Experimental Determination and Modeling of LiquidâLiquid

Article Cite This: J. Chem. Eng. Data XXXX, XXX, XXX−XXX

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Experimental Determination and Modeling of Liquid−Liquid Equilibrium for Ternary Mixtures of Ethylene Glycol + 1,2-Butanediol + 3‑Heptanone or Anisole Chunli Li, Xuefei Wang, Hao Li,* Cong Duan, Le An, and Qing Liu National-Local Joint Engineering Laboratory for Energy Conservation of Chemical Process Integration and Resources Utilization, School of Chemical Engineering, Hebei University of Technology, Tianjin, 300401, China

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S Supporting Information *

ABSTRACT: Experimental liquid−liquid equilibrium (LLE) data for the system ethylene glycol (EG) + 1,2-butanediol (1,2-BD) + 3heptanone were measured at atmospheric pressure at 293.15, 303.15, and 313.15 K and the ternary LLE for systems of EG + 1,2BD + anisole were also investigated at 303.15 K at 101.3 KPa by using liquid−liquid equilibrium kettle method. Distribution coefficient and selectivity were obtained and applied to evaluate the extraction capacity of 3-heptanone and anisole. The reliability of the experimental data was confirmed by the Hand correlation and the Othmer−Tobias correlation. The experimental LLE data were correlated by NRTL and UNIQUAC models, and the corresponding parameters were obtained. The root-mean-square deviations (RMSD) between the experimental data and calculated values were less than 1.22%. Topological concepts related to the Gibbs stability test were used to validate the consistency between model parameters and experimental data. The liquid− liquid equilibrium data provide the basic physicochemical properties for design of extraction process of 1,2-BD from EG by 3heptanone and anisole. According to comprehensive correlation coefficient analysis, 3-heptanone is more suitable for the extraction of 1,2-BD from EG than anisole.

1. INTRODUCTION Ethylene glycol (EG) is an important organic chemical raw material which is widely used in the industrial manufacture of polyesters, plasticizers, surfactants, antifreeze, and so forth. It is also a common high-boiling point solvent.1,2 With oil prices high, the production of organic chemicals from coal instead of petroleum has become a major research direction. The production cost of ethylene glycol derived from coal is less high than that of oil, which promoted the development and design of the new process. Therefore, in recent years many countries have become more and more attached to the EG manufacturing process based on syngas. The process is divided into two main steps: first, dimethyl oxalate is synthesized by carbonization coupling of carbon monoxide, and then the dimethyl oxalate is converted into EG by hydrogenation.3 Unfortunately, owing to excessive hydrogenation, some byproducts are formed in the process, such as 1,4-butanediol, 1,2-butanediol (1,2-BD), 1,2-propylene glycol, diethylene glycol, and so forth.4−7 Among those glycols, 1,2-BD and EG have similar boiling points (464 and 470 K, respectively) and a minimum azeotrope.8 Thus, it is difficult to achieve the separation of the mixture containing glycols (such as 1,2-BD and EG) via simple conventional distillation. The method of extractive distillation was widely applied to separate the mixture with a close boiling point.9 In this process, the extractant and the mixed alcohols were passed through the extraction column, and then the top product of © XXXX American Chemical Society

extraction column was recovered into the extractant recovery tower for recycle. The bottom product entered the rectification column for EG refining. The extracting agent contains 3-heptanone, toluene, n-octene, cumene, n-heptane, o-xylene, or methylphenidate, and so forth. As compared with the traditional distillation technology, this process can save energy by 31.2%.10 For ethylene glycol and 1,2-butanediol, to date only Folas et al.11 have measured the LLE data for the binary systems EG + toluene or benzene at atmospheric pressure. However, there is no the ternary LLE data of extractants + 1,2-BD + EG in the reported literatures. It is worth noting that the liquid−liquid equilibrium data has fundamental physicochemical properties for designing, modeling, and simulating extraction separation.1 According to literature, aromatic hydrocarbons, ketone compounds, and ether compounds generally were chosen to extract polybasic alcohol. We selected cheap and readily available extractants for the test, including 3-heptanone, diisobutyl ketone, toluene, anisole, cumene, n-heptane, petroleum ether, and so forth. The extractant and mixture of ethylene glycol and 1,2-butanediol were thoroughly mixed at a ratio of 1:1 after static stratification upper and lower level samples were taken for testing. By calculating, 3-heptanone Received: December 27, 2018 Accepted: March 4, 2019

A

DOI: 10.1021/acs.jced.8b01257 J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

and anisole with better extraction effect were selected. In this work, LLE data of the ternary system (EG + 1,2-BD + 3heptanone) and (EG + 1,2-BD + anisole) have been determined by a modified liquid−liquid equilibrium kettle at 101.3 KPa. The reliability of the experimental LLE data for each system was examined by HAND and Othmer−Tobias correlations. The NRTL12 and UNIQUAC13 models were used to correlate the experimental LLE data, providing important basic data for the separation of EG and 1,2-BD by extraction. The consistency of the NRTL and UNIQUAC model parameters were checked by a Graphical User Interface (GUI)14 written in MatLab software code on the basis of the topological information contained in the Gibbs energy of mixing function (GM).

