, System ethyl acetateeacetic acidewater at 30 C. Solvent extraction equilibrium data, Ind. Eng. Chem. 44 (1952) 1428e1429, https://doi.org/10.1021/ie50510a063. [25] M. Toikka, A. Samarov, M. Trofimova, A. Golikova, N. Tsvetov, A. Toikka, Solubility, liquid-liquid equilibrium and critical states for the quaternary system acetic acid-ethanol-ethyl acetate-water at 303.15 K and 313.15 K, Fluid Phase Equilib. 373 (2014) 72e79, https://doi.org/10.1016/j.fluid.2014.04.013. [26] R.W. Merriman, The mutual solubilities of ethyl acetate and water and the densities of mixtures of ethyl acetate and ethyl alcohol, J. Chem. Soc. Trans. 103 (1913) 1774e1789, https://doi.org/10.1039/CT9130301774. [27] S. Glasstone, A. Pound, Solubility influences. Part I. The effect of some salts, sugars, and temperature on the solubility of ethyl acetate in water, J. Chem. Soc. Trans. 127 (1925) 2660e2667, https://doi.org/10.1039/CT9252702660. [28] J. Kendall, L.E. Harrison, Compound formation in ester-water systems, Trans. Faraday Soc. 24 (1928) 588e596, https://doi.org/10.1039/TF9282400588. [29] D.G. Beech, S. Glasstone, 17. Solubility influences. Part V. The influence of aliphatic alcohols on the solubility of ethyl acetate in water, J. Chem. Soc. (Resumed) (1938) 67e73, https://doi.org/10.1039/jr9380000067. [30] R. Stephenson, J. Stuart, Mutual binary solubilities: water-alcohols and wateresters, J. Chem. Eng. Data 31 (1986) 56e70, https://doi.org/10.1021/ je00043a019. [31] A. Skrzecz, A. Maczynski, Liquid-liquid-vapor equilibrium in the ethyl acetate water system, Polish, J. Chem. 53 (1979) 715e718. € [32] N. Schlesinger, W. Kubasowa, Über die Aussalzung von Athylacetat, Z. Phys. Chem. 142A (1929) 25e36, https://doi.org/10.1515/zpch-1929-14203. [33] J. Griswold, P.L. Chu, W.O. Winsauer, Phase equilibria in ethyl alcoholeethyl acetateewater system, Ind. Eng. Chem. 41 (1949) 2352e2358, https:// doi.org/10.1021/ie50478a063. [34] M.U. Pai, K.M. Rao, Salt-effect on liquid-liquid equilibria in the ethyl acetateethyl alcohol-water system, J. Chem. Eng. Data 11 (1966) 353e356, https:// doi.org/10.1021/je60030a018. [35] F. Van Zandijcke, L. Verhoeye, The vapour-liquid equilibrium of ternary systems with limited miscibility at atmospheric pressure, J. Appl. Chem. Biotechnol. 24 (1974) 709e729, https://doi.org/10.1002/jctb.5020241202. [36] L.-S. Lee, W.-C. Chen, J.-F. Huang, Experiments and correlations of phase equilibria of ethanol-ethyl acetate-water ternary mixture, J. Chem. Eng. Jpn. 29 (1996) 427e438, https://doi.org/10.1252/jcej.29.427. [37] A. Arce, L. Alonso, I. Vidal, Liquid-liquid equilibria of the systems ethyl acetate þ ethanol þ water, butyl acetate þ ethanol þ water, and ethyl acetate þ butyl acetate þ water, J. Chem. Eng. Jpn. 32 (1999) 440e444, https:// doi.org/10.1252/jcej.32.440. [38] V. Gomis, F. Ruiz, J.C. Asensi, The application of ultrasound in the determination of isobaric vapoureliquideliquid equilibrium data, Fluid Phase Equilib. 172 (2000) 245e259, https://doi.org/10.1016/S0378-3812(00)00380-0. [39] H.M. Lin, C.E. Yeh, G.B. Hong, M.J. Lee, Enhancement of liquid phase splitting of water þ ethanol þ ethyl acetate mixtures in the presence of a hydrophilic agent or an electrolyte substance, Fluid Phase Equilib. 237 (2005) 21e30, https://doi.org/10.1016/j.fluid.2005.08.009. [40] M. Resa, M. Goenaga, M. Iglesias, R. Gonzalez-Olmos, D. Pozuelo, Liquid liquid equilibrium diagrams of ethanol þ water þ (ethyl acetate or 1pentanol) at several, Temperatures 51 (2006) 1300e1305, https://doi.org/

