Jacobs Engineering Co., report to State of California, Department of Water Resources, August 1960. Larson, J. D., Ph.D. dissertation, University of Illinois, University Microfilms, Ann Arbor, Mich., Pub. 15,235 (1955). Loparest, F. J., J . Phys. Chem. 61,1128 (1957). Lyman, John, Fleming, R. H., J . Marine Res. 3, 134 (1940). Markham, A. E., Kobe, K. A,, J . Am. Chem. Soc. 63, 449 (1941). Munjal, P. K., Ph.D. dissertation, University of California (Berkeley) , University Microfilms, Ann Arbor, Mich., Pub. 67-5126, 1966. National Research Council, “International Critical Tables,” Vol. 111, p. 260, McGraw-Hill, New York, 1928. Quinn, E. L., Jones, C. L., “Carbon Dioxide,” Reinhold, New York, 1936. Sander, W., 2. Physik. Chem. 78, 513 (1912). Seidell, A., Linke, W. F., “Solubilities of Inorganic and Organic Compounds,” 3rd ed., pp. 89-92, Van Nostrand, New York, 1952.
( 1 7 ) Stewart, P. B., Munjal, P. K., University of California, Berkeley Sea water Conversion Laboratory Report 65-1, 35 (1965). (18) Ibid., 66-1, 39 (1966). (19) Ibid., 69-2 (1969). (20) Stewart, P. B., Munjal, P. K., Quiring, F., Anal. Chem. 41, 1710 (1969). (21) Subow, N. N., “Oceanographical Tables,” p. 208, Oceanogr. Inst., Hydro-meteoral Corn., Moscow, U.S.S.R., 1931. (22) Wiebe, R., Chem. Rev. 29, 475 (1941). (23) Wroblewski, M. S., Ann. Phys. Chem. 17, 103 (1882). (24) Ibid., 18, 290 (1883). (25) Wroblewski, M. S., Compt. Rend. 94, 1355 (1882). (26) Zel’venskii, Y. D., J . Chem. I n d . ( U S S R ) , 14, 1250 (1937).
RECEIVED for review June 13, 1969. Accepted September 9, 1969. Work supported by state funds allocated t o it by the University Water Resources Center.
Physical Properties of a Refrigerant Mixture of
Monofluoromonochloromethane and Tetrafluorodichloroethane JOSEPH V. SINKA Specialty Chemicals Division, Allied Chemical Corp., Morristown, N. J .
07960
The physical properties presented describe the mixture of 55.1 wt. % monofluoromonochloromethane and tetrafluorodichloroethane, forming a minimum-boiling azeotrope at 291.2 K. The pressure-volume-temperature properties have been measured and correlated with the Martin-Hou equation of state. The vapor pressure and liquid densities were fitted to equations and the critical properties obtained.
THE
M A T E R I A L S , monofluoromonochloromethane ( R e f r i g e r a n t 31) a n d tetrafluorodichloroethane ( R e f r i g e r a n t 1 1 4 ) , w e r e obtained f r o m commercial sources a n d purified b y fractional distillation. T h e p u r i t y of each component, as determined b y gas chromatography, w a s 99.9 mole % o r b e t t e r , T h e precautions i n handling t h e m i x t u r e w e r e described i n a previous publication ( 4 ) . As previously ( 4 ) , t h e term vapor pressure will be used t o describe the p r e s s u r e exerted by a vapor w h e n a s t a t e of equilibrium h a s been reached between a liquid a n d i t s vapor. Obviously, t h i s t e r m i s used i n t h e general sense here, since t h e composition of t h e vapor a n d liquid a r e not exactly t h e same, except at t h e azeotropic state. However, every effort t h a t w a s practical was taken t o minimize t h e vapor space above t h e m i x t u r e a n d to o b t a i n d a t a at t h e bubble point. T h e a p p a r a t u s a n d techniques employed were discussed i n detail in earlier papers ( 1 , 3 , 4 ) . However, a f e w brief r e m a r k s a r e made. T h e pressure-volume measurements w e r e obtained on a constant-volume cell constructed of a 300-cc. high-press u r e stainless steel cylinder. T h e sample w a s confined in t h e cell w i t h a 5-cm. stainless steel d i a p h r a g m . The volu m e change due t o t h e displacement of t h e d i a p h r a g m f r o m t h e null point w a s negligible. N i t r o g e n w a s used as t h e pressure t r a n s f e r media a n d the pressure w a s read
