(180 ) 
benzylbromide is formed in addition to p-bromobenzylehloride; in 
this case the bromine leaves the nucleus and is introduced into the 
side-chain *). ‘This question merits further investigation. 
After several preliminary experiments which showed that the 
interchange of Cl and H is much promoted by the eatalytieal action 
of acids, I determined the velocity of reaction in the following manner. 
3—4 grams of the acetylchloroanilide were dissolved in 100 grams 
of glacial acetic acid (100°/,), 10 ce. of hydrochloric acid containing 
2,9127 grams of HCI were added and finally the liquid was diluted 
with water to 500 ce. This solution was put into a black bottle 
and kept in a thermostat at 25°. As soon as the temperature had 
reached 25° 50 cc. were removed with a pipette and delivered into 
100 ce. of water to stop the reaction. Excess of solution of potassium- 
iodide was added and the liberated iodine titrated with sodium 
thiosulphate (0,150 N). The following results were obtained. 
é in hours. ec, Na BO: k. 
0 49.3 
4/5 42 0.160 
1 35.6 0.162 
ye 30.25 0.163 
2 240 0.162 
ha 21.8 0.1638 
3 18.5 0.160 
4 13.8 0.160 
6 Vso 0.160 
8 4.8 0.162 
1 A 
By applying the formula for the monomolecular reaction aa Sr: 
values are found for / which may be regarded as constants. 
This proves that the reaction is really monomolecular and that we 
are dealing with an actual intramolecular rearrangement of atoms. 
If instead of 10 ec, 20 ce. of hydrochloric acid were added the 
value for 4 was found to be 0.610; (the average result of eight obser- 
vations); by using double the quantity of acid the velocity has there- 
fore increased nearly four times. If instead of hydrochloric acid 
sulphuric acid of the same concentration was used, the conversion 
was very slow and a good constant was not obtained (32.8 ce. of 
Na, 5,0, at first, 29 cc. after 24 hours). 
In glacial acetic acid (99—100 °/,) the reaction takes place much 
1) Cf. Hanzscu, Ber. 30, 2334. Trör and Ecker, Ber. 26, 1104. 
