water contents c a n be achieved by t h i s method by suitable adjustment of temperature and pressure conditions. ACKNOWLEDGMENT
T h e authors express their grateful appreciation to t h e Dreyfus Foundation, Inc., for a grant-in-aid t o Princeton University which provided partial support for t h e conduct of the research investigations on which this paper is based.
-
r
-
YIXER
___C
8ElTLER
do
NOMENCLATURE F = fluid phase existing above critical pressure of ethylenesolvent binary a t temperature of diagram L = single liquid p h a s e existing over entire range of watersolvent compositions, usually a t low ethylene concentrations L, = water-rich or more d e n s e liquid p h a s e L, = solvent-rich or less d e n s e liquid p h a s e P , = low pressure, about 1 to 5 atm. P, Imoderate pressure, below critical pressure of ethylenesolvent binary P , = h i g h pressure, above critical pressure of ethylene-solvent binary S = solvent component of system: ethylene, water, solvent V = vapor (or gas) phase, essentially pure ethylene REFERENCES
ETHYLENE COYCREIIOR
Figure 16. Sehernotic flowsheet for ethylene dehydrotlon of solvents
For t h i s example, t h e theoretical work of isothermal compression required t o supply the necessary amount of ethyle n e (40 pounds) a t t h e system pressure (515 p.s.i.a.) i s 1.5 kw.-hr. Applying conservative values of compressor efficiency(25T) and power cost (1.0 cent per kw.-hr.) t o t h i s figure, o n e arrives a t a magnitude for this portion of t h e operating cost of about 6 c e n t s per 100 pounds of methyl ethyl ketone processed. T h i s c o s t i s approximately equal t o the value of t h e a e t h y l ethyl ketone lost with the discarded water. Undoubtedly dehydration to remarkably small
(1) Carson, D. B., Katz, D. L., Trans. AlME 146, 150 (1941). (2) Diepen, G. A. M., Scheffer, F. E. C., J. Am. Chem. 'SOC. 70, 4081. 4085 (19481 . . (3) Diepen, G. A. M., Scheffcr, F. E C., Rec. trav. chirn. 69, 593. 604 (19.50). (4) Ewell, R. H., Harrison, J. M., Berg, L,Ind. Eng. Chem. 36, 871(1944). (5) Gottschlich, C., M. S. E. thesis, Department of Chemical Engineering, Princeton University, Princeton, N. J., 1 9 5 2 (6) Hammerschmidt, E G., Ind. End. Chem. 26, 8 5 1 (1934). (7) Jaglom, J., M. S E. t h e s i s , Department of Chemical Fngineering, Princeton University, Princeton, N. J., 1951. (8) Meter, D. M., fbid., 1955. (9) Sykes, H. EL, Zbid., 1948. (10)Taylor, H. S , "Treatise on P h y s i c a l Chemistry," vol. I, p. 449, Van Nostrand, New Yo&, 1925. (11) Todd, D. R, Ph. D. dissertation, Department of Chemical Engineering, Princeton University, Princeton, N. J,, 1951.
,
.
,
Received for review April 22, 1958.
Accepted h g u s t 25, 1958.
Phase Behavior of the System U 0 2 S 0 4 - C u S 0 4 -
H z S 0 4 - H 2 0a t Elevated Temperatures F. E. CLARK! J. S. GILL, RUTH SLUSHER, and C. H. SECOY Chemistry Division, Oak Ridgo National Laboratory, Oak Ridge, Tenn. T h e fuel solution proposed for u s e in the second homogeneous reactor experiment a t Oak Ridge w a s a heavy water solution, 0.04 molal in uranyl sulfate and 0.005 molal in copper sulfate. T h e purpose of the copper sulfate w a s to provide for the liquid-phase c a t a l y s i s (I) of t h e deuteriumoxygen recombination reaction, t h u s eliminating problems a s s o c i a t e d with handling large volumes of an explosive mixture of radiolytic g a s in t h e reactor system. Earlier experience with dilute uranyl sulfate solutions had indicated that i n c r e a s e s in temperature promoted hydrolysis of t h e uranyl ion to such an extent that b a s i c s a l t s or hydrated oxides of uranium precipitated. In concentration regions where a hydrolytic precipitate w a s not encountered, t h e t e r n perature limit of homogeneity w a s fixed by t h e appearance of a second liquid p h a s e (3). Posnjak and Tunell (2) have 'Present address, National Carbon R e s e a r c h Laboratories, P. 0. B o x 6116, Cleveland, Ohio.
