INDUSTRIAL AND ENGINEERING CHEMISTRY
2728
T A 4 B L E 1'111. EFFECTO F IRR.4DIlTION CONDITIOXR O N THE h O U N T O F COSTAMIXAKT IN P O T A S S I L X DIHYDROGEN
PHOSPHATE
Irradiation Conditions Low neutron flux, l o w temperature High neutron flux, intermediate temperature High neutron flux, high temperature
Contaminant of % Total Acti& 26.69 18.31 0.57
Vol. 44, No. 11
24 hours (Table IX). Since there was no x-eight loss or change in specific activity in any of the samples after the treatment, no material was lost by gasification. Therefore, the contaminant in irradiated potassium dihydrogen phosphate can be substantially eliminated by oven heating at temperatures low enough to prevent decomposition of the potassium dihydrogen phosphate. The same is not true of irradiated calcium phosphates (5,4 ) . ACKSO W LEDGM E h T
O F HEATO U COSTAVINlNT I N S E L T R O A I R R 4 D I 4 T E D POT4SSIUM DIHYDROGEY PHO SPH lTE
TABLE Ix
EFFECT
Temp , C. Room temp. 40 60 108 125 150 175
Contaminant 70 of Total hcti&ty 21.08 20.26 19.38 6.64 1.50
The potassium metaphosphate and potassium pyrophosphate used in this stud) were prepared by G. -4.Wieczorek of the bureau. The phosphorus anhydride was kindly supplied by the Research Section, Division of Chemical Engineering, Tennessee Valley Authority, TTilson Dam, Ala. LITERATURE CITED
1.01 0.24
COSVERSION OF THE NONORTHOPHOSPHATE COYTAMINANT INTO ORTHOPHOSPHATE
Pile-irradiated units of potassium dihydrogen phosphate prepared by the Oak Ridge National Laboratory under different conditions of neutron flux and temperature showed (Table T'III) nonorthophosphate contents in an order inverse to that of the irradiation temperature. This indication of the beneficial effect of temperature in reducing the amount of nonorthophosphate was confirmed in the laboratory by heating 100-mg. samples of an irradiated potassium dihydrogen phosphate containing 21.07% of nonorthophosphate P32in an oven at different temperatures for
Barton, G. L., Anal. Chem., 20, 1068 (1948). Fiskell, J. G. A , , Science, 113,244 (1951). Fiskell, J. G. A , et al., Can. J . Chem., 30, 9 (1952). Fried, M., and MacKensie, A. J., Science, 111,492 (1950). Libby, W. F., J . Am. Chem. Soc., 62,1930 (1940). MacKenzie, A. J., and Borland, J. W., Anal. Chem., 24, 176 (1952). Mission, G., Chem. Ztg., 32,633 (1908). Thomas, W, D. S.,and Sicholas, D. J. D., Nature, 163, 7 (1949). l o s t , D. RI., and Russell, H., "Systematic Inorganic Chemistry," New York, Prentice-Hall, h e . , 1944. RECEIVED for review December 18, 1931. A C C E P T E D June 9, 1952. Presented before the Division of Fertilizer Chemistry a t the 120th JIeeting of the .kMERICAN CHElriIC.4L 8 0 C I E T Y , New York, N. Y. Investigation supported in part by U. S.Atomic Energy Commission.
f Liquid Ammo gh Pressu L. T. CARMICHAEL AND B. H. SAGE California Znstitute of Technology, Pasadena, Cal;,f.
