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Thermodynamics of n-octane+hexynes binary mixtures
Fluid Phase Equilibria 167 Ž2000. 83–97 www.elsevier.nlrlocaterfluid
Thermodynamics of n-octaneq hexynes binary mixtures Ghenima Boukais-Belaribi ´
a, )
, Brahim Farid Belaribi
a,1
, Ahmed Ait-Kaci a , Jacques Jose
b
a
Laboratoire de Thermodynamique des Melanges Organiques (LTMO), Institut de Chimie, USTHB, BP 32 El-Alia, 16111 ´ Bab Ezzouar, Algeria b Laboratoire de Chimie Analytique I (LICAS), UniÕersite´ Claude Bernard (Lyon I), 43, BlÕd du 11 NoÕembre 1918, 69622 Villeurbanne, France Received 28 May 1999; accepted 30 September 1999
Abstract The vapor pressures of binary mixtures of n-octaneq hex-2-yne, or hex-3-yne and of the three pure components were measured by means of a static device at temperatures between 263 and 343 K. Molar excess Gibbs energies G E were calculated for several constant temperatures, taking into account the vapor phase imperfection in terms of the second molar virial coefficients, and were fitted to the Redlich–Kister equation. Calorimetric excess enthalpy H E measurements for n-octaneq hex-2-yne, qhex-3-yne, or qhex-1-yne are also reported at 303.15 K. These data, along with previous vapor–liquid equilibrum data for the n-octaneq hex1-yne mixture, are examined on the basis of DISQUAC, an extended quasichemical group-contribution model. In terms of DISQUAC, the mixtures studied were characterized by only one type of contact: aliphaticralkyne. The interchange coefficients are not available in the literature, and are estimated in this work. The model consistently describes the excess functions G E and H E of the investigated n-octaneq alkynes mixtures. q 2000 Elsevier Science B.V. All rights reserved. Keywords: Vapor–liquid equilibria; Excess enthalpy; DISQUAC model; n-Alkanes; Alkynes
1. Introduction The present paper continues our investigations on vapor–liquid equilibria Ž VLE. and excess enthalpies H E in alkyne q n-alkane or qn-alkan-1-ol binary mixtures, studying the effect of the chain of the n-alkane or the n-alkan-1-ol, and of the position of carbon–carbon triple bond in the alkyne, on the thermodynamic excess properties of these mixtures w1–6x. A survey of the literature revealed that experimental VLE and H E data on binary mixtures of alkynesq n-alkanes are very scarce. In effect, the VLE data are limited to those published by ) 1
Corresponding author. Tel.: q33-213-2-24-7912; fax: q33-213-2-24-7913; e-mail: [email protected] Also corresponding author.
0378-3812r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved. PII: S 0 3 7 8 - 3 8 1 2 Ž 9 9 . 0 0 3 0 6 - 4
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G. Boukais-Belaribi et al.r Fluid Phase Equilibria 167 (2000) 83–97
Ait-Kaci et al. w1,3x and Belaribi et al. w2x for hex-1-yneq n-heptane, qn-octane or qn-decane, and by Kudryavsteva et al. w7,8x and Otsa et al. w34x for hept-1-yne or hex-1-yneq n-hexane. The H E data available have been determined by Wilhlem et al. w9x, for hex-1-yne or hex-3-yneq n-heptane or qn-decane, by Woycicki and Rhenius w10x, for hex-1-yne or hex-3-yneq n-hexane and hept-1-yneq n-heptane, and by Letcher and Baxter w11x, for hex-1-yneq n-hexane and Otsa et al. w12x for hept-1-yneq n-heptane, octaneq oct-1-yne and nonaneq non-1-yne. A previous examination by Wilhelm et al. w9x of some of the very first H E measurements for hex-1-yne, or hex-3-yneq n-heptane or qn-decane mixtures, was made using the group-contribution model of Kehiaian et al. w13,14x in the random-mixing approximation. The purpose of the present work is to investigate VLE and excess enthalpy H E in binary mixtures of n-octaneq hex-2-yne, qhex-3-yne or qhex-1-yne, and to examine the applicability of the DISQUAC model w15,16x to the results. 2. Experimental technique The experimental vapor pressure, P, was measured with an apparatus described previously in detail by Blondel-Telouk et al. w17x, as a function of the temperature, T, for given constant values of the mole fraction composition, x i . The apparatus allows measurements in the P range from 27 to 200 = 10 3 Pa and from 258.15 to 468.15 K. Vapor pressures are measured by means of pressure gauges ŽRosemount, Model 1151DPE 22S2, Minneapolis, MN, USA. , protected by a differential pressure indicator Ž MKS, Model 615D, MKS Instruments, USA. . The pressure gauges were checked periodically by means of an Hg or oil manometer and a Bouty ŽParis, France. Type 70298 cathetometer, readings accurate to within 1 Pa. The temperature of the oil thermostat was maintained constant to within 0.01 K and was measured by means of a copper–constantan thermocouple calibrated against a Leeds and Northrup standard Pt resistance thermometer 8163-B, provided with the national Bureau of Standards ŽWashington, DC, USA. certificate, and connected to a Mueller type G2 bridge Ž precision 10y4 V . . All temperatures are on ITS-90. The estimated uncertainties in P and T are, respectively: s Ž P . s 0.15P Žif P - 13.3 Pa. , s Ž P . s 0.05P Žin the range 13.3 - P - 200 Pa., s Ž P . s 0.005P Žin the range 200 - P - 1000 Pa., s Ž P . s 0.002P Žin the range 1000 - P - 200 = 10 3 Pa., and s Ž T . s 0.01 K. Mixtures were prepared by mass and thoroughly degassed by distillation as described by BlondelTelouk et al. w17x. The final composition of the liquid was determined after each measurement of P by GLC on a column filled with Carbowax as stationary phase, using a thermal conductivity detector. The experimental H E data were taken at atmospheric pressure by means of a microcalorimeter, model C80 ŽSETARAM, Lyon, France. . The temperature T ŽITS-90. was maintained constant at Ž303.15 " 0.02. K. Check measurements on cyclohexaneq benzene are in agreement to within 3% Žover the entire range of concentration. with the data reported by Marsh w18x. The estimated uncertainties in the mole fraction composition x i and H E are, respectively, s Ž x i . s 0.0002 and s Ž H E . s 5 J moly1. 3. Materials The chemical substances were supplied by E. Merck Ž Darmstad, Germany. , Fluka Chemie Ž Buchs, Switzerland., Aldrich Chem. ŽMiwaukee, WI, USA. and Lancaster Synthesis Ž Bischheim-Strasbourg,
G. Boukais-Belaribi et al.r Fluid Phase Equilibria 167 (2000) 83–97
85
France. and were used without further purification. The mole fraction purities, tested by GLC, were: hex-1-yne Ž Merck, ) 0.99. , n-octane Ž Fluka ) 0.995., hex-2-yne ŽAldrich, ; 0.99. and hex-3-yne ŽLancaster, ; 0.99. .
4. Results Table 1 lists, for the pure components n-octane, hex-2-yne and hex-3-yne, the vapor pressures measured in this work, between 263 and 343 K, together with the molar volumes extrapolated from the densities w19–21x and the second molar virial coefficients estimated by the method of Tsonopoulos w22,23x using the literature data for acentric factor and critical properties of pure compounds w19–21x. Our vapor pressure data for the pure liquid components agree with those reported in the literature w24–29x. Table 2 gives, for hex-2-yne or hex-3-yneq n-octane mixtures, experimental data for total vapor pressures at different temperatures together with the corresponding compositions of the liquid and vapor phases, the activity coefficients g 1 and g 2 , and the values of the excess molar Gibbs energies G E calculated by Barker’s method w30x, using the Redlich–Kister equation Ž 1. : ny1 E
G rRT s x 1Ž 1 y x 1 .
A i Ž2 x 1 y 1.
Ý
i
Ž1.
is0
where x 1 is the molar fraction of the alkyne. Table 3 lists the values of the parameters A i and the standard deviation for the pressure. All binary mixtures exhibit positive deviations. The G E values, calculated from our vapor pressure data, of the mixtures containing hex-2-yne or hex-3-yne are of the same order of magnitude. The mixture containing hex-1-yne has a much greater G E w2x. The G E curves are slightly asymmetrical for hex-2-yne or hex-3-yneq n-octane mixtures.
