Phase Equilibrium Measurements on Nine Binary Mixtures - American

J. Chem. Eng. Data 1996, 41, 1239-1251

1239

Phase Equilibrium Measurements on Nine Binary Mixtures W. Vincent Wilding,† Neil F. Giles,* and Loren C. Wilson Wiltec Research Company Inc., 488 South 500 West, Provo, Utah 84601

Phase equilibrium measurements have been performed on nine binary mixtures. The PTx method was used to obtain vapor-liquid equilibrium data for the following systems at two temperatures each: (aminoethyl)piperazine + diethylenetriamine; 2-butoxyethyl acetate + 2-butoxyethanol; 2-methyl-2propanol + 2-methylbutane; 2-methyl-2-propanol + 2-methyl-2-butene; methacrylonitrile + methanol; 1-chloro-1,1-difluoroethane + hydrogen chloride; 2-(hexyloxy)ethanol + ethylene glycol; butane + ammonia; propionaldehyde + butane. Equilibrium vapor and liquid phase compositions were derived from the PTx data using the Soave equation of state to represent the vapor phase and the Wilson or the NRTL activity coefficient model to represent the liquid phase. A large immiscibility region exists in the butane + ammonia system at 0 °C. Therefore, separate vapor-liquid-liquid equilibrium measurements were performed on this system to more precisely determine the miscibility limits and the composition of the vapor phase in equilibrium with the two liquid phases.

Introduction This work is part of an ongoing investigation of the phase equilibrium for systems of industrial interest sponsored by Project 805 of the Design Institute for Physical Property Data, DIPPR, of the American Institute of Chemical Engineers. This paper reports experimental measurements that have been made under Project 805/93 to obtain phase equilibrium data on nine binary systems. These systems and their measurement conditions follow: 1. (aminoethyl)piperazine + diethylenetriamine at 125 and 210 °C 2. 2-butoxyethyl acetate + 2-butoxyethanol at 100 and 170 °C 3. 2-methyl-2-propanol + 2-methylbutane at 30 and 100 °C 4. 2-methyl-2-propanol + 2-methyl-2-butene at 30 and 100 °C 5. methacrylonitrile + methanol at 25 and 65 °C 6. 1-chloro-1,1-difluoroethane + hydrogen chloride at -40 and 0 °C 7. 2-(hexyloxy)ethanol + ethylene glycol at 100 and 180 °C 8. butane + ammonia at 0 and 50 °C 9. propionaldehyde + butane at 0 and 100 °C Vapor-liquid equilibrium were determined from total pressure-temperature-composition (PTx) measurements. With accurate pressure measurements and equations to model the vapor and liquid phases, PTx data can yield reliable phase composition information. An equation of state was used to represent the nonidealities in the vapor phase and an activity coefficient equation was used to represent the nonidealities in the liquid phase. Vaporliquid-liquid equilibrium data were obtained for the butane + ammonia system at 0 °C by directly analyzing each phase. Experimental Section The measurements required to derive vapor and liquid compositions from PTx data are total pressure versus charge composition at constant temperature and known cell volume. In the PTx experiments, the entire composition range was traversed at a given temperature. Two or more † Address: Chemical Engineering Department, Brigham Young University, Provo, UT 84602.

S0021-9568(96)00162-8 CCC: $12.00

runs were required for each isotherm. Where possible, the pure compounds were degassed prior to the start of a PTx run. To initiate a run, the cell was charged with a known amount of one component. The cell contents were degassed by removing vapor into a weighed, evacuated cell or sample train in order to remove any air that may have been introduced to the cell upon charging, as well as any light impurities that may still have been present in the chemicals. The cell contents were allowed to reach equilibrium at the desired temperature, and the pure component vapor pressure was measured. Further degassing was performed until a repeatable vapor pressure was obtained. Increments of the second component were then charged to the cell. After each increment, the cell contents were again degassed and allowed to equilibrate before the pressure was measured. The second and subsequent runs were similar to the first except that the second component was charged to the cell before adding increments of the first component. The ranges of compositions covered in the runs were designed to overlap to check for consistency between the runs. Temperatures were measured with platinum resistance thermometers that were calibrated using ice and steam points and referenced to a NIST traceable standard resistance thermometer using the ITS-90 temperature scale. Temperatures were measured to an accuracy of (0.05 deg or better. Measurements were performed in the glass still apparatus shown in Figure 1 for systems 1, 2, and 7. The cell was connected to a large ballast tank and to a mercury or oil manometer. Lines through the top of the cell were used for charging and degassing. A thermowell extended through the top of the cell into the liquid in the cell. The cell was placed in a constant temperature bath that was controlled at a temperature 2 deg warmer than the saturation temperature of the material in the cell to promote refluxing in the cell. The liquid in the cell was vigorously stirred to ensure good contact between the vapor and liquid phases and to prevent superheating in the liquid. The ballast tank pressure was used to control the cell temperature. This pressure was adjusted to obtain the desired temperature. Once equilibrium was established, the pressure and temperature were recorded. The oil and mercury levels in the manometer were read with a cathetometer to (0.05 mm. Pressures measured with this apparatus are estimated to be accurate to within (0.025 kPa. © 1996 American Chemical Society

1240 Journal of Chemical and Engineering Data, Vol. 41, No. 6, 1996

Figure 1. Glass still PTx apparatus. Table 1. PTx Measurement Results on (Aminoethyl)piperazine (A) + Diethylenetriamine (B) P/kPa run no.

a

100zA

100xA

100yA

meas

calc

γA

1 1 1 1 1 1 2 1 1 2 1 2 2 2 2 2 2 2

100.00 97.37 94.83 89.57 79.45 68.77 60.26 58.31 48.86 48.54 40.07 39.72 29.78 19.42 9.57 5.03 2.42 0.00

100.00 97.37 94.84 89.57 79.46 68.78 60.27 58.32 48.87 48.55 40.07 39.73 29.79 19.43 9.58 5.03 2.42 0.00

100.00 95.89 92.08 84.60 71.60 59.44 50.63 48.70 39.76 39.47 31.96 31.66 23.31 14.98 7.31 3.82 1.84 0.00

4.819 4.874 4.945 5.089 5.363 5.644 5.781 5.900 6.101 6.064 6.293 6.251 6.462 6.661 6.832 6.911 6.979 7.000

t ) 125 °Ca 4.819 1.000 4.894 1.000 4.965 1.000 5.108 1.001 5.371 1.004 5.631 1.009 5.827 1.015 5.871 1.017 6.076 1.025 6.083 1.026 6.258 1.035 6.265 1.035 6.461 1.048 6.656 1.064 6.834 1.081 6.914 1.090 6.959 1.095 7.000 1.100

1 1 1 1 1 1 2 1 2 1 2 1 2 2 2 2 2 2

100.00 96.70 94.91 90.69 80.30 69.69 63.41 59.28 52.50 48.95 42.64 38.62 32.15 20.78 10.79 5.44 2.54 0.00

100.00 96.74 94.96 90.78 80.45 69.85 63.50 59.43 52.62 49.07 42.78 38.70 32.30 20.91 10.87 5.49 2.56 0.00

100.00 95.03 92.42 86.50 73.14 60.91 54.17 50.04 43.42 40.10 34.41 30.83 25.38 16.10 8.25 4.14 1.92 0.00

75.710 76.459 77.566 79.384 83.378 87.836 90.089 91.825 94.061 95.294 97.317 98.657 100.61 104.20 107.19 108.97 109.74 110.44

t ) 210 °Cb 75.710 1.000 77.115 1.000 77.870 1.000 79.617 1.001 83.771 1.003 87.815 1.007 90.142 1.010 91.599 1.013 93.978 1.017 95.193 1.020 97.301 1.025 98.642 1.029 100.70 1.036 104.26 1.049 107.28 1.063 108.86 1.071 109.71 1.076 110.44 1.080

γB

φA

φB

PFA

PFB

RBA

1.100 1.094 1.089 1.079 1.062 1.046 1.035 1.033 1.023 1.023 1.015 1.015 1.008 1.004 1.001 1.000 1.000 1.000

0.997 0.997 0.997 0.997 0.997 0.997 0.997 0.997 0.997 0.997 0.996 0.996 0.996 0.996 0.996 0.996 0.996 0.996

0.998 0.998 0.998 0.997 0.997 0.997 0.997 0.997 0.997 0.997 0.997 0.997 0.997 0.997 0.997 0.997 0.997 0.997