11

10.1021/je060054þ.  Hajo nyes, E. s-Szikszay, A. Dallos, (Liquid þ liquid) [41] F. Ratkovics, B. Pal agyi-Fe equilibria of (ethanoic acid þ an alkanol or a ketone or an ester or an aromatic hydrocarbon þ water) at the temperature 293.15 K, J. Chem. Thermodyn. 23 (1991) 859e865, https://doi.org/10.1016/S0021-9614(05)80281-2. [42] A. Colombo, P. Battilana, V. Ragaini, C.L. Bianchi, G. Carvoli, LiquidLiquid equilibria of the ternary systems water þ acetic acid þ ethyl acetate and water þ acetic acid þ isophorone (3,5,5-trimethyl-2-cyclohexen-1-one), J. Chem. Eng. Data 44 (1999) 35e39, https://doi.org/10.1021/je9702910. [43] S. Bernatova, K. Aim, I. Wichterle, Vapor-liquid and chemical equilibria in the ethanol þ ethanoic acid system at 348.15 K, J. Chem. Eng. Data 52 (2007) 20e23, https://doi.org/10.1021/je060143m. [44] Y.W. Kang, Y.Y. Lee, W.K. Lee, Vapor-liquid equilibria with chemical reaction equilibrium e systems containing ethanoic acid, ethyl alcohol, water and ethyl acetate, J. Chem. Eng. Jpn. 25 (1996) 649e655, https://doi.org/10.1252/ jcej.25.649. [45] N. Calvar, A. Dominguez, J. Tojo, Vaporeliquid equilibria for the quaternary reactive system ethyl acetate þ ethanol þwater þ acetic acid and some of the constituent binary systems at 101.3 kPa, Fluid Phase Equilib. 235 (2005) 215e222, https://doi.org/10.1016/j.fluid.2005.07.010. [46] I.A. Furzer, Liquid-liquid equilibria in chemical reactive systems, Chem. Eng. Sci. 49 (1994) 2544e2548, https://doi.org/10.1016/0009-2509(94)e0087-7. [47] A.M. Toikka, M.A. Toikka, YuA. Pisarenko, L.A. Serafimov, Vapor-liquid equilibria in systems with esterification reaction, Theor. Found. Chem. Eng. 43 (2009) 129e142, https://doi.org/10.1134/S004057950902002X. [48] M. Trofimova, M. Toikka, A. Toikka, Solubility, liquideliquid equilibrium and critical states for the quaternary system acetic acideethanoleethyl acetateewater at 293.15 K, Fluid Phase Equilib. 313 (2012) 46e51, https:// doi.org/10.1016/j.fluid.2011.09.035. [49] A. Golikova, N. Tsvetov, Y. Anufrikov, M. Toikka, I. Zvereva, A. Toikka, Excess enthalpies of the reactive system ethanol þ acetic acid þ ethyl acetate þ water for chemically equilibrium states at 313.15 K, J. Therm. Anal. Calorim. 