Isobaric VaporâLiquid Equilibria for Two Binary Systems {Propylene

Article pubs.acs.org/jced

Isobaric Vapor−Liquid Equilibria for Two Binary Systems {Propylene Glycol Methyl Ether Acetate + Methanol} and {Propylene Glycol Methyl Ether Acetate + N,N‑Dimethylformamide} at p = 30.0, 50.0, and 70.0 kPa Nuo Shi, Chao Yan, Qian Yang, Juan Zhi, Feizhong Sun, and Changsheng Yang* Key Laboratory for Green Chemical Technology of State Education Ministry, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China ABSTRACT: The isobaric vapor−liquid equilibria (VLE) data for two binary systems of propylene glycol methyl ether acetate (PMA) + N,N-dimethylformamide (DMF) and propylene glycol methyl ether acetate (PMA) + methanol (MeOH) at 30.0, 50.0, and 70.0 kPa were measured by utilizing a modified Rose−Williams still type apparatus which could be able to quickly form the dual cycle of continuous vapor and liquid phase in this work. On the basis of Herington area test and Van Ness point test, the thermodynamic consistency of the experiment data was verified. Meanwhile, VLE data that we obtained were correlated with nonrandom two-liquid (NRTL) and Margules activity coefficient models. The results demonstrated that the calculated values were in good conformity with the experimental data in this study. In addition, azeotropic behavior was observed in the binary system of PMA and DMF at reduced pressures.

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investigated.6 In general, the transesterification cannot react completely when the equilibrium is reached, due to limitations of the reaction conditions. In order to obtain high-purity PMA, the preferred means of separation and purification process which factories usually choose are rectification or special distillation. The design of a distillation column capable of separating a mixture comprising PMA, PM, MeAc, and byproduct methanol (MeOH) is subject to vapor−liquid phase equilibrium data. Although there has been a few literature reports6,7 about the VLE data for binary systems of PMA and other reactants (byproducts), the associated data under reduced pressure conditions are less common, especially for PMA and MeOH. We just found the VLE data for this system at 101.3 kPa from Ye.6 These data are highly useful in designing the distillation process because high energy consumed by the separation of the high boiling point substance can be reduced under reduced pressure conditions. In the traditional PMA production process, the process of alkali neutralization and washing by water to remove the acidic catalyst used in the reaction results in the excess of metal ions in the product. In order to achieve electronic-level standards, engineering researchers are committed to solve the problem. N,N-Dimethylformamide is a colorless transparent organic solvent with a strong polarity and low toxicity. Assuming that the solubility of metal ions in DMF is higher than that of PMA,

INTRODUCTION As an important organic solvent in industry, propylene glycol methyl ether acetate (PMA) is extensively applied to multiple fields, such as coatings, inks, cleaning agents, printing, textile dyes, and leather tanning agents.1−3 The excellent solubility in both polar and nonpolar substances is attributed to the unique structure with carbonyl and ether bonds simultaneously.4 Moreover, owing to the advantage of low toxicity, more poisonous glycol ether and ester solvents are gradually replaced by PMA. In recent years, there is a strong need for a higher purity of PMA at the electronic level to clean photoresist generated from the process of electronic components manufacturing.5 The main manufacturers of PMA production are DOW, BASF, and SHELL and so on around the world. Over the past decade, manufacturers of China have been able to achieve largescale industrial production with the continuous improvement of production processes and representatives including Jiangsu Hualun Chemical Company. At present, there are many reports on the synthesis of PMA, such as direct esterification, transesterification, and one-step synthesis of propylene oxide and acetic acid ester, but the esterification with propylene glycol methyl ether (PM) and acetic acid is still employed in the industry. The generally adopted procedure is liquid acid as a catalyst for the production of intermittent process, resulting in a certain amount of environment pollution and equipment issues. In recent years, some new synthetic methods have been proposed; for example, a method of PMA by the transesterification with PM and methyl acetate (MeAc) is © 2017 American Chemical Society

Received: December 28, 2016 Accepted: March 6, 2017 Published: March 10, 2017 1507

DOI: 10.1021/acs.jced.6b01071 J. Chem. Eng. Data 2017, 62, 1507−1513

Journal of Chemical & Engineering Data

Article

Table 1. Suppliers and Purities of the Chemical Reagents chemical namea

CAS Registry No.

source

initial mass fraction

purification method

final mass fraction

analysis method

PMA DMF methanol

108-65-6 68-12-2 67-56-1

Jiangsu Hualun Chemical Co. Shandong Hualu Chemical Co. Tianjin Yuanli Reagent Co.