2. EXPERIMENTAL SECTION 2.1. Materials. Detailed specifications of chemicals used in this work were shown in Table 1. Purity of all reagents was Table 1. Specifications of the Chemicals chemical name

CAS

EG

107-21-1

1,2-BD

584-03-2

3heptanone anisole toluene

106-35-4

n-heptanol

111-70-6

100-66-3 108-88-3

source TCI Development Co.Ltd. TCI Development Co.Ltd. 9 Ding Chemistry Aladdin Tianjin FUCHEN Tianjin FUCHEN

mass purity (mass %)a

GC analysis (wt %)b

≥99.5

≥99.7

≥98

≥99.6

≥99

≥99.6

≥99 ≥99.5

≥99.8 ≥99.9

≥99.5

≥99.9

Figure 1. (Liquid + liquid) equilibrium cell. (1) Light phase port; (2) heavy phase port; (3) water outlet; (4) water inlet; (5) (6) thermometer; (7) condenser; (8) magnetic stirrer; (9) thermometer jack; (10) drying tube.

2.3. Procedures and Sample Analysis. For each experiment, the prepared mixtures of known compositions were added into the equilibrium chamber, and the chamber was heated to the objective temperature via using thermostatic water bath. The system was maintained at 101.3 KPa, and the pressure was determined by a precise mercury barometer with an accuracy of 0.01 kPa. When the cell reached a specified temperature, turn on the magnetic stirring and keep it for 1 h, and then keep it stabilization for 3 h. In order to prove that the static time for 3 h is long enough to reach the liquid−liquid equilibrium at each temperature (293.15, 303.15, and 313.15 K), the upper and lower layers were taken once an hour and the compositions were measured. During 3 h, the results of repeated measurements were reproducible with ±0.1%, indicating that the system can be achieve the liquid−liquid equilibrium in 3 h. The average results of repeated measurements of average value with time are listed in Table S2 in Supporting Information. After two phases have been reached equilibrium, samples of two layers were withdrawn by syringes separately. The taken samples were diluted in quantitative n-heptanol immediately. The gas chromatograph (GC) equipped with a flame ionization detector (FID) was applied to analyze the samples. Carrier gas used high-purity nitrogen (mass fraction purity 0.99999). The temperature of injection and detector were set to 260 °C and the column temperature was 135 °C. The total time was 11.5 min and the volume of the sample was 0.2 μL. A series of the standard solutions of EG, 1,2-BD, 3-heptanone or anisole, and n-heptanol of known concentration were prepared and used to confirm the correction factors of each component. Every sample was analyzed at least three times with a maximum relative error of ±0.0003, and the average values were determined as the sample final composition. The uncertainties estimated of each variable obtained experimentally are shown in the respective table footnote, which is calculated in according with the GUM.16

a

Obtained by the supplier. bExperimentally determined by gas chromatography, given as mass fraction.

detected by the SHIMADZU gas chromatograph (GC 2014) equipped with an OV-1701 chromatographic column (50 m × 0.32 mm × 0.5 μm) and a flame ionization detector (FID). All chemicals were used directly without any further refinement. 2.2. Apparatus. Schematic diagram of the experimental device used in this work is shown in Figure 1.15 The volume of the equilibrium chamber is about 50 mL. The equipment consists of a glass basin with a water jacket to keep constant temperature. The water bath was provided by a thermostatic water bath (ATPIO XOYS-2006) to control the temperature fluctuation range within ±0.01 K. A precise mercury thermometer that had a minimum scale of 0.1 °C from 0 to 50 °C was used in the course of the experimental runs. The mercury thermometer was corrected by standard thermometer before use, and standard uncertainty was no more than 0.05 °C. A magneton was used to thoroughly mix the solution in the container. The condenser ensures that the evaporated compound was completely condensed, which was introduced into ethanol at 10 °C. A drying tube was connected above the condenser to prevent moisture in the air from entering the liquid. A SHIMADZU gas chromatograph (GC 2014) equipped with an OV-1701 chromatographic column (50 m × 0.32 mm × 0.5 μm) and a flame ionization detector (FID) was used to analyze samples. The detector links the LabSolutions GC chromatograph workstation. B



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To verify the reliability of the experimental devices and the process, the liquid−liquid equilibrium data of the binary system {toluene (1) + ethylene glycol (2)} were measured in this work. The experimental LLE data in our study were compared with the literature data (shown in Table 2 and Figure 2), which indicated that the experimental device and the process applied in our work are reliable.

represents the mole fraction of 3-heptanone (or anisole) in the 3-heptanone-rich phase (or anisole-rich phase). 2.3.2. Distribution Coefficient and Separation Factor. Distribution coefficient (K) and separation coefficient (S) are calculated to evaluate the extraction capacity of 3-heptanone and anisole and are given by w k = 23 w21 (3)

Table 2. Experimental LLE Data of the Binary System Toluene (1) + Ethylene Glycol (2) for Temperature T, Toluene Mole Fraction in Light Phase is x11, Toluene Mole Fraction in Heavy Phase is x21 at 101.33 kPa T/K

x11

x21

293.15 303.15 313.15 323.15 333.15 343.15 353.15 363.15

0.998892 0.998314 0.997473 0.996487 0.994973 0.992219 0.988829 0.984983

0.019873 0.018859 0.027254 0.025592 0.027171 0.029153 0.028213 0.034276

s=

w23 w21 w13 w11

(4)

where w23 and w13 are the mole fractions of 1,2-BD and EG in the 3-heptanone or anisole-rich phase, respectively, while w21 and w11 are the mole fractions of 1,2-BD and EG in the EGrich phase, respectively. 2.3.3. Enthalpy Estimation in 3-Heptanone Extraction. In the process of extracting substances, for certain extractants and extracts when the extraction process reaches equilibrium, the distribution coefficient (K) is a constant at a temperature and ΔH is also a fixed value in the two phases at the certain of quality extractant and extract during the extraction process. Extraction process is suitable for Van’t Hoff equation. The extraction heat is regarded as a constant, the Van’t Hoff equation can be expressed as21−23

a

Standard uncertainties u are u(T) = 0.05 K, u(P) = 0.8 kPa, and u(x11) = u (x12) = 0.002.

