O S T H E REACTIONS O F BOTH THE I O S S A S D T H E JIOLECULES O F ACIDS, BASES A S D SALTS T H E REACTIOK OF SODIUM ETHYLSTE WITH ETHYL BROMIDE AKD ETHYL IODIDE IK ABSOLUTE ETHYL ALCOHOL AT 2 5 " BT
E. K. bIARSHAU,L, JR.
AND
S. F. ACREE
[Twentieth Communication on Catalysis] In March, 190j,' Brunel and ilcree began to measure the conductivities of urazoles and their salts and the velocities of their reactions with alkyl halides, to learn whether both the urazole ions and the nonionized urazole salts are active. Up to that time chemists had generally believed that the ions are the only portions of electrolytes which show any considerable actiT7ity. The contribution from our laboratory, therefore, was in calling the attention of chemists to the prooj q f the large a c t i z i f j , of itoizio?zized electrolj tes, to which Kahlenberg,3 especially, and also Michael4 and Armstrong, had so often and ably directed their efforts. The work of Blanksma,j and later of Johnson and Acree6in 1907, on the rearrangement of acetylchloraminobenzene ICH3CONC1C6Hj)in the presence of hydrochloric acid was interpreted by Johnson and Acree as a decomposition of the noif ionized salt, CH3COKHC12C6H5,
+
the cation, CH3CONHC1C6H5,seeming to enter into the reaction to a very small extent only, if a t all. TVe gave the For the earlier papers see Am. Chem. Jour., 49, 474 (1913). Jour. Chem. SOC.,105, 2582 (1914). This work was finished in 1910-1911 and withheld from publication till this chapter could be more nearly completed. As Dr. Marshall has withdrawn from the investigation on account of other duties it seems wise t o present the experimental evidence without further delay. \Ye are indebted t o the Carnegie Institution of Washington for aid in this work.S.F. ilcree. * Xm. Chem. Jour., 43, joj (1910). 3 Jour. Phys. Chem., 5, 339 (1901);6, I (1902). Am. Chem. Jour., 43, 322 (1910). Rec. trav. chim. Pays-Bas, 21, 366 (1902); 22, 290 (1903). Am. Chem. Jour., 37, 410; 38, 266 (1907); 41, 461 (1909).
E . K . Marshall, Jr., and S. F . Acree
5 90
equation dx dt = KtransX a ( A - x)’)for the ionic reaction,‘ as Arrhenius, Ostwald, Walker, Stieglitz, Bredig, Goldschmidt, Lapworth and others had done before, and then gave the equation dx dt = K’trans( I - a ) ( A - x)? for the activity of the “undissociated acid, base or salt,”? the first time this latter equation was ever used for the large3 activity of a nowionized electrolyte. I n May, 1908, Rogers and Nirdlinger4 completed their work on the action of ethyl iodide on sodium I-phenyl-3thiourazole in absolute alcohol a t 25 O, which showed beyond question that the ethyl iodide reacts with the urazole a?zion with a velocity K, = 0.43 and also with the nonioniged sodiunz urazole with a zelocity K, = 0.17. The same work was repeated recently, under somewhat better conditions, by Dr. J. Chandler, who finds nearly the same values, K, = 0.46 and K, = 0.16. Dr. S. K. Loy, in 1909, and Dr. H. C. Robertson, Jr., in 1910, did work with alkyl halides and sodium ethylate and sodium phenolate, respectively, which showed clearly that the ethylate and phenolate ions react side by side with the nonionized sodium ethylate and sodium phenolate. Since 1908 our efforts have been to apply our theory to as many cases as possible involving interreactions or metatheses, such as C2HiOKa I C z H j + (C2Hj)20 KaI, and purely catalytic changes, such as C2H50Ka CH3C IX C2HOH C2H50Na CH3C(:KH)OC2H5,and intramolecular rearrangements, such as
+
+
+
+
+
Shadinger and Acree: Am. Chem. Jour., 39, 227 (1908). Ibid., 39,2 2 8 (1908). Stieglitz (Jour. Am. Chem. SOC.,35, 1774(1913)) states that he looked upon the decomposition of free imidoesters as the slow change of a nonionized electrolyte. Although our theory had already appeared (Am. Chem. Jour. 37, 410; 38, 258 (1907)) Stieglitz overlooked the possibility that the “salt effect” discussed by him in his papers of 1908 could be due to the nonionized imidoester salts and has only recently used OUT equations to reinterpret his results in the light of this theory that both the ions and the molecules of imidoester salts can be hydrolyzed (Jour. Am. Chem. Soc., 34, 1687, 1688, 1689, 1690, 1694 (1912)) 4 Am. Chem. Jour., 43, j I g (1910); 49, 116 (1913). Ibid., 43, 519 (1910); 49, 474 (1913).