T
HE determination of the viscosity of ammonia is of iniportance in many industrial operations involving transfer of energy or momentum. Measurements in the liquid phase \%*ere made by Plank and Hunt ( l 7 ) , Stakelbeck ( W ) , Fitzgerald ( 2 ) , Shatenshtein and coworkers ( 2 6 ) , and Pinevich ( 2 6 ) . These data have served to establish the characteristics of ammonia near bubble point for most industrial applications at low temperatures. The viscosity a t elevated pressures has not been investigated in detail except for the work of Stakelbeck ( 2 7 ) and a few measurements upon gaseous ammonia a t lo^ pressures which were reported by Rankine and Smith (18) and Wobser and Muller (28). These last data appear to offer the most satisfactory measurements presently available. Apparently no data exist describing the effect of pressure upon the viscosity of ammonia in the liquid phase a t pressures markedly above that of the critical state. The present investigation involves measurements for ammonia at states a t which the viscosity is greater than 500 micropoises throughout the temperature range from 40" to 220" F. a t pressures up to 5000 pounds per qquare inch. For these measurements the rolling ball viscometer first proposed by Flowers ( 3 ) and developed by Hersey ( 5 , 6 , 12) was employed. Such an instrument was used earlier for the measurement of the viscosity of liquid and gaseous hydrocarbons at
pressures up to 5000 pounds per square inch (21-23, 25). This equipment, vias revised to permit measurements upon substances with electrical conductivity high enough to prevent the use of electrical cont,acts for determining t,he position of the hall. In some respects the instrument, is similar to that of Hopplrr ( 7 ) which is used at, a much greater angle of inclination. Figure 1 depicts the schematic arrangement of the viscometer used for the present studies. I n principle, it consisted of a steel tube inclined at approximately 15' from the horizontal shov-n a t A , viithin which a closely fitting steel ball was permitted to roll. The lower end of the tube was closed by the manually operated valve, B , the stem of, vc-hich extended outside the agitated oil bath, C. The fluid TT-ithin the system was circulated by means of a three-stage centrifugal pump, D, which was driven a t approximately 1200 r.p.m. t,hrough the water-cooled, pressurecompensated, shaft-sleeve unit a t E. The details of the arrangement of the ground joint are illustrated in Figure 2. This pump was used to return t,he ball to the upper end of the tirhe after a measurement of roll time. It was not operated while measurements were being made. Three symmetrically located cooling units like the one shown in this figure were provided for the circulation of water to prevent overheating of the joint. I n order to avoid leakage betvieen the shaft and sleeve, E , of Figure 1,
~
I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
November 1952
a lantern was provided midway along the' closely fitting, watercooled, pressure-compensated sleeve and was connected a t M to the oil system of the pressure balance, L. By keeping the diaphragm, J, in balance it was possible, through the difference in elevation of the mercury-oil interfaces in the U-tube, N , t o obtain any desired small excess pressure a t M necessary to avoid migration of ammonia into the seal, E. The clearance between the hardened steel rod and cylinder was less than 0.0002 inch. The
Figure 3. This method of determining roll time is t o be preferred to the use of a magnetized ball and a single pickup coil since the forces acting on the magnetized ball from the moving magnetic field are eliminated. Figure 5 shows the potential applied to the thyratron circuit, which operated the chronograph, as a function of the position of the ball. The chronograph was adjusted so as t o respond a t a potential of approximately3.5rootmean squarevolts. Underthese circumstances the position of the ball in the roll tube relative to the center line of the coil set could be determined with the stand-
Figure 3.
Figure 1.
Schematic Arrangement of Viscometer
pump, D,was connected t o the viscometer tube, A , by means of the tubing, F and C. A magnet was provided a t H t o hold the ball in the upper part of the tube while valve B was closed. The ball was set in motion by reversing the polarity of the electromagnet, H.