ln K = −

(5)

where ΔH is the enthalpy of apparent thermal effects in the procedure and the energy of absorbed or released during the extraction process. ΔS is the entropy change. 2.4. Uncertainty Determination. The data acquisition mainly includes temperature and composition in this experiment, therefore, it is necessary to analyze the uncertainty of temperature measurement and composition measurement. According to GUM (Guide to the Expression of Uncertainty in Measurement, International Organization for Standardization, Geneva, Switzerland, 1993),16 the uncertainty of temperature measurement consists of three parts: (1) Precision mercury thermometer deviation the accuracy of precision mercury thermometer accuracy is 0.05 K, so uT,1 = 0.05 K. (2) It is found that the temperature fluctuation of the constant temperature bath is less than 0.01 K through experimental measurement, so uT,2 = 0.01 K. (3) The standard error was calculated by measuring the temperature of ice water mixture several times, n = 10. Repeatability error of temperature measurement is uT,3 = 0.05 K. The total uncertainty of temperature measurement i is

Figure 2. Comparison between the experimental and the literature (liquid + liquid) equilibrium data for the binary system of toluene (1) + EG (2): (■) experimental data, (○) literature data,17 (△) literature data.18

2.3.1. Hand and the Othmer−Tobias Correlations. Hand19 and the Othmer−Tobias20 correlations were applied to test the reliability of all measured data in Table 3 and Table 4, The Hand correlation is as follows ij x yz ij x yz lgjjj 23 zzz = A lgjjj 21 zzz + B jx z j x33 z k 11 { k { The Othmer−Toias correlation is as follows

ΔH ΔS + RT R

3

uT =

(1)

∑ u T,2i i=1

i y ij 1 − x11 yz zz = a + b lnjjj1 − x33 zzz lnjjj jj z zz j x x33 z{ (2) k 11 { k where A, B, a, and b are Hand and Othmer−Tobias correlation parameters, x23 is the mole fraction of 1,2-BD in the 3-heptanone-rich phase (or anisole-rich phase) and x11 represents the mole fraction of EG in the EG-rich phase, x21 is the mole fraction of 1,2-BD in the EG-rich phase, and x33

= 0.0714 K (6)

The uncertainty of component measurement consists of two parts: (1) The measurement accuracy of Shimadzu gas chromatograph (GC2014) is 0.001%, so ux,1 = 0.00001. (2) In the course of measurement, a sample was analyzed many times until the maximum error of three times did not exceed 0.03%. Repeatability error of component measurement is ux,2 = 0.0003. The total uncertainty of component measurement is C



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Table 3. Experimental LLE Data of EG (1) + 1,2-BD (2) + 3-Heptanone (3) at 101.325 kPaa 3-heptanone-rich layer

EG-rich layer

T/K

x1

x2

x3

x1

x2

x3

K

S

293.15

0.0510 0.0550 0.0590 0.0653 0.0681 0.0735 0.0784 0.0867 0.0976 0.1083 0.1131 0.1254 0.1286 0.1386 0.1514 0.1674 0.0651 0.0675 0.0720 0.0804 0.0806 0.0857 0.0944 0.0979 0.1034 0.1077 0.1147 0.1261 0.1399 0.1533 0.0764 0.1004 0.1097 0.1208 0.1380 0.1451 0.1591 0.1667 0.1782 0.2304

0.0086 0.0164 0.0243 0.0354 0.0404 0.0475 0.0549 0.0670 0.0808 0.0952 0.1019 0.1142 0.1189 0.1294 0.1415 0.1564 0.0155 0.0177 0.0249 0.0354 0.0354 0.0413 0.0521 0.0566 0.0654 0.0676 0.0770 0.0904 0.1008 0.1134 0.0116 0.0403 0.0528 0.0658 0.0799 0.0853 0.0976 0.1057 0.1164 0.1513

0.9404 0.9286 0.9167 0.8993 0.8915 0.8790 0.8667 0.8463 0.8216 0.7965 0.7850 0.7604 0.7525 0.7320 0.7071 0.6762 0.9194 0.9148 0.9031 0.8842 0.8840 0.8730 0.8535 0.8455 0.8312 0.8247 0.8083 0.7835 0.7593 0.7333 0.9120 0.8593 0.8375 0.8134 0.7821 0.7696 0.7433 0.7276 0.7054 0.6183

0.9231 0.8834 0.8342 0.7868 0.7615 0.7336 0.7055 0.6668 0.6333 0.6005 0.5718 0.5505 0.5376 0.5187 0.4995 0.4788 0.8866 0.8773 0.8445 0.8066 0.7972 0.7759 0.7362 0.7219 0.7035 0.6889 0.6670 0.6309 0.6080 0.5813 0.9148 0.8046 0.7663 0.7257 0.6903 0.6794 0.6522 0.6287 0.6137 0.5563