0% the Reactions o j I o m , Etc. CH3CONClCsHj
+ H+ + -C
591
1 S CHsCONHCIzCe Hg + CH3CONHCcHdCl
+ + 51.
These three, together with oxidation and reduction, are the most important classes of reactions. Since we have found our theory to hold in about thirty cases worked out by us i71 both concentrated ( A , ,I to S 32) and ideal (S32 to 12.”zo&?) s o h t i o n s and in our reinterpretation1 of the work of Arrhenius, Ostwald, Koelichen, Tubandt, van Dam, Bredig, Goldschmidt, Stieglitz, Holmberg, Senter, Walker, Conrad and his coworkers, Segaller, Bruyn, Lulof, Steger, and others, on organic reactions, and in certain inorganic reactions, and especially as *4rrhenius, Goldschmidt, Bredig, Biddle, j Stieglitz, Holmberg, Dawson,8 Kilpi, Worleylo and others are now beginning to use this theory, we are now bringing out the details of our work. We wish to emphasizell that we realize that we must later correct the data for certain “abnormal salt effects’’ when we study more fully other possible side reactions, and the physical factors, such as viscosity, solvation, ionic velocities, electronic phenomena, and the reaction velocities in very dilute solutions in all cases. The present communication deals with the study of the reaction between ethyl bromide and sodium ethylate and ethyl iodide and sodium ethylate, in absolute ethyl alcohol at 25’. The experimental methdds used have been described in some detail in former papers.12 The ionization was measured by ilm. Chem. Jour., 48, 352 (1912); 49, 345, 369 (1913). Arrhenius and Taylor: Memoirs of the Nobel Institute, Vol. 2, Nos. 34, 35, 37. Zeit. Elektrochemie. 15, 6 (1909); Zeit. phys. Chem., 70, 627 (1910). Zeit. Electrochemie, 18, 535, 543 (1912); Zeit. phys. Chem., 85, 129, 170, 2 1 1 (1913). Jour. Am. Chem. SOC.,36, 99 (1914) and earlier papers. Jour.Am. Chem. SOC., 34, 1687, 1688, 1689, 1690, 1694 (1912); 35, 1774 (1913). Zeit. phys. Chem., 84, 451, 468, 469 (1913). * J o u r . Chem. SOC.,103, 2135 (1913). Zeit. phys. Chem., 86, 427, 644, 740 (1913). l a Phil. Mag., ( j ) 27, 459 (191j). Am. Chem. Jour., 49, 4 8 j (1913) and earlier papers. l2 Am. Chem. Jour., 49, 116, 1 2 7 , 369, 486 (1913) and earlier papers, ?
E . K . Marshall, Jr., iind S . F. Acree
5 92
Dr. H . C. Robertson, Jr., to whom we are greatly indebted for this and other valuable aid. The data presented here harmonize with the idea that the alkyl halide reacts with both the ethylate ion and the nonionized sodium ethylate according to the equation K N = K,a K,(I - a ) , developed in the earlier papers.' The values K, = 0.00576 and K, = 0.00233 found by us for ethyl bromide and sodium ethylate at 2 5 ' agree closely with K, = 0.00557 and K, = 0.00232 observed by Dr. Julia Peachy Harrison in a repetition of this work, and the same is seen in the tables on page 606 to hold for the work on ethyl iodide and sodium ethylat e. The best confirmation of our theory, however, comes from the study of the reactions of ethyl bromide (and also methyl iodide and ethyl iodide) with potassium ethylate and lithium ethylate. If our theory is correct we should find the same? value for the acti;iity of the ethylate ion, whether it comes from sodium, potassium or lithium ethylate. But the noniovlized sodium, potassium and lithium ethylates are difjerent substances and could, therefore, react with difjerevlt celocities with ethyl bromide. The confirmation of our theory lies in the fact that Dr. Harrison and Dr. Shrader, in work on ethyl bromide and potassium and lithium ethylates, have actually found practically the same values for K,, but difjerent values for K,, which are shown in the following table:
+
___
-
~~~ ~
~~~
~~
~
-
_____-
~-
K, _____
~~~
~
__
Dr. Marshall: sodium ethylate and ethyl 1 0.00576 bromide Dr. Harrison : the same 1 0 00543 Dr. Harrison: potassium ethylate and ethyl 0.00539 bromide Dr. Shrader: lithium ethylate and ethyl 1 bromide I o 00574
Kin _____
~
0.00233 0.00237 0
00296
0.00157
Am. Chem Jour, 37,410;38, 258 (1907);4 3 , 5 1 9 (1910); 48,352 (1912); 49,477 (1913) 2 See I b i d , 39, 229 (1908);43, 507, 519 (1910); 48, 352 (1912)and later papers.