1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0001 1.0001 1.0001 1.0001 1.0001 1.0001 1.0001 1.0001 1.0001 1.0001

0.9999 0.9999 0.9999 0.9999 0.9999 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000

1.596 1.588 1.580 1.564 1.535 1.504 1.480 1.474 1.448 1.447 1.424 1.423 1.396 1.369 1.343 1.332 1.325 1.319

1.080 1.074 1.072 1.065 1.051 1.038 1.031 1.027 1.021 1.019 1.014 1.012 1.008 1.003 1.001 1.000 1.000 1.000

0.975 0.975 0.975 0.974 0.973 0.972 0.971 0.970 0.970 0.969 0.969 0.968 0.967 0.966 0.965 0.965 0.965 0.964

0.980 0.979 0.979 0.979 0.977 0.976 0.976 0.975 0.975 0.974 0.974 0.973 0.973 0.972 0.971 0.970 0.970 0.970

1.0000 1.0001 1.0001 1.0002 1.0003 1.0005 1.0006 1.0006 1.0007 1.0008 1.0008 1.0009 1.0010 1.0011 1.0012 1.0013 1.0013 1.0014

0.9989 0.9989 0.9989 0.9990 0.9991 0.9993 0.9993 0.9994 0.9995 0.9995 0.9996 0.9996 0.9997 0.9998 0.9999 0.9999 1.0000 1.0000

1.558 1.550 1.546 1.536 1.511 1.487 1.472 1.463 1.447 1.439 1.425 1.416 1.402 1.378 1.357 1.345 1.339 1.334

Wilson equation parameters: ΛAB ) 0.9530, ΛBA ) 0.9530. b Wilson equation parameters: ΛAB ) 0.9620, ΛBA ) 0.9620.

Measurements for system 5 and for the lower isotherms of systems 3, 4, and 9 were performed in the glass cell shown in Figure 2. The cell was made of thick-walled borosilicate glass with a TFE cap and had an internal volume of approximately 300 cm3. The cap screwed into the cell and formed a seal with an O-ring. Small-bore lines through the cap were used for adding components and degassing. A thermowell into which a platinum resistance thermometer was inserted also extended into the cell.

The pressure was measured with the mercury manometer which extended from the side of the cell. The density and vapor pressure of the mercury at the bath temperature were properly accounted for in the pressure determinations. The manometer was connected to a McLeod gauge for cell pressures below about 50 kPa or was left open to the atmosphere for higher pressures. Atmospheric pressure was measured with a barometer. The mercury levels in the cell manometer were read with a cathetometer to (0.05

Journal of Chemical and Engineering Data, Vol. 41, No. 6, 1996 1241

Figure 2. Glass PTx apparatus.

Figure 5. Measured PTx data (O), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for (aminoethyl)piperazine (A) + diethylenetriamine (B) at 210 °C.

Figure 3. Stainless steel PTx apparatus.

Figure 6. Measured PTx data (O), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for 2-butoxyethyl acetate (A) + 2-butoxyethanol (B) at 100 °C.

Figure 4. Measured PTx data (O), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for (aminoethyl)piperazine (A) + diethylenetriamine (B) at 125 °C.

mm. Pressures were measured with this apparatus with an estimated accuracy of (0.05 kPa. Systems 6 and 8 as well as the higher isotherms of systems 3, 4, and 9 were studied in the stainless steel cell shown in Figure 3. The cell had a volume of 300 cm3 and was connected to a pressure transducer or to a manometer depending on the pressure range. Lines were connected

to the cell for charging, sampling, and degassing. A thermowell also extended into the cell into which a platinum resistance thermometer was inserted. The cell and its connections were attached to a rigid support and immersed in a constant temperature bath. The cell was manually agitated to ensure the contents were at equilibrium at the desired temperature. Pressures less than about 200 kPa were measured with a mercury manometer and are estimated to be accurate to (0.05 kPa. Higher pressures were measured using a calibrated Paroscientific pressure transducer. These pressures were measured to within (0.3 kPa. Vapor-liquid-liquid equilibrium (VLLE) data for the lower isotherm of system 8 were obtained by sampling and analyzing the equilibrium phases. Sample lines extended into the vapor and two liquid phases. The cell contents were agitated to ensure that they were well mixed and that equilibrium was attained. The phases were allowed to settle before withdrawing multiple samples of both liquid phases and the vapor phase into previously weighed sample

1242 Journal of Chemical and Engineering Data, Vol. 41, No. 6, 1996 Table 2. PTx Measurement Results on 2-Butoxyethyl Acetate (A) + 2-Butoxyethanol (B) P/kPa run no.

a

100zA

100xA

100yA

meas

calc

γB

φA

φB

PFA

PFB

RBA

1.293 1.282 1.272 1.254 1.216 1.172 1.142 1.141 1.108 1.077 1.046 1.024 1.006 1.002 1.000 1.000

0.996 0.996 0.995 0.995 0.995 0.994 0.994 0.994 0.993 0.993 0.993 0.992 0.992 0.992 0.992 0.992

0.998 0.998 0.998 0.997 0.997 0.997 0.996 0.996 0.996 0.996 0.996 0.995 0.995 0.995 0.995 0.995

1.0000 1.0000 1.0000 1.0000 1.0001 1.0001 1.0001 1.0001 1.0002 1.0002 1.0002 1.0002 1.0002 1.0002 1.0003 1.0003

0.9998 0.9998 0.9998 0.9998 0.9999 0.9999 0.9999 0.9999 0.9999 0.9999 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000

2.572 2.551 2.530 2.490 2.402 2.289 2.201 2.197 2.088 1.965 1.816 1.676 1.504 1.414 1.371 1.328

1.131 1.127 1.123 1.117 1.101 1.084 1.072 1.068 1.056 1.052 1.039 1.035 1.024 1.011 1.003 1.001 1.000 1.000

0.969 0.968 0.967 0.966 0.963 0.961 0.959 0.958 0.957 0.956 0.954 0.954 0.952 0.950 0.949 0.948 0.948 0.948

0.983 0.983 0.982 0.981 0.979 0.977 0.976 0.975 0.974 0.974 0.972 0.972 0.971 0.969 0.968 0.968 0.967 0.967

1.0000 1.0001 1.0002 1.0003 1.0006 1.0009 1.0011 1.0012 1.0013 1.0014 1.0016 1.0017 1.0019 1.0021 1.0023 1.0024 1.0024 1.0024

0.9981 0.9982 0.9983 0.9984 0.9986 0.9988 0.9990 0.9990 0.9992 0.9992 0.9994 0.9994 0.9996 0.9997 0.9999 0.9999 1.0000 1.0000

1.988 1.981 1.973 1.960 1.926 1.884 1.852 1.840 1.803 1.789 1.742 1.724 1.669 1.584 1.503 1.449 1.425 1.405

γA

1 1 1 1 1 1 2 1 2 2 2 2 2 2 2 2

100.00 97.59 95.19 90.74 81.40 70.24 62.17 61.82 52.42 42.58 31.50 21.78 10.66 5.14 2.55 0.00

100.00 97.59 95.21 90.76 81.43 70.28 62.19 61.86 52.44 42.61 31.52 21.80 10.67 5.14 2.56 0.00

100.00 94.08 88.70 79.77 64.61 50.81 42.77 42.47 34.56 27.42 20.22 14.26 7.36 3.69 1.88 0.00

4.329 4.521 4.673 4.931 5.541 6.098 6.487 6.494 6.926 7.350 7.762 8.100 8.438 8.538 8.585 8.638

t ) 100 °Ca 4.329 1.000 4.492 1.000 4.650 1.000 4.936 1.002 5.498 1.007 6.108 1.018 6.510 1.032 6.526 1.033 6.951 1.055 7.351 1.090 7.752 1.145 8.066 1.215 8.382 1.330 8.521 1.408 8.582 1.450 8.638 1.497

1 1 1 1 1 1 2 1 2 1 2 1 2 2 2 2 2 2

100.00 97.43 94.77 90.69 80.45 69.69 62.38 59.61 52.25 49.59 41.32 38.49 30.20 18.96 9.78 4.27 1.92 0.00

100.00 97.48 94.87 90.85 80.72 69.99 62.50 59.90 52.42 49.82 41.52 38.64 30.40 19.12 9.87 4.31 1.94 0.00

100.00 95.13 90.36 83.52 68.49 55.31 47.37 44.80 37.93 35.69 28.96 26.76 20.74 12.99 6.79 3.01 1.37 0.00

55.522 56.511 58.363 60.712 66.145 71.224 75.350 76.311 80.455 80.693 84.778 84.962 88.961 93.158 96.619 98.210 98.802 99.407

t ) 170 °Cb 55.522 1.000 56.946 1.000 58.409 1.000 60.628 1.001 66.058 1.003 71.526 1.008 75.165 1.014 76.396 1.017 79.821 1.025 80.977 1.029 84.536 1.044 85.723 1.050 88.997 1.072 93.166 1.115 96.319 1.166 98.096 1.206 98.825 1.226 99.407 1.244


Figure 7. Measured PTx data (O), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for 2-butoxyethyl acetate (A) + 2-butoxyethanol (B) at 170 °C.

