OCTOBER, 1940
INDUSTRIAL AND ENGINEERING CHEMISTRY
1351
could be obtained for the glycol eleostearate for reasons previously mentioned. The general nature of these curves does not differ appreciably from those obtained with the methyl esters.
after about 50 hours of exposure became soluble again after slightly over 100 hours of exposure, probably as a result of oxidative decomposition. The changes occurring in the density of the esters are shown in Figure 13. The similarity to the viscosity curves is at once apparent. It was impossible to obtain reliable density values with the micropycnometer after the esters had become highly viscous. Because of its peculiar semisolid nature, glycol eleostearate could not be measured a t all. The specific refraction values calculated from the refractive index and density measurements with the aid of the Lorentz-Lorenz equation are shown in Figure 14. No values
Acknowledgment The assistance of J. G. Smull, Lehigh University, and E. P. Clocker who prepared the esters used in this investigation, and of A. J. Farber of this laboratory who did most of the experimental work is gratefully acknowledged. PRESENTED before the Division of Paint and Varnish Chemistry a t t h r 99th Meeting of the .imerican Chemical Socictv. Cincinnati, Ohio.
Solubilitv of Methane in Cvclohexane J
J
E. P. SCHOCH, A. E. HOFFMANN, F. D. MAYFIELD
AND
The University of Texas, .4ust,in, Texas
The solubilities of methane in cyclohexane corresponding to pressures u p to the critical pressures and at temperatures of 100.27', 160°, and 220' F. are reported in the form of bubblepoint data. Specific volumes of the liquid phases, together with their compressibilities up to 6000 pounds per square inch, are reported.
I
temperatures of this study were determined by means of the weighing bottle shown in Figure 1, together with the injection portion of the previously described apparatus (3). For these determinations the weighing bottle was attached to the injection cell through a needle valve, and pump and pressure readings at equilibrium were recorded for a presYure of 800 pounds per square inch absolute and the temperature of the determination. After the weighing Iiottle was evacuated, 20 to 30 cc. of cyclohexane were forced out of the injection cell into the weighing bottle through the .lightly opened needle valve by means of the pump. The needle valve was then closed, and another equilibrium pump and pressure reading a t 800 pounds per aquare inch was recorded. The bulb of the weighing bottle was then immersed in ice until the cyclohexane was frozen and completely distilled over into the bulb. The mass of the cyclohexane forced out of the injection cell was determined by weighing the weighing bottle in the usual manner, and the volume of the cyclohexane a t 800 pounds per square inch corresponding to the mass forced out was obtained from the difference in the two pump readings together with the pump piston calibration. Duplicate determinations were made, and the proper buoyancy corrections were applied to the weighings. The densities thus obtained were employed in the calculations of F~~~~~ 1. 1$rEIGHING B~~~~~ FOR the injections and are presented in CYCLOHEXANE DEMITYSTUDIES Table I.
N A PREVIOUS paper (3) the writers described an apparatus and experimental procedure for the determination of high-pressure P-V-2'-X relations for two-component hydrocarbon systems, and presented bubble-point data on the methane-benzene system a t 100.27" F. The present paper presents similar data on the methane-cyclohexane system a t 100.27", 160°, and 220" F. The experimental data consist of the determined solubilities of methane in cyclohexane, together with the densities and compressibilities of the resultant solutions up to pressures of 6000 pounds per square inch. Two previous reports on this system are found in the literature. Sage, Webster, and Lacey (2') reported results similar to thoseof this paper, but their data are limited to two compositions at each temperature and to maximum pressures of 3000 pounds per square inch. Frolich and co-workers (1) presented data at 77" F. with a reported accuracy of *5.0 per cent.
Apparatus and Procedure The apparatus and experimental procedure have already been described ( 3 ) . In the previous work ( 3 ) the density of benzene a t 800 pounds per square inch could be obtained from the literature. However, no similar data on cyclohexane are available, and the densities of cyclohexane a t 800 pounds per square inch had to be determined in order to calculate the injections made into the equilibrium bomb. These densities at the three
INDUSTRIAL AND ENGINEERING CHEMISTRY
1352
TABLEI. ABSOLVFEDENSITIES OF CYCLOHEXANE hT 800 POUNDS PER SQUARE INCH ABSOLUTE PRESSURE Temp. F.