OIL CONNECT1
The timing of the roll of the ball was carried out by a series of three sets of three coils located externally around the axis of the roll tube. The arrangement of the coils is indicated in Figure 3. They were wrapped carefully within the grooves shown in this diagram. The three coils a t Q, R, and S were substantially identical in configuration and were connected to the electronic circuit depicted in Figure 4. This circuit was similar to but not identical with that described by Henney (4). It responded t o the presence of the ball and was relatively independent of the velocity with which the ball passed the coils a t Q, R,and S of
~
TRIPPING THYRATCOM CIRCdIT
:
POWER AMPLIFIER
PRE-AYPLBFIER ~
AUDIO OSCILLATOR 500 CYCLES
+a'' Figure 2. Sectional View of Seal for Rotating Shaft
Arrangement of One Set of Position Coils about Roll Tube
ard deviation, CT, of 0.012 inch as in Figure 5, which corresponds to an uncertainty in roll time of about 0.1%. The three sets of coils shown in Figures 1 and 4 were employed to ascertain that the velocity was uniform during the measuring period. It was found that for all situations involving a roll time in excess of 10 seconds the rate of travel between the first and second sets of coils was within 0.05% of that between the second and third. I n the case of shorter roll times the effects of acceleration of the ball were significant and there existed a slightly larger difference between the roll time from the first to the second set and that from the second t o the third set. The pressure within the apparatus shown in Figure 1 was determined by an aneroid-type diaphragm (19), J , connected to a pressure balance (84), L. An injector, K , was provided in order to maintain proper balance of the diaphragm a t various
PEN CHRONOGRAPH
W
2729
h
R
-VISCOMETER
21-VISCOMETER
PO'ILC
COILS
PICI(UP
COILS
COILS"'AND''S'CONNECT~D
Figure 4.
IN OPPOSED
Electronic Circuit Used to Indicate Position of Ball
pressures and also to make up for the small leakage of oil through the piston-cylinder combination of the pressure blance, L. The pressure balance (84) was calibrated against the vapor pressure of carbon dioxide, utilizing the measurements of Bridgeman ( I ). It is believed t h a t the pressures within the viscometer were known within 1 pound per square inch or O.l%, whichever is the larger uncertainty.
INDUSTRIAL AND ENGINEERING CHEMISTRY
2730
galvanometer connected to a resistance thermometer through a M u e 11 e r - t y p e bridge. The temperature in the bath was measured by a platinum resistance thermometer which had been calibrated against an instrument standardized by the National Bureau of Standards. It is believed that the temperature of the material in the roll tube was known within 0.04" F. of the international platinum scale. The characteristics of the rolling ball viscometer have been investigated in detail by Hersey and Shore (6) and Hubbard and Brown (8). I n the laminar flow regime the roll time is a single-valued function of the viscosity and specific weight of the fluid. Because the functional relationship of roll time to viscosity is linear except for acceleration effects, it may be shown that the following analytical expression describes the roll time throughout the laminar region of flow for a particular tube a t an established
6 w 10.0
a s Y
Y
e Y
?
5.0
0
I
P
w U w 0.5
1.5
1.0
RELATIVE
Figure 5.
BALL
2.0
POSITION
2.5
INCHES
Chronograph Signal as a Function of Position in Roll Tube
The temperature of the viscometer was controlled by immersing the entire apparatus in an agitated oil bath, C, as shown in Figure 1. The temperature of the bath was controlled by means of a modulated electronic circuit actuated by the light beam of a
OF CARBON DIOXIDE: AT 40" F. TABLE I. VISCOSITY
Pressure, Lb./Sq. Inch Absolute
Viscosity, ~Micropoises _ _ -4uthors Stakelbeck (%7) 1321 1242 1098
2261 1763 1138
Vol. 44, No. 11
angle of inclination :
m
_
1285 1182 1045
: 8000 -
,o U 0
u I
6000
-~ ~
?*IEASUREMENTS TABLE11. EXPERIMESTAL
O F ~71SCOSITIESO F
hIitfOhTA
Pressure, Lb./Sq. Inch Absolute
Roll Time, Seconds
Speclfic Keighta, Lb./Cu. Foot 40'
239 1211 2247 3276
33 77 80 94
Viscosity, hIicropoises
F
21.68 21.80 21 98 22 17
>
c
s p
4000
w
39 39 40 40
48b 70 00 24
1881.9 1904.0 1942.4 1986.7
38 38 38 38 38 38
00 02 16 21 61 99
1573.4 1585.6 1622.8 1657.4 1686.8 1710.9
k3
z 4
2000
70' F 137.07 183.20 978.01 2029.87 3127.19 4279.48
20.43 20.47 20.61 20.77 20.94 21.11 100' F.