011
the Reactions o j Io.tis, Etc.
5 93
Our work on sodium ethylate and ethyl iodide at 25' in the second section of the experimental portion gives the values Ki = 0.0120 and K, = 0.00427 found in Table XIV. These agree very well with the data Ki = 0 . 0 1 2 2 and K, = 0.00402 obtained by Dr. Shrader in his repetition of this work. I n confirmation of this theory Dr. Shrader and Dr. Harrison have found that potassium and lithium ethylates and ethyl iodide give practically the same values for Ki but different values for K, shown in the following table:
Dr. Marshall: sodium ethylate and ethyl iodide Dr. Shrader: the same Dr. Harrison: potassium ethylate and ethyl iodide Dr. Shrader: lithium ethylate and ethyl iodide
o o
0120 0122
0.00427
o
0122
0.004j7
0.0121
0.00402
0.00304
I n later articles giving our work on the reactions of methyl iodide, ethyl iodide and ethyl bromide with sodium, potassium, and lithium ethylates and phenolates we shall show that each alkyl halide gives practically the same value for its K,, whatever the ethylate or phenolate used, but that the nonionized ethylates and phenolates react with different velocities with the same alkyl halide, in conformity with our theory. The best evidence for our theory comes, not from the above work in co?zcevtrated solutiovs, but from the investigations of Dr. E. K . Marshall,' Dr. Julia P. Harrison,' and Dr. C. X . Myers3 on the purely catalytic action of dilute solutions (S32 to iV 2048) of sodium, potassium and lithium ethylates on the reversible addition of ethyl alcohol to nitriles, RC N HOC2Hj NaOC2HjC _ R C ( : NH)OC2Hj SaOC2H5. Dr. Myers' investigations on p-bromobenzonitrile show beyond question that both the ethylate ions and the nonionized ethylates
+
+
Am. Chem. Jour., 49, 1 2 7 (1913). Ibid., 49, 369 (1913). Ibid., 49, z z z , 132, 485 (1913).
+
5 94
E . K . !lfarskzall, J r . , and S.F . Acree
must be considered active even in the ideal or dilute solutions. In accordance with the theory he obtains the same value for Ki for the ethylate ion common to all three ethylates, but different values for the activity, K,, of the three nonionized ethylates. Sodium ethylate gave the values Ki = 0.161 and K, = 0.158, potassium ethylate gave K = 0.163 and K, = 0.144, while lithium ethylate gave K i= 0.159 and K, = 0.093. Dr. Marshall and Dr. Harrison found the values Ki = 0 .I I 72 and K, = 0.0976, and Ki = 0.344 and K, = 0.228 in their work on the action of sodium ethylate on benzimidoethylester and acetimidoethylester, respectively.
Salt Catalysis Arrhenius called the deviation from the purely ionic reaction a “salt catalysis.” This same idea has been used since by Eulerl and by Stieglitz,2both of whom believed that this change in velocity in reactions involving water is due to a change in the ionization of the water. We have shown in another article3 that though his ideas have much for praise, Stieglitz’s own very fine work shows that his reaction velocities do not increase with rise in temperature anywhere nearly as much as the increase in the ionization of the water demands. In our theory of salt catalysis we broke away4 entirely from the purely ionic reaction of chemical activity and began to investigate whether the so-called “salt catalysis” may not be due in part or in whole to the activity of the nonionized electrolytes. We proved experimentally that the added salt or other electrolyte may have a “normal salt effect” arising from the changes in ionization conforming to the Arrhenius theory of isohydric solutions, and may also have an extra specific abnormal salt effect” not yet understood. This theory has been 1 Zeit. phys. Chem., 32, 348 (1900); Ber. deutsch. chem. Ges., 39, 2726 (1906). ZAm. Chem. Jour., 39, 29, 166, 402, 437, j86, 719 (1908); Jour. Am. Chem. soc., 32, 2 2 1 (1910); 34, 1687 (1912); 35, 1774 (1913). 3 Am. Chem. Jour., 41, 466-483 (1909); 48, 369-372 (1912). 4 Ibid., 38, 273 (1907); 39,230 (1908); 48, 356 (1912) and later papers.
Ox the Reactions
OJ
I o m , Etc.