12
reported s t u d i e s of t h e copper sulfate system t o 200°C. in which analogous promotion of hydrolysis by increased temperatures w a s indicated, the predominant solid p h a s e encountered being the b a s i c copper sulfate, 3Cu0.S0,.2H20. T h e addition of sulfuric acid t o such solutions would be expected to oppose and retard the hydrolysis reaction. Furthermore, t h e addition of acid to uranyl sulfate solutions w a s known to c a u s e t h e liquid miscibility gap (two-liquid phase region) to shrink in scope. T h e effect of sulfuric acid in either c a s e w a s to elevate t h e temperature ceiling on the region of one liquid phase homogeneity. However, u s e of an e x c e s s i v e amount of acid in t h e reactor system w a s objectionable primarily because i t would increase the corrosiveness of t h e solution and secondarily b e c a u s e i t would increase t h e neutron l o s s e s in t h e reactor. T h e work reported here is a systematic determination of t h i s temperature ceiling for a single liquid phase homogeneity a s a function of t h e copper sulfate concentration, the uranyl sulfate JOURNAL OF CHEMICAL AND ENGINEERING DATA
Table
1. Second Liquid Phase Temperatures, O C .
Master solutions. 17.17% CuSo,, 0.00 mole % e x c e s s \SO,;
47.64% U02S0,. 0.00 mole % e x c e s s %SO,
-Weight Ratio, CuSO,/UO,SO, ~ ___ -
Weight Ratio, Solution/H@
8/2
6/4
7i3
5%/4%
5/5
2887
287 286 282.5
a
10/0 9/ 1 8/2 7/3 6/4 5/5 4/6 3/ 7 2/8 1/9 0.75/9.25 0.5/9.5 0.25/9.75
a
e
a
287 286 285.5 285 284.5 285 2 86 288 + 222.5bf and
a a
a a a a
a a
~
3/7
1/9
o/ 10
287.5
289.5
291 290 289 2 88 287 287 287.5 289. 5 293 302.7
4/6
289 292.5 +bb 30%+
b b b
a
'andb
b
h
h
b
312
h
b
"Blue-green solid. bRed-yellow solid.
Table
II. Second Liquid Phase Temperatures, OC.
EXPERIMENTAL
T h e method w a s a synthetic o n e in which solutions of known composition were s e a l e d in short s e c t i o n s of 1-mm. quartz tubing and heated in either an aluminum block furn a c e or a liquid bath. T h e bath liquid w a s a eutectic mixture of t h e nitrates of sodium, potassium, and lithium. Agitation w a s obtained by attaching t h e tubes to a Vibratool operated through a time clock s o that alternate periods of oscillation and rest were obtained. T h e frequency and amplitude of the Vibrato01 w e r e such that the contents of t h e tube were rather violently mixed. Temperature w a s measured by a calibrated iron-Constantan thermocouple. Visual observation of t h e tubes during heating was augmented by t h e u s e of a modified Bausch & Lamb Raliscope. T h i s instrument w a s equipped with e y e p i e c e s to give magnifications of l o x , 20x, and 60x, respectively. I t w a s modified t o give a large field and to h a v e a working dist a n c e of about 4 feet. All solutions used w e r e prepared from two master solutions, one a nearly saturated copper s u l f a t e solution and t h e other a nearly saturated uranyl sulfate solution. F i v e s e t s of submaster solutions w e r e prepared from t h e s e , each s e t having a selected mole per cent e x c e s s of sulfuric acld added to it. By a n a l y s i s followed by adjustment of t h e a c i d content, the mole per cent e x c e s s acid for t h e copper s u l f a t e solutions w a s made precisely t h e same a s that of t h e corresponding uranyl sulfate solution. Weight aliquots
Master solutions. 17.24% CuSO,, 9.91 mole % e x c e s s HSO,; 47.05% UOSO,, 9.91 mole % e x c e s s H S O , Weight Ratio, C u S O J U O S O ,
Weight Ratio, Solution/Hfl 8 / 2 10/0 9/ 1 8/2 7/3 6/4
7/3
5/5
'Blue-green
5/5
4/6
a
a a a
3/7
2/8
1/9
0/10
304.5 305 305.5 307 308.5 305.5 300.5 301 303 300.5 298.5 297.5 297.5 297.5 297 297 296.5 2 98 302 300.5 300.5 309 311 309.5 313 313 3 1 3 313 313 321 320 319 319 319 332 332 3 3 1 331
306.5 305.5 305 305 303 301.5 301.5 300 299.5 297.5 300 299.5 a a a a a a a a a a a a a
e
4/6 3/7 218 1/9 0.75/9.25 0.5/9.5 0.25/9.75
6/4
solid.