0.991 0.980 0.999

distillation distillation none

0.998 0.994 0.999

GCb GCb GCb

a

PMA: propylene glycol methyl ether acetate; DMF: N,N-dimethylformamide. bGas chromatography.

Table 2. Comparison of Densities (ρ), Refractive Index (nD), and Boiling Points (Tb) of Pure Components with the Literature Values ρ (g·cm−3) (298.15 K)

a

nD (298.15 K)

Tb/K (101.3 kPa)

compound

exptl

lit.

exptl

lit.

exptl

lit.

PMA DMF methanol

0.96152 0.94389 0.78659

0.9614a 0.945a 0.78656b

1.3986 1.4277 1.3264

1.3991a 1.4269a 1.3267b

418.72 426.65 337.63

418.95a 426.15a 337.80c

Reference 12. bReference 13. cReference 14. u(ρ) = 2.5 × 10−3 g·cm−3; u(nD) = 5 × 10−3; u(Tb) = 0.1 K; u(p) = 0.13 kPa.

we tried to add electron-grade DMF to high-purity PMA, then mixed them thoroughly and separated them by distillation to determine if the metal ions in PMA could be removed. Therefore, the VLE data of PMA and DMF measured are necessary for us. This paper presents isobaric vapor−liquid equilibria (VLE) data for two binary systems of propylene glycol methyl ether acetate (PMA) + methanol (MeOH) and propylene glycol methyl ether acetate (PMA) + N,N-dimethylformamide (DMF) at 30.0, 50.0, and 70.0 kPa measured by utilizing a modified Rose−Williams still. The experimental data were consistent with the thermodynamics of the Herington area test8 and Van Ness point test.9 The VLE data for two binary systems were respectively correlated with nonrandom two-liquid10 (NRTL) and Margules11 activity coefficient models to confirm the reliability of the experiment data.

Figure 1. Schematic diagram of the VLE apparatus: (1) electric heater, (2) liquid-phase sampling port, (3) vapor-phase sampling port, (4) vapor condenser, (5) coolant inlet, (6) coolant outlet, (7) U-shaped differential manometer, (8) vacuum pump, (9) buffer vessel, (10) needle valve, (11) precision mercury thermometer.

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EXPERIMENTAL SECTION Materials. The chemical HPLC grade MeOH was supplied by Tianjin Yuanli Reagent Co. with a mass fraction greater than 99.9% verified by gas chromatography (SP2100A) with a thermal conductivity detector (TCD). The other two solvents, PMA and DMF, were obtained from Jiangsu Hualun Chemical Co. and Shandong Hualu Chemical Co., respectively. There was an appreciable peak of water in both PMA and DMF detected by GC, and then further purification by vacuum distillation was prerequisite to ensure their purity before use. The specifications of the reagents used are listed in Table 1. In this work, physical properties of three pure components related to the experiment were determined. The densities (ρ) were measured at 298.15 K by using an Anton Paar DMA58 densimeter, and the standard uncertainty is 2.5 × 10−3 g·cm−3. The refractive indexes (nD) were tested with an ATAGO NAR3T Abbe refractometer (u = ±5 × 10−3). By means of the modified Rose-Williams still apparatus, the boiling points (Tb) of them were also surveyed at 101.3 kPa (u = ±0.1 K). All of the values determined in our laboratory as well as the corresponding literature data are presented in Table 2.12−14 Apparatus and Procedures. The apparatus shown in Figure 1 was adopted to measure the vapor−liquid equilibrium data of the binary system under reduced pressure. This device consists of double circulating vapor−liquid equilibrium still, vacuum pump, cooling circulation pump, heater, and other components. The modified Rose−Williams still as the key equipment could maintain vapor−liquid two-phase full contact

