NOTES
184
fects of alternative structures in computing the results have been minimized by attempting to calculate refractivities for the alternative possibilities in doubtful cases, and by eliminating cases in which significant ambiguities appeared.
SUMMARY OF BOND A N D O C T E REFRACTIVITIES ~ NO.
of
B : 0 :Calkyl
Structural refractivity This work Ref. 1
..
52 4
9
12
36
13,1525, 27 5.33
2 . 6 8 + 0.30
B:O:B B:O:Si
..
10
28
6,38.39
3,343~ 0.14
B:CI:
22
31
1,4,14,16. 6.79f0.16 6.7910.21 19.20 2,24,32,34 1.91 f 0.12
B : 0 :CaIyi
171
Ref.
..
F
11
B:Calkyl
16
37
B :Csryl
47
61
3
8
B:F:
B:N
INTERACTIONS I N T H E BINARY LIQUID SYSTEM N,N-DIMETHYLACETAMIDEWATER: VISCOSITY AND DENSITY BY RAYMOND C. PETERSEN Rerearch Laboralon'es, Sprague Electric Company, North Adam8 Maasachusetts Recezved August 11, I969
TABLE I
No. struct. of iteraStructure cpds. tions
Vol. 64
1,2,13-19 3.10f 0.14 3.14f 0.14
3.48f 0.26
1,9,21,22, 1.92fO.10 1.75f0.19 24,31, 36,37 1,3.24-28, 2.01f 0.23 2.96f 0.23 3Z34.35 30 1.85f 0.05
Plots of viscosity versus composition for binary liquid mixtures normally are not linear whether the composition be expressed in units of mole fraction, weight fraction or volume fraction. Beyond this lack of linearity, many binary liquid systems are known for which the viscosity goes through a minimum, while another, less well-known, class of mixtures exhibits a viscosity maximum, an example of this class being water-dioxane.' An especially striking example of this class, due to the exceptional magnitude of its maximum, is found in mixtures of water with N,N-dimethylacetamide (DMA). I n this system, the maximum viscosity is about 4.4 times the viscosity of water, while the viscosity of DMA is just slightly higher than that of water (all measured a t room temperature). Measurements were made of viscosities and, of necessity, densities of several mixtures of DMA with water a t a temperature of 24.05'.
Experimental
Materials.-Eastman Kodak Co. white label DMA was (131 H.Steinberg and D. L. Hunter, Ind. Eng. Cham., 49,174(1957). used without further purification. This material was compared by vapor fractometry with three samples of itself con114) W. Gerrard and &I. F. Lappert, J . Chem. Soc.. 3084 (1955). taining known added amounts of water (from 0.5 to 1,5%) (15) J. A. Blau, W. Gerrard and M. F. Lappert, ibid., 4116 (1957). and was found to contain 0.63 f 0.04% water by weight. (16) E. W. -4be1, J. D. Edwards, W. Gerrard and M. F. Lappert, No other impurities were revealed by the vapor fractomibid., 501 (1957). eter. Water used was ordinary laboratory distilled water. (17) hl. J. Frazer, W. Gerrard and M. F. Lappelt, ibid.. 739 (1957). Mixtures were prepared by weight and compositions deter(18) W. Gerrard, M. F. Lappert and H. B. Silver, ibid., 3285 (1956). mined assuming the DMA to contain 0.63% water. The (19) W. Gerrard, M.F. Lappert and H. B. Silver, ibid.. 1647 (1957). DMA used throughout this series of measurements all came from one bottle. Weights were calibrated against an (20) J. D. Edwards, W. Gerrard and M. F. Lappert, ibid., 1670 N .B .S.-calibrated set of weights. ( 1955). Temperatures .-Temperature was measured by a ther(21) R. Kcster, Ann., 618, 31 (1958). mometer which had been compared with an N.B.S.-Cali(22) W. Gerrard, M. F. Lappert and R. Shafferman, J . Chem. Sac., brated thermometer and was maintained a t 24.05' in an oil 3828 (1957). thermostat bath. Temperature generally varied less than (23) W. Gerrard. M. F. Lappert and R. Shafferman, ibid., 3648 0.05" from this. (1958). Viscosity.-Viscosities were measured in a single Ostwald(24) P. B. Brindley, W. Gerrard and M. F. Lappert, ibid., 824 Fenske size 100 viscometer. Samples were measured into (1956). the viscometer using a 10-ml. pipet, the liquid having been (25) S. H. Dandegaonker, W. Gerrard and M. F. Lappert, ibid.. filtered through glass wool in the process of filling the pipet to 2872 (1957). remove dust particles. Poiseuille's equation, with the (26) P. 8. Brindley, W. Gerrard and hi. F. Lappert, ibid., 1540 kinetic energy correction included,2 was used to calculate vis(1956). cosities. Pure water was used as the reference liquid, its viscosity at 24.05' being taken as 0.9101 ~entipoise.~Ef(27) E. W. Abel. W. Gerrard and M. F. Lappert, ibid., 112 (1957). dux time ranged from 1.2 to 5.4 minutes. (28) E. W. Abel, W. Gerrard and M. F. Lappert, ibid., 3833 (1957). Density.-Density was measured in a Reischauer specific (29) E. W. Abel, W. Gerrard and Af. F. Lappert, iMd., 5051 (1957). gravity bottle having a capacity of about 25 cc. T a t e r (30) W. Gerrard, M. F. Lappert and C. A. Pearce. ibid., 381 (1957). was again used as the calibrating liquid, the density of (31) G. F. Ilennion, P. A. McCusker, E. C. Ashby and A . J. Rutwater at 24.05'' being taken as 0.99728 g./cc.4 The apkowski. J . A m . Chem. Soc., 79,5190(1957). parent precision of measurement was about 0.01%. (32) C. Curran, P. A. McCiisker and H. S. Makowski, ibid., 79, Temperature Dependence of Viscosity.--Viscosities of 5188 (1957). several of the mixtures also were measured a t 26.55' and (33) P. A. McCusker, E. C. Ashby and H. S. Makowski, ibid., 78, the fractional change in viscosity per degree, d In v / d T , was 5179 (1957). computed. Values for mixtures not measured were esti(34) P.-4.McCueker and H. 9. Makowski,