Figure 8. Measured PTx data (O), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for 2-methyl-2-propanol (A) + 2-methylbutane (B) at 30 °C.

cylinders. The amount of ammonia in a sample was determined by titration, and the amount of butane was determined by difference.

tions and activity and fugacity coefficients. Various activity coefficient models were used to represent the liquid-phase nonidealities. The Soave-Redlich-Kwong equation of state (Soave, 1972) was used to represent the vapor phase in the data reduction procedure. All Soave binary interaction parameters were assumed to be zero. To derive equilibrium phase compositions from PTx data, an iterative procedure is used to solve the basic equation

PTx Data Reduction Procedure The results of the PTx measurements, which are total pressure as a function of charge composition at constant temperature, were reduced to equilibrium phase composi-

Journal of Chemical and Engineering Data, Vol. 41, No. 6, 1996 1243 Table 3. PTx Measurement Results on 2-Methyl-2-propanol (A) + 2-Methylbutane (B) P/kPa run no.

a

100zA

100xA

100yA

meas

calc

γA

1 1 1 1 1 1 2 1 1 2 2 1 2 2 2 2 2 2

100.00 98.14 96.73 92.25 83.00 67.97 65.18 63.80 53.59 52.95 42.22 42.20 31.07 20.38 10.04 4.01 2.30 0.00

100.00 98.22 96.88 92.53 83.40 68.34 65.33 64.13 53.82 53.16 42.46 42.32 31.31 20.56 10.13 4.03 2.31 0.00

100.00 53.47 40.14 23.27 13.45 8.53 7.97 7.77 6.35 6.27 5.22 5.21 4.38 3.75 3.16 2.28 1.65 0.00

7.750 14.204 18.752 31.376 51.520 72.616 75.923 76.884 85.613 86.421 93.292 93.310 99.068 103.43 106.84 108.53 108.70 108.57

t ) 30 °Ca 7.750 1.000 14.291 1.000 18.839 1.001 31.443 1.008 50.917 1.036 72.044 1.122 75.335 1.145 76.583 1.155 86.127 1.259 86.670 1.267 94.458 1.432 94.547 1.435 100.52 1.728 104.32 2.335 106.55 4.078 107.90 7.468 108.31 9.493 108.57 14.049

1 1 1 1 1 1 2 2 1 2 2 2 2 2

100.00 95.59 90.34 80.62 70.49 58.49 57.78 46.18 45.43 35.16 22.13 11.31 4.75 0.00

100.00 96.07 91.21 81.80 71.60 59.26 58.21 46.78 45.76 35.77 22.55 11.46 4.76 0.00

100.00 74.54 57.91 41.85 32.92 26.34 25.89 21.62 21.27 18.09 13.77 9.01 4.64 0.00

192.43 253.73 316.74 415.55 496.83 569.51 573.30 621.15 630.80 660.72 696.51 717.54 722.71 720.64

t ) 100 °Cb 192.43 1.000 252.99 1.002 317.22 1.008 416.03 1.033 496.24 1.080 568.75 1.169 573.97 1.178 623.60 1.309 627.47 1.323 661.19 1.500 696.40 1.886 717.65 2.485 723.64 3.104 720.64 3.762

γB

φA

φB

PFA

PFB

RBA

3.782 3.585 3.448 3.070 2.504 1.946 1.867 1.838 1.624 1.612 1.442 1.440 1.293 1.166 1.058 1.012 1.004 1.000

0.996 0.993 0.991 0.985 0.976 0.966 0.964 0.964 0.959 0.959 0.956 0.955 0.953 0.951 0.950 0.949 0.949 0.949

0.997 0.995 0.993 0.989 0.982 0.975 0.974 0.973 0.970 0.970 0.967 0.967 0.965 0.963 0.963 0.962 0.962 0.962

1.0000 1.0002 1.0004 1.0009 1.0016 1.0024 1.0026 1.0026 1.0030 1.0030 1.0033 1.0033 1.0035 1.0037 1.0037 1.0038 1.0038 1.0038

0.9953 0.9956 0.9958 0.9964 0.9973 0.9983 0.9984 0.9985 0.9989 0.9990 0.9993 0.9993 0.9996 0.9998 0.9999 1.0000 1.0000 1.0000

50.858 48.147 46.239 40.855 32.335 23.154 21.758 21.230 17.186 16.952 13.403 13.359 9.958 6.643 3.450 1.802 1.406 0.946

2.782 2.566 2.339 1.997 1.725 1.485 1.468 1.308 1.295 1.189 1.083 1.024 1.005 1.000

0.951 0.936 0.920 0.896 0.876 0.858 0.856 0.844 0.843 0.835 0.826 0.821 0.820 0.821

0.964 0.952 0.939 0.920 0.905 0.891 0.890 0.880 0.879 0.873 0.866 0.862 0.861 0.861

1.0000 1.0021 1.0044 1.0079 1.0107 1.0133 1.0135 1.0153 1.0154 1.0166 1.0179 1.0187 1.0189 1.0188

0.9769 0.9795 0.9823 0.9866 0.9901 0.9933 0.9935 0.9957 0.9959 0.9974 0.9989 0.9999 1.0001 1.0000

9.100 8.352 7.540 6.245 5.137 4.068 3.987 3.187 3.121 2.522 1.823 1.307 1.026 0.843

NRTL parameters: τAB ) 0.8230, τBA ) 2.1684, R ) 0.6700. b NRTL parameters: τAB ) 0.5546, τBA ) 0.9584, R ) 0.7465.

Figure 9. Measured PTx data (O), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for 2-methyl-2-propanol (A) + 2-methylbutane (B) at 100 °C.

of vapor-liquid equilibrium, given as follows:

[( )

Pyiφi ) xiγiP°iφ i° exp

]

Vi (P - P°i) RT

(1)

where P is the total pressure, yi is the vapor mole fraction of component i, φi is the fugacity coefficient of component i, xi is the liquid mole fraction of component i, γi is the activity coefficient of component i, P°i is the vapor pressure

Figure 10. Measured PTx data (O), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for 2-methyl-2-propanol (A) + 2-methyl-2-butene (B) at 30 °C.

of component i at the system temperature, φ°i is the fugacity coefficient of component i at the system temperature and corresponding vapor pressure of component i, and the exponential term is the Poynting correction where Vi is the molar volume of component i. In the above expression it is assumed that the molar volume of component i is equal to the partial molar volume of component i at these conditions. Pure component molar volumes were calculated from correlations of density data (Daubert et al., 1992).

1244

Journal of Chemical and Engineering Data, Vol. 41, No. 6, 1996

Table 4. PTx Measurement Results on 2-Methyl-2-propanol (A) + 2-Methyl-2-Butene (B) P/kPa run no.

a

100zA

100xA

100yA

1 1 1 1 1 1 1 2 2 1 2 1 2 2 2 2 2 2

100.00 97.75 95.95 91.41 82.44 72.96 63.81 63.92 52.59 51.36 42.10 41.66 31.47 20.52 9.70 4.46 2.38 0.00

100.00 97.81 96.06 91.60 82.70 73.22 64.04 64.01 52.72 51.50 42.25 41.75 31.61 20.63 9.75 4.48 2.38 0.00

100.00 60.06 46.10 29.85 18.50 13.59 10.89 10.89 8.71 8.52 7.26 7.20 6.11 5.13 4.01 2.82 1.88 0.00

1 1 1 1 1 1 2 1 2 1 2 1 2 2 2 2 2 2

100.00 97.75 95.19 90.94 81.02 71.52 64.78 61.77 53.90 50.51 43.35 40.63 31.97 21.21 10.26 4.95 2.94 0.00

100.00 97.95 95.60 91.63 82.06 72.59 65.15 62.68 54.47 51.09 43.99 40.93 32.53 21.56 10.34 4.94 2.92 0.00