concentration, and t h e sulfuric acid concentration. Although emphasis w a s placed on solutions of low concentration, the study w a s intended to include all concentrations which might be of interest in any reactor considerations now or in the future. T h e solvent used in all c a s e s w a s distilled natural water rather than heavy water.
Table
111. Second Liquid Phase Temperatures, 'C.
Master solutions. 16.90% CuSOa 19.25 mole 1 e x c e s s H S O , ; 46.29% U 0 2 S 0 4 , 19.25 mole % e x c e s s H S O l Weight Katio, CuSOJUOsOl Weight Ratio, Solution/H@ 10/0 9/ 1 8/2 7/3 6/4 5/5 4/6 3/7 2/8 1/9 0.75/9.25 0.5/9.5 0.25/9.75 .Blue-green
9/1
8%/l%
8/2
7%/2%
7/3
6%/3%
6/4
326 3;3
324.5
323 320 318
322.5
321.5 318.5
320
320 317 3 14
319 e e
314 314.5 a
solid
VOL. 4, NO. 1, JANUARY 1959
a a a
321
5/5
320
312.5 3 10
31: a
a
a
a
1/9
o/io
321 316.5
321.5
324
324.5
318 325 335
317 323 333
317 322 334
327 322 317 313.5 3 10 307.5 308. 5 306.5 3 10.5 315 317 322 334
307 306.5
312 319
a
2/8
310.5
309.5 a
3/7
309 309.5
-_~--
309.5 317.5 320 325 337
___
-
4/6
313.5
308 a
a a a a
311.5
313 311.5 310.5
5%/4%
306 309 316 319 325 335
~
_______ 13
two-liquid p h a s e region. I t w a s found impossible to determine t h e s e temperatures with any reasonable certainty bec a u s e of t h e slowness with which equilibrium seemed to be established. However, in nearly all c a s e s t h e temperature of appearance of t h e solids, a t l e a s t t h e blue-green solid, w a s far below (IOO'C. or more) t h e two-liquid p h a s e region. T h e solid c r y s t a l s could readily b e classified by color into two groups, blue-green s o l i d s and red-yellow solids. Each c l a s s w a s obtained only i n a specific region of t h e composition diagram: t h e blue-green s o l i d s from solutions with high copper-uranium ratio and t h e red-yellow s o l i d s with low copper-uranium ratio. An i n c r e a s e in sulfuric acid content reduced t h e scope of both regions. Efforts to i s o l a t e c r y s t a l s of t h e s o l i d s for further study produced no reliable information. In most cases the amount of solid available from a specific tube w a s very small, being scarcely visible without t h e a i d of a microscope. Furthermore, t h e stability of t h e s o l i d s when removed from t h e conditions of formation w a s not certain. A s a result of t h e visual observations, however, i t i s believed that there a r e a t l e a s t two solid p h a s e s i n each of the color regions and that o n e of t h e blue-green s o l i d s is probably the well known b a s i c copper sulfate, 3CuO.S0,.2H,O. T h e temperatures reported for the appearance of a second liquid p h a s e were obtained with both rising and falling temperature and were readily reproducible. T h e transition is sharp and e a s y to observe. T h e s e temperatures a r e believed to be accurate to t h e nearest degree. Plotting the temperature data along any one of t h e dilution paths
of t h e two solutions and of water could then b e mixed t o give any desired copper to uranium ratio and any desired dilution, T h e constancy of t h e mole ratio of e x c e s s sulfuric acid to the total copper sulfate p l u s uranyl sulfate w a s not affected by mixing or dilution errors. Nominal v a l u e s for e x c e s s acid for t h e five s e t s , respectively, were 0, 10, 20, 30, and 40 mole per cent. T h e u s e of weight aliquots i n a systematic pattern with constant acid-salt mole ratio permits interpolation within t h e limits of any p h a s e region t o yield a valid prediction of t h e temperature limit for any specified concentration. DATA AND DISCUSSION
T h e composition of solutions used and t h e experimentally observed temperatures a t which a second liquid p h a s e appeared a r e reported in T a b l e s I to V. T h e compositions a r e expressed in terms of t h e compositions of t h e master solutions and the weight aliquots, from which t h e true composition in terms of either weight per cent or mole per cent may b e readily calculated for any s p e c i f i c solution. T h e s e compositions are those of the solutions a t room temperature and a r e not t h e true compositions a t t h e temperature of t h e p h a s e transition. T h i s fact introduces no difficulty in t h e u s e of t h e data, a s there is point-topoint correspondence i n t h e p h a s e behavior and t h e room temperature composition. Temperatures a r e not reported in t h o s e i n s t a n c e s in which a solid phase appeared a t temperatures below t h e
Table
IV.
