162 Van Name and Maryott — Chlorination of Benzene. 



Table IV. 



Other Carbon Compounds as Depolarizers. 



Solution, approximately normal LiCl in CH 3 COOH (several different 

 solutions used). Current 0*05 ampere. 



Anode Potential, volts. 



Depolarizer added to - Before adding After adding 



50 co of sol. depolarizer depolarizer 



Phenol, 5 grm ; +1*80 +1*69 



Acetone, 5 CC 1*79 1-78 



10 cc _. 1-79 1*75 



Ether, 5 CC 1'76 1-82 



10 cc __ _ 1-76 1-86 



Chlorbenze, 5 CC 1*76 1-83 



p-Dichlorbenzene, 2 grm 1*77 1'83 



Benzene hexachloride, 2 grm. _ _ 1'72 1*76 



which was filtered off, dissolved in alkali, and reprecipitated by 

 acidifying. This substance, qualitatively tested, was found to 

 contain a large amount of chlorine, thus confirming the produc- 

 tion of chlorphenols in the electrolysis. 



In the case of acetone the lowering was small, and may have 

 been due almost entirely to increased ionization, which would 

 be expected here. The depolarizing power of acetone is there- 

 fore weak, and perhaps inappreciable. 



Ether, and the three chlorine derivatives of benzene, all 

 caused a decided rise in the potential. By itself, this fact is 

 indecisive, but the similarity in the behavior of these four 

 substances to that of carbon tetrachloride is perhaps sufficient 

 to justify the conclusion that no one of them has any very 

 marked depolarizing effect. 



Rate of Chlorination with and without Electrolysis. 



In these experiments we have measured the rate of chlor- 

 ination of benzene in a solution kept saturated by a flow of 

 chlorine gas, and contained in a cell through which, from time 

 to time, an electric current was passed. Under these conditions 

 anodic chlorination ought to manifest itself by a more rapid 

 chlorination during the periods of electrolysis. The solution 

 used consisted as before of benzene dissolved in glacial acetic 

 acid containing lithium chloride. 



The work was carried out by weak artificial light* in a room 

 carefully screened to exclude daylight, and as a further safe- 

 guard the reaction cell was of amber glass. This was a bottle 



* Generally, a single red glass incandescent lamp, but supplemented during 

 the pipetting by a low gas flame. 