100.00 89.63 80.16 68.06 50.07 39.71 34.08 32.52 28.10 26.53 23.54 22.35 19.20 14.87 9.08 5.07 3.20 0.00

meas 7.723 12.619 16.037 24.115 36.447 46.048 53.129 53.265 59.809 60.328 64.600 64.528 68.309 71.448 73.866 74.787 75.085 74.888 195.05 214.59 235.91 269.74 341.11 393.87 439.33 443.87 480.13 486.20 511.28 515.35 537.80 556.99 568.58 569.84 569.39 566.85

calc

γB

φA

φB

PFA

PFB

RBA

t ) 30 °Ca 7.723 1.000 12.619 1.001 16.195 1.002 24.101 1.008 36.234 1.034 45.770 1.078 52.964 1.140 52.981 1.140 59.965 1.249 60.619 1.264 65.017 1.404 65.227 1.414 68.883 1.670 71.644 2.231 73.568 3.786 74.466 5.857 74.774 7.369 74.888 10.100

3.341 3.162 3.032 2.746 2.318 1.997 1.769 1.768 1.556 1.536 1.400 1.393 1.266 1.145 1.045 1.012 1.004 1.000

0.996 0.994 0.992 0.988 0.983 0.978 0.975 0.975 0.971 0.971 0.969 0.969 0.967 0.966 0.965 0.965 0.964 0.964

0.997 0.995 0.994 0.991 0.986 0.983 0.980 0.980 0.977 0.977 0.975 0.975 0.974 0.973 0.972 0.972 0.971 0.971

1.0000 1.0002 1.0003 1.0006 1.0011 1.0014 1.0017 1.0017 1.0020 1.0020 1.0022 1.0022 1.0023 1.0024 1.0025 1.0025 1.0025 1.0025

0.9971 0.9973 0.9975 0.9978 0.9984 0.9988 0.9991 0.9991 0.9994 0.9994 0.9996 0.9996 0.9997 0.9999 0.9999 1.0000 1.0000 1.0000

31.468 29.757 28.486 25.616 21.063 17.389 14.563 14.556 11.682 11.398 9.343 9.235 7.100 4.807 2.586 1.617 1.275 0.927

t ) 100 °Cb 195.05 1.000 214.45 1.000 235.76 1.001 269.64 1.004 340.59 1.019 397.74 1.049 434.70 1.083 445.59 1.098 477.45 1.157 488.81 1.188 509.80 1.269 517.77 1.312 536.82 1.461 556.28 1.759 569.02 2.282 570.59 2.672 569.83 2.853 566.85 3.159

2.152 2.104 2.051 1.965 1.778 1.616 1.504 1.469 1.363 1.323 1.247 1.217 1.144 1.068 1.017 1.004 1.001 1.000

0.951 0.946 0.940 0.932 0.914 0.900 0.891 0.888 0.880 0.877 0.872 0.870 0.865 0.860 0.857 0.857 0.857 0.858

0.960 0.955 0.951 0.944 0.929 0.917 0.910 0.907 0.901 0.898 0.894 0.892 0.888 0.884 0.882 0.881 0.881 0.882

1.0000 1.0007 1.0014 1.0026 1.0050 1.0070 1.0083 1.0087 1.0098 1.0102 1.0109 1.0112 1.0119 1.0126 1.0130 1.0131 1.0130 1.0129

0.9852 0.9860 0.9868 0.9882 0.9910 0.9932 0.9947 0.9952 0.9964 0.9969 0.9977 0.9980 0.9988 0.9996 1.0001 1.0001 1.0001 1.0000

5.664 5.532 5.383 5.135 4.561 4.021 3.616 3.485 3.062 2.893 2.550 2.407 2.030 1.573 1.154 0.973 0.909 0.820

γA


generally used to reduce the data for that system. The Wilson equation (Wilson, 1964) and the NRTL equation (Renon and Prausnitz, 1968) were used in the data reduction procedure and are given below:

Wilson equation: ln γA ) -ln(xA + ΛABxB) +

(

xB

)

ΛBA ΛAB xA + ΛABxB ΛBAxA + xB

(2)

ln γB ) -ln(xB + ΛBAxA) xA

(

)

ΛBA ΛAB xA + ΛABxB ΛBAxA + xB

NRTL equation:

Figure 11. Measured PTx data (O), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for 2-methyl-2-propanol (A) + 2-methyl-2-butene (B) at 100 °C.

The data reduction procedure, similar to the method proposed by Barker (1953), consisted of fitting the pressure data to eq 1 across the entire composition range by adjusting the parameters of the activity coefficient model. The activity coefficient model that gave the best overall fit of the measured total pressure data for a given system was

[ ( [ (

) ( ) (

ln γA ) xB2 τBA

GBA xA + xBGBA

2

ln γB ) xA2 τAB

GAB xB + xAGAB

2

+

+

τABGAB

(xB + xAGAB)2 τBAGBA

(xA + xBGBA)2

GAB ) exp(-RτAB) GBA ) exp(-RτBA)

)] )]

(3)

Journal of Chemical and Engineering Data, Vol. 41, No. 6, 1996 1245 Table 5. PTx Measurement Results on Methacrylonitrile (A) + Methanol (B) P/kPa run no.

a

100zA

100xA

100yA

meas

calc

γA

1 1 1 1 1 1 2 1 2 1 2 1 2 2 2 2 2

100.00 94.74 90.49 81.59 70.58 60.43 51.35 49.66 41.29 39.62 31.04 29.16 20.51 9.93 4.51 2.13 0.00

100.00 94.76 90.51 81.62 70.60 60.45 51.35 49.67 41.30 39.63 31.05 29.16 20.51 9.93 4.50 2.13 0.00

100.00 73.38 62.10 49.34 41.47 37.08 34.00 33.46 30.73 30.16 26.86 26.03 21.45 13.12 6.86 3.48 0.00

8.370 10.798 12.442 14.610 16.008 16.859 17.372 17.441 17.757 17.813 18.042 18.071 18.068 17.723 17.391 17.114 16.942

t ) 25 °Ca 8.370 1.000 10.865 1.004 12.381 1.013 14.555 1.048 16.090 1.124 16.902 1.233 17.376 1.368 17.447 1.397 17.743 1.570 17.791 1.610 17.985 1.850 18.013 1.911 18.051 2.245 17.778 2.794 17.415 3.156 17.188 3.335 16.942 3.508

1 1 1 1 1 1 1 2 1 2 1 2 1 2 2 2 2 2

100.00 97.66 95.21 90.70 81.01 70.05 60.08 53.29 50.93 42.25 39.98 31.64 29.63 20.88 10.70 5.28 2.27 0.00

100.00 97.70 95.28 90.80 81.15 70.17 60.18 53.32 50.99 42.28 40.01 31.67 29.64 20.89 10.70 5.27 2.27 0.00

100.00 87.78 78.13 65.53 49.84 40.15 34.46 31.37 30.41 26.99 26.11 22.77 21.90 17.66 11.01 6.16 2.86 0.00

44.565 49.151 54.486 63.007 76.391 86.088 92.152 95.494 96.370 99.673 100.155 102.485 102.954 104.497 105.075 104.558 103.857 103.095

t ) 65 °Cb 44.565 1.000 49.730 1.000 54.682 1.002 62.699 1.008 75.941 1.033 86.111 1.088 92.407 1.165 95.640 1.238 96.588 1.267 99.609 1.397 100.284 1.438 102.414 1.616 102.852 1.668 104.347 1.936 104.951 2.372 104.451 2.679 103.805 2.879 103.095 3.045

γB

φA

φB

PFA

PFB

RBA

3.766 3.262 2.924 2.370 1.892 1.588 1.392 1.361 1.236 1.215 1.126 1.110 1.053 1.012 1.002 1.001 1.000

0.995 0.994 0.993 0.992 0.991 0.991 0.991 0.991 0.991 0.991 0.991 0.991 0.991 0.991 0.991 0.992 0.992

0.998 0.998 0.997 0.997 0.996 0.996 0.996 0.996 0.996 0.996 0.996 0.996 0.996 0.996 0.996 0.996 0.996

1.0000 1.0001 1.0001 1.0002 1.0003 1.0003 1.0003 1.0003 1.0003 1.0003 1.0003 1.0003 1.0003 1.0003 1.0003 1.0003 1.0003

0.9999 0.9999 0.9999 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000

7.601 6.555 5.823 4.561 3.390 2.594 2.049 1.963 1.586 1.520 1.226 1.170 0.945 0.730 0.640 0.605 0.575