Table 1 Molar volumes V U Ž10y6 m3 moly1 ., vapor pressures P U ŽkPa. and second molar virial coefficients, Bii Ž10y6 m3 moly1 . for pure compounds T ŽK.
n-octane V
263.15 273.15 283.15 293.15 298.15 303.15 313.15 323.15 333.15 343.15
U
157 159 161 163 164 165 166 168 170 172
Hex-2-yne P
U
0.193 0.399 0.774 1.421 1.890 2.484 4.160 6.703 10.439 15.785
U
Bii
V
y7993 y6686 y5682 y4896 y4567 y4272 y3768 y3356 y3013 y2725
108 109 111 112 113 114 115 117 118 120
P
Hex-3-yne U
1.393 2.608 4.631 7.845 10.051 12.753 19.986 30.316 44.662 64.092
Bii
VU
PU
Bii
y2679 y2364 y2109 y1999 y1899 y1723 y1575 y1447 y1336 y1238
109 112 112 114 115 116 117 118 120 121
1.613 3.001 5.293 8.909 11.377 14.388 22.403 33.766 49.436 70.515
y2575 y2276 y2034 y1929 y1834 y1666 y1523 y1401 y1294 y1200
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Table 2 Values of the vapor pressure P ŽkPa., relative deviations D P s100 Ž P y Pcal .r P, activity coefficients g 1 and g 2 and excess molar Gibbs energies G E ŽJ moly1 . T ŽK.
x1
Hex-2-yne (1)q n-octane (2) 263.15 0.2454 0.3948 0.5769 0.6750 0.7572 273.15 0.2454 0.3948 0.5769 0.6750 0.7572 283.15 0.2454 0.3948 0.5769 0.6750 0.7572 293.15 0.2454 0.3948 0.5769 0.6750 0.7572 298.15 0.2454 0.3948 0.5769 0.6750 0.7572 303.15 0.2454 0.3948 0.5769 0.6750 0.7572 313.15 0.2454 0.3948 0.5769 0.6750 0.7572 323.15 0.2454 0.3948 0.5769 0.6750 0.7572 333.15 0.2454 0.3948 0.5769 0.6750 0.7572
y1
P
DP
g1
g2
GE
0.7407 0.8372 0.9032 0.9287 0.9474 0.7134 0.8171 0.8922 0.9214 0.9426 0.6886 0.7983 0.8818 0.9145 0.9381 0.6664 0.7810 0.8718 0.9079 0.9337 0.6263 0.7729 0.8671 0.9047 0.9315 0.6468 0.7651 0.8624 0.9016 0.9294 0.6295 0.7507 0.8533 0.8954 0.9253 0.6144 0.7375 0.8446 0.8894 0.9211 0.6013 0.7256 0.8360 0.8835 0.9169
0.573 0.758 0.956 1.052 1.133 1.087 1.416 1.784 1.963 2.118 1.961 2.519 3.167 3.485 3.762 3.386 4.294 5.377 5.920 6.388 4.382 5.526 6.902 7.601 8.198 5.618 7.048 8.777 9.670 10.421 9.001 11.180 13.835 15.252 16.404 13.969 17.197 21.131 23.314 25.012 21.067 25.730 31.375 34.646 37.058
0.00 y0.01 0.06 y0.11 0.07 0.00 y0.02 0.10 y0.18 0.11 0.00 y0.02 0.11 y0.19 0.12 0.00 y0.02 0.09 y0.16 0.10 0.00 y0.02 0.07 y0.13 0.08 0.00 y0.01 0.05 y0.09 0.06 0.00 0.00 0.00 0.00 0.00 y0.00 0.01 y0.07 0.12 y0.07 y0.01 0.03 y0.14 0.25 y0.14
1.2437 1.1556 1.0749 1.0405 1.0196 1.2139 1.1250 1.0580 1.0298 1.0128 1.1920 1.1025 1.0458 1.0227 1.0089 1.1769 1.0866 1.0372 1.0184 1.0071 1.1717 1.0807 1.0341 1.0170 1.0068 1.1679 1.0761 1.0316 1.0162 1.0069 1.1644 1.0703 1.0284 1.0158 1.0081 1.1658 1.0684 1.0270 1.0166 1.0103 1.1716 1.0699 1.0272 1.0185 1.0132
1.0323 1.0684 1.1450 1.2092 1.2724 1.0443 1.0815 1.1467 1.1998 1.2508 1.0518 1.0899 1.1457 1.1894 1.2306 1.0556 1.0944 1.1432 1.1789 1.2123 1.0563 1.0956 1.1416 1.1738 1.2039 1.0564 1.0961 1.1399 1.1690 1.1961 1.0548 1.0957 1.1366 1.1602 1.1824 1.0513 1.0936 1.1335 1.1528 1.1712 1.0463 1.0904 1.0309 1.1469 1.1622
170 213 217 194 161 182 213 205 180 146 191 213 196 168 135 197 213 189 160 128 199 213 187 157 125 200 213 185 155 124 202 214 183 153 123 203 216 184 154 125 202 219 187 158 129
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Table 2 Žcontinued. y1
P
DP
g1
g2
GE
Hex-2-yne (1)q n-octane (2) 343.15 0.2454 0.3948 0.5769 0.6750 0.7572
0.5899 0.7146 0.8277 0.8775 0.9127
30.960 37.539 45.408 50.187 53.505
y0.01 0.05 y0.22 0.39 y0.23
1.1814 1.0742 1.0285 1.0212 1.0167
1.0401 1.0864 1.1292 1.1426 1.1555
201 224 193 164 137
Hex-3-yne (1)q n-octane (2) 263.15 0.2180 0.3885 0.5508 0.6851 0.7637 273.15 0.2180 0.3885 0.5508 0.6851 0.7637 283.15 0.2180 0.3885 0.5508 0.6851 0.7337 293.15 0.2180 0.3885 0.5508 0.6851 0.7337 298.15 0.2180 0.3885 0.5508 0.6851 0.7337 303.15 0.2180 0.3885 0.5508 0.6851 0.7337 313.15 0.2180 0.3885 0.5508 0.6851 0.7337 323.15 0.2180 0.3885 0.5508 0.6851 0.7337
0.7524 0.8532 0.9061 0.9386 0.9553 0.7275 0.8381 0.8968 0.9329 0.9513 0.7035 0.8231 0.8876 0.9272 0.9473 0.6806 0.8083 0.8784 0.9215 0.9433 0.6695 0.8011 0.8738 0.9186 0.9412 0.6586 0.7938 0.8692 0.9157 0.9392 0.6376 0.7795 0.8599 0.9098 0.9350 0.6176 0.7654 0.8507 0.9039 0.9308
0.617 0.862 1.064 1.220 1.311 1.160 1.610 1.982 2.276 2.446 2.073 2.855 3.507 4.027 4.326 3.542 4.835 5.927 6.798 7.302 4.560 6.196 7.587 8.694 9.339 5.816 7.865 9.620 11.012 11.828 9.215 12.341 15.064 17.198 18.472 14.145 18.754 22.844 25.997 27.924
y0.22 0.16 0.21 y0.07 y0.29 y0.18 0.16 0.11 y0.01 y0.22 y0.13 0.13 0.06 y0.01 y0.17 y0.09 0.08 0.05 y0.00 y0.12 y0.07 0.05 0.06 y0.01 y0.09 y0.04 0.02 0.08 y0.02 y0.07 0.00 y0.05 0.13 y0.06 y0.03 0.05 y0.14 0.19 y0.12 0.00
1.3259 1.1735 1.0832 1.0373 1.0200 1.2955 1.1575 1.0755 1.0338 1.0181 1.2699 1.1440 1.0689 1.0308 1.0164 1.2483 1.1324 1.0632 1.0282 1.0150 1.2387 1.1272 1.0606 1.0270 1.0143 1.2299 1.1224 1.0582 1.0258 1.0137 1.2141 1.1136 1.0539 1.0238 1.0125 1.2005 1.1058 1.0497 1.0218 1.0114
1.0269 1.0826 1.1617 1.2455 1.3019 1.0249 1.0760 1.1480 1.2234 1.2736 1.0232 1.0704 1.1363 1.2047 1.2499 1.0217 1.0656 1.1264 1.1888 1.2298 1.0210 1.0635 1.1220 1.1818 1.2208 1.0204 1.0615 1.1179 1.1753 1.2125 1.0194 1.0581 1.1107 1.1636 1.1977 1.0185 1.0552 1.1046 1.1536 1.1848
180 242 244 206 169 172 231 232 196 161 165 221 222 187 153 159 212 213 179 147 156 209 209 176 144 154 205 205 172 141 149 199 198 166 136 146 193 192 161 131
T ŽK.
x1
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Table 2 Žcontinued. T ŽK.
x1
Hex-3-yne (1)q n-octane (2) 333.15 0.2180 0.3885 0.5508 0.6851 0.7337 343.15 0.2180 0.3885 0.5508 0.6851 0.7337
y1
P
DP
g1
g2
GE
0.5984 0.7515 0.8414 0.8978 0.9264 0.5801 0.7377 0.8320 0.8917 0.9220
21.098 27.691 33.659 38.171 41.002 30.665 39.840 48.327 54.599 58.652
0.10 y0.22 0.28 y0.18 0.04 0.15 y0.32 0.37 y0.25 0.07
1.1887 1.0990 1.0461 1.0200 1.0104 1.1785 1.0928 1.0427 1.0183 1.0094
1.0178 1.0529 1.0994 1.1450 1.1737 1.0173 1.0509 1.0950 1.1376 1.1638
143 189 187 156 127 140 185 182 151 123
Table 3 Coefficients A i and standard deviations, s ŽkPa. for least-squares representation by Eq. Ž1. T ŽK. 263.15 273.15 283.15 293.15 298.15 303.15 313.15 323.15 333.15 343.15
Hex-2-yne Ž1.q n-octane Ž2.
Hex-3-yne Ž1.q n-octane Ž2.