through continuous circulation to achieve phase equilibrium whose temperature remained stable for 30−60 min. A precision mercury thermometer with a high accuracy of 0.1 K and a range of 50 K was chosen to record the temperature. When the phase equilibrium was reached, the thermometer also showed a fluctuation range of 0.2 K, because of the impact of internal structure of the equipment and vacuum pump. The system pressure was checked by means of a U-shaped differential manometer connecting the vacuum pump to the needle valve which could slowly adjust the amount of air to attain a stable pressure, and the accuracy was estimated to be 0.13 kPa. The action of buffer vessel as a protective device against suckingback could slow down the pressure fluctuation to improve the reliability of pressure value. Different compositions of the solvents were prepared by an electronic balance (Sartorius BP210S) with an accuracy of 0.0001 g. The energy required for the entire experiment is provided by an electric heater. The system of MeOH + PMA, due to low boiling point of methanol, was prone to the abnormal boiling phenomenon. According to the constant regulation of the voltage to control the heating rate, we have concluded that setting the voltage lower than 40 V at the first half of heating process and next slowly increasing in voltage to 60 V could help to form a stable vaporization center as soon as possible and ultimately achieve phase equilibrium. Ethanol was chosen as the coolant in the condenser whose working 1508



Article

Table 3. Antoine Parameters of Pure Components Used in Present Study Antoine coefficients A

B

C

D

E

range T/K

6.2287 75.8542 75.8102

1429.31 −7955.5 −6904.5

−80.36 −8.8038 −8.8622

4.2431 × 10−6 7.4664 × 10−6

2 2

212.72−649.6 175.47−512.5

compound a

PMA DMFb methanolb a

Reference 6. bReference 18.

temperature is 263.15−268.15 K, ensuring each component in vapor phase fully condensed. Finally, samples of the vapor and liquid equilibrium phase were withdrawn and analyzed, respectively. The reliability of the experimental system and the procedure has been confirmed in our previous literature.15−17 Analysis. The equilibrium compositions were analyzed by a BFRL SP-2100A GC which was equipped with flame ionization detector (FID) and a SE-54 capillary column (30 m × 0.32 mm × 0.5 μm). The GC response peaks were obtained from N2000 chromatography station. The high-purity hydrogen gas (mass fraction 0.99999) produced by the hydrogen generator (KPS HG-1805) was used as the carrier gas with a constant flow rate of 40 mL·min−1. The temperature of the column, injector, and detector for two systems were all set to 483.15, 493.15, and 533.15 K, respectively. Under these temperature conditions, the two components could form good peaks. In order to obtain more accurate composition, the external standard method was selected for calibration. Simultaneously, the injection volumes of each sample (0.4 μL) were analyzed at least three times for the reliability. The deviations of the vapor and liquid mole fractions were maintained within 0.005 and 0.002, respectively.

Figure 2. T−α12 plot for the system of PMA (1) + DMF (2) at three different pressures. ■, at 30.0 kPa; ●, at 50.0 kPa; ▲, at 70.0 kPa.

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RESULTS AND DISCUSSION Component Vapor Pressures. Regarding N,N-dimethylformamide and methanol, the saturated vapor pressures of pure components were commonly obtained by Antoine eq 1 stemmed from literature.18 The saturated vapor pressure of propylene glycol methyl ether acetate were given by Antoine eq 2 whose constants are measured and correlated by Ye.6 The relative Antoine parameters for all pure components are shown in Table 3. ln(pis /kPa) = A +

log(pis /kPa) = A −

B + C ln(T /K) + D(T /K)E T /K

B T /K + C

Figure 3. T−α12 plot for the system of MeOH (1) + PMA (2) at three different pressures. ■, at 30.0 kPa; ●, at 50.0 kPa; ▲, at 70.0 kPa.

