No.
OCTOBER, 1918.
V o t . XL.
IO.
THE JOURNAL OF THE
American Chemical Society with which has been incorporated the
American Chemical Journal (Founded by Ira Remsen)
[CONTRIBUTION FROM
THE JOHN
HARRISON LABORATORY OF THE UNIVERSITY OF PENNSYLVANIA. ]
NOTES ON NEUTRAL SALT CATALYSIS, I. THE ROLE OF THE SOLVENT IN NEUTRAL SALT.CATALYSIS IN ' AQUEOUS SOLUTIONS. BY HBRBERTS. HARNBD. Received April 5, 1918.
Introduction. Owing to the abnormalities observed in the velocity constants in reactions between ethyl iodide and sodium, potassium, and lithium ethylates Acreel and his associates made the suggestion that both the ions and the undissociated molecules of these substances (e. g., the ethylates) were reactive. Thus: C&I OCzHs' + (CzH5)zO I' C & , I KOCzH6 + (CzHs)zO f KI Let Ki be the velocity constant of the alkyl halide and ethylate ion, K,,, the velocity constant of the alkyl halide and the undissociated sodium ethylate, then the observed velocity constant K will be given by K = niKi nmKm where ni and n, are the respective concentrations of the ion and the undissociated sodium ethylate molecule. In this same series of papers, 1 Acree and Johnson,Am. Ckem. J., 38, 258 (1907);48, 352 (1912). These papers
+
+ +
+
contain a bibliography of the work done up until
1912 on
this type of reaction.
1462
HERBERT S. H S R S E L ? .
Acree employed the theory of the undissociated molecule I o account for the abnormalities observed in catalytic reactions in aqueous solutions such as the conversion of chlorylacetanilide to p-chloroacetanilide catalyzed by hydrochloric acid, the hydrolysis of esters by acids and others. More recently the suggestion that both the hydrogen ion and the undissociated acid molecule have catalytic activities has found supporters in Goldschrnidt, Bredig, Millar and Braune,2 S ~ ~ e t h l a gand e , ~ Taylor.4 If I
