J. Chem. Eng. Data 1993,38, 296-298
296
Isobaric Vapor-Liquid Equilibria in the Ternary System Acetonitrile Methyl Acetate + Propyl Bromide
+
Jaime Wisniak Department of Chemical Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel 84105
+
Vapor-liquid equilibrium at 101.3 kPa has been determined for the ternary system acetonitrile methyl acetate + propyl bromide. The data were correlated by the Redlich-Kister and Wisniak-Tamir equations, and the appropriate parameters are reported. The activity coefficientsof the ternary system can be predicted from those of the pertinent binary systems. No ternary azeotrope is present.
The present work was undertaken to measurevapor-liquid equilibrium (VLE) data for the title system for which no isobaric data are available. This is part of a program to determine UNIFAC parameters for organic bromides. Data for the binaries have already been reported (1-3).
Table I. Mole Percent GLC Purities, Refractive Indexes nD at the Na D Line, and Normal Boiling Points '2 of Pure Components component (purity/(mol % ' )) acetonitrile (99.5) methyl acetate (99.2)
Experimental Section
Purity ofMaterials. Methyl acetate (99.2 + mol 96 ) and propyl bromide (99.4 + mol % ) were purchased from Merck, and acetonitrile (99.5 + mol % ) was purchased from HPLC Bio-Lab. The reagentswere used without further purification after gas chromatography failed to show any significant impurities. The properties and purities (as determined by GLC) of the pure components appear in Table I. ApparatusandProcedure. Anall-glassmodifiedDvorak and Boublik recirculation still (4) was used in the VLE measurements. The experimental features have been described in a previouspublication (5). All analyseswere carried out by gas chromatography on a Packard-Becker Model 417 apparatus provided with a thermal conductivitydetector and a Spectra Physics Model SP 4290 electronic integrator. The column was 3 m long and 0.2 cm in diameter, filled with Poropak Q, and operated at 140 "C. The temperatures at the detector and injector were 240 and 220 "C, respectively. Very good separation was achieved under these conditions, and calibration analyses were carried out to convertthe peak ratio to the weight composition of the sample. Concentration measurements were accurate to better than f0.008 mole fraction unit. The accuraciesin determination of the pressure P and temperature t were at least f O . l kPa and 0.02 "C, respectively.
propyl bromide (99.4)
nd298.15K) 1.34100 1.34166 1.3588' 1.358Q6 1.43200 1.4317b
Measured. Reference 12.
Figure 1. Isothermals for the ternary system acetonitrile + methyl acetate + propyl bromide (101.3 kPa). Coefficients from eq 5. 6.. 11 = 2B..-B..-Bii 15 11
Results The temperature T and liquid-phase xi and vapor-phase yi mole fraction measurements at P = 101.3kPa are reported in Table 11, together with the activity coefficienta yi which were calculated from the following equation (6): In y i = In(Pyi/Pioxi)+ (Bii- up)(P- Pio)/RT+ n
n
where 0021-9568/93/1738-0296$04.00/0
T/K 354.65" 354.75b 330.090 330.Wb 343.700 344.156
(2)
The pure component vapor pressures Pi" were calculated according to the Antoine equation: log(Pio/kPa) = Ai-Bi/(T/K - Ci)
(3)