A1
A2
A3
A4
s
A1
A2
s
0.40537 0.37830 0.35472 0.33501 0.32664 0.31931 0.30775 0.30009 0.29615 0.29575
0.00043 y0.05553 y0.09468 y0.12066 y0.12968 y0.13644 y0.14431 y0.14622 y0.14363 y0.13776
0.01129 0.04934 0.07725 0.09641 0.10306 0.10792 0.11271 0.11155 0.10508 0.09392
y0.07863 y0.10838 y0.11832 y0.11235 y0.10440 y0.09355 y0.06430 y0.02662 0.01792 0.06794
0.001 0.002 0.003 0.002 0.002 0.002 0.000 0.002 0.003 0.005
0.45497 0.41730 0.38495 0.35702 0.34447 0.33278 0.31166 0.29319 0.27697 0.26267
y0.04900 y0.04710 y0.04548 y0.04425 y0.04381 y0.04350 y0.04325 y0.04356 y0.04445 y0.04593
0.002 0.003 0.004 0.005 0.005 0.005 0.011 0.027 0.060 0.119
Table 4 Experimental molar excess enthalpies H E at 303.15 K Hex-1-yne Ž1.q n-octaneŽ2. E
Hex-3-yne Ž1.q n-octane Ž2. E
Hex-2-yne Ž1.q n-octane Ž2.
x1
H ŽJ mol
x1
H ŽJ mol
x1
H E ŽJ moly1 .
0.1020 0.1845 0.1931 0.2972 0.3693 0.4822 0.5005 0.5723 0.6335 0.7084 0.7950 0.8425 0.8861 0.9335
222 368 383 538 615 675 680 667 630 570 465 370 289 180
0.1643 0.2375 0.3731 0.4301 0.4837 0.5229 0.6454 0.7940 0.8609
248 345 450 476 485 480 439 316 249
0.0980 0.1781 0.2492 0.2643 0.3746 0.4008 0.5010 0.5030 0.6023 0.6603 0.7038 0.7412 0.8100 0.9079
165 255 308 323 380 390 409 406 390 365 342 305 238 112
y1 .
y1 .
G. Boukais-Belaribi et al.r Fluid Phase Equilibria 167 (2000) 83–97
89
Table 5 Coefficients a i and standard deviations, s Ž H E . for least-squares representation by Eq. Ž2. of H E at 303.15 K Mixtures
a1
a2
a3
a4
a5
s Ž H E . ŽJ moly1 .
Hex-1-yne Ž1.q n-octane Ž2. Hex-2-yne Ž1.q n-octane Ž2. Hex-3-yne Ž1.q n-octane Ž2.
2709.930 1629.671 1929.049
181.429 77.580 y98.7727
y370.613 y8.5288 y40.5376
190.612 y593.440 545.346
387.160
3 2 4
Table 6 Relative group increments for molecular volumes, rG sVG rVCH 4 , and areas, qG s A G rA CH 4 , calculated by Bondi method w33x ŽVCH s17.12=10y6 m 3 moly1 ; A CH s 2.90=10y5 m2 moly1 . 4 4 Group
rG
qG
–H –CH 3 –CH 2 – –C[C–
0.20094 0.79848 0.59755 0.94042
0.26552 0.73103 0.46552 0.67580
Experimental molar excess enthalpies H E of the binary mixtures are listed in Table 4. The results have been fitted to the smoothing equation: ny1
HiE, exp s x 1 Ž 1 y x 1 .
Ý ai Ž2 x 1 y 1.
i
Ž2.
is0
The values of the coefficients a i and the standard deviations s Ž H E . are given by: 1r2
N E
s ŽH .s
Ýž
HiE, exp y HiE, cal
2
/ rŽ N y n.
Ž3.
is1
where N is the number of experimental points and n the number of coefficients a i ; they are determined by least-square analysis and are reported in Table 5. The experimental H E values of the mixtures containing hex-2-yne or hex-3-yne are of the same order of magnitude. A somewhat larger H E in the case of hex-3-yne, as observed, compared to
Table 7 Volumes ri , total surfaces qi , and molecular surface fractions a s i calculated from the group increments rG and qG given in Table 6 Compound
ri
qi
aa i
aki
n-Hexane n-Heptane n-octane n-Decane Hex-1-yne Hex-2-yne Hex-3-yne
3.9872 4.5847 5.1823 6.3774 3.7325 3.7325 3.7325
3.3241 3.7897 4.2552 5.1862 3.0689 3.0689 3.0689
1.0000 1.0000 1.0000 1.0000 0.7798 0.7798 0.7798
0.0000 0.0000 0.0000 0.0000 0.2202 0.2202 0.2202
90
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Table 8 DIS QUAC Ž Interchange coefficients, dispersive Cak,l and quasichemical Cak,l , l s1, Gibbs energy; l s 2, enthalpy. for contact Ža,k. ŽType a, CH 3 , CH 2 or H in n-alkanes or alkynes; Type k, C[C in alkynes.. The coordination number used for the QUAC part is z s 4 System
DIS Cak,1
DIS Cak,2
QUAC Cak,1
QUAC Cak,2
Hex-3-yne Ž1.q n-octane Hex-2-yne Ž1.q n-octane Hex-1-yne Ž1.q n- octane
2.30 2.20 2.30
4.55 3.80 4.55
0 0 0.60
0 0 1.55
hex-2-yne, may be due to the inductive effect of the ethyl group on the triple bond. The mixture containing hex-1-yne has a much greater H E , as observed, for the G E values. The H E values estimated from the temperature dependence of the G E follow the same trend and are in agreement with experimental results, considering that the quantitative evaluation of H E from vapor pressure data involves great uncertainty w31x. Our H E data for alkyne q n-octane binary mixtures, are in agreement with the H E data determined by Wilhlem et al. w9x, for hex-1-yne or hex-3-yneq n-heptane or qn-decane mixtures and by Woycicki and Rhenius w10x, for hex-1-yne or hex-3-yneq n-hexane mixtures.
5. Theory Hex-1-yne, hex-2-yne or hex-3-yneq n-octane systems are regarded as possessing two types of surface: Ži. type a ŽCH 3 , CH 2 groups in n-octane, hex-2-yne or hex-3-yne, together with H group in Table 9 Molar excess Gibbs energies G E and excess molar enthalpies H E of hex-3-yne, hex-2-yne or hex-1-yneq n-octane mixtures at temperature T and equimolar composition: comparison of direct experimental results Žexp.. with calculated values Žcalc.., using the interchange coefficients from Table 8 Mixture Hex-1-yne Ž1.q n-hexane Ž2. Hex-1-yne Ž1.q n-heptane Ž2. Hex-1-yne Ž1.q n-octane Ž2. Hex-1-yne Ž1.q n-decane Ž2. Hex-2-yne Ž1.q n-octane Ž2. Hex-3-yne Ž1.q n-hexane Ž2. Hex-3-yne Ž1.q n-heptane Ž2. Hex-3-yne Ž1.q n-octane Ž2. Hex-3-yne Ž1.q n-decane Ž2. a
From Ref. w10x. From Ref. w9x. c From Ref. w1x. d This work. e From Ref. w2x. b
T ŽK. 298.15 298.15 303.15 298.15 303.15 298.15 298.15 303.15 298.15
G E ŽT ; x 1 s 0.5. ŽJ moly1 .
H E ŽT ; x 1 s 0.5. ŽJ moly1 .
Calc.
Exp.
Calc.
Exp.
– – 275 253 199 – – 209 –
– – 265c 276 e 201d – – 210 d –
603 642 675 732 407 436 464 488 529
592 a 647 b 680 d 748 b 409 d 421a 454 b 482 d 554 b
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hex-1-yne. and Ž ii. type k ŽC[C group in alkynes.. The two types of surface, a and k, generate the single type of contact, Ž ak.. The equations used to calculate excess Gibbs energies, G E and H E are the same as in other publications w15,32x. The temperature dependence of the interaction parameters is expressed in terms DIS QUAC of the dispersive ŽDIS. or quasichemical Ž QUAC. interchange coefficients C st,1 and C st,1 , where Ž . Ž . s,t s a or k and l s 1 Gibbs energy or l s 2 enthalpy . Heat capacity coefficients, l s 3, have not been considered.
Fig. 1. Comparison of theory with experiment for the molar excess Gibbs energy G E and the molar excess enthalpy H E , at 303.15 K, of hex-3-yne Ž1.q n-octane Ž2. mixtures versus x 1, the mole fraction of hex-3-yne. Full lines, predicted values using DISQUAC; points, experimental results; G E Ž`. Žthis work.; H E Ž^. Žthis work..
92
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6. Assessment of geometrical parameters The relative molecular volumes, ri , the surfaces, qi , and the surface fractions, as i , of all the molecular species have been calculated on the basis of the group volumes and surfaces recommended by Bondi w33x, taking arbitrarily the volume and surface of methane as unity w13,14x. The applied values are shown in Tables 6 and 7.
Fig. 2. Comparison of theory with experiment for the molar excess Gibbs energy G E and the molar excess enthalpy H E , at 303.15 K, of hex-2-yne Ž1.q n-octane Ž2. mixtures versus x 1, the mole fraction of hex-2-yne. Full lines, predicted values using DISQUAC; points, experimental results; G E Ž`. Žthis work.; H E Ž^. Žthis work..