2.696 2.588 2.482 2.301 1.972 1.682 1.479 1.367 1.333 1.223 1.199 1.123 1.108 1.053 1.014 1.003 1.001 1.000

0.983 0.981 0.979 0.976 0.971 0.968 0.966 0.965 0.964 0.964 0.963 0.963 0.963 0.963 0.963 0.964 0.964 0.965

0.995 0.993 0.992 0.991 0.988 0.986 0.985 0.984 0.984 0.983 0.983 0.983 0.983 0.982 0.982 0.982 0.982 0.982

1.0000 1.0002 1.0003 1.0006 1.0010 1.0013 1.0015 1.0016 1.0017 1.0017 1.0018 1.0018 1.0019 1.0019 1.0019 1.0019 1.0019 1.0019

0.9991 0.9992 0.9993 0.9994 0.9996 0.9997 0.9998 0.9999 0.9999 0.9999 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000

6.154 5.900 5.643 5.195 4.333 3.506 2.874 2.499 2.381 1.982 1.887 1.572 1.502 1.231 0.968 0.848 0.788 0.745


calculated pressure was then the sum of these terms:

Pcalc )

∑(Py ) i

(4)

The vapor mole fraction for each component was then determined:

yi ) (Pyi)/Pcalc

Figure 12. Measured PTx data (O), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for methacrylonitrile (A) + methanol (B) at 25 °C.

As a beginning point, the ideal-solution parameters of the activity coefficient model were selected. Then assuming the liquid composition was the same as the charge composition and the fugacity coefficients were unity, eq 1 was solved for the product Pyi for each component. The

(5)

With values for the vapor-phase composition, the fugacity coefficients were calculated from the equation of state. The next step was to correct the liquid composition for the amounts of each component in the vapor and to return to the step in which the activity coefficients were calculated and continue iterating until the calculated pressure converged. As part of each iteration step, the amount of material taken out of the cell as degas was subtracted from the total charge at the calculated vapor composition. This procedure was performed for each of the measurement points across the composition range. The calculated pressures were compared to the measured pressures. The activity coefficient parameters were adjusted to improve the fit of the total pressure data, and the entire procedure was repeated until the best fit of the measured total pressure curve was obtained. Results and Discussion The results of the phase equilibrium measurements are described below. The PTx data are presented in tables which give the run number, the charge compositions (zA),

1246 Journal of Chemical and Engineering Data, Vol. 41, No. 6, 1996 Table 6. PTx Measurement Results on 1-Chloro-1,1-difluoroethane (A) + Hydrogen Chloride (B) P/kPa run no.

a

100zA

100xA

100yA

1 1 1 1 1 1 1 2 1 2 1 2 1 2 2 2 2 2 2

100.00 97.82 95.48 90.01 79.55 71.40 63.56 61.41 51.48 50.64 41.69 40.23 32.36 30.30 19.97 9.26 4.76 2.56 0.00

100.00 98.00 95.83 90.71 80.66 72.64 64.80 61.75 52.50 51.31 42.44 41.17 32.81 31.38 20.97 9.90 5.14 2.78 0.00

100.00 58.40 39.98 22.44 11.46 7.89 5.82 5.22 3.83 3.68 2.75 2.63 1.96 1.86 1.18 0.54 0.28 0.15 0.00

1 1 1 1 1 1 1 2 1 2 1 2 1 2 2 2 2 2 2

100.00 97.70 93.59 90.69 82.10 72.48 61.01 59.37 53.22 48.84 42.92 39.58 32.25 30.24 19.40 9.65 5.37 3.18 0.00

100.00 98.09 94.61 92.10 84.42 75.36 63.99 60.13 55.95 50.50 45.01 42.06 33.48 33.20 22.48 11.98 6.91 4.22 0.00

100.00 76.84 53.54 43.67 27.23 18.13 12.05 10.63 9.31 7.87 6.63 6.04 4.52 4.48 2.89 1.51 0.87 0.53 0.00

meas 23.752 40.111 57.867 99.015 177.94 239.86 298.47 320.05 387.83 396.05 459.40 468.81 526.56 537.64 610.56 690.39 725.76 743.67 764.73 144.42 185.94 264.25 320.19 492.89 699.94 962.91 1055.3 1152.6 1282.2 1414.9 1482.4 1697.0 1699.9 1972.1 2254.9 2400.1 2480.7 2611.6

calc

γB

φA

φB

PFA

PFB

RBA

t ) -40 °Ca 23.752 1.000 40.142 1.000 57.734 1.000 98.978 1.001 178.10 1.005 239.63 1.011 298.44 1.019 320.91 1.023 388.06 1.039 396.52 1.042 459.40 1.064 468.29 1.068 526.60 1.098 536.56 1.104 609.23 1.159 688.75 1.242 724.49 1.290 742.70 1.317 764.73 1.351

1.204 1.198 1.192 1.178 1.151 1.130 1.110 1.102 1.080 1.077 1.057 1.054 1.037 1.034 1.017 1.004 1.001 1.000 1.000

0.990 0.984 0.978 0.964 0.940 0.921 0.903 0.897 0.877 0.875 0.856 0.854 0.837 0.834 0.814 0.792 0.782 0.777 0.771

1.000 0.997 0.995 0.990 0.981 0.975 0.968 0.966 0.959 0.958 0.951 0.950 0.944 0.943 0.935 0.926 0.923 0.921 0.918

1.0000 1.0007 1.0014 1.0031 1.0063 1.0088 1.0113 1.0122 1.0149 1.0153 1.0179 1.0183 1.0207 1.0211 1.0241 1.0275 1.0290 1.0297 1.0306

0.9869 0.9872 0.9875 0.9882 0.9896 0.9907 0.9918 0.9922 0.9933 0.9935 0.9946 0.9948 0.9958 0.9960 0.9972 0.9987 0.9993 0.9996 1.0000

35.121 34.826 34.507 33.747 32.235 31.003 29.772 29.287 27.783 27.588 26.091 25.873 24.404 24.147 22.223 20.058 19.085 18.593 18.005

t ) 0 °Cb 144.42 1.000 186.80 1.000 264.34 1.000 320.36 1.000 493.22 1.002 699.42 1.004 962.36 1.010 1052.8 1.013 1151.4 1.016 1281.0 1.022 1413.2 1.028 1484.9 1.033 1696.9 1.047 1703.8 1.048 1978.3 1.074 2261.4 1.109 2405.1 1.131 2484.0 1.144 2611.6 1.168

1.098 1.095 1.091 1.088 1.079 1.068 1.054 1.049 1.044 1.038 1.032 1.028 1.020 1.019 1.010 1.003 1.001 1.000 1.000

0.960 0.949 0.931 0.919 0.884 0.845 0.797 0.780 0.763 0.741 0.718 0.706 0.671 0.670 0.627 0.584 0.562 0.551 0.532

1.002 0.996 0.988 0.983 0.969 0.954 0.935 0.929 0.922 0.913 0.904 0.899 0.885 0.884 0.866 0.846 0.837 0.831 0.822

1.0000 1.0016 1.0045 1.0066 1.0132 1.0211 1.0313 1.0348 1.0387 1.0437 1.0490 1.0518 1.0602 1.0605 1.0715 1.0830 1.0889 1.0921 1.0974

0.9576 0.9583 0.9596 0.9606 0.9635 0.9670 0.9715 0.9730 0.9747 0.9769 0.9792 0.9804 0.9841 0.9842 0.9889 0.9939 0.9964 0.9978 1.0000

15.606 15.469 15.218 15.037 14.480 13.816 12.971 12.681 12.365 11.950 11.527 11.299 10.625 10.604 9.741 8.868 8.436 8.202 7.830

γA


Figure 13. Measured PTx data (O), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for methacrylonitrile (A) + methanol (B) at 65 °C

the calculated liquid (xA) and vapor (yA) compositions, the measured and correlated pressures, the activity (γA and γB) and fugacity coefficients (φA and φB), the Poynting corrections (PFA and PFB), and the relative volatilities

Figure 14. Measured PTx data (O), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for 1-chloro-1,1-difluoroethane (A) + hydrogen chloride (B) at -40 °C.