0.0444 0.0799 0.1166 0.1522 0.1719 0.1910 0.2095 0.2335 0.2552 0.2723 0.2846 0.2921 0.2947 0.3000 0.3039 0.3070 0.0726 0.0800 0.1056 0.1348 0.1415 0.1574 0.1834 0.1933 0.2062 0.2112 0.2264 0.2447 0.2537 0.2635 0.0448 0.1297 0.1555 0.1804 0.2011 0.2060 0.2181 0.2259 0.2354 0.2567

0.0325 0.0367 0.0492 0.0610 0.0666 0.0754 0.0850 0.0997 0.1115 0.1272 0.1436 0.1574 0.1677 0.1813 0.1966 0.2142 0.0408 0.0427 0.0500 0.0586 0.0613 0.0667 0.0804 0.0848 0.0903 0.0999 0.1066 0.1244 0.1383 0.1552 0.0404 0.0657 0.0782 0.0939 0.1086 0.1146 0.1297 0.1454 0.1509 0.1870

0.1934 0.2046 0.2081 0.2327 0.2348 0.2484 0.2620 0.2870 0.3166 0.3494 0.3581 0.3910 0.4036 0.4313 0.4655 0.5096 0.2125 0.2217 0.2360 0.2627 0.2501 0.2622 0.2838 0.2928 0.3173 0.3203 0.3403 0.3694 0.3974 0.4305 0.2593 0.3110 0.3395 0.3649 0.3974 0.4140 0.4474 0.4678 0.4946 0.5893

3.4976 3.2863 2.9410 2.8059 2.6264 2.4771 2.3581 2.2072 2.0542 1.9375 1.8114 1.7164 1.6874 1.6139 1.5359 1.4579 2.8929 2.8823 2.7673 2.6355 2.4733 2.3746 2.2125 2.1581 2.1590 2.0485 1.9782 1.8481 1.7266 1.6321 3.1039 2.4932 2.3708 2.1931 1.9885 1.9385 1.8341 1.7644 1.7034 1.4229

303.15

313.15

a

S is the selectivity coefficients of 1,2-BD versus EG. K is the distribution coefficient of 1,2-BD. Standard uncertainties, u, u(x1) = u(x2) = u(x3) = 0.002. u(T) = 0.05 K, u(P) = 0.8 kPa.

niI + niII = ni (i = 1, 2, and 3)

2

ux =

∑

u x,2 i

= 0.0009

i=1

where ni represents the total moles of component i. For the prediction of LLE phase equilibrium, the solution satisfying eqs 6 and 7 needs to be tested for stability. The method is based on the tangent plane criterion24 or the method proposed by Marcilla et al.25 3.1. NRTL. The NRTL equations are given by ÅÄ ÑÉ ∑j τjiGjixj ∑k xkτkjGki ÑÑÑ xjGij ÅÅÅ Å ÑÑ ln γi = +∑ ÅÅÅτij − ÑÑ ∑ ∑k Gkixk ∑ G x G x Å ÑÑÖ kj k kj k Å k k j Ç

(7)

3. THERMODYNAMIC MODELING The isoactivity criterions of components in two phases on a molar fraction basis are applied for calculation of LLE of ternary systems xiIγi I = xiIIγi II(i = 1, 2, and 3)

(9)

(8)

(10)

where xi is the mole fraction and γi represents activity coefficient of component i; I and II are the two phases. The isoactivity criteria are constrained by the mass balance equations of the components, that represented as follows

where xi represents the mole fraction of component i, γi represents the activity coefficient of component i, and T is the absolute temperature. D



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Table 4. Experimental LLE Data of EG (1) + 1,2-BD (2) + Anisole (3) at 101.325 kPaa anisole-rich layer

EG-rich layer

T/K

x1

x2

x3

x1

x2

x3

K

S

303.15

0.0103 0.0107 0.0125 0.0135 0.0134 0.0158 0.0160 0.0165 0.0172 0.0179 0.0187

0.0034 0.0095 0.0165 0.0196 0.0218 0.0282 0.0305 0.0338 0.0373 0.0449 0.0495

0.9863 0.9798 0.9710 0.9669 0.9648 0.9560 0.9535 0.9497 0.9455 0.9372 0.9318

0.8996 0.8127 0.7282 0.6987 0.6726 0.6281 0.6079 0.5860 0.5644 0.5161 0.4925

0.0482 0.1280 0.1979 0.2198 0.2417 0.2764 0.2895 0.3060 0.3201 0.3519 0.3681

0.0522 0.0593 0.0739 0.0815 0.0857 0.0955 0.1026 0.1080 0.1155 0.1320 0.1394

0.0696 0.0741 0.0834 0.0893 0.0904 0.1021 0.1054 0.1103 0.1164 0.1277 0.1344

6.0750 5.6079 4.8744 4.6345 4.5302 4.0687 3.9958 3.9077 3.8193 3.6757 3.5374

a S is the selectivity coefficients of 1,2-BD versus EG. K is the distribution coefficient of 1,2-BD Standard uncertainties, u, u(x1) = u(x2) = u(x3) = 0.002. u(T) = 0.05 K, u(P) = 0.8 kPa.