595
recently accepted and used generously by Arrheniusl and Stieglitz.2 It should be suggested that the “abnormal salt effects” perhaps involve electronic transfers through portions of the electrolyte not directly concerned in the reaction. I n this connection we wish to emphasize especially that the addition of neutral salts in our own and the reactions studied by others seems to keep the reaction velocities much more constant, especially toward the end of the reaction. These facts will be discussed later in great detail. That there may be a small “abnormal salt catalysis” in the present data can be seen from the following: Suppose that there is a small negative salt catalysis proportional to the total concentration of sodium ethylate, or sodium bromide formed, irrespective of the ionization, the factor being 8 percent per gram molecule. The equation Kr; = [K,a K,(I a ) ] [I - 0.08 Csalt]then gives us the true d u e s for K,a K,(I - a ) = K’s found in Table XVI instead of those in Table XI. From these new values of K’K we find the values for P and K, given in Table XVI, namely K, = o.ooj40 and K, = 0.00260, respectively. These differ only slightly from those found by Dr. Harrison for potassium ethylate and by Dr. Shrader for lithium ethylate and the differences may then . be considered close to the experimental errors. I n the work on sodium ethylate and ethyl iodide a t 2 5 ’ in the second section of the experimental portion we give in Tables XVII and XVIII the data that would be obtained for K, and K, if the sodium ethylate, or sodium iodide formed, can exert a positive abnormal salt effect ” of 8 percent per gram molecule of total salt, ionized or nonionized. It is seen in Table XVIII that K, and K m are changed from 0 . 0 1 2 0 and 0.00427, found in Table XIV, to 0.0132 and 0.00372, respectively. This positive ‘‘ abnormal salt catalysis” of 8 percent per gram molecule therefore lowers the K, about 9 percent
+
+
Arrhenius and Taylor hIemoirs of the hTobel Institute, T’ol 2, S o s . 34, 35, 37 *Jour. Am. Chem. SOC.,34, 1687, 1688, 1689, 1690, 1694 (1912); 3 5 , I774 (1913)
596
E . k‘. 3larslzal1, J r . , and S.F . Acree
and raises the K, about 14 percent. These values are much larger than the experimental errors of the work. This shows us that a small “abnormal salt catalysis” may be involved in all the values of K, and K, calculated by the above methods, even though we secure excellent agreement among the values for K, from the sodium, potassium and lithium ethylates. We are, therefore, justified in concluding that the “abnormal salt effect,” whether m a l l or large, is about the same for all three of these ethylates. TVe cannot determine the exact magnitude until our work in the dilute solutions is completed, but the work of Dr. B. Marion Brown on the influence of sodium iodide on the reaction of methyl iodide with sodium ethylate a t 25’ seems to show conclusively that both the sodium iodide and sodium ethylate have a measurable influence on the reactions of the ethylate ions and nonionized sodium ethylate. In order to secure the data necessary for a final solution of this problem of “abnormal salt catalysis” much more work is needed. Experimental The reactions of sodium ethylate with the alkyl halides have been studied by several investigators, most notably Hecht,l Conrad and Briickner, and Conrad2 and Bruckner. That these workers did not consider these reactions as even ionic, much less both ionic and molecular in the sense that we use in our theory, is shown by their ~ t a t e m e n t : ~“ D a dieses Gesetz fur die Elektrolyte allgemeine Giiltigkeit besitzt, so war es von Interesse zu untersuchen, ob dasselbe auch auf nichtleitende (Italics ours!) Korper, wie Alkylhaloide und Metallalkylate, ausgedehnt werden darf. ” Furthermore, Conrad and his workers apparently never made any conductivity measurements with the ethylates in alcoholic solutions, which Bruyn and Tijmstra‘ and also Dr. H. C. Robertson, Jr., have found to be comparatively strong electrolytes. These Zeit. phys. Chem., 3, 4 j o ; 4, 274 (1889); 5, 289 (1890) Ibid., 4, 631 (1889); 7, 274, 283 (1891). Ibid., 5 , 289 (1890). Ibid., 49, 345 (1909).
0 7 1
the Reactions o j I o m , Etc.