Abs. Density Gram/cc.
Temp.
100.27
0.7647 0.7649 0.7652 Av. 0.7649
160.00
F.
Abs. Density Gram/cc.
Temp. Abs. Density F. Gram/cc.
0.7366 0.7361 Av. 0.7363
220.00
0.7061 0.7050 Av. 0.7056
VOL. 32, NO. 10
The temperatures of the study were determined as previousb described ( 3 ) ; however, the 160' and 220" F. values are believed to be accurate only to *0.05', as compared to *0.01' for the 100.27" F. value.
Purification of Materials The purification of the methane has already been described (3). The cyclohexane data presented in this paper ~~~~~
~
~
~
VOLUMES OF METHANE-CYCLOHEXANE TABLE111. SPECIFICVOLUMESOF METHANE-CYCLOHEXANE TABLE 11. SPECIFIC MIXTURES MIXTURESAT 100.27' F. AT 160" F. Abs. Pressure, Lb./ Sq. In.
Sp. Vol., Cu. Ft./Lb.
11.85 Mole %, 2 . 5 0
Mass % Methane, Run 1 6000 5500 5000 4500 4000 3500 3000 2500 2000 1500 1000 900 800 700 60Za 598 59 1 586 580
38.33 Mole
0,02091 0.02097 0.02104 0.02111 0,02118 0.02125 0.02133 0.02142 0.02150 0.02160 0.02169 0.02171 0.02173 0.02175 0.02178 0.02185 0.02195 0.02205 0.02215
'?&, 10.59
Mass yo Methane; Run 1 6000 5500 5000 4500 4000 3500 3000 2500 2400 2300 2200 214s" 2131 2108 2085 2062
0.02317 0.02328 0.02340 0.02351 0.02363 0.02377 0.02392 0.02408 0.02410 0.02414 0,02417 0.02419 0.02429 0.02442 0.02455 0.02469
Abs. Pressure, Lb./ 8s.In. 2 1 . 6 0 Mole
Sp. Vol., Cu. Ft./Lb.
%, 4.99
Mass % Methane; Run 1
6000 5500 5000 4500 4000 3500 3000 2500 2000 1500 1400 1300 1200 11185 1115 1111 1105 1096
4 5 . 6 1 Mole
0.02158 0.02166 0.02174 0.02181 0.02190 0.02198 0.02208 0.02217 0.02227 0.02238 0.02240 0.02243 0.02245 0.02247 0.02252 0.02259 0.02272 0,02291
yo, 1 3 . 7 8
Mass % Methane: Run 1
6000 5500 5000 4500 4000 3500 3000 2900 2800 2700 2620a 2589 2553 2519 2484
0.02416 0.02431 0.02446 0.02461 0.02476 0.02492 0.02510 0.02513 0.02517 0.02521 0.02524 0.02539 0.02556 0.02573 0.02590
5 8 . 7 0 Mole %, 21.32
Mass % Methane; Run 1
Abs. Pressure, Lb./ Sq. In. Mass
yo,7.54 Yo Methane;
6000 5500 5000 4500 4000 3500 3000 2500 2000 1900 1800 1700 1620a 1602 1589 1565 1540
0.02231 0,02239 0.02248 0,02257 0.02267 0.02278 0.02289 0.02301 0.02313 0.02316 0 02318 0 02321 0.02323 0 02338 0 02348 0 02367 0.02387
29.96 Mole
Run 1
Ei1.17 Mole %, 1 6 . 6 5 Mass % Methane; Run 1 6000 5500 5000 4500 4000 3500 3400 3300 3200. 3100 29726 2944 2900 2858 2814
yo,30.18
Mass % Methane: Run 2
6000 5500 5000 4500 4100 4000 3900 3800 3747= 3680 3608 3556 3504
0.03035 0.03074 0.03115 0.03162 0.03207 0.03220 0.03233 0.03247 0.03255 0.03294 0.03337 0.03369 0.03399
74.14 Mole
96, 35.34
Mass yo Methane; Run 2
6000 5500 5000 4500 4200 4100 4000 3900 3804" 3745 3645 3595 3494
0.03255 0.03307 0.03362 0.03429 0.03477 0.03493 0.03509 0.03528 0.03547 0.03589 0,03662 0.03698 0.03770
0.02511 0.02529 0.02546 0.02565 0,02884 0.02603 0.02608 0.02612 0.02617 0.02622 0.02627 0.02640 0.02660 0.02680 0,02701
Abs. Pressure, Lb./ Sq.In.