3.2. UNIQUAC. The UNIQUAC model applied in this work is ln γi = ln

ϕi xi

ϕ θ z q ln i + li − i 2 i ϕi xi

+

ij

yz

∑ xjlj − qi lnjjjjj∑ θτj jizzzzz + qi 3

j=1

3

j j=1 k

z {

3

θτ j ij 3 j = 1 ∑k = 1 θkτkj

− qi ∑

(11)

where z is set to 10 that is the number of close interacting molecules around a central molecule, φi represents the volume fraction of component i, and θi represents the area fraction of component i. The NRTL and UNIQUAC model binary interaction parameters are calculated by minimizing the objective function (OF) 3

OF =

2

n

∑ ∑ ∑ (xijkexp − xijkcal)2 i=1 j=1 k=1

(12)

Figure 3. Liquid−liquid equilibria of the ethylene glycol (1) + 1,2butanediol (2) + 3-heptanone (3) system at T = 293.15 K. ; (○) experimental data, () experimental tie lines, (■) NRTL data, (. . . . . .) NRTL model tie lines, (△) UNIQUAC data, (− − − ) UNIQUAC model tie lines.

The optimality of the parameters can be assessed basing to the mean deviation in the compositions of the coexisting phases.27,28 The root mean square deviation (RMSD) is used to measure the accuracy between experimental and calculated results from the NRTL or UNIQUAC models, which is defined as É1/2 ÅÄÅ 3 exp cal 2 Ñ ÅÅ ∑i = 1 ∑2j = 1 ∑nk = 1 (xijk ) ÑÑÑÑ − xijk ÅÅ RMSD = ÅÅ ÑÑÑ ÅÅ ÑÑ 6n ÅÅÇ ÑÑÖ (13)

displayed separately. The calculated tie-lines of ternary systems from NRTL and UNIQUAC models in Tables S6 and S7 in the Supporting Information. The systems {EG (1) + 1,2-BD (2) + anisole (3)} and {EG (1) + BD (2) + 3-heptanone (3)} can be classified as Treybal’s type I.29 It can be found from Figures 3−5, the area of two-phase heterogeneous region (that is area under the curve) decreased slightly with temperature in the order of 313.15 K < 303.15 K < 293.15 K, which indicated that solubility decreased with the decrease of temperature. Thus, the heterogeneous area has in turn decreased in high temperature. From Figures 4 and 6, compared with anisole, ethylene glycol is more soluble in 3heptanone, which indicates that 3-heptanone has a strong extraction ability. Among the boiling point of 3-heptanone is lower than that of anisole and that is farther away from the boiling point of ethylene glycol and 1,2-butanediol. The subsequent separation can obtain pure components easily and consume less energy. The relative volatility of 3-heptanone relative to ethylene glycol is much higher than that of anisole relative to ethylene

where xexp represents experimental mole fractions and xcal represents calculated mole fractions. The subscript i is the components in the mixture, and the subscripts j and k indicate the phases and the tie-lines, respectively. n is the amount of tie-lines.

4. RESULTS AND DISCUSSION The experimental LLE data for the ternary systems {EG (1) + 1,2-BD (2) + 3-heptanone (3)} at 293.15, 303.15, and 313.15 K and {EG (1) + 1,2-BD (2) + anisole (3)} at 303.15 K are shown in Tables 3 and 4. All the LLE data were obtained as mole fraction. In Figures 3−6, the ternary phase diagrams with tie lines obtained from the experimental data and the values obtained by NRTL and UNIQUAC model regression are E



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Figure 6. Liquid−liquid equilibria of the ethylene glycol (1) + 1,2butanediol (2) + anisole (3) system at T = 303.15 K; (○) experimental data, () experimental tie lines, (■) NRTL data, (. . . . . .) NRTL model tie lines.

Figure 4. Liquid−liquid equilibria of the ethylene glycol (1) + 1,2butanediol (2) + 3-heptanone (3) system at T = 303.15 K; (○) experimental data, () experimental tie lines, (■) NRTL data, (. . . . . .) NRTL model tie lines, (△) UNIQUAC data, (− − − ) UNIQUAC model tie lines.

Table 5. Hand and Othmer−Tobias Correlation Parameters for the Ternary Systems {Ethylene Glycol (1) + 1,2Butanediol (2) + 3-Heptanone (3)} and {Ethylene Glycol (1) + 1,2-Butanediol (2) + Anisole (3)} correlation

EG + BDO + 3-heptanone

temperature/K Hand

Othmer−Tobias

A B R2 a b R2

EG + BDO + anisole

293.15 K

303.15 K

313.15 K

303.15 K

1.2827 −0.4818 0.9900 0.8136 0.67954 0.9900

1.2609 −0.42486 0.9930 0.6831 0.6354 0.9920

1.2310 −0.3150 0.9900 0.4190 0.6660 0.9900

1.0500 −1.1565 0.9980 2.8594 0.5928 0.9900

Figure 5. Liquid−liquid equilibria of thee ethylene glycol (1) + 1,2butanediol (2) + 3-heptanone (3) system at T = 313.15 K; (○) experimental data, () experimental tie lines, (■) NRTL data, (. . . . . .) NRTL model tie lines, (△) UNIQUAC data, (− − − ) UNIQUAC model tie lines.

glycol, so in theory it consumes less energy when extractant is recovered.30 The regressed Hand and Othmer−Tobias results are presented in Table 5 at different temperatures. It can be known in Table 5 the values of the correlation coefficient (R2) are close to unity. It indicates the goodness of fit confirms the reliability of the results. The selectivity data (S) and distribution coefficient (K) for EG (1) + 1,2-BD (2) + 3-heptanone (3) and EG (1) + 1,2-BD (2) + anisole (3) are shown in Tables 3 and 4 and Figures 7 and 8 separately. Selectivity is used to evaluate the efficiency of solvent of separation 1,2-BD from EG. Based on the results are reported in Figure 7, selectivity coefficients in all systems are greater than one, and this means that the 3-heptanone and anisole as an extraction is feasible. From the Figure 7, the

Figure 7. Selectivity (S) plots for the ethylene glycol (1) + 1,2butanediol (2) + 3-heptanone (3) system experimental data at (●) 293.15 K; (▲) 303.15 K; (■) 313.15 K ; NRTL data at (○) 293.15 K; (△) 303.15 K; (□) 313.15K; w23, 1,2-butanediol mole fraction in the 3-heptanone-rich layer. Selectivity (S) plots for the ethylene glycol (1) + 1,2-butanediol (2) + anisole (3) system experimental data at (◆) 303.15 K; NRTL data at (◊) 303.15 K; w23, 1,2butanediol mass fraction in the anisole-rich layer.