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7. Estimation of the interaction parameters We first estimated the dispersive interchange coefficients of the contact Ž ak. using the experimental G and H E data, at equimolar composition and 303.15 K, of hex-2-yneq n-octane and hex-3-yneq n-octane, mixtures. All quasichemical interchange coefficients were assumed equal to zero. As expected, there is little difference between the dispersive interchange coefficients of the contact Žak. in hex-3-yne and hex-2-yne. E
Fig. 3. Comparison of theory with experiment for the molar excess Gibbs energy G E and the molar excess enthalpy H E , at 303.15 K, of hex-1-yne Ž1.q n-octane Ž2. mixtures versus x 1, the mole fraction of hex-1-yne. Full lines, predicted values using DISQUAC; points, experimental results; G E Ž`. w1x; H E Ž^. Žthis work..
94
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Using the Ža,k.-contact dispersive parameters in hex-3-yne, we then adjusted the quasichemical interchange coefficients of this contact, on molar excess enthalpy and free Gibbs energy data, at equimolar composition and 303.15 K, of hex-1-yneq n-octane mixture. These quasichemical coefficients have been adjusted to reproduce as well as possible the concentration dependence of the experimental G E and H E curves. The non-zero quasichemical contribution in the case of hex-1-yne is due to weak H-bonding. For the quasichemical part, the coordination number is z s 4. Table 8 lists the final coefficients.
Fig. 4. Comparison of theory with experiment for the molar excess enthalpy H E , at 298.15 K, of hex-3-yne Ž1.q n-alkane Ž2. mixtures versus x 1, the mole fraction of hex-3-yne. Full lines, predicted values using DISQUAC; points, experimental results: hexane ŽU . w10x; heptane Ž`. w9x; decane ŽI. w9x.
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8. Comparison with experiment and discussion We examined the influence of the position of carbon–carbon triple bond in the alkyne, and, as expected, we found that hex-3-yne and hex-2-yne present the same behavior. We noted also that there is a sizeable difference with hex-1-yne. We then examined the effect of the chain of the n-alkane and we found that H E s of hex-3-yneq nalkane and hex-1-yneq n-alkane Žhexane w10x, heptane and decane w9x., are well represented using the sets of parameters, adjusted on hex-3-yneq n-octane and hex-1-yneq n-octane, respectively.
Fig. 5. Comparison of theory with experiment for the molar excess enthalpy H E , at 298.15 K, of hex-1-yne Ž1.q n-alkane Ž2. mixtures versus x 1, the mole fraction of hex-1-yne. Full lines, predicted values using DISQUAC; points, experimental results: hexane ŽU . w10x; heptane Ž`. w9x; decane ŽI. w9x.
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Using structure-dependent parameters, the model describes consistently the excess functions G E and H E of the investigated n-alkaneq alkyne mixtures. A comparison between experimental data and DISQUAC results is collected in Table 9 and is presented in a graphical way in Figs. 1–5. List of symbols C Interchange coefficient G Molar Gibbs energy H Molar enthalpy T Temperature P Pressure N Number of experimental points q Relative molecular area r Relative molecular volume s Contact surface x Molar fraction in liquid phase Greek letters a Molecular surface fraction s Standard deviation Superscripts E DIS QUAC Subscripts a,k i l
Excess properties Dispersive term Quasichemical term Type of contact surface: a, H, CH 3 , CH 2 ; k, C[C Type of molecule Order of interchange coefficient: l s 1, Gibbs energy; l s 2,enthalpy
References w1x w2x w3x w4x w5x w6x w7x w8x w9x w10x w11x w12x w13x
A. Ait-Kaci, J. Jose, G. Belaribi, Int. Data Ser., Sel. Data Mixtures, Ser. A 2 Ž1989. 105–107. B.F. Belaribi, A. Ait-Kaci, J. Jose, Int. Data Ser., Sel. Data Mixtures, Ser. A 1 Ž1991. 74–76. A. Ait-Kaci, G. Belaribi, C. Michout-Saucet, J. Jose, Int. Data Ser., Sel. Data Mixtures, Ser. A 1 Ž1992. 32–34. G. Belaribi-Boukais, A. Ait-Kaci, H. Delepine, J. Jose, ELDATA: Int. Electron. J. Phys.-Chem. Data 3 Ž1997. 109–118. G. Belaribi-Boukais, A. Ait-Kaci, I. Mokbel, J. Jose, ELDATA: Int. Electron. J. Phys.-Chem. Data 3 Ž1997. 173–182. G. Belaribi-Boukais, A. Ait-Kaci, I. Mokbel, J. Jose, ELDATA: Int. Electron. J. Phys.-Chem. Data 3 Ž1997. 205–214. L.S. Kudryavtseva, K. Viit, O.G. Eisen, Eesti NSV Tead. Akad. Toim., Keem., Geol. 17 Ž1968. 242. L.S. Kudryavtseva, M. Toome, E. Otsa, Eesti NSV Tead. Akad. Toim., Keem. 30 Ž2. Ž1981. . E. Wilhelm, A. Inglese, J.P.E. Grolier, H.V. Kehiaian, Monatsh. Chem. 109 Ž1978. 235–243. W. Woycicki, P. Rhenius, J. Chem. Thermodyn. 11 Ž1979. 153–159. T.M. Letcher, R. Baxter, J. Chem. Thermodyn. 19 Ž1987. 321–326. E. Otsa, L.S. Kudryavtseva, O.G. Eisen, Monatsh. Chem. 111 Ž1980. 37–42. H.V. Kehiaian, K. Sosnkowska-Kehiaian, R. Hryniewicz, J. Chim. Phys. 68 Ž1971. 922.
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w14x w15x w16x w17x w18x w19x w20x w21x w22x w23x w24x w25x w26x w27x w28x w29x w30x w31x w32x w33x w34x
97
H.V. Kehiaian, J.-P.E. Grolier, G.C. Benson, J. Chim. Phys. 15 Ž1978. 1031–1041. H.V. Kehiaian, Fluid Phase Equilib. 13 Ž1983. 243–252. H.V. Kehiaian, Pure Appl. Chem. 57 Ž1985. 15–30. A. Blondel-Telouk, H. Loiseleur, A. Barreau, E. Behar, J. Jose, Fluid Phase Equilib. 10 Ž1995. 315–339. K.N. Marsh, Int. Data Ser., Sel. Data Mixtures, Ser. A 1 Ž1973. 1–3. TRC, TRC Thermodynamic Tables-Hydrocarbons, Thermodynamic Research Center, Texas A&M University, College Station, TX, USA, 1957 Žloose-leaf data sheets, extant.. TRC, TRC Thermodynamic Tables — Hydrocarbons, Thermodynamic Research Center, Texas A&M University, College Station, TX, USA, 1966 Žloose-leaf data sheets, extant.. R.C. Reid, J.M. Prausnitz, B.E. Poling, The Properties of Gas and Liquids, 4th edn., McGraw-Hill, New York, USA, 1987, pp. 1–742 ŽISBN 0-07-051799-1.. C. Tsonopoulos, AICHE J. 20 Ž1974. 263. C. Tsonopoulos, AICHE J. 21 Ž1975. 827. R. Dreisbach, Physical properties of chemical compounds — II, Adv. Chem. Ser. 22 Ž1959. 1–491. J. Dykyj, M. Repas, The Vapor Pressure of Pure Organic Compounds, Slovak Academy of Sciences, Bratislava, 1979, pp. 1–516 Žin Slovak.. D.R. Lide, H.V. Kehiaian, CRC Handbook of Thermophysical and Thermochemical Data, CRC Press, Boca Raton, FL, USA, 1994, pp. 1–518 ŽISBN 0-8493-0197-1.. L. Negadi, T. Guetachew, A. Ait-Kaci, J. Jose, ELDATA: Int. Electron. J. Phys.-Chem. Data 3 Ž1997. 91–100. TRC, TRC Thermodynamic Tables — Hydrocarbons, Thermodynamic Research Center, Texas A&M University, College Station, TX, USA, 1968 Žloose-leaf data sheets, extant.. TRC, TRC Thermodynamic Tables — Hydrocarbons, Thermodynamic Research Center, Texas A&M University, College Station, TX, USA, 1988 Žloose-leaf data sheets, extant.. J.A. Barker, Aust. J. Chem. 6 Ž1953. 207. J.S. Rowlinson, F.L. Swinton, Liquids and Liquid Mixtures, 3rd edn., Butterworth, London, 1982, p. 183. M.R. Tine, ´ H.V. Kehiaian, Fluid Phase Equilib. 32 Ž1987. 211–248. A. Bondi, Physical Properties of Molecular Crystals, Liquids and Glasses, Wiley, New York, 1968. E. Otsa, L.S. Kudryavtseva, O.G. Eisen, O. Piotrovskaya, Monatsh. Chem. 111 Ž1980. 607–617.