on calibrated Heise gages, connected t o t h e system, covering various ranges. T h e critical t e m p e r a t u r e w a s determined by observation of t h e meniscus in a sealed glass tube, which w a s slowly heated and cooled i n a s t i r r e d liquid bath. T h e a v e r a g e value of several observations w a s 415.2” f 0.1” K. Extrapolation of t h e near-critical isochor t o t h e critical t e m p e r a t u r e determined t h e critical pressure. T h i s 1 p.s.i.a. gave a value of 749 T h e critical density w a s determined b y a s t a n d a r d rectilinear diameter plot, using t h e liquid densities calculated f r o m t h e liquid density equation a n d s a t u r a t e d vapor densities calculated f r o m t h e equation of s t a t e . T h e value determined w a s 0.539 0.001 gram per cc. T h e t e m p e r a t u r e w a s measured w i t h a platinum resistance thermometer calibrated b y t h e U. s. National Bureau of S t a n d a r d s ( ” C. Int., 1948). T h e volume w a s determined by calibration w i t h w a t e r a n d corrected f o r thermal expansion, using t h e coefficient of t h e r m a l expansion f o r stainless steel. T h e liquid densities were determined b y a float technique. T h e calibrated glass floats w e r e corrected f o r t h e r m a l expansion a n d f o u n d a c c u r a t e t o 0 . 1 7 ~over t h e r a n g e covered. T h e floats were found incompressible in t h e given p r e s s u r e r a n g e by checking t h e i r accuracies in known liquids. +_
*
Journal of Chemical and Engineering Data, Vol. 15, No. 1, 1970
71
The uncertainties in t h e input variables were determined d u r i n g the calibration procedures t o be 0.1% f o r volume, 0.01'; for temperature, 0.2% f o r pressure, and 0.037~f o r weight of sample d u r i n g repeated runs.
Table Ill. Equation of State
A, RT p=V - b f
+ B,T + C2e-KT'Tc (V -
b)'
DATA
Tables I t o 111 contain vapor pressure, liquid density, pressure-volume-temperature data, and correlating equations. T h e underlined digits a r e kept for consistency a n d may be omitted f o r hand calculations.
Table I. Vapor Pressure
P = V = T = R = b
T o ,K.
Obsd.
Calcd.
cC Dev.
260.85 273.16 291.00 303.35 323.18 343.22 363.20 373.14 393.16 403.16 413.16
14.696 24.105 45.162 64.3 113.0 186.4 288.5 352.0 511.1 609.9 721.5
14.7764 23.9460 44.5612 65.42 113.61 185.68 287.28 351.10 511.60 610.10 722.61
-0.54 0.65 1.33 -1.74 -0.54 0.38 0.42 0.25 -0.09 -0.03 -0.15
260.71" K.
Standard deviation = 0.37 p.s.i.a. Average per cent deviation = 0.56
Table II. Liquid Density
where: D T T, Do
= = = =
Ai A2 = As = Ad =
gram per cc. t"K. 415.22"K. 0.5391 0.569272 0.148902 X l o 1 -0.164833 X l o 1 0.988902 -
Density T o ,K .
Obsd.
Calcd.
ch Dev.
205.02 248.16 287.43 322.32 351.50 375.22 404.92
1.503 1.402 1.300 1.199 1.099 0.998 0.798
1.5032 1.4014 1.3004 1.1990 1.0990 0.9979 0.7980
-0.01 -
0.03 0.03
-0.00 -0.00
0.01 - 0.00
Standard deviation = 0.25 X 10-3 Average per cent deviation = 0.015
72
=
K = T, = Ar = B2 =
Pressure
=
A,
+ B,T + (V -
A4
C3e-KT/Tc b)3
+-
The equation parameters are:
LogP = A + B / T + C T + D T ' where: P = p.s.i.a. T = T"K. A = 8.312656 B = -0.147347 X l o 4 C = -0.771637 X 10-2 D = 0.761974 X
Normal boiling point, calcd.