F



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Figure 8. Distribution coefficient (K) plots for the ethylene glycol (1) + 1,2 butanediol (2) + 3-heptanone (3) system experimental data at (●) 293.15 K; (▲) 303.15 K; (■) 313.15 K; NRTL data at (○) 293.15 K; (△) 303.15 K; (□) 313.15K, w23, 1,2-butanediol mole fraction in the 3-heptanone-rich layer. For ethylene glycol (1) + 1,2butanediol (2) + anisole (3) system experimental data at (◆) 303.15 K; NRTL data at (◊) 303.15 K; w23, 1,2-butanediol mass fraction in the anisole-rich layer.

Figure 9. Ploting ln K vs 1000/T for the ethylene glycol (1) + 1,2butanediol (2) + 3-heptanone (3) system experimental data.

diagrams in Figures 3−6 and shown in Tables S3−S5 in the Supporting Information, which is consistent with experimental LLE data. The binary interaction parameters computed from the two thermodynamic models for the systems researched, along with the RMSD between experimental values and calculated results, are gathered in Table 7. In NRTL model, αij is a nonrandom parameter that can be set to a predetermined value between 0.2 and 0.5 as suggested by Renon and Prausnitz.12 According to the character of the substance, αij has been fixed to 0.2 and 0.3 for EG (1) + 1,2BD (2) + 3-heptanone (3) system and EG (1) + 1,2-BD (2) + anisole (3) system. However, the binary interaction parameters cannot pass the parameter consistency detection. So according to other literature that set up αij values greater than 0.5,32 and even negative values for it,33 we considered a wider interval for the αij values which can be treated as adjustable parameter between 0 and 1. In the UNIQUAC model, the pure component structural parameters volume (r) and surface area (q) are obtained from literatures and the parameters are shown in Table 8. The binary interaction parameters pass the parameter consistency detection well, and the experimental and calculated LLE data are fitted well, and the RMSD value is less than 0.0027. The αij values were listed in Table 7. As shown in Table 7, all the RMSD results are lower than 0.0126, it can be considered both the NRTL and UNIQUAC models provide good performance for the correlation of the measured LLE data.34 Further, based on the RMSD values, the calculated results by the NRTL model is slightly better than the calculated results by the UNIQUAC model. However, due to Aspen 8.4 as a regression parameter tool, we cannot intuitively express the correlation of phase equilibrium. It is necessary to check for stability of all the solutions found in the correlations of phase equilibria.25 In this work, we used a Graphical User Interface (GUI)17written in MatLab software code, which based on the Gibbs energy of mixing function (GM) of the topological information contained. This is GUI for the representation of GM/RT surfaces and curves, and tie-lines and Hessian matrix, which can systematically test whether the results obtained in the NRTL or UNIQUAC correlations of LLE data for ternary systems are consistent.

temperature has little effect on selectivity. Besides high selectivity (S), high distribution coefficient (K) value as a standard of solvent containment is definitely appropriate, which will reduce the device size and solvent losses and may reduce the cost of recovering the solvent by distillation.31 On the basis of the data in Figure 8, it is clearly found that the distribution coefficient of the 3-heptanone is much larger than that of anisole. The distribution coefficients increase with the increase of temperature range from 293.15 to 313.15 K. The results show that the anisole has the higher selectivity and 3heptanone has the higher distribution coefficient. In this work, the influence of temperature on the extraction of 1,2-butanediol from ethylene glycol by 3-heptanone was investigated. The mixture of 10g EG and 1.2-BD was extracted by pure 10g 3-heptanone at 293.15, 303.15 and 313.15K. The distribution coefficient (K) was calculated by eq 1 results and shown in Table 6. Plot a graph with lnK as the ordinate and 1000/T as the abscissa by eq 3, which is a straight line on Figure 9. Table 6. Distribution Coefficient for 1,2-BD in 3Heptanone at Different Temperatures T/K

K

1000/T/K−1

ln K

293.15 303.15 313.15

0.2579 0.3302 0.4053

3.4112 3.2987 3.1934

−1.3552 −1.1079 −0.9031

According to the slope, the value of ΔH was calculated as 17.264 kJ/mol and the ΔS was calculated as 47.66 kJ/mol. The extraction process of ΔS > 0 is a spontaneous reaction. The result illustrated that the extraction procedure of 1,2butanediol from ethylene glycol by 3-heptanone is endothermic, thus the high temperature is conducive to the extraction in this system. The optimality of simulated data of NRTL and UNIQUAC model of EG (1) + 1,2-BD (2) + 3-heptanone (3) system and the optimality of simulated data of NRTL model of EG (1) + 1,2-BD (2) + anisole (3) were drawn in triangle phase G