597
investigators showed that the velocity of the reaction increases with dilution, they measured the increase in reaction velocity with the rise in temperature, and they proved that the formula Ks - K, = a log V, or more generally K’K - K K = a log iV‘ V) in which KIF and Ks represent V‘KV and VKV, as used in our former articles, gives very close agreement between their found and calculated reaction velocities. This equation took no account of the changes in ionization and we2 have K’K - K s now found that it holds because the equation a = ~- log (V’, T)
(I(t
--I(nJ(a’
-a )
can be derived from a comparison of our
log (V’ ’ v r -
equation Kx
+
K,CY K,(I - a ) with theirs. The dilution formula. kgcVtiq) = K, derived from these equations has =
a’ - a
been found to hold fairly closely for all of our concentrated solutions of strong and weak electrolytes in alcohol and we shall attempt to extend this to all other known data on ionization. The experimental methods described in previous papers have been used, with modifications, in the present studies. The reaction was followed by titrating the ethylate with acid, the values given for A and x representing the number of cc 2 , -Y 4, etc., acid required to neutralize 20 cc or of S I , 40 cc portions in the presence of methyl orange. The unit of time, t , is the minute. When the values of Kv, Kv(, Kv. are multiplied by V, V’, V”, etc., we obtain Ks, K f x , KIIs, etc., the reaction velocities of normal solutions having the ionizations corresponding to the concentrations I V, I V’, I V”, etc. A comparison of the simultaneous equations K s = K,CY K,(I - a ) , K’N = Ksa’ K,(I - C Y ’ ) ,K‘‘N = K,aN 3- K,(I - CY”)which are solved by the use of the equa-
+
+
l Ibld , 5 , 289 (1890). Dr J. H Shrader [Jour. Chem. Soc , 105, 2 j S 2 (1914)] and Dr. \V. A Taylor have reinterpreted their excellent data by the use of our theory and shown that both the ethylate ions and nonionized sodium
ethylate seem to be active Shrader and Acree: Jour. Chern. SOC, 105, Taylor will soon publish his results along this line.
2jS2
(1914). Dr
W. A.
E . K . ;ZIarshall, J r . , and S.F. Acree
598
gives us the values of K, and K,, as illustrated in Table XI11 of both sections. Those values of K, and K m with asterisks involve smaller errors in a’-a, but the average of these is practically the same as the average of all the values of K, and K,, as can be seen in Table XI11 of both sections. K, and K, represent the velocities of the reaction of a gram equivalent of ethylate ions, and of nonionized sodium ethylate, respectively, with a gram molecule of the alkyl halide in one liter. When the average values of K, and Km are substituted in the equation KX = K,a -tK , ~ I - a ) we obtain the theoretical reaction velocity, ‘‘ Ks Calculated,” which is compared with “ K s Found” in order to give the experimental “Error in Percent” shown in Table XIV of both sections. The percent of reaction due to ions and that due to molecules are given in Table X V of both sections. The values of 01 are taken from’ a former article. The addition of considerable quantities of ether and sodium iodide to some of the reaction mixtures shows that the small amounts of these substances formed during the time periods measured have no great effect on the reaction velocities, as is also shown in the next communication on this subject. Sodium Ethylate and Ethyl Bromide at 25” C TABLE 1 TABLE I1 -1-Sodium Ethylate and S Ethyl -YSodium Ethylate and Ethyl Bromide
[ 30 60 go I10
130
0.819 1.486 2.064 2.413 2.703
Bromide
0.0029;] 0.00~91 0.00289 0.00289 0.00289
Mean = 0.00290 Kr; = 0.00290 Jour. Phys. Chem., 19,407 (IgIj)
60 90 I20
150 I70
1.459 2.056 2.557 3.003 3.260
0.00284 0.00287 0.00286 0.00286 0.00285
Mean = 0.00286 Kx = 0.00286
On the Reactions o j I O N S Etc. ,
TABLEI11 0.5 iY Sodium Ethylate and 0 . j X Ethyl Bromide -4 = t
30 IOO
130
160 I1180
x
= 10.00
t
KV
0.452 0,724 0.980 1.342 1.690 1.990 6.366
50 70
TABLG IV
S Sodium Ethylate and 0.5 S Ethyl Bromide
0.5
10.00
X
599
X
KY
0.00157
jO
0,738
0.00154
80
1.112
0.00159 0.00156
0.001jj
I10
1.444
0.0OIjq
0.00155 0.00156 0.00155
140
1.800 2.090
0.001j7
I70
0.OOIjj
Mean = 0.001j6 KN = 0.00312
0.001~gl
Nean = o.oo15j KN = 0.00310
TABLEVI
TABLEV
S Sodium Ethylate and
0.25
0.jAi
-1=
___t
Ethyl Bromide B = 20.00
10.00
~
____
1
x KV
0.25
S Sodium Ethylate and A
S Ethyl Bromide B = 40.00 __
= 10.00
~~-
t l X
Kv
1
0
0.000806]
1
62 1.26 1.82 2.33
'
2.77
0.000854 0.0008j6 0.000854 0.000843
~-
[zo jO
I 1
80 IIO
170 1260
0.296
1 0.808
I
1.216 1.612 2.360 7.760
1
o 0007561 0.000858 0.000836 0.0008~2
0.000843 0.000796 ___-
Mean = 0.000845 KN = 0.00338
[20
40 60 80 IO0
1
1
Mean = 0.000852
K~v. = 0.00340
E. K . Marshall, Jr., and S. F. d c r e e
600
TABLEVI1 0.125 N Sodium Ethylate and 12' Ethyl Bromide A = 10.00 B = 80.00 ~~
TABLEVI11
-
-
t
jo 80 IOO
I20
140 [275
X
Kv
1.68 2.52 3.03 3 .j 3 3.96 6.12
0.00046j 0.00046I 0.00046 I 0.000463 o 000463
-Y Sodium Ethylate and
0.125
X _
S Ethyl Bromide B = 80.00
= 10.00 _
f
~~________
.
