INDUSTRIAL AND ENGINEERING CHEMISTRY
978
TABLEI.
--
--Temp.----
c.
\'ISCOSITY
AND
Propaned t/4 (9, Centi6, 9 , 12) stokes
F. - 100 80 - 60 40 - 20 n 26 40 60 80
DENSITY OF PROPANE, n-BUT.kNE, n-Butaned t/4 (8 Centi5,6, 7 , 19) stokes
Ceptipoises
0 487 0.301 -73.3 0.618 0.262 0:432 -62.2 0.606 0 390 0.23l -51.1 0.593 0.580 0 :353 0.205 -40.0 0.567 0.3Z2 0.183 -28.9 0.553 0.163 0.295 -17.8 0.273 0.539 0.14? - 6.7 0.254 0.13; 0.525 4.4 0.237 0.12 0,509 1-16.6 0.492 (0,224) (0.110) +26.7 0.474 (0.210) (0,100) 100 +37.8 0 Values in parentheses obtained by extrapolation.
-
+
The hydrocarbons on which data were obtained mere commercial products of the Ohio Chemical & Manufacturing Company. Purity as determined in our laboratory was 99f per cent; the purities stated in their catalog are propane 99.9 per cent, n-butane 99, isobutane 99.
Results The kinematic viscosities over a temperature range were determined on propane, n-butane, and isobutane (Figure 3). The data form good straight lines when plotted on A. S. T. M. chart D-341-37TI which has been modified by dividing the viscosity scale by 10 and subtracting 100" F. from the temperature scale. Ten centistokes on the original graph equal one centistoke on the revised graph, and 0" F. on the original graph equals -100" F. on the revised graph. No single determination deviates more than 4 per cent from its line. Viscosities determined on propane and n-butane at: the lower temperatures and pressures in the modified Fenske viscometer are in excellent alignment with the viscosities determined in the other instrument at the higher temperatures and pressures. Data from International Critical Tables on n-butane, determined in 1913 by Kuenen and Visser ( 8 ) ,fall on our curve. Sage and Lacey (11, 14) gave a value 2 per cent lower than our best value for n-butane and 12 per cent lower than our best value for both propane and isobutane. J
;* d
b
2.0,
I
w
oOATA OF SHEPARO HENNE 8 MIOGLEY .DATA 4
5
6
7
OF AUTHORS 8
AND
7 -
9 1 0 1 1 1 2
NUMBER OF CARBON ATOMS
FIGURE4. VISCOSITY OF XORMAL PARAFFINS AT 25" C. (77" F.) KO other data are available from the literature. However, a plot (Figure 4) of log kinematic viscosity a t 25" C. vs. number of carbon atoms for the normal liquid hydrocarbons, wing data of Shepard, Henne, and Midgley (15), gives a straight line with which our experimental data for propane and n-butane agree within + 2 and +4 per cent, respectively. Similar type plots by Wiggins (16) of log absolute viscosity :it 20" C. us. number of carbon atoms, and by Kissan and Dunstan (10) of log absolute viscosity vs. molecular volume
Centipoises 0.4S5
0.415 0.36l 0.315 0 . 278 0.248 0 221 0:200 0.181 0.164 0.15O
Vol. 34, No. 8
IsOBUTANEa ------Isobutane---
d t/4 ( I , 2, 9, 11)
0.661 0,649 0.638 0.626 0.614 0.602 0,589
0.577 0.564 0.551 0.537
Centistokes 0 . 85O
0,725 0 . 6ZJ 0.55O 0 . 4S5 0 . 433 0 392 0:356 (0.3Z7) ( 0 .30°) (0.
Centipoises 0 . 562 0.47l 0 . 3Q9 0 . 344 0.29: 0.26 0.231 0.20" (0.184) ( 0 . 165) (0.149)
and log molecular volume, give similar agreement with our data. For engineering purposes, absolute viscosity is often desired rather than kinematic viscosity. Table I gives the kinematic viscosity, density, and absolute viscosity a t 20" F. intervals from -100" t o +100" F. for the three hydrocarbons. The kinematic viscosities were read from Figure 3 and are accurate within *2 per cent. The densities are best values obtained after a search of the literature (1, 2 , 3 , 5, 6, 7 , 9-12) and are dependable within +=0.001. The absolute viscosity is calculated from these data and is also accurate within ~2 per cent.
Acknowledgment The authors wish to acknowledge the assistance of W. T. Harvey and I. W. Mills in connection with a portion of this work.
Literature Cited (1) Burrell, G. A., and Robertson, I. W., J . Bm. Chem. SOC.,37,2188 ( 1915). (2) Coffin, C. C., and Maass, O., Ibid., 50, 1427 (1928). (3) Dana, L. I., Jenkins, A. C., Burdick, J. X., and Timni, H. C., Repig. Eng., 12, 387 (1926). (4) Evans, E. B., J . Inst. Petroleum Tech., 24, 38-53, 321-37 (1938). (5) Grosse, A. von, in Egloff's "Physical Constants of Hydrocarbons", Vol. I, New York, Reinhold Publishing Corp., 1939. (6) Huckel, W., Kraemer, A,, and Thiele, E., J . prakt. Chem., 142, 207 (1935). (7) Kay, W. B., IND.ENQ.CHEM.,32, 358 (1940). (8) Kuenen and Visser, Proc. Roy. Acad. Sci. Amsterdam, 16, 355 (1913); Commun. P h y s . Lab. Univ. Leiden. 138--1(1913); International Critical Tables, Vol. VII, p. 215 (1930). (9) Maass, O., and Wright, C. H., J . A m . Chem. Soc., 43, 1098 (1921). (10) Nissan, A. H., and Dunstan, A. E., J . Inst. Petroleum Tech., 27, 222 (1941). (11) Sage, B. H., and Lacey, W. M., IND. EXG.CHBM.,30, 673-81, 829-34 (1938). (12) Sage, B. H., Schaafsma, J. G., and Lacey, R. N., Ibid., 26, 1218 (1934). '. N., Ibid., 29. 1188 (13) Sage, B. H., Webster, D. C., and Lacey, W (1937). (14) Sage, B. H., Yale, W. D., and Lacey, W. N., Ibid., 31, 223 (1939). (15) Shepard, A. F., Henne, A. I,., and Midgley, T . , J . A m . Chem. SOC.,53, 1948 (1931). (16) Wiggins, W. R., J . Inst. Petroleum Tech., 22, 305 (193W.
Chemistry of Chlorites-Correction An error has been noted on page 788 of the above article which appeared in the July issue. The curve for the formation of sodium chlorate in acid solution in Figure 2 is incorrect. The value as plotted is ten times too large. It should br 0.0001 mole sodium chlorate which accords with the statements in the text JAMES F. WHITS