Sp. Vol., Cu. Ft./Lb.
11.75 Mole
yo,2 . 4 8
Mass Yo Methane; Run 2
6000 5500 5000 4500 4000 3500 3000 2500 2000 1500 1000 900 800 700 649" 639 627 616 607
0.02159 0.02168 0.02177 0.02186 0.02196 0,02206 0.02217 0,02228 0,02240 0.02252 0.02265 0.02268 0.02271 0.02273 0.02274 0.02286 0.02301 0.02316 0,02329
3 4 . 2 3 Mole %, 9 . 0 3
Mass yo Methane; Run 1
0.02357 0.02371 0.02386 0.02401 0.02418 0.02436 0.02455 0.02477 0.02486 0.02496 0.02491
6000 5500 5000 4500 4000 3500 3000 2500 2300 2200 2100 2030" 1991 1955 1921 1886
0.02499 0,02533 0.02564 0.02595 0,02626
Abs. Pressure, Lb./ Sq. In.
Sp. Vol., Cu. Ft./Lb.
Abs. Pressure, Lb./ Sq. In.
21.65 Mole yo,5 . 0 0
25.99 Mole
Mass % Methane; Run 1
6000 5500 5000 4500 4000 3500 3000 2800 2700 2600 2516a 2471 2426 2367 2337
Run 1
0.02239 0.02250 0.02260 0.02271 0,02283 0.02296 0.02309 0.02323 0.02338 0.02350 0.02383 0.02356 0.02359 0.02362 0.02381 0,02405 0.02436 0.02460
41.66 Mole %, 11.98
yo,6.27
Mass 70Methane;
Mass yo Methane: Run 2
6000 5500 5000 4500 4000 3500 3000 2500 2000 1600 1500 1400 1300 1228" 1207 1182 1149 1123
Sp. Vol., Cu. Ft./Lb.
6000 5500 5000 4800 4000 3500 3000 2500 2000 1800 1700 1600 1521a 1492 1457 1434 1412
0.02270 0.02281 0.02239 0.02305 0.02318 0.02333 0.02348 0.02364 0.02383 0.02390 0.02394 0.02398 0.02401 0.02428 0.02460 0.02482 0.02504
48.12 hlassMole % Methane; %, 15.03
Run 1 6000 5500 5000 4500 4000 3500 3300 3200 3100 3000 2936a 2880 2821 2703 2624
0.02465 0.02482 0.02501 0,02521 0.02542 0.02867 0.02592 0.02604 0.02610 0.02615 0.02620 0.02652 0,02683 0.02724 0.02744
0.02576 0.02598 0,02622 0.02648 0.02676 0.02707 0.02721 0.02729 0.02737 0,02745 0.02751 0.02787 0.02825 0.02902 0.02953
63.30 Mole %, 24.74
Mass % Methane; Run 1
6000 5500 5000 4500 4100 4000 3900 3800 3700 3636a 3600 3550 3500 3450
69.39 Mole
Sp. Vol., Cu. Ft./Lb.
78.10 Mole
0.02825 0.02851 0.02881 0.02912 0.02941 0.02950 0.02957 0.02965 0.02975 0.02981 0.02997 0.03020 0.03041 0.03064
7
Mass
'70Methane; Run 1
6000 5500 5000
4500 4nnn
0.02759 0.02790 0.02825 0 02862 0 02904
63.58 hlole
70,24,97
Mass % Methane; Run 1
6000 5500 5000 4500 4100 4000 3900 3800 3731' 3676 3614 3521 3428
69.16 Mole yo,29.94
Mass yo Methane; Run 1
0.02996 0.03039 0.03088 0.03144 0.03198 0.03217 0.03228 0.03245 0.03257 0.03294 0.03335 0.03398 0.03461
40.47
Mass % it&hane; Run 2
6000 5500 5000 4500 4200 4100 4000 3900 381Sa 3738 3688 3588 3538
56.77 Mole '%, 20.02
0.03525 0.03889 0.03660 0.03747 0.03810 0.03835 0.03861 0.03888 0.03914 0 03979 0,04020 0 04104 0.04145
Denotes bubble-point state. All values below bubble-point state are in the two-phase region.