~
IO0 I20
140 160
0.00046j 0.000466 0.000463 0.00046I
0.00046 I 0.0004j 8
Mean = 0.000462 K s = 0.00370
TABLE X 0.062j
-IiSodium Ethylate and
0.j
A
AT Ethyl Bromide B = 160.00
= 20.00
~~~~
t
Kv
X
-
~
j O
80 IIO
130 150
~~~
~
I 86 2.92 3.92 4 50 5.12
-~~
t
Z
'
KV
-~
o 000244 0.000249 0 000251 o 000249 0 000249
Mean = 0.000248 K N = 0.00397
__
KV
1.98 2.61 3.0j 3 .j I 3.95 4.34
Mean = 0.000463 K s = 0.00370
TABLEIX 0.062j S Sodium Ethylate and 0.j S Ethyl Bromide A = 20.00 B = 160.00
_
3:
60 82
O.OOO~~Z]
_
60
2.20
80
2.88
IOO
3.61 4.51 j.13
130 IjO
0.000244 0.000244 0.0002 j I
o.000249 0,0002 j 0
Mean = 0.000247 Kr,. = 0.0039j
On the Reactions
2
oj
Ions, Etc.
o 00311
o 00312 0
60 I
00338
1-
1-0.
0. ~~~~
o 148 0 234 0.312 0 393 o 481 0 577 o 605
I l
2
4 8 16 32
I
40
TABLE XIII-K,
AXD
~~
~
~
o o o o 0
0 0
852 766 688 607 519 423 395
K, FOUND FOR SODIUM ETHYLATE AND BROMIDE AT 2j"
ETHYL
Ki
I ~~~
v v v V V
I = 1 : v = 2
= = =
1:v = 4 1:v = 8
I:V= 16 4
V
= 2:v= = 2:V = = 2:V= = 4:v= = 4:V =
V
=
8:V
16
V V
v
=
8 16 8 16
!
i
! ~
~
i
0.00527 0.00533 0.00573* 0.00567* 0.00586 0.00595* 0.00 j 75* 0.00602 0 . ooj 71 * 0.0Ojjo
&Mean, 0 . 00570 Mean,l 0.00576 The average of all values with stars.
0.00248 0.00242 0 . 00238*
0.00240* 0.00228 0.00224*
0.00230* 0.00220
0.00235* 0.00253 0.00236 0.00233
E . K . Marshall, J Y . , and S. F . Acree
602
TABLE XIV-Kr;
CALCULATED AND FOUND FOR SODIUM ETHYLATE AND ETHYL BROMIDEAT z j o _______ Variation in percent from K N found
Kr; calculated
I 2
4 8 16
0.00288
0.0028j
0.00311 0.00339 0.00370 0.00396
0.00314 0.00340 0.00367 0.00396
TABLE XV-PERCEXT
OF
.o .o +0.3
0.00284 0.00313 0.00340 0.00368 0.00398
.3 +0.6 +0.3 -0.5 +0.5
--I
--I
+I
-0.8 0.0
REACTION DUE TO IONSAND TO MOLECULES
-
~
-
~
~
~
'
I
Concentration of NaOCzHs
Percent of reaction due to CYK,
17
Percent of reaction due
to
'
4
8
16
-c~)Km
70.0 56.9 47.1 38.5
30.0 43 1 52.9 61.5 69.6
I 2
(I
30.4
TABLE XVI-KN FOR SODIUM ETHYLATE AND ETHYL BROMIDEAT 25 ', CORRECTED FOR A NEGATIVE SALT CATALYSIS O F 8 PERCENT PER GRAMMOLECULE OF SODIUM ETHYLATE -
T'
~
~
_
~
_
_
~
~~- ~ ,
~~
ff
I I
0.148
2
0.234 0.312 0.393 0.481
4 8
16
_-
K N corrected for
i i
0.852
o.766 0.688 0.607 0.519
~
0.00284 0.00313 0.00340 0.00368 0.00398
0.00307 0.00326 ~
0.00372 o.00400
01%the
TABLEXVII-Ki
ASD
Reactioizs o j Ions, Etc.