where the constants Ai, Bi, and Ci are reported in Table 111. The molar virial coefficientsBii and Bi, were estimated by the method of O'Connell and Prausnitz (7)using the molecular parameters suggested by the authors and assuming the association parameter 9 to be zero. The last two terms in eq 1 contributed less than 3% to the activity coefficient, and their influence was important only at very dilute concen0 1993 American Chemical Society
Journal of Chemical and Engineering Data, Vol. 38, No. 2,1993 297 Table 11. Experimental Vapor-Liquid Equilibrium Data for Acetonitrile (1) + Methyl Acetate (2) + Propyl Bromide (3) at 101.3 kPa
331.95 332.58 332.65 332.65 333.19 333.32 333.35 333.42 333.76 334.42 334.44 334.66 334.69 334.75 335.11 335.21 335.66 335.15 335.86 336.36 336.40 336.71 336.74 337.09 337.18 337.21 337.32 337.64 337.65 337.85 337.90 338.06 338.12 338.80 338.82 338.94 339.00 339.15 339.40 340.02 340.46 340.46 341.11 342.40 343.28 343.65 343.94 345.30 345.74 346.05 348.91 349.92 350.79
0.189 0.169 0.244 0.248 0.203 0.212 0.193 0.219 0.279 0.212 0.297 0.353 0.327 0.385 0.368 0.252 0.262 0.432 0.422 0.291 0.254 0.219 0.431 0.325 0.279 0.473 0.234 0.540 0.195 0.196 0.167 0.525 0.547 0.286 0.576 0.567 0.622 0.576 0.528 0.659 0.629 0.672 0.686 0.736 0.792 0.784 0.737 0.809 0.857 0.817 0.881 0.909 0.934
0.773 0.613 0.701 0.657 0.552 0.621 0.557 0.498 0.594 0.361 0.466 0.487 0.531 0.454 0.474 0.371 0.330 0.378 0.506 0.229 0.188 0.157 0.259 0.183 0.151 0.314 0.118 0.349 0.094 0.134 0.084 0.139 0.399 0.050 0.169 0.322 0.237 0.180 0.066 0.263 0.081 0.103 0.225 0.156 0.041 0.094 0.220 0.155 0.047 0.143 0.095 0.074 0.053
0.132 0.118 0.144 0.153 0.139 0.165 0.160 0.150 0.176 0.188 0.199 0.226 0.207 0.247 0.239 0.189 0.202 0.288 0.264 0.240 0.228 0.213 0.304 0.277 0.254 0.318 0.230 0.356 0.208 0.201 0.182 0.384 0.357 0.285 0.426 0.388 0.422 0.402 0.404 0.450 0.453 0.484 0.468 0.535 0.575 0.604 0.539 0.624 0.659 0.637 0.738 0.813 0.853
0.824 0.680 0.792 0.738 0.622 0.666 0.598 0.578 0.693 0.403 0.549 0.583 0.630 0.549 0.567 0.454 0.406 0.463 0.633 0.301 0.247 0.212 0.336 0.236 0.195 0.397 0.173 0.470 0.145 0.184 0.110 0.185 0.545 0.070 0.220 0.437 0.336 0.245 0.090 0.395 0.108 0.141 0.349 0.244 0.061 0.144 0.359 0.288 0.080 0.253 0.189 0.159 0.114
1.448 1.410 1.191 1.241 1.349 1.525 1.621 1.336 1.217 1.664 1.256 1.189 1.178 1.185 1.187 1.370 1.386 1.210 1.114 1.444 1.573 1.691 1.211 1.452 1.552 1.135 1.673 1.095 1.802 1.720 1.834 1.197 1.069 1.612 1.176 1.087 1.072 1.099 1.199 1.042 1.085 1.082 1.004 1.022 0.9929 1.038 0.9803 0.9867 0.9693 0.9738 0.9555 0.9880 0.9822
1.006 1.030 1.043 1.039 1.028 0.9730 0.9758 1.054 1.043 0.9917 1.037 1.045 1.032 1.054 1.030 1.057 1.051 1.059 1.050 1.106 1.110 1.133 1.076 1.066 1.069 1.030 1.211 1.079 1.266 1.116 1.071 1.072 1.075 1.115 1.022 1.047 1.098 1.056 1.063 1.126 1.005 1.029 1.128 1.103 1.036 1.050 1.094 1.205 1.104 1.125 1.175 1.240 1.217
1.783 1.373 1.747 1.712 1.411 1.467 1.392 1.376 1.480 1.312 1.474 1.652 1.592 1.746 1.674 1.270 1.267 1.775 1.922 1.228 1.203 1.164 1.484 1.241 1.205 1.694 1.141 1.977 1.113 1.117 1.145 1.569 1.271 1.149 1.667 1.910 2.065 1.720 1.458 2.334 1.723 1.905 2.332 2.230 2.298 2.170 2.491 2.475 2.690 2.270 2.788 1.477 2.224