222.46 242,80 454.23 448 20 966.16 1187 00 2489.20 3492.90 4570.60
19.29 19.34 19.37 19 41 19.49 19.55 19.73 19.89 20.07
504.15 498.55 712.84 1204.57 2241.30 3313.90 4448.50 5979.55
16.73 16.80 16.81 17 0 3 17.36 17.87 18.15 18.50
3181,56 4572.80 5995.80
15.49 15.92 16.26
36.40 36.42 36.52 36.50 36.75 36.90 37.45 37.72 38.12
1305.6 1321.9 1323.9 1339.9 1347.3 1356.7 1373.0 1407.0 1437.2
32.67 32.72 32.91 33.56 34.36 34.84 35.32 36.11
691.1 713.6 691.8 721.9 773.1 922.6 983.7 1042.8
31.15 32.12 33.11
348.8 424.5 462.1
160' F.
2206 F.
5 Speoific weight of steel bail = 481.94 lb,/cii, foot a t 70" F. a n d 1 atmosphere. b Specific weight of ammonia.
4000
e(ce-ur)
8000 POUND
SECONDS
12000 PER CUBIC
16000 FOOT
Figure 6. Behavior of Instrument in Laminar and Turbulent Regimes
I n this region the behavior of the ball and tube was determined from measurements upon n-pentane. Values of the viscosity of n-pentane, as determined by Rossini from a critical review of available data (ID), were employed. These data permitted the coefficients of Equation 1 to be determined with a standard deviation of 0.5%. Equation l was used in establishing the viscosity from measured roll times. I n the case of short roll times for which laminar flow past the rolling ball is not obtained, a somewhat different situation exists. I n this regime the roll time of the ball is a function not only of the viscosity and the specific weight of the fluid, but also of the Reynolds number of flow (23). Throughout all of the measurements reported here, the flow around the ball was in the laminar regime. For the combination of ball and tube used in this particular study the constants A and B of Equation 1 assumed dimensional values of 0.4790 and 14.8976 when the viscosity was expressed in micro-
INDUSTRIAL AND ENGINEERING CHEMISTRY
November 1952
'
2131
viscosity to roll time of the ball in the turbulent and laminar regions for a series of values of specific weight of the fluid. I n Table I is shown the viscosity of carbon dioxide 2500 a t bubble point as determined by Stakelbeck ( $ 7 ) and from the present measurements. Fair agreement was VI W obtained. Recent measurements of the specific weight ?! of carbon dioxide (10) were employed to determine the 2 2000 specific weight of this fluid a t the states investigated. 2I! Measurements were made by introducing the required amount of ammonia into the viscometer in order to fill > 1500 it completely with liquid a t a temperature of approxic mately 10' F. and a t a pressure corresponding to the 0 :5: vapor pressure of ammonia a t approximately 160" F. The system was then closed off from the weighing bomb w 1000 ($8) and the viscometer was brought t o a predeterIa mined temperature a t which measurements were desired. As a result of the rise in temperature the pressure 4 . increased to values in excess of 5000 pounds per square 500 inch and the roll time was determined for a series of pressures between this maximum and the vapor pressure, the pressure being adjusted by withdrawal of I I I I I I 1 ammonia. The system was cooled again t o approxi1003 2000 3000 4003 5000 mately 30' F., refilled with the liquid phase, and PRESSURE POUNDS PER SOUARE INCH brought to the next higher temperature. This process Figure 7. Effect of Pressure upon Viscosity of Ammonia in the was repeated throughout the temperature ranffe - of the Liquid Phase investigation. It was not necessary to employ any auxiliary means to increase the pressure within the viscometer. It was found that the roll time a t a given pressure poises, the roll time in seconds, and the specific weight of the ball and temperature could be duplicated within approximately and fluid in pounds per cubic foot. The diameter of the tube was 0.2%. The calibrations involved an over-all uncertainty of not approximately 0.5005 inch and that of the ball was 0.4967 inch, more than 0.6% for viscosities above 500 micropoises. It is Roll times from 60 down to 20 seconds for a roll distance of 15 believed that the viscosity of ammonia in the liquid phase a t inches were experienced in this work. The second term of Equaviscosities greater than this value was established with an untion 1 becomes of importance only a t short roll times and is often certainty of not more than 0.7%. not included in calibrations of Hoppler (7) or other types of rolling ball instruments when used with fluids of high viscosity. I n order to determine the limits of the laminar regime the RESULTS behavior of the particular ball and tube used in this investigation The experimentally measured values for the viscosity of amwas ascertained in the turbulent regime by measurements with monia in the liquid phase are recorded in Table I1 and shown as 8 air and carbon dioxide. The data of Nasini and Pastonesi (13), function of pressure for several temperatures in Figure 7. The Phillips (16),and Stakelbeck (27) were used t o establish the visdata of Keyes (11) and of the National Bureau of Standards cosity of air and carbon dioxide at elevated pressures. Kellstrom's (9) value of 183.49 micropoises a t 73.4" F. and atmospheric pressure was employed to establish the absolute values of the viscosity of air. In Figure 6 is shown the relationship of
1
40
BO
Figure 8.