Second Liquid Phase Temperatures, OC.
Master solutions. 16.64% C u S 0 4 , 29.11 mole % e x c e s s HISO,; 45.63% U0*O4, 29.11 mole % e x c e s s H S 0 4 Weight Ratio, Solution/H,O
10/0 9/ 1 8/2 7/3 6/4
Weight Ratio. CuSOJUOfiO4
10/0
9%/%
9/1
347.5
342.5
341.7 337 334 332 330 328.5 3 2.7
342.2 340 33:. 2 332.2
5/5
4/6 3/7 2/8 1/9 0.75/9.25 0.5/9.5 0.25/9.75
8Wl% 3 39
324.5 323.5 322.5
a a a a
8/2
7%/2?4
7/3
6/4
5/5
4/6
3/7
2/8
1/9
0/10
338 335.5 331.5 328 325.5 323.5 322.5 322 323.5
337
337 332 3285 325 322 320.5 319.5 3 19 3 la& 5
334 330.5 326 323 320.2 318 3 16 316 3 16.5 323 327 33.'
335 329.5 325 322 319 316.5 315 315 313.5 318 327 331 339
336 329.5 325 321 318.2 315.5 314 313.5 313.5 318 325 331 339
336
336.5
339.5
325 329 339
322 329 339
320 327 340
343.5 334 329 324 3 19 316 313.5 312.2 313 318.5 320 327 339
a
a
a
a
a a
a
"Blue-green solid.
Table V. Second Liquid Phase Temperatures, 'C. Master solutions. 16.53% C u S 0 4 , 3 8 7 5 mole % e x c e s s HISO,; 45.36%UO,SO4, 3 8 7 5 mole % e x c e s s H$04 Weight Ratio, Solution/H@
10/ 1 9/ 1 8/ 2
7/3 6/4 5/5 4/6 3/7 2/8 1/9 0.75/9.25 0.5/9.5 0.25/9.75
Weight Ratio, CUSOJUO~SO,
_-
10/0
9/ 1
8/2
7/3
36 1 357.5 355 352 349.5 347 345 3484
355 35 1 34 8 345 341.5 339 336.5 3385.5
351.5
350.2 345
349 344
336.5
335
a
a
330.5 328.5 327 328 333.5 334 33.9
327.5 325.5 324 325 3 30 330 336 34 7
a a a
6/4
344
a a
4/6
3/7
2/8
1/9
0/10
349
350.5 343.5 338
3525 345 339
355
328
3285
321.5 320 320.5 326 327 332 342
321 3 19.5 3 20 325 326 332 342
358 3 53.5 347 3385 331.5 327.5 3 24 321.5 320 324.5 326 330 340
338
337.5 332 331 332 33p5
5/5 349.5
329.5 326 323.5 322 322.5 328 330 3 36 343
328 333 343
326 330 ~~
340
*Blue-green solid.