K,
603
FOCND FOR SODIUM ETHYLATE AND
ETHYLBROMIDE-41 2 j 0 , CORRECTED CATALYSIS
OF
~. _ . ~ ~ -
~
FOR A NEGATIVE SALT 8 PERCENT PER GRAMMOLECULE OF SODIUMETHYLATE - -~ _ ~~~~~~
~~~~
~~
~
.
~~
_
_
_
_
__ ____ ~ ____
_
K,
K?n
0.0049j
0.00274
0.OOjIj
0.0027 I
0.00 j33
0.00268
0.0054j
0.00266 0.00263 0.00259 0.00256
0.00532 0.00534 O.OOj5j
0.00251
0.00559 0.00563 0.0056j
0.00249 0.00247
Av., 0.00540
0.00260
Sodium Ethylate and Ethyl Iodide at 2 5 " C TABLE I TABLE I1 AT Sodium Ethylate and iY Ethyl N Sodium Ethylate and A: Ethyl
A
Iodide = 10.03
Iodide = 10.03
A
I
t
x
1.003 1.452 1.830 2.168 2.370
1
1
Kv
t
l
x
0.0055
20
I
,042
0.0058
0.0056
30 40 50 60
1.424
0.OOjj
1.787
0.0054 0.0054 0.0054
0.00jj 0.0055 0.0052
Mean = 0.00546 K s = 0.00546
I34 2,455
2 .
Mean = o.ooj43 KN = 0.00j43
E . K . ,Warshall, Jr., and S . F. Acree
604
iY
0.5
TABLE I11 Sodium Ethylate and 0.5 N Ethyl Iodide A = 9.99
___-
___ I
t
TABLEI V 0.5 -7- Sodium Ethylate 0.5 4VEthyl Iodide A = 9.98 -_
~
-
Kv
X
__
-~
-
t
~
1
83 1 09 1.32 1.53 1 73
0
70
00305 o 00306 0.00305 o 00302 0.00300
_~
0
I
~
Mean = o 00304 KN = 0.00608
TABLEV
AV Sodium
0.25
0.j
A _
_
-
= ~
Ethylate and A' Ethyl Iodide 10.02 B = 20.04 ~
~ _ -~ _ __ _ _
Kv
X
~
30 40 50 60
--
30 40 50 60
~___
0.00307 0.00306 0.00306 0.00306 0.00305
0.58 0.84 1.09 1 33 I 55
20
and
Mean = 0.00306 KN = 0.00612 T.4BLE VI 0.25 A- Sodium Ethylate and 0.5 A' Ethyl Iodide
__
I
t __ ~-
X
--
I
40 50 60 70 80
t
KV
I
1.24
0.0017 I
20
I . 52 I 76 2.02
o 00171 o 00169 o 00169 o 00169
40 60 80
2.25
Mean = o 00170 KN = o 00680 TABLE VI1 0.125 N Sodium Ethylate and 0.5 N Ethyl Iodide A = 10.00 B = 40.00 _ _ _ _ ~ -
t
40 60
80 IO0
120
__ I
0.64 1.25 1.77
0.00168 0 . OOI 7 0 0.00170 0.00166 0.00 I 68
2.21
2.68
IOO
Mean = 0.00168 Kx = 0.00672 TABLE VI11 0.125 S Sodium Ethylate and 0.5 A- Ethyl Iodide X = 10.00 B = 40.00
~~
Kv
X
___
X
~
-
I 30 1.94 2.50 3.01 3 34
~~~
'
t
X
Kv
1.34 1.97 2 . jo 2.98 3.46
0.000g11
~-
o.oo0881 o 000918 o 000928 0.000932 0.000886
Mean = o 00091 KN = o 00728
40
60 80
,
IOO 120
I
1
0.000937 0.000928 0.00092 I 0.000928
Mean = o.ooog2g Kx = 0.00740
On the Reactions of’Ions, Etc.