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Table 7. Binary Interaction Parameters Calculated from NRTL and UNIQUAC Models for the Ternary Systems: {Ethylene glycol (1) + 1,2-butanediol (2) and (3-heptanone or anisole) (3)} component

NRTL gij-gjja

−1

T/K

i-j

293.15

1-2 1-3 2-3 1-2 1-3 2-3 1-2 1-3 2-3

−4688.48 7530.26 2242.39 2536.60 7817.80 2911.20 2323.61 7764.17 2677.66

1-2 1-3 2-3

−4407.70 5742.54 1924.23

303.15

313.15

303.15

(J·mol )

gji-giia

−1

(J·mol )

UNIQUAC α

RMSD

b

c

−1

uij-ujj (J·mol )

Ethylene Glycol (1) + 1, 2-Butanediol (2) + 3-Heptanone (3) 2635.19 1.00 0.002014 2592.20 6320.35 0.36 798.00 449.56 0.60 −180.20 −1995.20 0.50 0.001537 2376.48 6209.50 0.37 850.36 3102.20 0.40 804.88 −1763.36 0.5 0.002325 2180.40 6025.74 0.37 762.10 3109.63 0.44 −317.90 Ethylene Glycol (1) + 1,2-Butanediol (2) + Anisole (3) 4559.61 1.00 0.002725 9065.99 0.30 2648.12 0.70

uji-uiic (J·mol−1)

RMSDb

−2215.20 2950.60 1019.60 −2258.04 2797.47 −49.11 −1984.70 2892.90 1007.90

0.012294

0.007956

0.012631

a gij is interaction energy between species i and j in the ternary system (J/mol). bCalculated with eq 13. cuij is the UNIQUAC binary interaction parameter (J/mol).

Table 8. UNIQUAC Structural Parameters r and q component

r

q

ethylene glycol 1,2 butanediol 3-heptanone anisole

2.4088a 4.696b 5.2709c 4.1667d

2.248a 4.552b 4.4960c 3.2080d

The three sets of parameters obtained from the NRTL and UNIQUAC correlations of LLE data for ternary systems in this work passed the check of binary subsystems consistency and tie-lines consistency. For example, Figures 10 and 11 show the consistency of the parameters obtained for the LLE data of the ternary systems {EG (1) + 1,2-BD (2) + 3-heptanone (3)} at 303.15 K by means of the descriptions proposed in this part. It is observed that only the 1-3 pair are partially miscible as

a Taken from ref 24. bTaken from ref 25. cTaken from ref 20. dTaken from ref 26.

Figure 10. Representation of the GM/RT function for each one of the three binary subsystems for the EG(1) + 1,2-BD(2) + 3-heptanone(3) ternary system at T = 303.15 K, obtained in the present paper by LLE correlation using the NRTL model with the parameter values shown in Table 7: (a) binary (1)-(2); (b) binary (1)-(3), and (c) binary (2)-(3). H



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Figure 11. Calculated GM/RT surface (NRTL model with the parameter values in Table 7) and experimental LLE tie-lines for the EG (1) + 1,2BD (2) + 3-heptanone (3) ternary system at T = 303.15 K: (a) 3D representation and (b) sectional plane in the direction defined by the calculated ternary tie-line #3; (c) sectional plane in the direction defined by the experimental ternary tie-line #3; (d) sectional plane in the direction defined by the calculated ternary tie-line #6; (e) sectional plane in the direction defined by the experimental ternary tie-line #6.

expected from Figure 10 and consistency between the calculated tie-lines and the GM/RT surface obtained by the calculated parameters is shown in Figure 11. Figure 11b−e shows projections along two specific experimental and calculated tie-lines #3 and #6 on cross sections (number increases with the molar fraction of (2)-component), which are as samples were shown. All the tie-lines of calculated and experimental were checked and the common tangent lines between conjugated liquids were obtained. These figures once again show the consistencies between the experimental tielines and the NRTL regression parameters of this ternary system. Meanwhile, the consistency of the parameters obtained for the LLE data for the ternary systems {EG (1) + 1,2-BD (2) +

3-heptanone (3)} at 293.15, 303.15, and 313.15 K and {EG (1) + 1,2-BD (2) + anisole (3)} at 303.15 K are shown in Figures S1−S12 in the Supporting Information. In accordance with RMSD values and consistency check it can get binary interaction parameters very well, which could be used to design and simulate the extraction procedure.

5. CONCLUSIONS In this work, liquid−liquid equilibrium (LLE) data involving in ethylene glycol, 1,2-butanediol, 3-heptanone, and anisole was determined at 101.3 kPa. The influence of temperature on the extraction performance of 3-heptanone was studied by the enthalpy change in the extraction process. The result show that the extraction of 1,2-BD from EG by 3-heptanone is I