134 (2018) 835e841, https://doi.org/10.1007/s10973-018-7010-8. [50] A. Golikova, A. Samarov, M. Trofimova, S. Rabdano, M. Toikka, O. Pervukhin, A. Toikka, Chemical equilibrium for the reacting system acetic acideethanoleethyl acetateewater at 303.15 K, 313.15 K and 323.15 K, J. Solut. Chem. 46 (2017) 374e387, https://doi.org/10.1007/s10953-017-0583-1. [51] K. Kroenlein, C.D. Muzny, A.F. Kazakov, V. Diky, R.D. Chirico, J.W. Magee, I. Abdulagatov, M. Frenkel, NIST/TRC Web Thermo Tables (WTT), US Secretary of Commerce, 2012. [52] M.A. Anisimov, Critical Phenomena in Liquids and Liquid Crystals, Moscow USSR (Engl. Transl.), 1978. [53] M. Fisher, The Nature of the Critical Points, University of Colorado Press, 1965. [54] M. Toikka, A. Sadaeva, A. Samarov, A. Toikka, Solubility and critical surface in the system propionic acideethanoleethyl propionateewater at 293.15, 303.15 and 313.15 K, J. Chem. Thermodyn. 132 (2019) 113e121, https:// doi.org/10.1016/j.jct.2018.12.026. [55] A. Smirnov, A. Sadaeva, K. Podryadova, M. Toikka, Quaternary liquid-liquid equilibrium, solubility and critical states: acetic acid - n-butanol - n-butyl acetate - water at 318.15 K and atmospheric pressure, Fluid Phase Equilib. 493 (2019) 102e108, https://doi.org/10.1016/j.fluid.2019.04.020. [56] A. Toikka, M. Toikka, Solubility and critical phenomena in reactive liquideliquid systems, Pure Appl. Chem. 81 (2009) 1591e1602, https:// doi.org/10.1351/PAC-CON-08-11-04. [57] D.F. Othmer, R.E. White, E. Trueger, Liquid-liquid extraction data, Ind. Eng. Chem. 33 (1941) 1240e1248, https://doi.org/10.1021/ie50382a007. [58] J.P. Nov ak, J. Matous, J. Pick, Liquid-liquid Equilibria, Academia, Prague, 1987. [59] H. Renon, J.M. Prausnitz, Local compositions in thermodynamic excess functions for liquid mixtures, AIChE J. 14 (1968) 135e144, https://doi.org/10.1002/ aic.690140124. [60] M. Trofimova, A. Sadaev, A. Samarov, M. Toikka, A. Toikka, Solubility, liquidliquid equilibrium and critical states for the quaternary system formic acid e ethanol e ethyl formate e water at 298.15 K and 308.15 K, Fluid Phase Equilib. 485 (2019) 111e119, https://doi.org/10.1016/j.fluid.2018.12.024. [61] M. Toikka, A. Samarov, A. Toikka, Solubility, liquideliquid equilibrium and critical states for the system acetic acid þ n-propanol þ n-propyl acetate þ water at 293.15K and 303.15K, Fluid Phase Equilib. 375 (2014) 66e72, https:// doi.org/10.1016/j.fluid.2014.04.034. [62] M.A. Toikka, N.S. Tsvetov, A.M. Toikka, Splitting of the liquid solution and the compositions of liquid phases in the water-n-propanol-n-propyl acetate system at 293.15, 303.15, and 313.15 K, Theor. Found. Chem. Eng. 45 (2011) 429e435, https://doi.org/10.1134/S0040579511040142. [63] A. Samarov, M. Toikka, M. Trofimova, A. Toikka, Liquid-liquid equilibrium for the quaternary system propionic acid þ n-propanol þ n-propyl propionate þ water at 293.15, 313.15 and 333.15 K, Fluid Phase Equilib. 425 (2016) 183e187, https://doi.org/10.1016/j.fluid.2016.05.033. [64] F.W. Getzen, G.T. Hefter, A. Maczynski, Solubility Data Series: Esters with Water. Part 1: Esters 2-C to 6-C vol. 48, 1992, p. 357. [65] Guide to the Expression of Uncertainty in Measurement (GUM), International Organization for Standardization, Switzerland, 2004. [66] A. Marcilla, J.A. Reyes-Labarta, M.M. Olaya, Should we trust all the published LLE correlation parameters in phase equilibria? Necessity of their assessment prior to publication, Fluid Phase Equilib. 433 (2017) 243e252, https://doi.org/ 10.1016/j.fluid.2016.11.009.