73.85 Mole
70,35 .OO
hIass % Methane: Run 1
6000 5500 5000 4500 4300 4200 4100 4000 3927a 3852 3785 3652 3585
0,03474 0.03551 0.03640 0.03735 0.03805 0.03833 0.03864 0.03898 0.03926 0.03992 0.04081 0.04167 0.04226
7 8 . 3 8 Mole
lo. 40.87
Mass % Methane; Run 1
6000 5500 5000 4500 ~~. 4200 4100 4000 3950 3905" 3878 3814 3716 3621 ~
0.03788 0.03889 0.04006 0.04158 0,04264 0,04305 0,04353 0.04380 0.04403 0.04432 0.04500 0.04602 0.04705
Denotes bubble-point state. All values below bubble-point state are in the two-phase region. Q
INDUSTRIAL AND ENGl'NEERING CHEMISTRY
OCTOBER, 1940
corresponding to a temperature of 100.27" F. were obtained by using a portion of the =me methane supply employed in the benzene study previously reported (8). A new supply of methane was employed for the 160" and the 220" F. data. For the cyclohexane supply, the best grade of Eastman Kodak Company's cyclohexane was purified by distillation. The freezing point of the final product used was 43.34" I?. (6.3" C.) as compared with values of 43.52" F. (6.4' C.) (6) and 43.646" F. (6.47O C.) (4)reported in the literature.
Results In Table I the absolute densities of cyclohexane at 8oU pounds per square inch are presented. The results of the bubble-point studies, calculated from the experimental data, are given in Tables 11, 111, and IV. These tables present the bubble-point pressures, compositions, and specific volumes, together with the compressibilities of the liquid phases.
Tan1.E Abs. Piesawe, I W
Iv.
SPECrFlC VoLUXEs OF METHANE-CYCLOHEXANE MIXTURES AT 220'
F.
Sp.
Sq.In.
Vol.. Cu. Ft./Lb.
6000 5600
0.02233 O.OJ244
moo
0.02286 0.02208 0.02281 0.02285 0.02309 0.02325 0.02341 0.02360 0.02319 0.02383 0.02387 n ,02391 0.02393 n ,02401
4500 4000 3500 3000 2500 2000 1500
1wO 900
so0 730 683'
680 677 671 669
0.02411
0.02420 0.02430
Aha. P r e r
Lb./ Sa. In.
sure,
Go00
5p. Voi.. Cu.
Ft./Lb.
5500 5000
0.02324 0.02337 0.02351
4500 4000
0.023611
1400 1330
0.02382 0,02399 0.02417 0.02437 0.02459 0.02479 0.02484 0.02489 0.02493
12701259 1245
0.02496 0.02511 0.02530
3600
moo 2500
2000 1600
m o
1231 1219
0.02549
2200 2259 2228
Ft./Lb.
n ,02414
6000
5500 5000 4500
0.02431 0.02448 0.02467 0,02486
4000
3500 3000
50.00 Mole 9 16.01 Mass % Me%tdane; Run I 0.02526 BOOO 0.02750 0.02547 5500 0.027~1 0.02560 5ow 0.02~17 0.02595 4500 0.02~56 0.02621 .inon 0.02900 0 . 0 2 6 ~ ~ 3500 n.ozsa 0.02685 3300 0.02976 0.0270s 32w 0.02988 0.02716 3100 o.08001 0.02725 3022. 0.03012 0.02733 2902 0.03034 0.02738 2941 0.03073 0.02762 2890 0.03111 0.02789 2840 0.03151
Met6ane:
0.02815
Acknowledgment
0.02508
2200
0.02532 0.02559 0.02576
2100
0.02582
2500
2wo
0.02589 0,02595
l9Go 1802' 1786 1765 1726 1709
The authors are indebted to the Humble Oil and Refining Company for a fellowship grant to A. E. Hoffmann.
