154 Van Name and Maryott — Chlorination of Benzene. 



and more or less distributed through the liquid. It is a matter 

 of some importance to distinguish between these two processes. 

 It may happen that (a) and (b) occur together but give dif- 

 ferent products, but in any case where the products are the 

 same and process ( b) predominates, the use of the electric cur- 

 rent is for practical purposes entirely superfluous, since the 

 results could be duplicated by the generally more convenient 

 method of treating directly with chlorine gas. 



Schleuderberg specifically states his views on this point only 

 in the case of acetic acid, which he places under (b). It seems 

 evident, however, that he regards his chlorination of benzene 

 and toluene as largely of the kind (aj, both from the nature of 

 the conclusions drawn from his experiments, and from the fact 

 that the very much lower efficiency observed with acetic acid 

 is cited as the reason for regarding its chlorination as secondary. 



The observation of Zehrlant, that phenol may behave as a 

 depolarizer toward bromine, is strong evidence that phenol is 

 capable of entering into a strictly anodic reaction with the halo- 

 gen. It remains to be determined whether in practice the con- 

 ditions can be so regulated that the bromination obtained is 

 mainly of this kind. 



The evidence for the anodic chlorination of toluene is hardly 

 conclusive, and seems to rest entirely upon a difference ob- 

 served * in the electrolytic product in the ratio of ring to side 

 chain substitution, as compared with that obtained by direct 

 treatment with chlorine in the absence of a carrier. Still more 

 uncertain is the case of benzene, hitherto investigated only by 

 Schleuderberg. Although, as stated above, Schleuderberg 

 appears to accept the anodic chlorination of benzene as an 

 established fact, it is hard to see how any strong argument in 

 its favor can be based upon his published results alone. 



In the present paper it will be shown that the electrolytic 

 chlorination of benzene, at least under the conditions covered 

 by our experiments, is largely and perhaps wholly the result of 

 secondary action. Attention has been confined in our experi- 

 ments to the effects produced by the electrolysis of a homo- 

 geneous solution of benzene together with an inorganic chloride 

 in a non-aqueous solvent. Most of the commoner solvents are 

 excluded by the requirements of the case. "We have carried 

 out quantitative measurements with only two, ether and glacial 

 acetic acid. The latter proved far more satisfactory and was 

 employed in all experiments except one preliminary series. 

 Lithium chloride, dehydrated by heating nearly to fusion, was 

 used as electrolyte with acetic acid; anhydrous zinc chloride 

 was employed with ether. 



* Schleuderberg, Jour. Phys. Chem., xii, 598, 1908; Cohen, Dawson and 

 Crossland, Jour. Lond. Chem. Soc, lxxxvii, 1034, 1905. See also comments 

 of Bancroft, Jour. Phys. Chem., xii, 417. 