(RBA). The relative volatility was determined from

RBA )

yB/xB yA/xA

(6)

Journal of Chemical and Engineering Data, Vol. 41, No. 6, 1996 1247 Table 7. PTx Measurement Results on 2-(Hexyloxy)ethanol (A) + Ethylene Glycol (B) P/kPa run no.

a

100zA

100xA

100yA

meas

calc

γB

φA

φB

PFA

PFB

RBA

2.896 2.821 2.745 2.611 2.346 2.080 1.841 1.620 1.397 1.328 1.273 1.261 1.136 1.124 1.038 1.011 1.002 1.000

0.998 0.998 0.998 0.998 0.998 0.998 0.998 0.998 0.998 0.998 0.998 0.998 0.998 0.998 0.998 0.998 0.998 0.998

1.000 0.999 0.999 0.999 0.999 0.999 0.999 0.999 0.999 0.999 0.999 0.999 0.999 0.999 0.999 0.999 0.999 0.999

1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0001 1.0001 1.0001 1.0001 1.0001 1.0001 1.0001 1.0001 1.0000 1.0000 1.0000 1.0000

1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000 1.0000

2.968 2.890 2.810 2.660 2.344 1.994 1.648 1.301 0.923 0.801 0.700 0.679 0.443 0.421 0.241 0.170 0.134 0.110

2.359 2.299 2.272 2.213 2.060 1.846 1.676 1.506 1.385 1.345 1.235 1.216 1.113 1.102 1.029 1.007 1.002 1.000

0.979 0.977 0.976 0.975 0.973 0.970 0.969 0.968 0.968 0.968 0.968 0.968 0.969 0.969 0.970 0.973 0.975 0.977

0.994 0.993 0.993 0.992 0.990 0.989 0.988 0.987 0.987 0.987 0.987 0.987 0.987 0.987 0.987 0.988 0.988 0.989

1.0000 1.0002 1.0002 1.0004 1.0007 1.0010 1.0012 1.0013 1.0013 1.0014 1.0014 1.0014 1.0013 1.0013 1.0012 1.0010 1.0008 1.0006

0.9998 0.9999 0.9999 0.9999 1.0000 1.0001 1.0002 1.0002 1.0003 1.0003 1.0003 1.0003 1.0003 1.0002 1.0002 1.0001 1.0001 1.0000

2.957 2.878 2.842 2.761 2.538 2.191 1.884 1.544 1.281 1.190 0.927 0.882 0.611 0.579 0.351 0.259 0.219 0.186

γA

1 1 1 1 1 1 1 1 2 1 2 1 2 1 2 2 2 2

100.00 97.30 94.58 89.66 79.76 69.32 59.30 49.20 37.61 33.58 30.12 29.35 20.13 19.16 9.91 5.13 2.28 0.00

100.00 97.30 94.59 89.68 79.77 69.34 59.31 49.20 37.61 33.58 30.12 29.34 20.12 19.15 9.90 5.12 2.28 0.00

100.00 92.58 86.16 76.56 62.73 53.15 46.93 42.67 39.50 38.71 38.09 37.96 36.23 35.99 31.32 24.13 14.79 0.00

2.063 2.160 2.284 2.463 2.715 2.894 2.984 3.033 3.041 3.029 3.034 3.018 2.984 2.959 2.868 2.711 2.465 2.115

t ) 100 °Ca 2.063 1.000 2.169 1.000 2.269 1.002 2.431 1.006 2.692 1.026 2.879 1.069 2.986 1.144 3.037 1.276 3.048 1.551 3.044 1.700 3.039 1.862 3.038 1.904 3.009 2.625 3.004 2.734 2.880 4.414 2.674 6.110 2.431 7.649 2.115 9.342

1 1 1 1 1 1 1 1 2 1 2 1 2 1 2 2 2 2

100.00 96.03 94.27 90.55 81.30 68.83 58.99 48.78 41.06 38.33 30.36 28.94 19.86 18.64 9.37 4.60 2.25 0.00

100.00 96.15 94.44 90.81 81.66 69.18 59.26 48.93 41.11 38.38 30.34 28.92 19.76 18.59 9.20 4.46 2.17 0.00

100.00 89.68 85.66 78.15 63.70 50.61 43.57 38.29 35.27 34.36 31.97 31.56 28.74 28.30 22.39 15.30 9.16 0.00

46.604 49.940 50.519 53.959 61.375 68.552 71.570 73.631 74.193 74.367 74.366 74.367 73.676 73.392 70.751 66.892 63.191 58.748

t ) 180 °Cb 46.604 1.000 50.085 1.001 51.563 1.001 54.536 1.003 61.058 1.015 67.706 1.052 71.213 1.111 73.386 1.218 74.207 1.350 74.357 1.411 74.461 1.663 74.431 1.723 73.819 2.278 73.667 2.379 70.853 3.664 66.853 4.884 63.447 5.731 58.748 6.760

NRTL parameters: τAB ) -0.0953, τBA ) 2.3325, R ) 0.3000. NRTL parameters: τAB ) -0.2818, τBA ) 2.2177, R ) 0.3000.

Figure 15. Measured PTx data (O), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for 1-chloro-1,1-difluoroethane (A) + hydrogen chloride (B) at 0 °C.

Figure 16. Measured PTx data (O), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for 2-(hexyloxy)ethanol (A) + ethylene glycol (B) at 100 °C.

The activity coefficient parameters used to obtain the correlation are given at the bottom of each table. Figures showing total pressure as a function of liquid and vapor composition are included to illustrate the data. The results of vapor-liquid-liquid equilibrium measurements on bu-

tane + ammonia at 0 °C are included with the PTx results for that binary. 1. (Aminoethyl)piperazine + Diethylenetriamine. Results of the PTx measurements on (aminoethyl)piperazine + diethylenetriamine at 125 and 210 °C are given in

1248 Journal of Chemical and Engineering Data, Vol. 41, No. 6, 1996 Table 8. PTx Measurement Results on Butane (A) + Ammonia (B) P/kPa run no.

100zA

1 1 1 1 3b 1 1 1 1 2 1 1 2 1 2 2 2 2 3b 2

100.00 96.85 95.10 91.76

1 1 1 1 1 1 1 1 2 1 2 1 2 1 2 2 2 2

100xA

100yA

meas

100.00 97.71 96.35 93.56 85.26

100.00 53.41 43.62 33.50 19.18

0.00

1.06 0.00

19.18 0.00

103.69 198.50 235.48 317.99 529.15 488.72 518.68 524.94 527.47 529.94 527.72 529.15 529.94 529.83 529.85 529.98 530.10 530.04 529.15 429.19

100.00 97.14 93.80 87.78 80.78 70.64 60.69 52.80 48.50 39.19 30.44 30.06 19.94 17.69 11.01 5.31 2.76 0.00

100.00 98.36 96.29 92.13 86.50 76.81 65.92 56.79 48.77 40.84 30.92 30.62 19.87 17.62 10.26 4.50 2.21 0.00

100.00 77.33 61.99 47.05 38.06 31.23 27.51 25.50 24.16 23.07 21.95 21.92 20.76 20.41 18.21 12.76 7.95 0.00

494.84 654.16 838.20 1148.4 1481.0 1879.7 2149.7 2278.8 2352.1 2384.7 2406.8 2406.3 2413.5 2414.8 2406.6 2352.1 2240.2 2035.2

81.43 72.74 62.91 50.55 42.29 41.12 31.00 30.60 20.02 19.48 8.83 5.14 2.24

calc

γB

φA

φB

PFA

PFB

RBA

10.958 9.579 8.884 7.687

0.966 0.939 0.927 0.908

0.998 0.985 0.979 0.971

1.0000 1.0039 1.0059 1.0090

0.9962 0.9973 0.9978 0.9987

43.348 37.150 34.072 28.830 24.373

77.351

1.000

0.893

0.957

1.0139

1.0000

0.045 0.049

t ) 50 °Cc 494.84 1.000 656.51 1.000 840.52 1.002 1152.4 1.011 1477.4 1.030 1858.4 1.087 2120.4 1.188 2257.6 1.313 2335.8 1.470 2384.1 1.692 2414.8 2.142 2415.4 2.161 2423.8 3.169 2422.6 3.520 2396.8 5.424 2293.7 8.705 2194.4 11.004 2035.2 14.260

5.401 5.094 4.745 4.155 3.535 2.786 2.232 1.903 1.678 1.498 1.313 1.308 1.152 1.124 1.049 1.011 1.003 1.000

0.899 0.868 0.835 0.784 0.733 0.675 0.637 0.618 0.608 0.602 0.600 0.600 0.601 0.602 0.612 0.639 0.664 0.702

0.998 0.983 0.968 0.945 0.923 0.899 0.882 0.873 0.868 0.864 0.861 0.861 0.860 0.859 0.859 0.862 0.867 0.875

1.0000 1.0065 1.0139 1.0266 1.0400 1.0560 1.0671 1.0729 1.0763 1.0784 1.0797 1.0797 1.0801 1.0800 1.0789 1.0745 1.0702 1.0634

0.9828 0.9846 0.9866 0.9901 0.9937 0.9980 1.0010 1.0025 1.0034 1.0039 1.0043 1.0043 1.0044 1.0044 1.0041 1.0029 1.0018 1.0000

19.138 17.611 15.926 13.174 10.423 7.291 5.099 3.839 2.989 2.302 1.591 1.572 0.947 0.834 0.513 0.322 0.262 0.212

γA

t ) 0 °Ca 103.69 1.000 196.22 1.002 240.98 1.004 314.49 1.012

429.19

a NRTL parameters: τ b AB ) 1.5328, τBA ) 3.5181, R ) 0.4000. Run 3 is the vapor-liquid-liquid equilibrium measurement determined separately from the PTx measurements. c NRTL parameters: τAB ) 0.9622, τBA ) 2.0669, R ) 0.5073.