n.oz6oz
0.02617 0.02636 0.02873 0.02892
Literature Cited (1) Frolioh, P. K., Tauoh, E. J., Hogan, J. J., and Peer, A. A.. IND. ENO.CBEM..73,548 (1931). (2) Sage, B. H., Webster, D. C., and LBDOY. W. N..Ibid., 28, 1045
57.84 Mole %. 20.73 Maaa % Methane; Run I BOW 0.02980 5500 0.03025 5wo 0.0:~075 4500 0.03136 4000 0.03205 3800 0.03239 3700 0.03255 3m 0.03274 3 : w 0.03294 3405s 0.03314 8346 0.03359 3312 0.08383 3248 0,03434 ~~
3215
~
~
(3) Schoch, E. P., Hoffmann. A. E., Kasperik. A. S., Lightfoot, J. H.,and Mayfield, F. D..Zbid.. 32,788 (1940). (4) 9 8 ~ e r .W. F.. Wriuht, M. M., and Bell, R. C..zbid., 31, 759
~_"-",_
llOR4,
( 5 ) Timmermans, J.. and Martin. F.. J . chim. phya., 23,733 (1926).
0.03458
0.02841
66.13 Mole %, 27.12 Maas % Methene; Run 1 6004 0.03284 5.500 0.03353 5000 0.03434 4500 0.03533 4000 0.03656 3900 0.03684 0.03717 3800 0.03752 3700 0.03776 3635" 3572 0.03835 3538 0.03867 3470 0.03932 3436 0.03964
71.75 Mole %. 32.62 Mses % Methane:
Kun 1 6000 0.03596 55w
5000 4500 4000 3900 3800 3700 36743617 3583 351s
3483
0.03689 0.03802 0.03944 0.04124 0.04166 0.04217 0.04271 0.04287 0.04353 0.04393 0.04470 0.04510
77.54 Mole %, 39.69 Msss
6000 5500 5000
% Methane: Run 1
0.04071
4500
0.04202 0.04358 0.04551
4000
0.04812
3900 3800 3700 3667' 3602 3568 349s 3463
0.04872 0.04940 0.05021 n.05031 0.05135 0.05183 0.06278 0.OM26
Denotes bubblrpoint state. All value8 below bubble-point state *re in the two-phase redon. Z .
For comparison, large-scale plots were made of the data of Sage, Webster, and Lacey (2) and of this paper. Bnbblepoint pressure was plotted against mass per cent methane, and bubble-point specific volume against mass per cent niethane. The bubble-point pressures of the two papers agreed within 0.4 per cent, with the exception of the 13.44 per cent methane value of Sage, Webster, and Lacey at 16OO" F. which agreed within 1.1 per cent. The bubble-point specific volumes agreed within 1.0 per cent with the exception of the 13.44 per cent methane value of Sage, Webster, and Lacey at looo F. which agreed within 1.6 per cent. The data of Frolich and eo-workers ( I ) were not considered, since their data were for a temperature of 77" F. All of the fundamental data of Tables 11, 111, and IV can be represented by two diagrams for each table. These are isothermal plots of bubble-point pressure against composition, and isothermal plots of specific volume against pressure. When thus prepared, these plots have the same general a p pearance as those presented in themethane-benzene study (8). The data presented here indicate that the critical state for the methan+cyclnhexane system corresponding to a maximum critical pressure exists at a temperature somewhere between loOOsild 220" F. This becomes apparent when it is noted that the maximum pressure on a bubblepoint pressure-composition isotherm represents the critical state for that temperature, and when it is noted further that the critical pressure for the methane-cyclohexane system at 160"F.isgreater than thecriticalDressuresat lOO"and220"F. This latter fact is evident from &I inspection of the data of Tables 11,111, and IV.
I~.___,. IQXF.~
Run 1
~000 5500 5000 4500 4000 3500 3000 2700 2000 2500 2400 2350n 2320
Vol.. Ca
54. In.
0.02568
38.55 Mole % 10.68 Mean %
SD.
Aha. Pres-
a w e , Lb./
1353
MOLDED Goons MADEFROM BUTYLRUBBER (See page 1283.)