Thermodynamics of n-octaneq hexynes binary mixtures Ghenima Boukais-Belaribi ´
a, )
, Brahim Farid Belaribi
a,1
, Ahmed Ait-Kaci a , Jacques Jose
b
a
Laboratoire de Thermodynamique des Melanges Organiques (LTMO), Institut de Chimie, USTHB, BP 32 El-Alia, 16111 ´ Bab Ezzouar, Algeria b Laboratoire de Chimie Analytique I (LICAS), UniÕersite´ Claude Bernard (Lyon I), 43, BlÕd du 11 NoÕembre 1918, 69622 Villeurbanne, France Received 28 May 1999; accepted 30 September 1999
Abstract The vapor pressures of binary mixtures of n-octaneq hex-2-yne, or hex-3-yne and of the three pure components were measured by means of a static device at temperatures between 263 and 343 K. Molar excess Gibbs energies G E were calculated for several constant temperatures, taking into account the vapor phase imperfection in terms of the second molar virial coefficients, and were fitted to the Redlich–Kister equation. Calorimetric excess enthalpy H E measurements for n-octaneq hex-2-yne, qhex-3-yne, or qhex-1-yne are also reported at 303.15 K. These data, along with previous vapor–liquid equilibrum data for the n-octaneq hex1-yne mixture, are examined on the basis of DISQUAC, an extended quasichemical group-contribution model. In terms of DISQUAC, the mixtures studied were characterized by only one type of contact: aliphaticralkyne. The interchange coefficients are not available in the literature, and are estimated in this work. The model consistently describes the excess functions G E and H E of the investigated n-octaneq alkynes mixtures. q 2000 Elsevier Science B.V. All rights reserved. Keywords: Vapor–liquid equilibria; Excess enthalpy; DISQUAC model; n-Alkanes; Alkynes
1. Introduction The present paper continues our investigations on vapor–liquid equilibria Ž VLE. and excess enthalpies H E in alkyne q n-alkane or qn-alkan-1-ol binary mixtures, studying the effect of the chain of the n-alkane or the n-alkan-1-ol, and of the position of carbon–carbon triple bond in the alkyne, on the thermodynamic excess properties of these mixtures w1–6x. A survey of the literature revealed that experimental VLE and H E data on binary mixtures of alkynesq n-alkanes are very scarce. In effect, the VLE data are limited to those published by ) 1
Corresponding author. Tel.: q33-213-2-24-7912; fax: q33-213-2-24-7913; e-mail: [email protected] Also corresponding author.
0378-3812r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved. PII: S 0 3 7 8 - 3 8 1 2 Ž 9 9 . 0 0 3 0 6 - 4
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Ait-Kaci et al. w1,3x and Belaribi et al. w2x for hex-1-yneq n-heptane, qn-octane or qn-decane, and by Kudryavsteva et al. w7,8x and Otsa et al. w34x for hept-1-yne or hex-1-yneq n-hexane. The H E data available have been determined by Wilhlem et al. w9x, for hex-1-yne or hex-3-yneq n-heptane or qn-decane, by Woycicki and Rhenius w10x, for hex-1-yne or hex-3-yneq n-hexane and hept-1-yneq n-heptane, and by Letcher and Baxter w11x, for hex-1-yneq n-hexane and Otsa et al. w12x for hept-1-yneq n-heptane, octaneq oct-1-yne and nonaneq non-1-yne. A previous examination by Wilhelm et al. w9x of some of the very first H E measurements for hex-1-yne, or hex-3-yneq n-heptane or qn-decane mixtures, was made using the group-contribution model of Kehiaian et al. w13,14x in the random-mixing approximation. The purpose of the present work is to investigate VLE and excess enthalpy H E in binary mixtures of n-octaneq hex-2-yne, qhex-3-yne or qhex-1-yne, and to examine the applicability of the DISQUAC model w15,16x to the results. 2. Experimental technique The experimental vapor pressure, P, was measured with an apparatus described previously in detail by Blondel-Telouk et al. w17x, as a function of the temperature, T, for given constant values of the mole fraction composition, x i . The apparatus allows measurements in the P range from 27 to 200 = 10 3 Pa and from 258.15 to 468.15 K. Vapor pressures are measured by means of pressure gauges ŽRosemount, Model 1151DPE 22S2, Minneapolis, MN, USA. , protected by a differential pressure indicator Ž MKS, Model 615D, MKS Instruments, USA. . The pressure gauges were checked periodically by means of an Hg or oil manometer and a Bouty ŽParis, France. Type 70298 cathetometer, readings accurate to within 1 Pa. The temperature of the oil thermostat was maintained constant to within 0.01 K and was measured by means of a copper–constantan thermocouple calibrated against a Leeds and Northrup standard Pt resistance thermometer 8163-B, provided with the national Bureau of Standards ŽWashington, DC, USA. certificate, and connected to a Mueller type G2 bridge Ž precision 10y4 V . . All temperatures are on ITS-90. The estimated uncertainties in P and T are, respectively: s Ž P . s 0.15P Žif P - 13.3 Pa. , s Ž P . s 0.05P Žin the range 13.3 - P - 200 Pa., s Ž P . s 0.005P Žin the range 200 - P - 1000 Pa., s Ž P . s 0.002P Žin the range 1000 - P - 200 = 10 3 Pa., and s Ž T . s 0.01 K. Mixtures were prepared by mass and thoroughly degassed by distillation as described by BlondelTelouk et al. w17x. The final composition of the liquid was determined after each measurement of P by GLC on a column filled with Carbowax as stationary phase, using a thermal conductivity detector. The experimental H E data were taken at atmospheric pressure by means of a microcalorimeter, model C80 ŽSETARAM, Lyon, France. . The temperature T ŽITS-90. was maintained constant at Ž303.15 " 0.02. K. Check measurements on cyclohexaneq benzene are in agreement to within 3% Žover the entire range of concentration. with the data reported by Marsh w18x. The estimated uncertainties in the mole fraction composition x i and H E are, respectively, s Ž x i . s 0.0002 and s Ž H E . s 5 J moly1. 3. Materials The chemical substances were supplied by E. Merck Ž Darmstad, Germany. , Fluka Chemie Ž Buchs, Switzerland., Aldrich Chem. ŽMiwaukee, WI, USA. and Lancaster Synthesis Ž Bischheim-Strasbourg,
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France. and were used without further purification. The mole fraction purities, tested by GLC, were: hex-1-yne Ž Merck, ) 0.99. , n-octane Ž Fluka ) 0.995., hex-2-yne ŽAldrich, ; 0.99. and hex-3-yne ŽLancaster, ; 0.99. .
4. Results Table 1 lists, for the pure components n-octane, hex-2-yne and hex-3-yne, the vapor pressures measured in this work, between 263 and 343 K, together with the molar volumes extrapolated from the densities w19–21x and the second molar virial coefficients estimated by the method of Tsonopoulos w22,23x using the literature data for acentric factor and critical properties of pure compounds w19–21x. Our vapor pressure data for the pure liquid components agree with those reported in the literature w24–29x. Table 2 gives, for hex-2-yne or hex-3-yneq n-octane mixtures, experimental data for total vapor pressures at different temperatures together with the corresponding compositions of the liquid and vapor phases, the activity coefficients g 1 and g 2 , and the values of the excess molar Gibbs energies G E calculated by Barker’s method w30x, using the Redlich–Kister equation Ž 1. : ny1 E
G rRT s x 1Ž 1 y x 1 .
A i Ž2 x 1 y 1.
Ý
i
Ž1.
is0
where x 1 is the molar fraction of the alkyne. Table 3 lists the values of the parameters A i and the standard deviation for the pressure. All binary mixtures exhibit positive deviations. The G E values, calculated from our vapor pressure data, of the mixtures containing hex-2-yne or hex-3-yne are of the same order of magnitude. The mixture containing hex-1-yne has a much greater G E w2x. The G E curves are slightly asymmetrical for hex-2-yne or hex-3-yneq n-octane mixtures.