1029 1023 1023 1023 1018 1017 1016 1016 1013 1007 1007 1005 1004 1004 1001 1000 996 lo00 994 990 989 987 986 983 982 982 981 979 978 977 976 975 974 969 968 967 967 966 964 958 955 955 949 939 932 929 926 916 912 910 888 881 874
Table 111. Antoine Coefficients,Equation 3 comDound acetonitrile" methyl acetateb propyl bromideb
Ai
6.198 43 6.186 21 6.035 55
Bi 1279.20 1156.43 1194.889
1029 1024 1023 1023 1018 1017 1017 1016 1013 1007 1007 1005 1004 1004 1001 1000 996 1001 994 990 990 987 987 984 983 983 982 979 979 977 977 976 975 969 969 968 968 967 964 959 956 956 951 940 933 930 928 917 914 912 890 883 877
921 916 916 916 911 910 910 910 907 902 900 900 900 899 896 896 892 886 891 887 886 884 884 881 881 880 880 877 877 876 875 874 874 868 868 867 867 868 864 860 856 856 852 842 836 834 832 822 819 817 798 791 786
2384 2371 2369 2369 2359 2356 2355 2354 2347 2334 2334 2329 2329 2328 2321 2319 2310 2320 2306 2296 2295 2289 2289 2282 2280 2280 2278 2272 2271 2268 2267 2264 2262 2250 2249 2247 2246 2243 2238 2227 2218 2218 2206 2183 2167 2160 2155 2130 2123 2117 2067 2050 2035
1815 1805 1804 1804 1795 1793 1792 1791 1786 1775 1775 1771 1771 1770 1764 1763 1756 1764 1752 1745 1744 1739 1739 1733 1732 1731 1730 1725 1725 1721 1721 1718 1717 1707 1707 1705 1704 1702 1698 1688 1682 1682 1672 1653 1640 1634 1630 1610 1604 1599 1559 1545 1532
1984 1973 1972 1972 1964 1961 1961 1960 1955 1944 1943 1940 1939 1939 1933 1931 1924 1932 1921 1913 1913 1908 1907 1902 1900 1900 1898 1893 1893 1890 1889 1887 1886 1875 1875 1873 1872 1870 1866 1857 1850 1850 1840 1821 1808 1803 1798 1778 1772 1768 1727 1713 1701
Kister expansion (9): Ci
49.15 53.46 47.64
Reference 13. Reference 12.
trations. The calculated activity coefficients are reported in Table I1 and are estimated accurate to within *3 %
.
The ternary data reported in Table 11 were found to be thermodynamically consistent as tested by the McDermotEllis method (10) modified by Wisniak and Tamir (8). The values of D,, were at least 0.044 while the values of D for any given point never exceeded 0.039. The test requires that D < D,, for every point. The activity coefficients for the ternary system were correlated by the following Redlich-
where bij, cij, and dij are constants for the pertinent binary and C1 is a ternary constant. The equations for two other pairs of activity Coefficients were obtained by cyclic rotation of the indices. The binary data used for calculating the binary constants have been reported elsewhere (1-3). The ternary Redlich-Kister coefficient was obtained by a Simplex optimization technique. The differences between the values of the root mean square deviation for the activity coefficient for the two cases-with and without the ternary constant C1 (Table 1V)-are statistically not significant,
298 Journal of Chemical and Engineering Data, Vol. 38,No. 2,1993
Table IV. Redlich-Kister Coefficients, Ternary Data, and Root Mean Square Deviations in Activity Coefficients, rmsd rmsd
+
acetonitrile (1) methyl acetate (2)+ propyl bromide (3)
0.1395 -0.1253 0.0980 0.4512
0
0
0.0836 -0,1428 0.2507 0 0.011 0.020 0.011 0.011 0.017
