CONDUCTANCE OF SOMESALTS IN ACETONE
July, 1951 c'(d)
0.00810~- 0.003903~'//, 0.00810~- 0.00260ca/n
= 0.99704
+
-
(m/C) X 10''
= 35.6512 -
+ (5)
The third column in Table I contains the results computed by equations (l), (3), (4) and ( 5 ) . With the exception of the result a t the lowest concentration, the agreement of the observed results with theory is remarkably good. A more detailed description of the calculation is illustrated in Fig. 1. I n this figure, the upper (solid) curve represents the calculation by the complete theory and the lower (solid) curve the result obtained by the limiting law of the theorys which for silver nitrate becomes
-
1.040&
(6)
The plot which lies between these results is obtained when (m/C X lozo) is constant and equal to its value a t zero concentration. The difference be(8) Ref. 6, p. 118. (9) Ref. 6, p. 128. (10) MacInnes, Shedlovsky a n d Longsworth, THISJ O U R N A L , 64, 2758 (1932).
[CONTRIBUTION FROM
THE
1.74 10
0
i
Fa
18.959c+(0.995&)
D X 1Oj = 1.7675
1.76
X
0 082414; o.995~/1 +
I
(4)
The mobility term was computed by substituting the values: D = 78.54,8 qo = 8.949 X 10-3,9 T = 298.16, = 61.92 and A! = 71.44 in equation ( 2 ) . The values of the limiting conductances of the silver and nitrate ions were those obtained by MacInnes, Shedlovsky and Longsworth. lo The equation for the mobility term reduces to the numerical form
3293
1.72
1.70
0
0.02
0.04
0.06
0.08
C1/2. Fig. 1.-Upper curve represents complete theory. Lower curve represents the limiting law (Eq. 6). The intermediate curve was obtained by assuming constancy of ( % / c ) .
tween the center and top curve represents the calculated effect of electrophoresis. There seems t o be little doubt from the positions of the circles representing the experimental results that the mobility term is required for the calculation. NEW HAVEN,CONN.
RECEIVED FEBRUARY 26, 1951
METCALP RESEARCH LABORATORY OF BROWN UNIVERSITY ]
Properties of Electrolytic Solutions. LII. Conductance of Some Salts of Acetone BY MAURICE J. MCDOWELL' AND CHARLES A. KRAUS To fill Some gaps in the list of ion conductances in acetone, the conductances of a number of salts were determined in this solvent. Thus, the conductances of the ammonium, the tetramethyl-, tetrapropyl- and tetraarnylammonium ions have been determined. The conductances of octadecyltributyl- and dioctadecyldibutylammonium ions have been determined as also has been that of the chloride ion. Dissociation constants have been evaluated on the basis of the Fuoss analysis. Some comparisons are made of dissociation constants and ion conductances in different solvents.
I. Introduction Reynolds and Kraus2 have measured the conductance of a number of salts in acetone a t 25'. For purposes of intercomparison of ion conductances and dissociation constants of electrolytes in different solvents, the earlier measurements in acetone leave a number of gaps which the present investigation is intended to fill. In particular, the conductances of several symmetrical quaternary ammonium salts have been measured so as to provide data on the conductances of the quaternary ammonium ions from tetramethyl- to tetra-namyl, inclusive. The conductances of the octadecyltributyl- and the dioctadecyldibutylammonium ions have been determined. The conductances (
1) E t h l l Corporation
Fellon
(1947-1948),
ITniversity Fellon
(1948-1849). Metcalf Fellow (1949-1950) in Brown University ( 2 ) M B Reynolds a n d C A Kraus, THISJ O U R N A L , 70, 1709
(lY48)
of the chloride and the ammonium ions have likewise been evaluated.
11. Experimental Apparatus, Procedure and Materials.-The
electrical measuring apparatus and the thermostat were the same as those of P y n o l d s . * The temperature was controlled a t 25 2z 0.002 . With the exception of tetrabutylammoniutn chloride, with which the dilution method was employed, all measurements were carried out according to the procedure described by Daggett, Bair and Kraus3 for aqueous solutions. The conductance cell of the erlenmeyer type had a capacity of approximately 1 liter. Salt samples were weighed out on a microbalance in quartz cups. Since acetone is insensitive to carbon dioxide, samples were introduced into the cell as it rested in the thermostat. The cell was provided with a magnetic stirrer. Acetone4 was purified according to the method of Rey1.
(3) H. M. Daggett, E. J. Bair and C . A. Kraus, ibid., 73, 709 (1951) (4) T h i s material was kindly furnished b y t h e Tennessee Eastmail Company of Kingsport, Tennessee.
Vol. 73 nolds. The solvent coiiductaiice varied between 1-4 X I ( J -g aiicl the maximum correction for solvent cotiductaricc in the most dilute solution was 0.2%. The following salts were prepared by coiiventiorial iriethods and purified by recrystallization from suitable solvents; tetramethylammonium picrate, 1n.p. 318-320'; tetra-npropvlsmmoniurn io:li,le, m . p . 293"; tetra-n-amylammotiium bromide, ni .p. l ( J O o ; octadecykri-n-butylammoiiium iodide, in .p . 101-1 ; tlioctadecyldi-n-butylarnmoiiium iodide, 111.p. 107'. Airunouiuni picrate was recr repeatedly from alcohol and acetone.
Results.---In Table I are presented conductance values for the salts a t the concentrations indicated. Concentrations are expressed in moles of salt per liter of solution assuming the density of the solution to be that of the solvent. I n rriakitig buoyancy corrections, the density of the organic salts has been assumed to be 1.5. In making computations, the density of acetone has been taken to be 0.7843, the dielectric constant, W . 4 i and the viscosity X.040 X poise.: 2.
TABLE^ I COXDLCTANCE OF SOMESALTS IN ACETOSE Ar 25" c x 10' < c x 104 A A . Ainiiioiiiuiii B. Tetrainethylarnpicrate nionium picrate 170.016 0.44390 0 . 0538 176.95 I ) . 83417 164.354 1.3292 173.86 1.7149 1S4.734 2,9794 168.5i .3' , 0237 144.452 4.625Cj 163.05 .5.2188 132.389 6,2838 ltil 44
C. Tetra-n-propylstninoniuin iodide 0 ,4105 184,94.5 0.8040C 182.129 1 ,5732 177.832 3 1533 1i1.286 3 , 0574 165 :121
D. Tetra-n-ainylammonium bromide 0.29802 169,'30 0.72344 166.66 1,3930 162.71 2 7820 135.48 5 6153 147.64
E. Octxlecyltributyinnimonium iodide 0 10813 61. 12 ii0 00 2387 143455 58.49 636288 57.04 10712 54 0 1
1'.
Dioctadecyldibutyl;tininoiiium iodide
0 . 18042
26540 54327 1.2474 I , 95G6
151.ti6 1,53 , 55 151.tj7 148.21 145.31
G. Tetra-iz-hutylaminonium chloride'' I . 97x9 154.79 1,0084 160,2