Table 1 Molar volumes V U Ž10y6 m3 moly1 ., vapor pressures P U ŽkPa. and second molar virial coefficients, Bii Ž10y6 m3 moly1 . for pure compounds T ŽK.
n-octane V
263.15 273.15 283.15 293.15 298.15 303.15 313.15 323.15 333.15 343.15
U
157 159 161 163 164 165 166 168 170 172
Hex-2-yne P
U
0.193 0.399 0.774 1.421 1.890 2.484 4.160 6.703 10.439 15.785
U
Bii
V
y7993 y6686 y5682 y4896 y4567 y4272 y3768 y3356 y3013 y2725
108 109 111 112 113 114 115 117 118 120
P
Hex-3-yne U
1.393 2.608 4.631 7.845 10.051 12.753 19.986 30.316 44.662 64.092
Bii
VU
PU
Bii
y2679 y2364 y2109 y1999 y1899 y1723 y1575 y1447 y1336 y1238
109 112 112 114 115 116 117 118 120 121
1.613 3.001 5.293 8.909 11.377 14.388 22.403 33.766 49.436 70.515
y2575 y2276 y2034 y1929 y1834 y1666 y1523 y1401 y1294 y1200
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86
Table 2 Values of the vapor pressure P ŽkPa., relative deviations D P s100 Ž P y Pcal .r P, activity coefficients g 1 and g 2 and excess molar Gibbs energies G E ŽJ moly1 . T ŽK.
x1
Hex-2-yne (1)q n-octane (2) 263.15 0.2454 0.3948 0.5769 0.6750 0.7572 273.15 0.2454 0.3948 0.5769 0.6750 0.7572 283.15 0.2454 0.3948 0.5769 0.6750 0.7572 293.15 0.2454 0.3948 0.5769 0.6750 0.7572 298.15 0.2454 0.3948 0.5769 0.6750 0.7572 303.15 0.2454 0.3948 0.5769 0.6750 0.7572 313.15 0.2454 0.3948 0.5769 0.6750 0.7572 323.15 0.2454 0.3948 0.5769 0.6750 0.7572 333.15 0.2454 0.3948 0.5769 0.6750 0.7572
y1
P
DP
g1
g2
GE
0.7407 0.8372 0.9032 0.9287 0.9474 0.7134 0.8171 0.8922 0.9214 0.9426 0.6886 0.7983 0.8818 0.9145 0.9381 0.6664 0.7810 0.8718 0.9079 0.9337 0.6263 0.7729 0.8671 0.9047 0.9315 0.6468 0.7651 0.8624 0.9016 0.9294 0.6295 0.7507 0.8533 0.8954 0.9253 0.6144 0.7375 0.8446 0.8894 0.9211 0.6013 0.7256 0.8360 0.8835 0.9169
0.573 0.758 0.956 1.052 1.133 1.087 1.416 1.784 1.963 2.118 1.961 2.519 3.167 3.485 3.762 3.386 4.294 5.377 5.920 6.388 4.382 5.526 6.902 7.601 8.198 5.618 7.048 8.777 9.670 10.421 9.001 11.180 13.835 15.252 16.404 13.969 17.197 21.131 23.314 25.012 21.067 25.730 31.375 34.646 37.058
0.00 y0.01 0.06 y0.11 0.07 0.00 y0.02 0.10 y0.18 0.11 0.00 y0.02 0.11 y0.19 0.12 0.00 y0.02 0.09 y0.16 0.10 0.00 y0.02 0.07 y0.13 0.08 0.00 y0.01 0.05 y0.09 0.06 0.00 0.00 0.00 0.00 0.00 y0.00 0.01 y0.07 0.12 y0.07 y0.01 0.03 y0.14 0.25 y0.14
1.2437 1.1556 1.0749 1.0405 1.0196 1.2139 1.1250 1.0580 1.0298 1.0128 1.1920 1.1025 1.0458 1.0227 1.0089 1.1769 1.0866 1.0372 1.0184 1.0071 1.1717 1.0807 1.0341 1.0170 1.0068 1.1679 1.0761 1.0316 1.0162 1.0069 1.1644 1.0703 1.0284 1.0158 1.0081 1.1658 1.0684 1.0270 1.0166 1.0103 1.1716 1.0699 1.0272 1.0185 1.0132
1.0323 1.0684 1.1450 1.2092 1.2724 1.0443 1.0815 1.1467 1.1998 1.2508 1.0518 1.0899 1.1457 1.1894 1.2306 1.0556 1.0944 1.1432 1.1789 1.2123 1.0563 1.0956 1.1416 1.1738 1.2039 1.0564 1.0961 1.1399 1.1690 1.1961 1.0548 1.0957 1.1366 1.1602 1.1824 1.0513 1.0936 1.1335 1.1528 1.1712 1.0463 1.0904 1.0309 1.1469 1.1622
170 213 217 194 161 182 213 205 180 146 191 213 196 168 135 197 213 189 160 128 199 213 187 157 125 200 213 185 155 124 202 214 183 153 123 203 216 184 154 125 202 219 187 158 129
G. Boukais-Belaribi et al.r Fluid Phase Equilibria 167 (2000) 83–97
87
Table 2 Žcontinued. y1
P
DP
g1
g2
GE
Hex-2-yne (1)q n-octane (2) 343.15 0.2454 0.3948 0.5769 0.6750 0.7572
0.5899 0.7146 0.8277 0.8775 0.9127
30.960 37.539 45.408 50.187 53.505
y0.01 0.05 y0.22 0.39 y0.23
1.1814 1.0742 1.0285 1.0212 1.0167
1.0401 1.0864 1.1292 1.1426 1.1555
201 224 193 164 137
Hex-3-yne (1)q n-octane (2) 263.15 0.2180 0.3885 0.5508 0.6851 0.7637 273.15 0.2180 0.3885 0.5508 0.6851 0.7637 283.15 0.2180 0.3885 0.5508 0.6851 0.7337 293.15 0.2180 0.3885 0.5508 0.6851 0.7337 298.15 0.2180 0.3885 0.5508 0.6851 0.7337 303.15 0.2180 0.3885 0.5508 0.6851 0.7337 313.15 0.2180 0.3885 0.5508 0.6851 0.7337 323.15 0.2180 0.3885 0.5508 0.6851 0.7337
0.7524 0.8532 0.9061 0.9386 0.9553 0.7275 0.8381 0.8968 0.9329 0.9513 0.7035 0.8231 0.8876 0.9272 0.9473 0.6806 0.8083 0.8784 0.9215 0.9433 0.6695 0.8011 0.8738 0.9186 0.9412 0.6586 0.7938 0.8692 0.9157 0.9392 0.6376 0.7795 0.8599 0.9098 0.9350 0.6176 0.7654 0.8507 0.9039 0.9308
0.617 0.862 1.064 1.220 1.311 1.160 1.610 1.982 2.276 2.446 2.073 2.855 3.507 4.027 4.326 3.542 4.835 5.927 6.798 7.302 4.560 6.196 7.587 8.694 9.339 5.816 7.865 9.620 11.012 11.828 9.215 12.341 15.064 17.198 18.472 14.145 18.754 22.844 25.997 27.924
y0.22 0.16 0.21 y0.07 y0.29 y0.18 0.16 0.11 y0.01 y0.22 y0.13 0.13 0.06 y0.01 y0.17 y0.09 0.08 0.05 y0.00 y0.12 y0.07 0.05 0.06 y0.01 y0.09 y0.04 0.02 0.08 y0.02 y0.07 0.00 y0.05 0.13 y0.06 y0.03 0.05 y0.14 0.19 y0.12 0.00
1.3259 1.1735 1.0832 1.0373 1.0200 1.2955 1.1575 1.0755 1.0338 1.0181 1.2699 1.1440 1.0689 1.0308 1.0164 1.2483 1.1324 1.0632 1.0282 1.0150 1.2387 1.1272 1.0606 1.0270 1.0143 1.2299 1.1224 1.0582 1.0258 1.0137 1.2141 1.1136 1.0539 1.0238 1.0125 1.2005 1.1058 1.0497 1.0218 1.0114
1.0269 1.0826 1.1617 1.2455 1.3019 1.0249 1.0760 1.1480 1.2234 1.2736 1.0232 1.0704 1.1363 1.2047 1.2499 1.0217 1.0656 1.1264 1.1888 1.2298 1.0210 1.0635 1.1220 1.1818 1.2208 1.0204 1.0615 1.1179 1.1753 1.2125 1.0194 1.0581 1.1107 1.1636 1.1977 1.0185 1.0552 1.1046 1.1536 1.1848
180 242 244 206 169 172 231 232 196 161 165 221 222 187 153 159 212 213 179 147 156 209 209 176 144 154 205 205 172 141 149 199 198 166 136 146 193 192 161 131
T ŽK.
x1
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88
Table 2 Žcontinued. T ŽK.
x1
Hex-3-yne (1)q n-octane (2) 333.15 0.2180 0.3885 0.5508 0.6851 0.7337 343.15 0.2180 0.3885 0.5508 0.6851 0.7337
y1
P
DP
g1
g2
GE
0.5984 0.7515 0.8414 0.8978 0.9264 0.5801 0.7377 0.8320 0.8917 0.9220
21.098 27.691 33.659 38.171 41.002 30.665 39.840 48.327 54.599 58.652
0.10 y0.22 0.28 y0.18 0.04 0.15 y0.32 0.37 y0.25 0.07
1.1887 1.0990 1.0461 1.0200 1.0104 1.1785 1.0928 1.0427 1.0183 1.0094
1.0178 1.0529 1.0994 1.1450 1.1737 1.0173 1.0509 1.0950 1.1376 1.1638
143 189 187 156 127 140 185 182 151 123
Table 3 Coefficients A i and standard deviations, s ŽkPa. for least-squares representation by Eq. Ž1. T ŽK. 263.15 273.15 283.15 293.15 298.15 303.15 313.15 323.15 333.15 343.15
Hex-2-yne Ž1.q n-octane Ž2.
Hex-3-yne Ž1.q n-octane Ž2.