(1)

(2)

that MeOH and PMA are more easily separated under lowpressure conditions. Experimental Data. The vapor−liquid equilibrium data for two binary systems of PMA + DMF and MeOH + PMA measured in this work at 30, 50, and 70 kPa are listed in Tables 4 and 5, which also includes experimental activity coefficients γi. The results revealed the appearance of azeotropic behavior in PMA + DMF binary mixtures. The general vapor−liquid equilibrium relationship is as follows:

Relative Volatility. The relative volatility α12 for two binary systems at three pressures were calculated by eq 3: α12 =

y1 /y2 x1/x 2

(3)

where y1, y2 and x1, x2 are the mole fraction of the vapor and liquid phase, respectively. T−α 12 plots evaluating the experimental data are shown in Figures 2 and 3. Figure 2 shows that the relative volatility for PMA+DMF is close to 1, which indicates that the two solvents are difficult to separate by ordinary distillation, and it has little effect on α12 under different pressures. From Figure 3 we can see that the relative volatility for PMA + DMF is much larger than 1, and the value of α12 is the largest (37.05) at 30.0 kPa. It indicates

⎡ V l(P − P s) ⎤ v i s s ⎥ yi ϕî P = xiγφ P exp⎢ i i i i ⎥⎦ ⎢⎣ RT

(4)

In this experiment, the vapor phase can be regarded as the ideal gas under low pressure conditions, so ϕ̂ vi = 1 and φsi = 1. Equation 4 can be simplified as, 1509



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Table 4. Experimental VLE Data for the Equilibrium Temperature (T), the Liquid-Phase Mole Fraction (x1), the Vapor-Phase Mole Fraction (y1), and Calculated Activity Coefficient (γi) for the System of PMA (1) + DMF (2) at p = 30.0, 50.0, and 70.0 kPaa 30.0 kPa

50.0 kPa

70.0 kPa

T/K

x1

y1

384.76 383.11 382.17 381.22 380.52 379.83 379.75 379.73 379.79 379.84 379.99 380.12 380.42 380.82 381.41 400.65 398.87 397.65 396.70 395.93 395.16 394.91 394.86 394.89 394.95 395.02 395.13 395.44 395.78 396.04 411.56 409.94 408.16 406.89 406.04 405.39 405.13 405.06 405.09 405.15 405.28 405.42 405.91 406.27 406.59

0.000 0.094 0.170 0.262 0.363 0.527 0.610 0.641 0.730 0.752 0.815 0.834 0.902 0.956 1.000 0.000 0.087 0.170 0.258 0.374 0.542 0.648 0.707 0.729 0.739 0.804 0.828 0.925 0.981 1.000 0.000 0.073 0.169 0.269 0.381 0.535 0.647 0.706 0.729 0.741 0.804 0.829 0.927 0.983 1.000

0.000 0.141 0.233 0.328 0.417 0.551 0.616 0.642 0.714 0.734 0.791 0.814 0.883 0.944 1.000 0.000 0.131 0.238 0.332 0.438 0.569 0.656 0.706 0.722 0.730 0.789 0.813 0.912 0.974 1.000 0.000 0.119 0.245 0.344 0.440 0.568 0.659 0.704 0.723 0.734 0.791 0.815 0.917 0.976 1.000

γ1 1.398 1.322 1.250 1.176 1.098 1.064 1.056 1.029 1.025 1.013 1.014 1.006 1.000 1.000 1.366 1.322 1.253 1.170 1.076 1.046 1.034 1.024 1.019 1.010 1.007 1.001 0.997 1.000 1.463 1.374 1.260 1.168 1.096 1.060 1.040 1.034 1.030 1.019 1.014 1.005 0.997 1.000

Table 5. Experimental VLE Data for the Equilibrium Temperature (T), the Liquid-Phase Mole Fraction (x1), the Vapor-Phase Mole Fraction (y1), and Calculated Activity Coefficient (γi) for the System of MeOH (1) + PMA (2) at p = 30.0, 50.0, and 70.0 kPaa

γ2 1.000 1.004 1.011 1.030 1.061 1.127 1.173 1.188 1.260 1.273 1.334 1.317 1.389 1.460

30.0 kPa

50.0 kPa

1.000 1.001 1.003 1.014 1.036 1.113 1.165 1.199 1.224 1.232 1.279 1.287 1.376 1.587

70.0 kPa

1.000 1.001 1.008 1.034 1.069 1.120 1.174 1.226 1.243 1.247 1.290 1.303 1.349 1.657 -

x1

y1

0.000 0.012 0.035 0.071 0.144 0.261 0.344 0.482 0.884 0.918 0.987 1.000 0.000 0.012 0.034 0.062 0.134 0.276 0.347 0.483 0.741 0.875 0.913 0.979 1.000 0.000 0.016 0.033 0.058 0.132 0.276 0.345 0.483 0.743 0.876 0.912 0.985 1.000