+
Journal of Chemical a n d Engineering Data, Vol. 15, No. 1, 1970
Cr As
= =
Bs C? A, As Be C,
= = =
=
p.s.i.a. cc. per gram t"C. 273.16 0.1287070 X l o 2 cc., p.s.i.a./" K., gram 0.3777405 cc. per gram 0.5475 X 101 415.22 -0.2351595 x 105 0.2302919 X 102 -0.3169159 X 106 0.3111256 x l o 5 -0.2750807 X 102 0.5292572 X 106 -0.1575132 X l o 5 -0.3253440 X 104 0.2012582 X 102 -0.1332969 X 10'
+
Observed Data
Calculated Data c7
/e
Volume
Temperature
Pressure
Pressure
deviation
18.9988 19.0397 19.0806 19.1165 19.1510 9.8407 9.8513 9.8619 9.8778 9.8936 9.9090 6.3068 6.3170 6.3272 6.3373 6.3472 4.9200 4.9266 4.9332 4.9450 3.2305 3.2323 3.2340 3.2375 2.5049 2.5063 2.5076 2.5084 1.9704 1.9708 1.9718 1.9729 1.7917 1.7960 1.7969
373.17 413.18 453.1 6 488.25 522.06 393.16 413.16 433.16 463.16 493.16 522.14 403.17 433.16 463.16 493.16 522.16 423.16 448.08 473.16 517.96 423.16 433.16 443.16 463.16 423.16 433.16 443.16 449.16 415.22 418.16 428.16 438.16 418.16 428.16 438.16
212.5 245.0 276.6 304.0 329.9 380.0 415.2 449.5 499.1 548.0 596.3 521.0 613.8 700.7 784.0 864.3 666.5 768.8 868.3 1036.9 780.0 854.5 922.1 1054.6 821.2 919.6 1014.6 1070.1 750.4 787.0 911.6 1041.6 793.2 929.8 1074.3
211.92 244.10 275.08 301.65 326.87 378.94 414.11 448.31 498.23 546.94 593.16 522.44 613.11 700.04 784.36 864.07 668.17 769.27 867.76 1038.05 782.20 852.52 921.79 1057.59 823.21 918.97 1013.57 1069.82 749.36 786.66 913.14 1039.03 791.05 932.45 1074.06
0.27 0.36 0.54 0.77 0.91 0.27 0.26 0.26 0.17 0.19 0.52 -0.27 0.11 0.09 -0.04 0.02 -0.25 -0.06 0.06 -0.11 -0.28 0.23 0.03 -0.28 -0.24 0.06 0.10 0.02 0.13 0.04 -0.16 0.24 0.27 -0.28 0.02
Standard error = 0.18 Average per cent deviation
=
0.23
ACKNOWLEDGMENT
The a u t h o r acknowledges t h e assistance of E l i Rosenthal i n t h e calculations a n d Ronald Dixon in collecting t h e data.
( 2 ) Mears, W. H.,Rosenthal, E., Sinka, J. V., Ibid., 11, 338 (1966). ( 3 ) Mears, W. H., Sinka, J. V., Malbrunot, P. F., Meunier, P. A., Dedit, A. G., Scatena, G. M., Ibid., 13, 344 (1968). (4) Sinka, J . V., Murphy, K. P., Ibid., 13,16 (1968).
LITERATURE CITED (1) Malbrunot, P. F., Meunier, P. A., Scatena, G . M., Mears, W. H., Murphy, K. P., Sinka, J. V., J. CHEM. ENG.DATA13,16 (1968).
RECEIVEDf o r review June 5, 1969. Accepted October 17, 1969.
Pressure-Volume-Temperature Relationship for a Mixture of
Monochlorotrifluoromethane and Trifluoromethane The pressure-volume-temperature properties of a 50-50 mole % mixture of monochlorotrifluoromethane and trifluoromethane in the ranges of 14.7 to 74.8 atm., 1.6 to 19.1 cc. per gram, and 298O to 492O K. were correlated, using the Martin-Hou equation of state. Vapor pressures and saturated liquid densities were determined to near the critical temperature (292.6O K.) from 203O and 229.8O K., respectively.