A1
A2
A3
A4
s
A1
A2
s
0.40537 0.37830 0.35472 0.33501 0.32664 0.31931 0.30775 0.30009 0.29615 0.29575
0.00043 y0.05553 y0.09468 y0.12066 y0.12968 y0.13644 y0.14431 y0.14622 y0.14363 y0.13776
0.01129 0.04934 0.07725 0.09641 0.10306 0.10792 0.11271 0.11155 0.10508 0.09392
y0.07863 y0.10838 y0.11832 y0.11235 y0.10440 y0.09355 y0.06430 y0.02662 0.01792 0.06794
0.001 0.002 0.003 0.002 0.002 0.002 0.000 0.002 0.003 0.005
0.45497 0.41730 0.38495 0.35702 0.34447 0.33278 0.31166 0.29319 0.27697 0.26267
y0.04900 y0.04710 y0.04548 y0.04425 y0.04381 y0.04350 y0.04325 y0.04356 y0.04445 y0.04593
0.002 0.003 0.004 0.005 0.005 0.005 0.011 0.027 0.060 0.119
Table 4 Experimental molar excess enthalpies H E at 303.15 K Hex-1-yne Ž1.q n-octaneŽ2. E
Hex-3-yne Ž1.q n-octane Ž2. E
Hex-2-yne Ž1.q n-octane Ž2.
x1
H ŽJ mol
x1
H ŽJ mol
x1
H E ŽJ moly1 .
0.1020 0.1845 0.1931 0.2972 0.3693 0.4822 0.5005 0.5723 0.6335 0.7084 0.7950 0.8425 0.8861 0.9335
222 368 383 538 615 675 680 667 630 570 465 370 289 180
0.1643 0.2375 0.3731 0.4301 0.4837 0.5229 0.6454 0.7940 0.8609
248 345 450 476 485 480 439 316 249
0.0980 0.1781 0.2492 0.2643 0.3746 0.4008 0.5010 0.5030 0.6023 0.6603 0.7038 0.7412 0.8100 0.9079
165 255 308 323 380 390 409 406 390 365 342 305 238 112
y1 .
y1 .
G. Boukais-Belaribi et al.r Fluid Phase Equilibria 167 (2000) 83–97
89
Table 5 Coefficients a i and standard deviations, s Ž H E . for least-squares representation by Eq. Ž2. of H E at 303.15 K Mixtures
a1
a2
a3
a4
a5
s Ž H E . ŽJ moly1 .
Hex-1-yne Ž1.q n-octane Ž2. Hex-2-yne Ž1.q n-octane Ž2. Hex-3-yne Ž1.q n-octane Ž2.
2709.930 1629.671 1929.049
181.429 77.580 y98.7727
y370.613 y8.5288 y40.5376
190.612 y593.440 545.346
387.160
3 2 4
Table 6 Relative group increments for molecular volumes, rG sVG rVCH 4 , and areas, qG s A G rA CH 4 , calculated by Bondi method w33x ŽVCH s17.12=10y6 m 3 moly1 ; A CH s 2.90=10y5 m2 moly1 . 4 4 Group
rG
qG
–H –CH 3 –CH 2 – –C[C–
0.20094 0.79848 0.59755 0.94042
0.26552 0.73103 0.46552 0.67580
Experimental molar excess enthalpies H E of the binary mixtures are listed in Table 4. The results have been fitted to the smoothing equation: ny1
HiE, exp s x 1 Ž 1 y x 1 .
Ý ai Ž2 x 1 y 1.
i
Ž2.
is0
The values of the coefficients a i and the standard deviations s Ž H E . are given by: 1r2
N E
s ŽH .s
Ýž
HiE, exp y HiE, cal
2
/ rŽ N y n.
Ž3.
is1
where N is the number of experimental points and n the number of coefficients a i ; they are determined by least-square analysis and are reported in Table 5. The experimental H E values of the mixtures containing hex-2-yne or hex-3-yne are of the same order of magnitude. A somewhat larger H E in the case of hex-3-yne, as observed, compared to
Table 7 Volumes ri , total surfaces qi , and molecular surface fractions a s i calculated from the group increments rG and qG given in Table 6 Compound
ri
qi
aa i
aki
n-Hexane n-Heptane n-octane n-Decane Hex-1-yne Hex-2-yne Hex-3-yne
3.9872 4.5847 5.1823 6.3774 3.7325 3.7325 3.7325
3.3241 3.7897 4.2552 5.1862 3.0689 3.0689 3.0689
1.0000 1.0000 1.0000 1.0000 0.7798 0.7798 0.7798
0.0000 0.0000 0.0000 0.0000 0.2202 0.2202 0.2202
90
G. Boukais-Belaribi et al.r Fluid Phase Equilibria 167 (2000) 83–97
Table 8 DIS QUAC Ž Interchange coefficients, dispersive Cak,l and quasichemical Cak,l , l s1, Gibbs energy; l s 2, enthalpy. for contact Ža,k. ŽType a, CH 3 , CH 2 or H in n-alkanes or alkynes; Type k, C[C in alkynes.. The coordination number used for the QUAC part is z s 4 System
DIS Cak,1
DIS Cak,2
QUAC Cak,1
QUAC Cak,2
Hex-3-yne Ž1.q n-octane Hex-2-yne Ž1.q n-octane Hex-1-yne Ž1.q n- octane
2.30 2.20 2.30
4.55 3.80 4.55
0 0 0.60
0 0 1.55
hex-2-yne, may be due to the inductive effect of the ethyl group on the triple bond. The mixture containing hex-1-yne has a much greater H E , as observed, for the G E values. The H E values estimated from the temperature dependence of the G E follow the same trend and are in agreement with experimental results, considering that the quantitative evaluation of H E from vapor pressure data involves great uncertainty w31x. Our H E data for alkyne q n-octane binary mixtures, are in agreement with the H E data determined by Wilhlem et al. w9x, for hex-1-yne or hex-3-yneq n-heptane or qn-decane mixtures and by Woycicki and Rhenius w10x, for hex-1-yne or hex-3-yneq n-hexane mixtures.
5. Theory Hex-1-yne, hex-2-yne or hex-3-yneq n-octane systems are regarded as possessing two types of surface: Ži. type a ŽCH 3 , CH 2 groups in n-octane, hex-2-yne or hex-3-yne, together with H group in Table 9 Molar excess Gibbs energies G E and excess molar enthalpies H E of hex-3-yne, hex-2-yne or hex-1-yneq n-octane mixtures at temperature T and equimolar composition: comparison of direct experimental results Žexp.. with calculated values Žcalc.., using the interchange coefficients from Table 8 Mixture Hex-1-yne Ž1.q n-hexane Ž2. Hex-1-yne Ž1.q n-heptane Ž2. Hex-1-yne Ž1.q n-octane Ž2. Hex-1-yne Ž1.q n-decane Ž2. Hex-2-yne Ž1.q n-octane Ž2. Hex-3-yne Ž1.q n-hexane Ž2. Hex-3-yne Ž1.q n-heptane Ž2. Hex-3-yne Ž1.q n-octane Ž2. Hex-3-yne Ž1.q n-decane Ž2. a
From Ref. w10x. From Ref. w9x. c From Ref. w1x. d This work. e From Ref. w2x. b
T ŽK. 298.15 298.15 303.15 298.15 303.15 298.15 298.15 303.15 298.15
G E ŽT ; x 1 s 0.5. ŽJ moly1 .
H E ŽT ; x 1 s 0.5. ŽJ moly1 .
Calc.
Exp.
Calc.
Exp.
– – 275 253 199 – – 209 –
– – 265c 276 e 201d – – 210 d –
603 642 675 732 407 436 464 488 529
592 a 647 b 680 d 748 b 409 d 421a 454 b 482 d 554 b
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hex-1-yne. and Ž ii. type k ŽC[C group in alkynes.. The two types of surface, a and k, generate the single type of contact, Ž ak.. The equations used to calculate excess Gibbs energies, G E and H E are the same as in other publications w15,32x. The temperature dependence of the interaction parameters is expressed in terms DIS QUAC of the dispersive ŽDIS. or quasichemical Ž QUAC. interchange coefficients C st,1 and C st,1 , where Ž . Ž . s,t s a or k and l s 1 Gibbs energy or l s 2 enthalpy . Heat capacity coefficients, l s 3, have not been considered.
Fig. 1. Comparison of theory with experiment for the molar excess Gibbs energy G E and the molar excess enthalpy H E , at 303.15 K, of hex-3-yne Ž1.q n-octane Ž2. mixtures versus x 1, the mole fraction of hex-3-yne. Full lines, predicted values using DISQUAC; points, experimental results; G E Ž`. Žthis work.; H E Ž^. Žthis work..
92
G. Boukais-Belaribi et al.r Fluid Phase Equilibria 167 (2000) 83–97
6. Assessment of geometrical parameters The relative molecular volumes, ri , the surfaces, qi , and the surface fractions, as i , of all the molecular species have been calculated on the basis of the group volumes and surfaces recommended by Bondi w33x, taking arbitrarily the volume and surface of methane as unity w13,14x. The applied values are shown in Tables 6 and 7.
Fig. 2. Comparison of theory with experiment for the molar excess Gibbs energy G E and the molar excess enthalpy H E , at 303.15 K, of hex-2-yne Ž1.q n-octane Ž2. mixtures versus x 1, the mole fraction of hex-2-yne. Full lines, predicted values using DISQUAC; points, experimental results; G E Ž`. Žthis work.; H E Ž^. Žthis work..