0.000 0.246 0.513 0.707 0.854 0.929 0.948 0.963 0.985 0.989 0.998 1.000 0.000 0.223 0.469 0.637 0.817 0.923 0.941 0.956 0.971 0.985 0.988 0.996 1.000 0.000 0.274 0.453 0.610 0.807 0.918 0.939 0.952 0.966 0.981 0.986 0.997 1.000

γ1 1.692 1.696 1.702 1.650 1.581 1.503 1.377 1.037 1.023 0.999 1.000 1.659 1.645 1.634 1.588 1.517 1.460 1.335 1.107 1.025 1.018 1.005 1.000 1.700 1.698 1.683 1.630 1.533 1.479 1.348 1.114 1.031 1.016 0.998 1.000

γ2 1.000 0.991 0.993 1.006 1.001 1.021 1.096 1.334 3.565 3.796 4.584 1.000 1.008 1.000 1.001 1.005 1.012 1.068 1.339 2.348 2.772 3.321 4.881 1.000 1.003 1.002 1.001 1.004 1.009 1.020 1.359 2.576 3.267 3.485 4.654

a

Standard uncertainties u are u(T) = 0.1 K, u(p) = 0.13 kPa, u(x) = 0.002, and u(y) = 0.005.

Thermodynamic Consistency Test. In an attempt to confirm the reliability of our work, all of the experimental VLE data were examined by thermodynamic consistency test adopting the semiempirical method recommended by Herington8 and the point test of Van Ness.9 The criteria of Herington method is |D − J| < 10, while the value of D and J can be derived from eq 6 and eq 7, respectively.

a Standard uncertainties u are u(T) = 0.1 K, u(p) = 0.13 kPa, u(x) = 0.002, and u(y) = 0.005.

yP = xiγiPis i

T/K 381.15 374.14 363.65 352.34 339.28 327.73 322.94 317.67 311.19 310.77 309.94 309.68 395.90 388.57 378.78 369.56 354.87 339.84 335.49 329.95 324.63 322.89 322.15 321.05 320.76 406.39 396.78 388.94 380.18 364.04 348.35 343.91 337.94 332.31 330.57 330.06 328.92 328.55

(5)

where xi and yi represent the molar fraction of component i in the vapor and liquid phase, respectively; P denotes the experimental pressure; PiS expresses the saturated vapor pressure of pure component i. Thus, the activity coefficients γi can be calculated based on the formulation above.

D=

S+ − S− × 100 S+ + S−

(6)

where S+ is the area above the x-axis in the ln(γ1/γ2)−x1 plot, and S− is the area below. 1510


Journal of Chemical & Engineering Data J = 150 ×

Article

(Tmax − Tmin) Tmin

commonly used empirical model. The binary interaction parameters of both models were obtained by the minimization of the objective function as follows:

(7)

where Tmax and Tmin are the maximum and the minimum temperatures of the systems, respectively. In order to further verify the reliability of experimental data, the Van Ness point test ought to be utilized. For the method, Gmehling and Onken19 considered that the average deviation of the vapor mole fraction no more than 0.01 indicated the credibility of measured points. The excess Gibbs free energy could be described by Legendre polynomial with four parameters.

⎡⎛ ⎞2 ⎤ ⎢⎜ γexp − γcal ⎟ ⎥ OF = ∑ ⎢⎜ γexp ⎟⎠ ⎥ ⎣⎝ ⎦

where γexp is the activity coefficient calculated by experimental data and γcal is the activity coefficient derived from models. The contrast of the correlated and the measured data could give expression to the agreement between the calculation and the experiment. The average absolute deviations (AAD) of the equilibrium temperatures and vapor-phase mole fractions for two systems at different pressures were chosen to evaluate the results. The quantities of AAD are defined as follows:

k

GE = x1(1 − x1) ∑ ak Lk (x1) (8) RT where k is 4. The objective function, eq 9, is optimized by a nonlinear approach. g=

F=

∑ (y1cal

+ y2cal − 1)

