172
J. Chem. Eng. Data 1990, 35. 172-174
Table IV. Second Molar Virial Coefficients Bi,and Liquid Molar Volumes V, (cm3 mol-') as a Function 04 TemDerature T
TiK
component pyrrolidine (i = 1)
cyclohexane (i = 2) water ( i = 2) ethanol (i = 2) tetrahydrofuran (i = 2)
-9(,00
~
,
313.15 313.35 333.15 333.35 353.15 313.15 333.15 333.15 353.15 313.15 333.35 313.35 333.35
....
~
e
~
,
Vi 84.7 84.5 86.6 86.6 88.4 111.9 114.6 18.4 18.8 59.2 60.9 83.4 84.8 ~
Caiorimttrir n i t ~ s u r e ~ n ~ n l iZE f'Filson Mode:>
BI~
Rig
-1235 -1233 -1054 -1052 -914 -1691 -1423 -912 -637 -1652 -1201 -1118 -968
Acknowledgment -1278 -1081 -479 -415 -985 -847 -1101 -9:37
We thank Dr. H. Kehiaian for his comments and for providing us with the results of the DISQUAC calculations. Registry No. Pyrrolidine, 123-75-1; cyclohexane, 110-82-7; ethanol, 64-1 7-5; tetrahydrofuran, 109-99-9.
.
---
Literature Cited
~-
, 1500
our VLE data reported here can be reproduced by the DISQUAC model with reported parameters (77),with average deviations in pressure of the order of 0.5 kPa and in composition of 0.01 or better.
-
,
(1) (2) (3) (4)
(5) (6) (7) (8)
(9) (10) (11) 0
(12) (13) (14)
00
0 1
0 2
0 3
0 4
05
0.6
07
0 8
0.9
1 0
Mole Fraction of P y r r o l i d i n e
Figure 5. Molar excess enthalpy, H E ,for the pyrrolidine (1) -I-cyciohexane (2) system. The points are direct calorimetric measurements ( 73),and the lines resulted from the values of GEgenerated from our vapor-liquid equilibrium measurements. Tine and Kehiaian (76)that the cyclic secondary amine group in pyrrolidine may have to be considered a different functional group from the noncyclic secondary amine group in future improvements of the UNIFAC model. I t is also worth noting that
(15) (16) (171
Wu, H. S.;Sandler, S. I.J . Chem. Eng. Data 1988, 33, 157. Wu, H. S.; Sandler, S. I. J . Chem. Eng. Data 1989, 34,209. Wu, H. S.; Sandler, S. I.AIChEJ. 1989, 35(1),168. Fredenslund, A.; Gmehling, J.; Rasmussen, P. Vapor-LiquidEqui/i~iu~ Using UNIFAC; Elsevier: Amsterdam, 1977. Eng. R.; Sandler, S. I.J . Chem. Eng. Data 1984, 29, 156. Riddick, J. A.; Bunger, W. B.; Sakano, T. K. Organic Solvents, Physical Properties and Methods of Purification; Techniques of Chemistry, Volume 11, 4th ed.; Wiley: New York, 1986. TRC-Thermodynamic Table-Hydrocarbons; Thermodynamics Research Center, The Texas A&M University System: College Station, TX, 1975; p k-1960, cyclohexane (loose-leaf data sheets). TRC-Thermodynamic Table-Non-hydrocarbons; Thermodynamics Research Center. The Texas A&M University System: College Station, TX, 1964; p k-40, water; 1976, p. k-5000, ethanol; 1985, p. k-6170, tetrahydrofuran. Hayden, J. G.; O'Connell, J. P. Ind. Eng. Chem. Process Res. Dev. 1975, 14. 209. Kemeny, S.; Manczinger, J.; SkjoldJorgensen, S.;Toth. K. AICh€ J . 1982, 28. 20. Cabani, S . ; Ceccanti, N.; Tine, M. R. Int. DATA Ser., Sel. Data Mixtures, Ser. A 1986, 185. Cabani, S.;Conti, G.; Lepori, L. Trans. Faraday SOC.1971, 6 7 , 1933. Cabani, S.;Ceccanti, N. J . Chem. Thermodyn. 1973, 5 , 9. Srivastava. R.; Smith, S. D. J . Chem. Eng. Data 1985, 30, 308. Smith, B. D. Int. DATA Ser., Sel. Data Mixtures, Ser. A 1985, 252. Abbott, M. M.; Karlsruher, S. A.; Smith, B. D. Int. DATA Ser., Sel. DATA Mixtures, Ser. A 1985, 259. Reid, R. C.; Prausnitz, J. M.; Poling, B. E. The froperties of Gases and Liquids, 4th ed.; McGraw-Hill: New York, 1987. Tine. M. R.; Kehiaian, H. V. Fhid Phase Equilib. 1987, 32,211. Kehiaian, H. V. Private communication, 1989.