IS0
120 TEMPERATURE
200
OF
Effect of Temperature upon Viscosity of Ammonia in the Liquid Phase
J TEMPERATURE
OF
Figure 9. Comparison of Viscosity of Ammonia at Bubble Point as Determined by Several Investigators
INDUSTRIAL AND ENGINEERING CHEMISTRY
2732
q =
TABLE111.
40' F.
Pressure, Lb./Sq. Inch
Absolute Bubble point 200 400 600 800
OF
I'ISCOSITY
70' F.
AMMONIAIS
100' F. 130' F. 160' F.
(73.32)a(128 8) (211 9) (330 3) 1880b 1884 1892 1898 1905 1911
1592 1595 1603 1611 1618 1624 1641 1656 1670 1684 1697 1712
THE
1306
.. ,.
1316 1324 1332 1338 1362 1367 1380 1398 1410 1427 1460
1028
.. , .
LIQUIDPHdSE 190' F.
220'
F.
(492 8) (708 9) (989.5) 748
1030 1038 1044 ioji 1070 1088 1108 1127 1145 1163 1201
. ... ....
488
..... ..... . .. ..
-~
= u = UB = uf =
absolute viscosity, micropoises roll time of ball, seconds standard deviation, Figure 5 specific weight of ball, pounds per cubic foot specific weight of fluid, pounds per cubic foot LITERATURE C I T E D
[240Ic
..
,
..
. , ...
..
754 .. . 762 492 1000 772 503 [iiij; 795 527 [274Ic 1500 1924 822 551 304 2000 1940 846 2500 576 330 1954 870 3000 1972 600 355 890 628 362 1987 3500 4000 3004 910 650 390 5000 .. . .... 654 700 429 6000 . .. . . . .. .... . . . . I000 750 468 a Figures in parentheses represent bubble point pressures expressed in pounds per square inch. b Viscosity expressed in micropoises. 0 Figures in brackets involve added uncertainties.
.
e
~
( 1 4 ) were used to establish the specific weight of ammonia at the states in question. The effect of temperature upon the viscosity of ammonia is relatively small in comparison to that for many liquids and is shown in Figure 8. I n Figure 9 the measurements of Pinevich ( 1 6 ) , Shatenshtein et al. ( b 6 ) , and Stakelbeck (W7) at bubble point have been compared with the present measurements. It was possible to investigate the behavior of ammonia at temperatures above that of the critical state for pressures high enough to yield roll times of approximately 10 seconds. For short roll times the flow may be turbulent as indicated in Figure 6 and the accuracy of measurement is markedly decreased. I n Table I11 is recorded the viscosity of ammonia in the liquid phase as a function of pressure and temperature. These data were smoothed from the experimental information submitted in Figures 7 and 8 ACKNOWLEDGMENT
These measurements were carried out with financial support from the Office of Kava1 Research The assistance of R. F. Meldau in preparing the data in a form suitable for publication is acknowledged. TT. N. Lacey reviewed the manuscript in detail. NOMENCLATURE
A = dimensional coefficient of Equation 1 B = dimensional coefficient
Vol. 44, No. 11