14
JOURNAL OF CHEMICAL AND ENGINEERING DATA
I5
(5
15 SULFURIC 4CID
-s-” to -
- IO
6’
-
c s
8 IO c
c
3
3
I
0 “
0“
m 2 5
5
0
m 3 5 0
0 0
40
5
15
20
0
0
IO
5
uo2so,
UO2SO4Iwt%)
15
20
0
(wt %I
15
---
29lImole.I.EXCESS
$\$
IO
5
I5
20
0
uo2so, Iu t % I Figure
10
5
15
to uozso, ( w l %I
15
20
TEMPERATURE CONTOUR LINES O ~ o t i - e r m ~ l FOR APPEARANCE OF T W O LIQUID PHASES REGION OF BLUE-GREEN CRYSTALLINE SOLIDS
11111
0
5
1’11
REGION OF RED SOLIDS
A
REFERENCE COMPOSITION OF 0 1 m CuSOq 0 I m uOzS04
+
REFERENCE COMPOSITION
20
OF HRT FUEL
0 005 m CuSO, 0 0 4 m UOzS04 (PLUS ca 0 0 2 5 m H2SOe1(55%1
uo2s04( w t % l
1. P h a s e t r a n s i t l o n temperatures I n solutions containing cupric sulfate, uranyl sulfate, a n d sulfuric acid
against o n e of t h e composition variables yields smooth curves from which interpolation values may b e obtained. Figure 1 s h o w s temperature contour plots obtained i n t h i s manner for e a c h of the five acidity values. T h e regions in which solid p h a s e s were encountered a r e indicated. A comparison s h o w s that a s the amount of e x c e s s sulfuric a c i d is increased the s c o p e of t h e precipitation regions s h r i n k s a n d t h a t t h e temperature a t which liquid p h a s e separation occurs for a specific concentration is elevated. If sufficient a c i d is present to prevent precipitation of a solid, pure copper sulfate-sulfuric acid solutions will yield a second liquid p h a s e i n a manner completely analogous to t h e behavior o r uranyl s u l f a t e solutions. Solution compositions falling within t h e precipitation regions a r e probably of n o interest for reactor use, b e c a u s e of t h e temperature limitation. T h e d a t a i n t h e two-liquid p h a s e region provide a n upper temperature limit for reactor u s e for any composition within t h e s c o p e of t h i s study. Relying on p a s t experimental data (4), t h e two liquid phase appearance temperatures for t h e heavy water system a r e
expected to b e of the order of 5‘’ t o 10°C. lower than for t h e corresponding ordinary water system. LITERATURE CITED (1) McDuffie, H. F., Compere, E. L., Stone, H. H., Woo, L. F . . Secoy, C. H., “Homogeneous Catalyais for Homogeneous Reactors. Catalysis of the Reaction Between Hydrogen and Oxygen, ” Southwide Chemical Conference, ACS, Memphis, Tenn., Dec. 6, 1956. (2) Posnjak, E., Tunell, G., Am. J. Scf. 218, 1-34 (1929). (3) Secoy, C H., J . Am. Chem. SOC.72, 3343 (1950). (4) Semy, C. H., others, “The Reactor Handbook AECD-3646,” Vol. 2, 1st ed., Chap. 4.3, p. 559, Technical Information Service, U. S. Atomic Energy Commission. Oak Ridge, T e n n , May 1955. Received for review May 24, 1 9 5 8 Accepted October 9 , 1958. Division of Industrial and Engineering Chemistry, Symposium on Chemistry and R e p r o c e s s k g of Circulating Nudear Reactor Fuels, 133rd meeting, ACS, San Francisco, Calif., Aprii 1958. Based on work performed at Oak Ridge National Laboratory, operated by Union Carbide Corp. for the Atomic Energy Commission. Other articles from this symposium will be published in the February 1959 i s s u e of Industrial and Engineering Chemistry.
Diffusion Coefficients in Hydrocarbon Systems. Methane
in the Liquid Phase of the Methane-Santa Fe Springs Crude Oil System H. H. R E A M E R and
0 . H. SAGE California institute of Technology, Pasadena, Calif.
L i t t l e experimental work i s available concerning the molecular transport of methane in t h e liquid p h a s e of hydrocarbons except t h e earlier work of Pomeroy (10) and of Lacey and others (1, 4, 5, 7. More recently, interest in t h i s field h a s revived and a t the present time some information i s available concerning the transport of methane in binary systems made up of t h i s hydrocarbon and the paraffin hydrocarbons from propane through n-decane, with the exception VOL. 4, NO. 1, JANUARY 1959
of o c t a n e and nonane (11, 13-16). Kirkwood (6) h a s s e t forth some of t h e basic relationships of molecular transport and t h e s e have been extended t o a number of situations of particular interest t o petroleum production (9). T h e work of Drickamer h a s made a marked contribution to an understanding of transport in liquid and g a s phases at elevated pressures. H i s studies, directed toward an understanding of the behavior at a gas-liquid interface (24, 29,
15