AAD =

(9)

system PMA (1) + DMF (2)

methanol (1) + PMA (2)

a

p/kPa

|D − J|

|Δy1|

30 50 70 30 50 70

0.158 5.192 8.679 −0.5.943 −1.971 −0.386

0.003 0.003 0.003 0.003 0.003 0.003

a12 = a21 g12−g22 (J·mol−1) g21−g11 (J·mol−1) AADTa (K) AADy1b A12 A21 AADT (K) AADy1 a

NRTL 2 ⎡ ⎤ G Gij2τij τ ji ji ⎥ ln γi = xj2⎢ + ⎢⎣ (xi + xjGji)2 (xj + xiGij)2 ⎥⎦

,

Gij = exp(− aijτij),

AADT =

1 N

N

50.0 kPa

NRTL Parameters 0.3 755.78 619.89 607.95 605.53 0.03 0.05 0.002 0.003 Margules Parameters 0.402 0.368 0.431 0.357 0.04 0.05 0.002 0.003

∑i = 1 |Tical − Tiexp|. bAADy1 =

1 N

70.0 kPa

648.26 822.01 0.07 0.003 0.448 0.398 0.05 0.003

N

∑i = 1 |yical − yiexp |.

DMF at p = 30.0, 50.0, and 70.0 kPa, the maximum absolute deviations of vapor-phase components (|Δy1|max) and the temperatures (|ΔT|max) correlated with two activity coefficient models were (0.009, 0.009, and 0.007), (0.24, 0.16, and 0.17 K), (0.009, 0.009, and 0.007), and (0.24, 0.16, and 0.17 K), respectively. For another system of MeOH + PMA in the same conditions, |Δy1|max and |ΔT|max with two models were (0.014, 0.014, and 0.011), (0.47, 0.36, and 0.41 K), (0.013, 0.013, and 0.014), and (0.40, 0.42, and 0.68 K), respectively. T−x1−y1 diagrams for the two systems at three pressures, with the experimental VLE data and smoothed curves fitted by the calculated data derived from different models, are shown in Figures 4−9. As can be seen from Figures 4−6, there are intersections between the vapor and yjr liquid curves, which proves that azeotropic behavior exists in binary systems of PMA

Table 7. Mathematical Formulas of the Activity Coefficient Equations Used in Present Work

RT

Uical

30.0 kPa

absolute values of the difference between D and J are less than 10, and the average deviations in vapor mole fractions are also less than 0.01. It satisfied the consistency and reliability of all experimental VLE data. Data Correlations. The NRTL10 and Margules11 activity coefficient models were applied to correlating the experimental VLE data for all binary systems we investigated. The equations of two methods, containing related parameters for a binary system, are listed in Table 7. For the NRTL equation, gij−gjj represents the binary interaction energy parameters, and the nonrandomness parameter (aij) is assigned to 0.3. Aij and Aji represent the parameters of the Margules equation which is a

gij − gjj

(11)

i=1

Table 8. Interaction Energy and Nonrandomness Parameters of the NRTL and Parameters of Margules Equations, the Absolute Average Deviations of the Boiling Temperatures (AADT/K), and the Vapor-Phase Mole Fractions (AADy1) for PMA (1) and DMF (2) at p = 30.0, 50.0, and 70.0 kPa

Reference 10. bReference 11.

τij =

N

∑ |Uiexp − Uical|

where and are the experimental and calculated variable quantities which represent the equilibrium temperature and vapor-phase mole fraction; N is the number of experimental data points. The values of the binary interaction energy parameters and the deviations between the experimental and the calculated data are listed in Tables 8 and 9. For the binary systems of PMA +

Table 6. Consequences of the Thermodynamic Consistency Test by Two Methods point testb

1 N

Uiexp

where y1cal and y2cal are the calculated values of vapor-phase mole fractions of component 1 and 2, respectively. The results concerning thermodynamic consistency test are summarized in Table 6. As it can be seen from Table 6,

area testa

(10)

aij = aji

Margules

ln γi = xj2[Aij + 2xi(Aji − Aij)] 1511



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Table 9. Interaction Energy and Nonrandomness Parameters of the NRTL and Parameters of Margules Equations, the Absolute Average Deviations of the Boiling Temperatures (AADT/K), and the Vapor-Phase Mole Fractions (AADy1) for MeOH (1) and PMA (2) at p = 30.0, 50.0, and 70.0 kPa 30.0 kPa a12 = a21 g12−g22 (J·mol−1) g21−g11 (J·mol−1) AADTa (K) AADy1b A12 A21 AADT (K) AADy1 a

