156 Van Name and Maryott — Chlorination of Benzene. 



Ether was used as solvent in the first series of experiments. 

 Both the experimental conditions and the general nature of 

 the results obtained were similar to those in Schleuderberg's 

 experiments with benzene in ether, referred to above. Schleu- 

 derberg's method of conducting the analyses'* was followed in 

 most cases. 



Two serious objections to this procedure soon led us to 

 abandon it. In the first place there is little doubt that the 

 ether is chlorinated to some extent, f which tends to make the 

 current yields too large. Moreover, the presence of the zinc 

 salt was found to interfere seriously with the reduction of the 

 chlorbenzene in the analysis, causing low results. Although 

 these two sources of error act in opposite directions they make 

 the accuracy of the current yields very doubtful. Little con- 

 fidence can be placed in the numerical values obtained under 

 these conditions, and we have therefore included in the table 

 only two of the ether experiments, as examples. 



In the rest of the experiments of Table I glacial acetic acid 

 was used as solvent, with lithium chloride as electrolyte, and 

 the analyses were made with the aid of a new method devel- 

 oped for the purpose and elsewhere described by one of us.J 

 In these, and all subsequent determinations of total organic 

 chlorine, the procedure was as follows : The liquid was first 

 treated with an excess of aqueous sulphurous acid to remove 

 free chlorine, and then neutralized with sodium hydroxide. 

 After shaking and standing in a separatory funnel the two lay- 

 ers of liquid were carefully separated, using more water and 

 benzene as required, and the aqueous layer rejected. The 

 upper layer, consisting of benzene containing the chlorbenzenes 

 and a trace of water, was then treated with alcohol and metallic 

 potassium according to the method described in the article 

 just cited, and the chlorine finally weighed as silver chloride. 

 Duplicate analyses so conducted showed close agreement. It 

 will be noticed that if any chlorination of the acetic acid has 

 occurred it will not affect the result, since the chloracetates are 

 removed with the aqueous layer. 



Under the conditions of Table I the principal products of 

 the electrolysis are monochlorbenzene and a small amount of 

 benzene hexachloride. The current yields for the first twelve 

 experiments include both addition and substitution chlorine. 

 In the last Hve both the total chlorine and the addition chlorine 



* Based upon the use of the method of Stephanoff (Berichte, xxxix, 4056, 

 1906), for determining the organic chlorine. 



f Two experiments in which no benzene was present, but which in other 

 respects were comparable with experiments 1 and 2 of Table I, showed a 

 chlorination of the ether equivalent to current yields of about 12 per cent 

 and 19 per cent respectively. 



% This Journal (4), xxx, 378, 1910. 