JOSEPH V. SINKA, ELI ROSENTHAL, and RONALD P. DIXON Specialty Chemicals Division, Buffalo Research Laboratory, Allied Chemical Corp., Buffalo, N. Y.
I N A PROGRAM to supply accurate a n d reliable d a t a on r e f r i g e r a n t s , t h e a u t h o r s measured t h e pressurevolume-temperature properties, vapor pressure, a n d liquid densities of R e f r i g e r a n t 503. T h i s r e f r i g e r a n t (1 ), which h a s a composition of 50-50 mole 'lc trifluoromethane and monochlorotrifluoromethane, f o r m s a minimum-boiling azeotrope a t -87.85" C., 1 a t m . No published equations correlating t h e above properties a r e presently available. EXPERIMENTAL
E a c h component of t h e m i x t u r e w a s purified t o 99.9 mole c/; or better, a s indicated by g a s chromatographic analysis. T h e bulk m i x t u r e being above t h e critical t e m p e r a t u r e a t 23" C., no segregation problems w e r e encountered upon sampling. Due to t h e low freezing point of t h e m i x t u r e , special precautions w e r e t a k e n i n degassing t h e sample to avoid pumping off a n y r e f r i g e r a n t . D u r i n g t h e vapor p r e s s u r e measurements, the degassing cycles w e r e repeated until reproducible pressure readings w e r e observed. Temperature Measurements. All t e m p e r a t u r e measurements were made by a calibrated platinum resistance t h e r m o m e t e r (degrees Centigrade, I n t . 1948) whose resistance w a s measured by a Leeds a n d N o r t h r u p Speedomax high-precision resistance recording bridge. P e r i odically, t h e accuracy of t h e recorder w a s checked w i t h t h e ice point resistance of t h e thermometer. T h e absolute t e m p e r a t u r e scale is defined as 0" C. = 273.15" K. Pressure Measurements. All p r e s s u r e measurements w e r e t a k e n with t h e PVT a p p a r a t u s described in a n earlier paper ( 5 ) . Vapor Pressure. T h e t e r m vapor pressure i s used h e r e in t h e general sense, since the composition of t h e azeoSample Preparation.
trope does not remain i n v a r i a n t w i t h changes in t e m p e r a t u r e ( 5 ) . However, accurate vapor p r e s s u r e d a t a of t h i s m i x t u r e can be obtained by t a k i n g measurements a t the bubble point. For t h e vapor p r e s s u r e measurements, t h e sample cell was filled t o a point which enabled measurement of several d a t a points a t close to t h e bubble point pressure. T h e d a t a covered t h e t e m p e r a t u r e r a n g e f r o m 203" to 283" K. (Table I ) and is represented by t h e following equation. LOglcP(atm) =
where T i s OK.
=
273.13
A
+ B / T + CT + DT2
(11
+ t o C.
T h e constants f o r E q u a t i o n 1 a r e shown in Table I. T h i s equation h a s a s t a n d a r d per cent deviation of 0.10 f o r t h e experimental data. E x t r a significant figures have been kept f o r consistency in computation. Liquid Density. T h e s a t u r a t e d liquid densities were determined by a float technique which h a s been described in detail in a n earlier paper ( 5 ) . T h e d a t a covered t h e t e m p e r a t u r e r a n g e f r o m 229.8" to 284.2" K. T h e equation used to correlate t h e s a t u r a t e d liquid densities w a s t h a t of M a r t i n and Hou ( 3 ) . d = do
+ i $= l
A,[(1
-&)"']I'
T h e constants f o r E q u a t i o n 2 and the experimental d a t a a r e shown in Table 11. PVT Measurements. T h e r a n g e which w a s covered by t h e PVT d a t a (Table 111) i s f r o m 298" to 492" K., 1.6 t o 19.1 cc. p e r g r a m , 14.7 to 75.0 a t m . T h e data, consisting of e i g h t isochors, were fitted w i t h a Martin-Hou equation Journal of Chemical and Engineering Data, Vol. 15, No. 1, 1970
73