AADT =

1 N

N

50.0 kPa

NRTL Parameters 0.3 5163.6 5003.6 −1363.5 −1416.8 0.21 0.18 0.006 0.006 Margules Parameters 0.504 0.472 1.179 1.090 0.18 0.20 0.007 0.005

∑i = 1 |Tical − Tiexp|. bAADy1 =

1 N

70.0 kPa

5110.2 −1363.6 0.17 0.004 0.504 1.118 0.25 0.006

Figure 6. T−x1−y1 plot for the system of PMA (1) + DMF (2) at 70.0 kPa. ■, experimental data for T−x1; □, experimental data for T−y1. The solid line refers to calculated data by the NRTL equation for T− x−y; the dotted line refers to calculated data by the Margules equation.

N

∑i = 1 |yical − yiexp |.


Figure 7. T−x1−y1 plot for the system of MeOH (1) + PMA (2) at 30.0 kPa. ■, experimental data for T−x1; □, experimental data for T− y1. The solid line refers to calculated data by the NRTL equation for T−x−y; the dotted line refers to calculated data by the Margules equation.



+ DMF. From all T−x1−y1 diagrams, the measured data almost overlap with the fitting curves from the NRTL and Margules equations, whose distribution indicates that the two models 1512



Article

(3) Hsieh, C. T.; Lee, M. J.; Lin, H. Multiphase Equilibria for Mixtures Containing Acetic Acid, Water, Propylene Glycol Monomethyl Ether, and Propylene Glycol Methyl Ether Acetate. Ind. Eng. Chem. Res. 2006, 45, 2123−2130. (4) Yoshihara, H.; Tobita, T.; Tomizawa, R.; Ishikawa, K. Process for the Production of Alkylene Glycol Ether Ester of Organic Carboxylic Acid. U.S. Patent 4,115,415, Sep 19, 1978. (5) Pampalone, T. R. Positive Photoresist Compositions with OQuinone Diazide, Novolak, and Propylene Glycol Alkyl Ether Acetate. U.S. Patent 4,550,069, Oct 29, 1985. (6) Ye, C. S.; Dong, X. L.; Zhu, W. J.; Cai, D. R.; Qiu, T. Isobaric Vapor−Liquid Equilibria of the Binary Mixtures Propylene Glycol Methyl Ether+ Propylene Glycol Methyl Ether Acetate, Methyl acetate + Propylene Glycol Methyl Ether and Methanol+ Propylene Glycol Methyl Ether Acetate at 101.3 kPa. Fluid Phase Equilib. 2014, 367, 45− 50. (7) Tochigi, K.; Takahara, H.; Shiga, Y.; Kawase, Y. Isobaric Vapor− Liquid Equilibria for Water+ Propylene Glycol Monomethyl Ether (PGME), Water+ Propylene Glycol Monomethyl Ether Acetate (PGMEA), and PGME+ PGMEA at Reduced Pressures. Fluid Phase Equilib. 2007, 260, 65−69. (8) Herington, E. F. G. Tests for the Consistency of Experimental Isobaric Vapor-Liquid Equilibrium Data. J. Inst. Petrol. 1951, 37, 457− 470. (9) Van Ness, H. C.; Byer, S. M.; Gibbs, R. E. Vapor-Liquid Equilibrium: Part I. An Appraisal of Data Reduction Methods. AIChE J. 1973, 19, 238−244. (10) Renon, H.; Prausnitz, J. M. Local Compositions in Thermodynamic Excess Functions for Liquid Mixtures. AIChE J. 1968, 14, 135−144. (11) Gess, M.; Danner, A. R. P.; Nagvekar, M. Thermodynamic Analysis of Vapor-Liquid Equilibria: Recommended Models and a Standard Data Base; DIPPR; AIChE: New York, 1991. (12) Yaws, C. L. Chemical Properties Handbook, 1st ed.; Mc Graw-Hill Yaws Co.: New York, 1999. (13) Resa, J. M.; Gonzalez, C. G.; de Landaluce, S. O.; Lanz, J.; Fanega, M. Isobaric Vapor-Liquid Equilibria for Methanol + Pentyl Acetate, Yinylacetate + Pentyl Acetate, and Methanol + Isopentyl Acetate. Fluid Phase Equilib. 2001, 182, 177−187. (14) Iglesias, M.; Orge, B.; Canosa, J. M.; Rodriguez, A.; Dominguez, M.; Pineiro, M.; Tojo, M. Thermodynamic Behaviour of Mixtures Containing Methyl Acetate, Methanol, and 1-Butanol at 298.15K: Application of the ERAS Model. Fluid Phase Equilib. 1998, 147, 285− 300. (15) Yang, C. S.; Qin, Z. L.; Xu, Y. L.; Zeng, H.; Sun, F. Z.; Zhang, P.; Feng, Y. Isobaric Vapor-Liquid Equilibrium for the Binary Systems of Methanol, Diethylamine, and N,N-Diethylethanolamine at p = (60.0 and 101.3) kPa. J. Chem. Eng. Data 2013, 58, 482−487. (16) Yang, C. S.; Feng, X.; Sun, Y. K.; Yang, Q.; Zhi, J. Isobaric Vapor-Liquid Equilibrium for Two Binary Systems {Propane-1,2-diol + Ethane-1,2-diol, and Propane-1,2-diol + Butane-1,2-diol} at p = (10.0, 20.0, and 40.0) kPa. J. Chem. Eng. Data 2015, 60, 1126−1133. (17) Yang, C. S.; Sun, Y. K.; Qin, Z. L.; Feng, Y.; Zhang, P.; Feng, X. Isobaric Vapor-Liquid Equilibrium for Four Binary Systems of Ethane1, 2-diol, Butane-1, 4-diol, 2-(2-Hydroxyethoxy)ethan-1-ol, and 2-[2(2-Hydroxyethoxy)ethoxy]ethanol at 10.0 kPa, 20.0 kPa, and 40.0 kPa. J. Chem. Eng. Data 2014, 59, 1273−1280. (18) Aspen Plus, version 7.0; Aspen Technology, Inc.: Burlington, MA, 2011. (19) Gmehling, J.; Onken, U.; Weidlich, U. Vapor-Liquid Equilibrium Data Collection, Chemistry Data Series; DECHEMA: Frankfurt/Main, 1982.