Figure 17. Measured PTx data (O), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for 2-(hexyloxy)ethanol (A) + ethylene glycol (B) at 180 °C.

Table 1. The Wilson activity coefficient equation was used to reduce the data. These data are plotted in Figure 4 for

Figure 18. Measured PTx data (O), measured LLE point (*), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for butane (A) + ammonia (B) at 0 °C.

the 125 °C measurements and in Figure 5 for the 210 °C measurements. This system exhibits nearly ideal behavior with very slight positive deviation from Raoult’s law. The

Journal of Chemical and Engineering Data, Vol. 41, No. 6, 1996 1249 Table 9. PTx Measurement Results on Propionaldehyde (A) + Butane (B) P/kPa run no.

a

100xA

100zA

100yA

1 1 1 1 1 1 2 1 2 1 2 1 2 2 2 2 2 2

100.00 97.94 95.76 89.90 77.84 71.57 64.19 61.63 54.02 50.66 41.24 40.53 30.30 20.47 9.65 4.76 2.29 0.00

100.00 98.04 95.95 90.24 78.23 71.93 64.34 61.90 54.20 50.83 41.44 40.61 30.47 20.58 9.69 4.77 2.29 0.00

100.00 58.88 42.15 25.47 16.08 14.10 12.57 12.20 11.23 10.88 10.03 9.95 9.06 7.94 5.67 3.63 2.05 0.00

1 1 1 1 1 1 1 2 1 2 1 2 2 2 2 2 2

100.00 94.91 92.88 90.49 79.91 71.64 61.21 54.67 47.70 43.90 37.85 31.86 18.79 10.63 6.59 2.97 0.00

100.00 95.96 94.29 92.31 82.76 74.67 63.79 56.24 49.14 45.66 38.52 33.37 19.53 10.81 6.59 2.91 0.00

100.00 79.57 73.63 67.78 49.96 41.50 34.09 30.29 27.24 25.84 23.08 21.07 14.97 9.81 6.60 3.21 0.00

meas 13.088 21.844 29.919 48.173 70.449 77.231 84.294 84.428 89.122 90.057 93.334 92.832 96.367 99.067 102.010 103.096 103.453 103.097 474.72 589.73 629.68 677.42 887.51 1025.7 1170.1 1264.7 1314.3 1354.5 1395.0 1438.6 1509.4 1533.7 1537.1 1534.3 1526.7

calc

γB

φA

φB

PFA

PFB

RBA

t ) 0 °Ca 13.088 1.000 21.895 1.001 30.114 1.003 47.846 1.016 70.325 1.075 77.420 1.125 83.477 1.206 85.015 1.238 88.934 1.359 90.314 1.425 93.443 1.664 93.684 1.690 96.355 2.105 98.787 2.797 101.559 4.358 102.678 5.732 103.044 6.757 103.097 8.031

4.905 4.591 4.292 3.617 2.663 2.320 2.000 1.913 1.681 1.595 1.398 1.383 1.226 1.113 1.030 1.008 1.002 1.000

0.994 0.991 0.987 0.979 0.970 0.967 0.964 0.964 0.962 0.961 0.960 0.960 0.959 0.958 0.957 0.956 0.956 0.956

0.996 0.993 0.990 0.984 0.977 0.975 0.973 0.972 0.971 0.970 0.969 0.969 0.968 0.968 0.967 0.966 0.966 0.966

1.0000 1.0003 1.0005 1.0011 1.0018 1.0020 1.0022 1.0022 1.0023 1.0024 1.0025 1.0025 1.0026 1.0026 1.0027 1.0027 1.0028 1.0028

0.9964 0.9967 0.9971 0.9978 0.9987 0.9990 0.9992 0.9993 0.9994 0.9995 0.9996 0.9996 0.9997 0.9998 0.9999 1.0000 1.0000 1.0000

37.348 34.912 32.546 27.038 18.764 15.609 12.545 11.693 9.352 8.464 6.351 6.185 4.400 3.006 1.785 1.328 1.120 0.941

t ) 100 °Cb 474.72 1.000 588.01 1.001 631.38 1.003 680.62 1.005 886.03 1.026 1025.0 1.057 1172.8 1.121 1255.0 1.184 1320.7 1.260 1349.5 1.305 1402.6 1.416 1436.5 1.514 1509.5 1.895 1536.4 2.269 1540.4 2.511 1536.4 2.764 1526.7 3.000

2.503 2.340 2.278 2.208 1.915 1.716 1.504 1.385 1.292 1.252 1.180 1.136 1.049 1.016 1.006 1.001 1.000

0.915 0.895 0.887 0.878 0.842 0.817 0.791 0.777 0.765 0.760 0.750 0.744 0.732 0.727 0.727 0.729 0.731

0.938 0.923 0.917 0.910 0.883 0.864 0.844 0.833 0.825 0.821 0.814 0.809 0.799 0.795 0.795 0.795 0.797

1.0000 1.0031 1.0042 1.0056 1.0112 1.0150 1.0190 1.0213 1.0231 1.0239 1.0254 1.0263 1.0283 1.0291 1.0292 1.0291 1.0288

0.9585 0.9629 0.9646 0.9665 0.9745 0.9800 0.9859 0.9891 0.9917 0.9929 0.9950 0.9964 0.9993 1.0004 1.0005 1.0004 1.0000

6.553 6.092 5.913 5.706 4.807 4.155 3.405 2.958 2.582 2.411 2.089 1.876 1.379 1.114 0.998 0.903 0.832

γA


Table 10. Constants Used in Data Reduction Procedure compound

MW

TC/K

PC/kPa

ZC

ω

ref

(aminoethyl)piperazine diethylenetriamine 2-butoxyethyl acetate 2-butoxyethanol 2-methyl-2-propanol 2-methylbutane 2-methyl-2-butene methacrylonitrile methanol 1-chloro-1,1-difluoroethane hydrogen chloride 2-(hexyloxy)ethanol ethylene glycol butane ammonia propionaldehyde

129.205 103.167 160.0 118.176 74.123 72.150 70.134 67.090 32.042 100.495 36.461 146.2 62.068 58.123 17.031 58.080

708.0 676.0 637.33 600.0 506.20 460.43 471.00 554.0 512.58 410.20 324.65 636.0 645.0 425.18 405.65 496.0

3850 4220 2505 3240 3971.9 3381.2 3400 3880 8095.9 4123.9 8308.7 2738.3 7530 3796.9 11278 4660

0.266 0.257 0.249 0.260 0.260 0.270 0.292 0.223 0.224 0.279 0.249 0.2695 0.268 0.274 0.242 0.237

0.5546 0.7002 0.4522 0.8174 0.6158 0.2275 0.2767 0.3013 0.5656 0.2368 0.1322 0.9235 1.1367 0.1993 0.252 0.3015

a a b a a a a a a a a b a a a a

a Measured and/or estimated values reported by Daubert et al. (1992). b Estimated using techniques shown in Chapter 2 of Reid et al. (1987).

expression P ) ∑(P°i xi) defines Raoult’s law, where P is the total system pressure, P°i is the vapor pressure of component i, and xi is the liquid mole fraction of component i. 2. 2-Butoxyethyl Acetate + 2-Butoxyethanol. PTx measurements on 2-butoxyethyl acetate + 2-butoxyethanol were performed at 100 and 170 °C. The Wilson activity coefficient equation was used to reduce the data. Results of the measurements are given in Table 2 and plotted in Figures 6 and 7. This system shows slight positive deviation from ideality.