Received for review May 23, 1989. Accepted November 27, 1989. The research reported here was supported, in part, by the National Science Foundation Grant CBT-8612285 to the University of Delaware.
Thermodynamics of Binary Mixtures Containing Alkanenitriles. I . Excess Enthalpies of Some n-Alkanenitrile 4- n-Alkane or 4Cyclohexane Mixtures Bruno Marongiu and Silvla Porcedda Dipartimento di Scienze Chimiche, Universita di Cagliari, Via Ospedale 72, 09 700 Cagliari, Italy A Tian-Caivet-type calorimeter was used to determine excess enthalpies, H E ,as a function of concentration at pressure and 298.15 for some binary liquid mixtures containing linear alkanenitriles of the general formula CHS(CH,),-,CN ( n = 2, 3, 4, 5) with n-alkanes (hexane, heptane) or Cyclohexane. 0021-9568/90/1735-0172$02.50/0
I ntroduclion This work is part of a systematic study of the thermodynamic properties of organic mixtures, TOM Project ( 7- 76),with the purpose of characterizing the type and magnitude of molecular interactions in binary liquid mixtures and to improve the group contribution models currently used to predict thermodynamic 1990 American Chemical Society
Journal of Chemical and Engineering Data, Vol. 35, No. 2, 7990 173
Table I. Experimental Molar Excess Enthalpies, HE,at 298.15 K for Binary Mixtures of n -Alkanenitriles [CH,(CH,),-,CN ( l ) ] n-Alkanes [CH,(CH&,CHI] or Cyclohexane (2); Coefficients aj, Equation 1; and Standard Deviations, o(HE),Equation 2 HE, HE, HE, x1 J mol-' x1 J mol-' n, J mol-' CH&N (1)+ C7Hi6 (2) 0.0295 452 0.2857O 595 0.9711 322 0.0403 550 0.5143O 501 0.9808 227 0.0507 634 O.714Oa 403 0.9894 130
+
CHBCHzCN (1)+ C6H1, 1435 724 0.3892 1459 0.4906 1071 0.5844 1397 1363
0.1059 0.1889 0.3136
+
(2) 0.7103 0.8269 0.9035
1191 842 519
a, = 5822; a, = -636; a, = 1573; a3 = -707; a(HE)= 2.4
J mol-'
CHSCHZCN (1) + C7H16 (2) 0.7050 1310 1515 0.3988 0.0975 720 0.7836 1095 1545 1055 0.4802 0.1712 594 1483 0.9037 0.6021 0.3107 1410 a, = 6164; a, = -292; a, = 1978; a3 = -852; .(HE) = 4.8 J mol-'
Y 0.2
0.0
0.4
0.6
0.8
Xt
Figure 1. Experimental molar excess enthalpies, He, of alkanenitrile (1) i- heptane (2) mixtures at 298.15 K vs x , , the mole fraction of alkanenitrile: W, ethanenitrile; 0 , propanenitrile; 0, butanenitrile; A, pentanenitrile.
+
properties. Mixtures containing short-chain nitriles n-alkanes or cyclohexane exhibit large positive deviations from ideality, often reflected in partial miscibility. As the chain length of the nitrile increases, the positive deviations from ideality decrease and total miscibility becomes more common. McLure et al. (7) reported the upper critical solution temperatures (UCST) for binary mixtures of ethanenitrile, propanenitrile, or butanenitrile with n-alkanes containing 5-1 8 carbon atoms. The liquid-liquid equilibrium of ethanenitrile cyclohexane has been carefully investigated by Vani et al. (8). A search of the literature reveals that thermodynamic studies on alkanenitrile alkane or cyclohexane are rather scarce, and moreover some discordances exist in the results reported by different authors. Molar excess enthalpies, HE,of alkanenitrile n-alkane or cyclohexane have been measured calorimetrically by several authors (9-74). In order to better characterize the behavior of the CN group, we decided to measure, or remeasure, H E in a systematic way for mixtures of n-alkanenitriles [CH,(CH,),&N (n = 2-5)] n-alkanes [CH3(CH2),-,CH3 (m = 6, 7)] or cyclohexane [C8H121.
+
+
+
+
+
+
+
Experlmental Section The enthalpies of mixing have been measured with use of a Tian-Calvet ("CRMT") type calorimeter manually tilted. The batch mixing cell and the experimental procedure are described elsewhere (75). The calorimeter was calibrated by Joule effect, and the calibration was repeated after each experiment. The reliability of the apparatus and procedure adopted were checked by performing HE measurements on the test system benzene cyclohexane. Our results differed by