G. Boukais-Belaribi et al.r Fluid Phase Equilibria 167 (2000) 83–97
93
7. Estimation of the interaction parameters We first estimated the dispersive interchange coefficients of the contact Ž ak. using the experimental G and H E data, at equimolar composition and 303.15 K, of hex-2-yneq n-octane and hex-3-yneq n-octane, mixtures. All quasichemical interchange coefficients were assumed equal to zero. As expected, there is little difference between the dispersive interchange coefficients of the contact Žak. in hex-3-yne and hex-2-yne. E
Fig. 3. Comparison of theory with experiment for the molar excess Gibbs energy G E and the molar excess enthalpy H E , at 303.15 K, of hex-1-yne Ž1.q n-octane Ž2. mixtures versus x 1, the mole fraction of hex-1-yne. Full lines, predicted values using DISQUAC; points, experimental results; G E Ž`. w1x; H E Ž^. Žthis work..
94
G. Boukais-Belaribi et al.r Fluid Phase Equilibria 167 (2000) 83–97
Using the Ža,k.-contact dispersive parameters in hex-3-yne, we then adjusted the quasichemical interchange coefficients of this contact, on molar excess enthalpy and free Gibbs energy data, at equimolar composition and 303.15 K, of hex-1-yneq n-octane mixture. These quasichemical coefficients have been adjusted to reproduce as well as possible the concentration dependence of the experimental G E and H E curves. The non-zero quasichemical contribution in the case of hex-1-yne is due to weak H-bonding. For the quasichemical part, the coordination number is z s 4. Table 8 lists the final coefficients.
Fig. 4. Comparison of theory with experiment for the molar excess enthalpy H E , at 298.15 K, of hex-3-yne Ž1.q n-alkane Ž2. mixtures versus x 1, the mole fraction of hex-3-yne. Full lines, predicted values using DISQUAC; points, experimental results: hexane ŽU . w10x; heptane Ž`. w9x; decane ŽI. w9x.
G. Boukais-Belaribi et al.r Fluid Phase Equilibria 167 (2000) 83–97
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8. Comparison with experiment and discussion We examined the influence of the position of carbon–carbon triple bond in the alkyne, and, as expected, we found that hex-3-yne and hex-2-yne present the same behavior. We noted also that there is a sizeable difference with hex-1-yne. We then examined the effect of the chain of the n-alkane and we found that H E s of hex-3-yneq nalkane and hex-1-yneq n-alkane Žhexane w10x, heptane and decane w9x., are well represented using the sets of parameters, adjusted on hex-3-yneq n-octane and hex-1-yneq n-octane, respectively.
Fig. 5. Comparison of theory with experiment for the molar excess enthalpy H E , at 298.15 K, of hex-1-yne Ž1.q n-alkane Ž2. mixtures versus x 1, the mole fraction of hex-1-yne. Full lines, predicted values using DISQUAC; points, experimental results: hexane ŽU . w10x; heptane Ž`. w9x; decane ŽI. w9x.
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Using structure-dependent parameters, the model describes consistently the excess functions G E and H E of the investigated n-alkaneq alkyne mixtures. A comparison between experimental data and DISQUAC results is collected in Table 9 and is presented in a graphical way in Figs. 1–5. List of symbols C Interchange coefficient G Molar Gibbs energy H Molar enthalpy T Temperature P Pressure N Number of experimental points q Relative molecular area r Relative molecular volume s Contact surface x Molar fraction in liquid phase Greek letters a Molecular surface fraction s Standard deviation Superscripts E DIS QUAC Subscripts a,k i l
Excess properties Dispersive term Quasichemical term Type of contact surface: a, H, CH 3 , CH 2 ; k, C[C Type of molecule Order of interchange coefficient: l s 1, Gibbs energy; l s 2,enthalpy
References w1x w2x w3x w4x w5x w6x w7x w8x w9x w10x w11x w12x w13x
A. Ait-Kaci, J. Jose, G. Belaribi, Int. Data Ser., Sel. Data Mixtures, Ser. A 2 Ž1989. 105–107. B.F. Belaribi, A. Ait-Kaci, J. Jose, Int. Data Ser., Sel. Data Mixtures, Ser. A 1 Ž1991. 74–76. A. Ait-Kaci, G. Belaribi, C. Michout-Saucet, J. Jose, Int. Data Ser., Sel. Data Mixtures, Ser. A 1 Ž1992. 32–34. G. Belaribi-Boukais, A. Ait-Kaci, H. Delepine, J. Jose, ELDATA: Int. Electron. J. Phys.-Chem. Data 3 Ž1997. 109–118. G. Belaribi-Boukais, A. Ait-Kaci, I. Mokbel, J. Jose, ELDATA: Int. Electron. J. Phys.-Chem. Data 3 Ž1997. 173–182. G. Belaribi-Boukais, A. Ait-Kaci, I. Mokbel, J. Jose, ELDATA: Int. Electron. J. Phys.-Chem. Data 3 Ž1997. 205–214. L.S. Kudryavtseva, K. Viit, O.G. Eisen, Eesti NSV Tead. Akad. Toim., Keem., Geol. 17 Ž1968. 242. L.S. Kudryavtseva, M. Toome, E. Otsa, Eesti NSV Tead. Akad. Toim., Keem. 30 Ž2. Ž1981. . E. Wilhelm, A. Inglese, J.P.E. Grolier, H.V. Kehiaian, Monatsh. Chem. 109 Ž1978. 235–243. W. Woycicki, P. Rhenius, J. Chem. Thermodyn. 11 Ž1979. 153–159. T.M. Letcher, R. Baxter, J. Chem. Thermodyn. 19 Ž1987. 321–326. E. Otsa, L.S. Kudryavtseva, O.G. Eisen, Monatsh. Chem. 111 Ž1980. 37–42. H.V. Kehiaian, K. Sosnkowska-Kehiaian, R. Hryniewicz, J. Chim. Phys. 68 Ž1971. 922.
G. Boukais-Belaribi et al.r Fluid Phase Equilibria 167 (2000) 83–97
w14x w15x w16x w17x w18x w19x w20x w21x w22x w23x w24x w25x w26x w27x w28x w29x w30x w31x w32x w33x w34x
97
H.V. Kehiaian, J.-P.E. Grolier, G.C. Benson, J. Chim. Phys. 15 Ž1978. 1031–1041. H.V. Kehiaian, Fluid Phase Equilib. 13 Ž1983. 243–252. H.V. Kehiaian, Pure Appl. Chem. 57 Ž1985. 15–30. A. Blondel-Telouk, H. Loiseleur, A. Barreau, E. Behar, J. Jose, Fluid Phase Equilib. 10 Ž1995. 315–339. K.N. Marsh, Int. Data Ser., Sel. Data Mixtures, Ser. A 1 Ž1973. 1–3. TRC, TRC Thermodynamic Tables-Hydrocarbons, Thermodynamic Research Center, Texas A&M University, College Station, TX, USA, 1957 Žloose-leaf data sheets, extant.. TRC, TRC Thermodynamic Tables — Hydrocarbons, Thermodynamic Research Center, Texas A&M University, College Station, TX, USA, 1966 Žloose-leaf data sheets, extant.. R.C. Reid, J.M. Prausnitz, B.E. Poling, The Properties of Gas and Liquids, 4th edn., McGraw-Hill, New York, USA, 1987, pp. 1–742 ŽISBN 0-07-051799-1.. C. Tsonopoulos, AICHE J. 20 Ž1974. 263. C. Tsonopoulos, AICHE J. 21 Ž1975. 827. R. Dreisbach, Physical properties of chemical compounds — II, Adv. Chem. Ser. 22 Ž1959. 1–491. J. Dykyj, M. Repas, The Vapor Pressure of Pure Organic Compounds, Slovak Academy of Sciences, Bratislava, 1979, pp. 1–516 Žin Slovak.. D.R. Lide, H.V. Kehiaian, CRC Handbook of Thermophysical and Thermochemical Data, CRC Press, Boca Raton, FL, USA, 1994, pp. 1–518 ŽISBN 0-8493-0197-1.. L. Negadi, T. Guetachew, A. Ait-Kaci, J. Jose, ELDATA: Int. Electron. J. Phys.-Chem. Data 3 Ž1997. 91–100. TRC, TRC Thermodynamic Tables — Hydrocarbons, Thermodynamic Research Center, Texas A&M University, College Station, TX, USA, 1968 Žloose-leaf data sheets, extant.. TRC, TRC Thermodynamic Tables — Hydrocarbons, Thermodynamic Research Center, Texas A&M University, College Station, TX, USA, 1988 Žloose-leaf data sheets, extant.. J.A. Barker, Aust. J. Chem. 6 Ž1953. 207. J.S. Rowlinson, F.L. Swinton, Liquids and Liquid Mixtures, 3rd edn., Butterworth, London, 1982, p. 183. M.R. Tine, ´ H.V. Kehiaian, Fluid Phase Equilib. 32 Ž1987. 211–248. A. Bondi, Physical Properties of Molecular Crystals, Liquids and Glasses, Wiley, New York, 1968. E. Otsa, L.S. Kudryavtseva, O.G. Eisen, O. Piotrovskaya, Monatsh. Chem. 111 Ž1980. 607–617.