3. 2-Methyl-2-propanol + 2-Methylbutane. Results of measurements on 2-methyl-2-propanol + 2-methylbutane at 30 and 100 °C are reported in Table 3. The data were reduced using the NRTL activity coefficient equation. This system exhibits positive deviation from ideality with minimum-boiling azeotropes at both temperatures in the dilute 2-methyl-2-propanol region. The results are plotted in Figures 8 and 9. 4. 2-Methyl-2-propanol + 2-Methyl-2-butene. The 2-methyl-2-propanol + 2-methyl-2-butene system also ex-

1250 Journal of Chemical and Engineering Data, Vol. 41, No. 6, 1996 Table 11. Measured and Literature Vapor Pressures P/ kPa compound (aminoethyl)piperazine diethylenetriamine 2-butoxyethyl acetate 2-butoxyethanol 2-methyl-2-propanol

t/°C measured 125 210 125 250 100 170 100 170 30 100

2-methylbutane

30 100 2-methyl-2-butene 30 100 methacrylonitrile 25 65 methanol 25 65 1-chloro-1,1-difluoroethane -40 0 hydrogen chloride -40 0 2-(hexyloxy)ethanol 100 180 ethylene glycol 100 180 butane 0

ammonia propionaldehyde

50 100 0 50 0 100

4.819 75.710 7.000 110.44 4.329 55.522 8.638 99.407 7.750 7.723 192.43 195.05 108.57 720.64 74.888 566.85 8.370 44.565 16.942 103.095 23.752 144.42 764.73 2611.6 2.063 46.604 2.115 58.748 103.69 103.097 494.84 1526.7 429.19 2035.2 13.088 474.72

lit.a

% devb

4.145 77.618 7.508 108.89

16.3 -2.46 -6.77 1.42

8.755 98.222 7.649 192.26 109.15 721.22 75.066 559.66 9.489 45.391 16.801 103.122 26.334 147.09 759.48 2559.3 2.130 58.089 103.59 496.54 1527.8 429.13 2029.6 13.480 469.88

-1.34 1.21 1.32 0.97 0.09 1.45 -0.53 -0.08 -0.24 1.28 -11.8 -1.82 0.84 -0.03 -9.80 -1.82 0.69 2.04

-0.70 1.13 0.10 -0.48 -0.34 -0.07 0.01 0.28 -2.91 1.03

a Literature data calculated from correlations in Daubert et al. (1992). b Percent deviation: 100 × (measured - literature)/ literature.

hibits positive deviation from ideality and has a minimumboiling azeotrope at both temperatures studied, 30 and 100 °C. Results of the PTx measurements are listed in Table 4 and are plotted in Figures 10 and 11. The NRTL activity coefficient equation was used to reduce the data. 5. Methacrylonitrile + Methanol. PTx data for methacrylonitrile + methanol were obtained at 25 and 65 °C. These data are reported in Table 5 and Figures 12 and 13. The data were reduced using the NRTL activity

Figure 19. Measured PTx data (O), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for butane (A) + ammonia (B) at 50 °C.

coefficient equation. This system shows positive deviation from ideality. Both sets of data have a minimum-boiling azeotrope. 6. 1-Chloro-1,1-difluoroethane + Hydrogen Chloride. Results of the PTx measurements on 1-chloro-1,1difluoroethane + hydrogen chloride at -40 and 0 °C are given in Table 6. The Wilson activity coefficient equation was used to reduce the data. This system exhibits nearly ideal behavior with activity coefficients that are only slightly greater than unity. Figures 14 and 15 show plots of these data. 7. 2-(Hexyloxy)ethanol + Ethylene Glycol. Positive deviation from ideality is exhibited by 2-(hexyloxy)ethanol + ethylene glycol at 100 and 180 °C. The PTx measurement results are shown in Table 7. These data were reduced using the NRTL activity coefficient equation. The results are plotted in Figures 16 and 17. The vapor pressures of the two components are very similar; therefore, minimum-boiling azeotropes occur at both temperatures. 8. Butane + Ammonia. PTx data were obtained for butane + ammonia at 0 and 50 °C. These data are reported in Table 8 and are plotted in Figures 18 and 19. At 0 °C there is a large immiscibility region extending from 1.06

Table 12. Source and Purity of Chemicals purity, mass %

a

compound

CAS No.a

supplier

(aminoethyl)piperazine diethylenetriamine 2-butoxyethyl acetate 2-butoxyethanol 2-methyl-2-propanol 2-methylbutane 2-methyl-2-butene methacrylonitrile methanol 1-chloro-1,1-difluoroethane hydrogen chloride 2-(hexyloxy)ethanol ethylene glycol butane ammonia propionaldehyde

140-31-9 111-40-0 112-07-2 111-76-2 75-65-0 78-78-4 513-35-9 126-98-7 67-56-1 75-68-3 7647-01-0 112-25-4 107-21-1 106-97-8 7664-41-7 123-38-6

Aldrich Aldrich Aldrich Aldrich Aldrich Aldrich Aldrich Fluka Aldrich PCR Matheson Union Carbide Aldrich Phillips Matheson Kodak

Wiltec analysis

99.9 99.7

supplier analysis 99.2 99.6 99.5 99.79 99.6 99.1 99.2 99.5+ 99+

99+ 97b 99.6 99.9+

Supplied by the authors. b Mixture of several compounds that are isomers or at least close boilers.

99.9+ 99.2 99.9 99.9+ 99.9+ 99+

Journal of Chemical and Engineering Data, Vol. 41, No. 6, 1996 1251

Figure 20. Measured PTx data (O), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for propionaldehyde (A) + butane (B) at 0 °C.

mol % butane to 85.26 mol % in the liquid. A separate VLLE measurement was performed to determine more precisely the miscibility limits and the composition of the vapor phase in equilibrium with the two liquid phases. At 50 °C there is strong positive deviation resulting in a minimum-boiling azeotrope, but there is no immiscible region. The NRTL activity coefficient equation was used to reduce the data. 9. Propionaldehyde + Butane. The propionaldehyde + butane system shows positive deviation from ideality at 0 and 100 °C with minimum-boiling azeotropes in the dilute propionaldehyde region. Results of the PTx measurements are reported in Table 9 and plotted in Figures 20 and 21. The data were reduced using the Wilson activity coefficient equation. Ancillary Data. Table 10 gives the physical constants for each compound used in the data reduction procedure. Table 11 compares the measured pure component vapor pressures to correlations reported by Daubert et al. (1992). Table 12 lists the source and purity of the chemicals used in this study. The chemicals were all degassed before being used. Table 12 also lists the Chemical Abstracts Service Registry number for each chemical.

Figure 21. Measured PTx data (O), P-x correlation (s), P-y correlation (‚‚‚), and Raoult’s law (- - -) for propionaldehyde (A) + butane (B) at 100 °C.

Acknowledgment We wish to thank Mark Swenson who helped measure the experimental data. Literature Cited Barker, J. A. Determination of activity coefficients from total pressure measurements. Aust. J. Chem. 1953, 6, 207-210. Daubert, T. E.; Danner, R. P.; Sibul, H. M.; and Stebbins, C. C. Physical and Thermodynamic Properties of Pure Compounds: Data Compilation, Extant 1992; Taylor and Francis: Bristol, PA, 1992. Reid, R. C.; Prausnitz, J. M.; Poling, B. E. The Properties of Gases and Liquids, 4th ed.; McGraw-Hill, Inc.: New York, 1987. Renon, H.; Prausnitz, J. M. Local Compositions in Thermodynamic Excess Functions for Liquid Mixtures. AIChE J. 1968, 14, 135144. Soave, G. Equilibrium constants from a modified Redlich-Kwong equation of state. Chem. Eng. Sci. 1972, 27, 1197-1203. Wilson, G. M. Vapor-Liquid Equilibrium. XI. A New Expression for the Excess Free Energy of Mixing. J. Am. Chem. Soc. 1964, 86, 127130.

Received for review May 9, 1996. Accepted September 3, 1996.X We are grateful to the DIPPR 805 steering committee and to the companies it represents for funding this research.

JE9601624 X

Abstract published in Advance ACS Abstracts, November 1, 1996.

Phase Equilibrium Measurements on Nine Binary Mixtures - American

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