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Ethylene Glycol and 1,4-Butylene Glycol under 6.67 kPa. Journal of Chemical Engineering of Chinese Universities 2015, 238−241. (8) Ai, S.; Zheng, M. Y.; Jiang, Y.; Yang, X. F.; Li, X. S.; Pang, J. F.; Sebastian, J.; Li, W. Z.; Wang, A. Q.; Wang, X. D.; Zhang, T. Selective Removal of 1,2-Propanediol and 1,2-Butanediol from Bio-Ethylene Glycol by Catalytic Reaction. AlChE J. 2017, No. 00. (9) Xiao, J.; Zhong, L.; Chen, L. Method for separating ethylene glycol, propylene glycol and butanediol. CN 102372601A. 2012. (10) Xiao, J.; Zhong, L.; Guo, Z. Y.; Ju, F. Method for separating ethylene glycol, propylene glycol and butanediol. CN 102372600A. 2012. (11) Folas, G. K.; Kontogeorgis, G. M.; Michelsen, M. L.; Stenby, E. H.; Solbraa, E. Liquid-liquid equilibria for binary and ternary systems containing glycols, aromatic hydrocarbons, and water: Experimental measurements and modeling with the CPA EoS. J. Chem. Eng. Data 2006, 51, 977−983. (12) Renon, H.; Prausnitz, J. M. Local compositions in thermodynamic excess functions 365 for liquid mixtures. AIChE J. 1968, 14, 135−144. (13) Abrams, D. S.; Prausnitz, J. M. Statistical thermodynamics of liquid mixtures: A new expression for the excess Gibbs energy of partly or completely miscible systems. AIChE J. 1975, 21, 116−128. (14) Reyes-Labarta, J. A. Graphical User Interface (GUI) for the representation of GM surfaces (using the NRTL model) and curves, including tie-lines and Hessian matrix. Institutional Repository of the University of Alicante (RUA). (15) Wang, Z. R.; Xia, S. Q.; Ma, P. S.; Liu, T.; Han, K. W. (Liquid +liquid) equilibrium for binary systems of N-formylmorpholine with alkanes. J. Chem. Thermodyn. 2012, 47, 228−233. (16) BIPM, I.; IFCC; ISO; IUPAC; IUPAP; OIML. Guide to the expression of uncertainty in measurement (GUM), first ed.; International Organization for Standardization (ISO), 1995. (17) Gao, X.; Yang, Z.; Xia, S.; Ma, P. Liquid−liquid equilibrium data for binary systems containing o-dichlorobenzene and nitrobenzene. Fluid Phase Equilib. 2015, 385, 175−181. (18) R̂̌ ehák, K.; Dreiseitlová, J. Binary liquid−liquid equilibrium in the systems containing monofunctional benzene derivates and 1,2ethanediol. Fluid Phase Equilib. 2006, 249, 104−108. (19) Hand, D. B. Dineric Distribution. J. Phys. Chem. 1992, 34, 1961−2000. (20) Donald, F.; Othmer; Philip, E.; Tobias. Liquid -Liquid Extraction Data -Toluene and Acetaldehyde Systems. Ind. Eng. Chem. Res. 1942, 34, 690−692. (21) Zhang, S.; W. Chen, J. L. Deduction of van’t Hoff equation. Journal of the First University (Natural Science Edition) 1987, 2, 36− 42. (22) Xu, G.; Yang, D.; Ning, P.; Wang, Q.; Gong, F.; Cao, H. Measurements and correlation of liquid-liquid equilibrium data for the ternary (3-heptanone+phenol+water) system. J. Chem. Thermodyn. 2017, 106, 295−302. (23) Dai, Y.; Qin, W.; Zhang, J. Complex Extraction Technology of Organics; Chemical Industry Press: Beijing, 2003. (24) Michelsen; Michael, L. The isothermal flash problem: Part I. Stability. Fluid Phase Equilib. 1982, 91, 19. (25) Marcilla, A.; Reyes-Labarta, J. A.; Olaya, M. M. Should we trust all the published LLE correlation parameters in phase equilibria? Necessity of their assessment prior to publication. Fluid Phase Equilib. 2017, 433, 243−252. (26) Feng, Y.; Yang, E.; Dang, L.; Wei, H. Liquid−liquid phase equilibrium for ternary mixtures of formamide (or ethylene glycol, or monoethanolamine)+indole+2-methylnaphthalene at 308.15K. Fluid Phase Equilib. 2015, 398, 10−14. (27) Novak, J. P.; Matous, J.; Pick, J. Liquid - Liquid Equilibria; Elsevier, 1987. (28) Hwang, I. C.; Park, S. J. Liquid−liquid equilibria of ternary mixtures of dimethyl carbonate, diphenyl carbonate, phenol and water at 358.15K. Fluid Phase Equilib. 2011, 301, 18−21. (29) Treybal, R. Liquid-liquid Extraction; McGraw-Hill: New York,1963.

endothermic. The NRTL and UNIQUAC models were applied to regress the measured LLE data and both models gave relatively good results. Binary interaction parameter of the regression can be used for designing and optimizing the related separation process.

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ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.jced.8b01257. Table S1, properties of the chemicals; Table S2, the results of repeated measurements of the ternary system EG (1) + 1,2-BD (2) + 3-heptanone (3) and anisole (3); Tables S3−S5, the LLE data of EG (1) + 1,2-BD (2) + 3-heptanone (3) and anisole (3) from NRTL and UNIQUAC model; Tables S6 and S7, the calculated tielines of EG (1) + 1,2-BDO (2) + 3-heptanone (3) and anisole (3) from NRTL and UNIQUAC model; Figures S1−S12, Representation of the GM/RT function for each one of the three binary subsystems and calculated GM/RT 3D surface and experimental LLE tie-lines for the EG (1) + 1,2-BD (2) + 3-heptanone (3) and anisole (3) ternary system at different temperatures (PDF)

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AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. ORCID

Chunli Li: 0000-0003-1495-5740 Hao Li: 0000-0002-4151-0707 Funding

Financial support from the National Key Research and Development Program of China (2017YFB0602500) and the Basic Research Program of Hebei Province (16964502D) are gratefully acknowledged. Notes

The authors declare no competing financial interest.

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REFERENCES

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