Table V. Coefficients in the Correlation of Boiling Points, Equation 5 ( D = 0), and Root Mean Square Deviations in Temperature, rmsd(T/K) svstem acetonitrile (1) methyl acetate (2) acetonitrile (1) propyl bromide (3) methyl acetate (2)+ propyl bromide (3)
+ +
Cn
C1
c2
-17.837 -35.530 -19.418
-5.7460 -11.723 5.3963 A 5.4876
6.4429 -19.298 0 B -82.087
system
+
acetonitrile (1) methyl acetate (2)+ propyl bromide (3)
suggesting that ternary data can be predicted directly from the binary systems. The boiling points of the systems were correlated by the equation proposed by Wisniak and Tamir (10):
Acknowledgment Yehudit Reizner and Moshe Golden helped in the experimental part and numerical calculations. Glossary Ai,Bi,Ci BiitBij biitcijpdii N P Pi"
R
Antoine constants, eq 3 second molar virial coefficients, eqs 1 and 2 Redlich-Kister constants, eq 4 number of measurements total pressure vapor pressure of pure component i gas constant
C
rmsd 0.03 0.04 0.03 rmsd
-
0.12
-
~
~~~
6ij
root mean square deviation, { ~ ( T , , ,-t ~ Tcaicd)2~0~5/N root mean square deviation, {C(yi,erptl Y~,C~~~)O.~/N boiling temperature of a mixture boiling temperature of pure component i molar volume of liquid component i mole fraction of component i in the liquid and vapor phases activity coefficient of component i molar virial coefficient parameter, eq 2
Subscripts exptl calcd
experimental value calculated value
rmsd(T)
n
~ 1 x g J A+ B(x, - x Z ) + C ( X ~x3) - + D(x2 - ~ 3 ) )(5) In these equations n is the number of components ( n = 2 or 31, Tiois the boiling point of the pure component i (K or "C), and 1 is the number of terms in the series expansion of xi rj. Ck are the binary constants whereas A, B, C, and D are ternary constants. An equation of the same structure can be used for the direct correlation of ternary data, without use of binary data. Both forms will require about the same number of constants for similar accuracy, but the direct correlation allows an easier calculation of boiling isotherms (Figure 1). The various constants of eq 5 are reported in Table V, which also contains information indicatingthe degree of goodness of the correlation.
CR -
Yi
~
Literature Cited (1) Wisniak, J.; Tamir, A. J. Chem. Eng. Data 1986,31,363. (2) Wisniak, J.; Tamir, A. J. Chem. Eng. Data 1989,34,16. (3) Mato, F.; Cabezas, J. L.; Coca, J. Anal. Quim. 1973,69,123. (4) Boublikova, L. K.;Lu, B. C.-Y. J. Appl. Chem. 1969,19,89. ( 5 ) Wisniak, J.; Tamir, A. J. Chem. Eng. Data 1976,20, 168. (6)Van Ness, H. C.; Abbott, M. M. Classical Thermodynamics of Nonelectrolyte Solutions; McGraw-Hill BrookCo.: New York, 1982. (7) O'Connell, J. P.; Prausnitz, J. M. Ind. Eng. Chem., Process Des. Deu. 1967,6, 245. (8)McDermott, C.; Ellis, S. R. M. Chem. Eng. Sci. 1965,20, 293. (9)Wisniak, J.; Tamir, A. J. Chem. Eng. Data 1977,22,253. (10)Hala, E.;Pick, J.; Fried, V.; Vilim, 0. Vapor-Liquid Equilibrium; Pergamon Press: London, 1967. (11) Wisniak, J.; Tamir, A. Chem. Eng. Sci. 1975,30,335. (12) TRC-ThermodynamicTables-Non-hydrocarbons;Thermodynamica Research Center, The Texas A&M University System, College Station, TX (loose-leaf data sheets, extant 1974). (13)Reid, R.C.;Prausnitz, J. M.; Sherwood,T.K. ThePhysicalProperties of Gases and Liquids, 3rd ed.; McGraw-HillBook Co.: New York,
1977. Received for review July 21,1992. Accepted December 7, 1992.