correlated well with the experimental data for the two binary systems of (PMA + DMF) and (MeOH + PMA). According to Figures 4−6, we can analyze that the first system exhibits a strong positive deviation from ideality, causing the formation of a minimum boiling azeotrope whose composition moves toward the lighter component for increasing pressures. Moreover, it is difficult to separate the mixtures of PMA and DMF by normal rectification because of the close VLE behaviors of two compounds. For Figures 7−9, the second one which presents a slight positive deviation without azeotrope behavior could be separated preferably by distillation. In this work, we also have tried to use the UNIQUAC model, but it proved to be obviously inaccurate, particularly with the system of PMA + DMF.

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CONCLUSION The isobaric VLE data of the binary systems PMA + DMF and MeOH + PMA at 30.0, 50.0, and 70.0 kPa were measured in a modified Rose−Williams still. The thermodynamic consistency of all of the experimental data were verified by Herington area test and Van Ness point test. The remarkable agreement embodied between the experimental data and the calculated curves fitted by the NRTL and Margules models gives the study a high degree of dependability, supplying a valuable reference for the design of separating mixtures with additional components.

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AUTHOR INFORMATION

Corresponding Author

*E-mail address: [email protected]. Fax: 02227403389. Telephone: 022-27890907. ORCID

Changsheng Yang: 0000-0002-3226-8517 Notes

The authors declare no competing financial interest.

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REFERENCES

(1) Johnson, S. H., Jr.; Wright, H. N. Process for the Manufacture of Glycol Ether Acetates. U.S. Patent 3,700,726, Oct 24, 1972. (2) Breton, M. P.; Pontes, F. M.; Henseleit, K. M.; Helbrecht, B.; Croucher, M. D.; Wong, R. W. Ink for Ink Jet Printing. U.S. Patent 5,156,675, Oct 20, 1992. 1513


Isobaric VaporâLiquid Equilibria for Two Binary Systems {Propylene

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