(1) Bridgeman, 0. C., J . Am. Chem. SOC.,49, 1174-83 (1927). (2) Fitzgerald, F. F., J . Phys. Chem., 16, 621-61 (1912). (3) Flowers, A. E., Proc. Am. SOC.Testing Materials, 14, 11,565-616 (1914). (4) Henney; K., "Electron Tubes in Industry," p. 134, New York, McGraw-Hill Book Co., 1937. (5) Hersey, M.D., J . Washington Acad. Sci., 6,525, 628 (1916). (6) Hersey, M. D., and Shore, H., Mech. Ena., 50. 221-32 (1928). (7) Happier, F., $Todd Petroleum Congr.-I, London, 1933, P r o c . , Refining, Chemical, and Testing Section, 2, 503-7 (1934). (8) Hubbard, R. M., and Brown, G. G., IND. ENG.CHEM.,ANAL. ED.,15, 212-18 (1943). (9) Kellstrom, G., Phil. Mag., 7th Ser., 23, 313-38 (1937). (IO) Kendall, B. H., and Sage, B. H., Petroleum (London), 14, 184-6 (1951). (11) Keyes, F. G., J . Am. Chem. Soc., 53,965-7 (1931). (12) Kingsbury, A,, Hersey, M. D., Duff, A . W., Dickenson, H. C., and Flowers, A. E., Mech. Eng., 45, 315 (1923). (13) Nasini, A. G., and Pastonesi, G., Gazz. Chim. ItaZ., 63, 821-32 (1933). (14) Katl. Bur. Standards (U. S.),Circ. 142 (1945). (15) Phillips, P., Proc. Roy. Soc. (London), A87,48-61 (1912). (16) Pinevich, G., Kholadil Tekh., 20, 30-7 (1948). (17) Plank, C. J., and Hunt, H., J . Am. Chem. Soc., 61, 3590-1 (1939). (18) Rankine, A. O., and Smith, C. J., Phil. Mag., 42, 601-14 (1921). (19) Reamer, H. H., and Sage, B . H., IND. ENG.CHEM.,44, 185-7 (1952). (20) Rossini, F. D., "Selected Properties of the Lighter Hydrocarbons," New York, BPI, 1947. ENG.CHEM.,ANAL.ED.,5,261-3 (1933). (21) Sage, B. H., IXD. (22) Sage, B. H., and Lacey, 1%'. N., IXD.ESG. CHEM.,30, 829-34 (1938). (23) Sage, B. H., and Lacey, W. N., Trans. Am. Inst. Mech. Engrs., 127, 118-34 (1938). (g4)Zbid.,174, 102-20 (1948). (25) Sage, B. H., Sherborne, J. E., and Lacey, W. N., IXD.ENG. CHEM.,27,954-6 (1935). ( 2 6 ) Shatenshtein, A. I., Izrailevich, E. A., and Ladyshnikova, N. I., Zhur. Fiz. Khim., 23,497-9 (1949). (27) Stakelbeck, H., Z . K&Zte-Ind.,40,33-40 (1933). (28) Tyobser, R., and Muller, F., Kolloid-Beihefte, 52, 165-276 (1941). RECEIVZD for review April 29, 1952.
ACCEPTED July 17, 1952.
Eauilibria of Several eactions of Aromatic Amines I
G . N. VRIENS AND A. G. HILL Calco Chemical Division, American C y a n a m i d Co., Bound Brook, N . J .
I
Tu' THE study of the variables of a chemical process, with the
object of improving the yield or conversion, the most important basic consideration is the distinction between those effects due to an equilibrium and those due to a rate process. Since this distinction is not always eaay to make without an extended experimental investigation, it is of great practical interest to be able to calculate both the rate of a reaction and its equilibrium conversion from fundamental information. I n the former case, progress has been slow; however, the determination and correla-
tion of thermodynamic properties have proceeded to the point where it is now possible to predict reaction equilibria with considerable assurance. I n this paper, previous calculations (19) have been revised and extended to include the therniodynamic properties of aniline, the A'-methylanilines, the iV-ethylanilines, and diphenylamine. The values obtained are summarized in Table I. The equilibrium conversions based on these data are then compared with experimental results for a number of reactions involving these compounds.