TABLE IX o.062j A- Sodium Ethylate and 0.2 j AT Ethyl Iodide A = 20.00 B = 80.00 ~~ ~
t
o o o o o
1 58 2.34 2 96 3.60 4.20
60 80
IOO I20
__
~
t
Kv
X
~~
~~
40
TABLEX 0.0625 S Sodium Ethylate and 0.2j N Ethyl Iodide A = 20.08 B = 80.32
KV
X
605
000518
40
1.55
0.000506
oooj25
60 80
2 27
0 . 0 0 0506
2.94 3.j 2
0.000502
IO0
I20
4 22
oooj09 oooj06 oooj04
0.000493 0.000jog
Mean = o.ooojo2 K N = o 00803
Mean = o.ooojo7 K s = o 00811
TABLEX I 0.0625 AT Sodium Ethylate and 0 . 2 j S Ethyl Iodide
X
= 20.00
B
= 80.00
~ ~
t ~~
X ~
____~
60
27 95 3 57 4 23 6.14
80 100 120
190
- - ~
2
o oooj09
2
o OOOjO8
o
000502
0
ooojog
0.000 j02
Mean = o oooj06 KN = o 00809
FOUND FOR SODIUM ETHYLATE AND ETHYL IODIDE
TABLE XII-KN -~
-~ _ _ -~ ~~
Cone. KaOCzHfi
~-
~~
0 . 0 0j46
0.00545
0.00 j43
. 0.00608
0.006I 2 0.00680 0.00672 I
, 16 ~
0,00728
0.00740
0.00811 0.00803 0.00809
____ -
~-
~~
K x Average
KN
v
~~~~
0.006IO 0.00676 ~
I
I
I
4
0 .007 3
0.00808
E. K . Marshall, Jr., a.lzd S . F. Acree
606
a
I
b ~
0.00545 2
o.00610
0.00537 0.00602
o.ooj41 0.00608
-
+I.5 +1.3
+0.8 +0.3
O?z the Reactiom o j Iovs, Eti.
607
FOR SODIUM ETHYLATE A N D ETHYL IODIDE AT 25 O , CORRECTED FOR A POSITIVE SALT CATALYSIS OF 8 PERCENT P E R
TABLE XVI-Ka
GRAMMOLECULI ~
vi
I-CY
___
2 I
K s calculated
KN corrected for
0.00541 0.00608 0.00668 0.00781
0.00498 0.00584 0.00655 0.00773
a:
~
4 8 16
0.148 0.234 0.312 0,393 0.481
salt catalysis
T
1 ABLE hL ll-& AKD K , n FOUND FOR 30DIUR.I D l H Y L X T E AND ETHYLIODIDE AT 2 j 0 , CORRECTED FOR A POSITIVE SALT CATALYSIS OF 8 PERCENT PER GRAMIIOLECULE O F --
_ _ ~
~-
~
-~
~~~~
SODIVM ETHYLATE
K,
KZ
0.0135 0.0131 0.0145 0.0126 0.0129 0.0150 0.0124 0.0166
0.00350 0.00356
0.0122
0.00398 0.00679
0.0092
0.00322
0,00353
0.00372 0.00305 0.0038j 0.00201
.
u “U3,
L
Conclusions I . In this article we have shown that the theory that the ions are the only chemically active portions of the electrolytes is only partly correct, and that much of the earlier work on which this theory was based was interpreted unfortunately. We have, therefore, proposed the hypothesis that both the ions and nonionized forms of acids, bases and salts may undergo transformation with comparable velocities. These reactions may be influenced by so-called “salt effects” and other physical factors which we are investigating further. 2 . A list of tables is given in which we present the velocities of the reactions of sodium ethylate with ethyl bromide and
608
E . K . Marshall, J r . , and S. F. Acree
with ethyl iodide a t 2 5 ' in absolute ethyl alcohol, the concentrations varying from i"V"1 to LV 16. 3. The proper numerical data have been substituted in the general formula K N = K,a Km(1 - CY), and the series of simultaneous equations so obtained solved. Constant values are obtained for K, and K m ,which represent the velocity of transformation of unit concentrations of ethylate ions, nonionized sodium ethylate and alkyl halide. We have interpreted this fact as evidence that both the ethylate ions and the nonionized sodium ethylate react with the nonionized alkyl halide, although we wish to point out that there may be still other side reactions or "abnormal salt effects" involved which we do not yet understand. 4. If this theory is correct the same values should be obtained for K,, the velocity of transformation of unit concentrations of the ethylate ions and a given alkyl halide, whether the source of the ethylate ions be the sodium, potassium, lithium or other salt. The work reported here and other studies by Dr. Julia P. Harrison and Dr. J. H. Shrader, which were given in the table on page 593 and will be presented in later articles, show that the same alkyl halide actually does give practically the same value for K, for sodium, potassium and lithium ethylates. 5. The effect on K, and K, of a positive or negative salt catalysis of 8 percent per gram molecule of the electrolyte was calculated in order to see the extent of the errors involved in these constants. 6. We are investigating the peculiarities, or abnormalities, of the concentrated solutions (absolute alcohol) as rapidly as possible by attempting to measure their physical properties, especially the fluidities of the solutions by Bingham's methods, the effect of added salts on the reaction velocities and physical properties, and the probable extent of solvation (alcoholation) of the reacting constituents by Washburn's methods. These physical factors and the electronic phenomena probably play a r61e having far greater significance than we can possibly understand with our present knowledge.
+
Johns Hopkins Universzty
