204 



Tlie excess of aoelic acid anhydride was taken so great that the 

 variations of concentration of tliis component could be neglected 

 with respect to those of the component diphenj'lamin. Hence the 

 reaction was psendo-mono-molecnlar. Many catalysts were tried ^) 

 before some substances weie found which were not paralysed during 

 the reaction ; tliey were p. bromo-benzene-sulphonic acid and p. 

 toluene-sulphonic acid. 



The following tables give the observations from — 50° without 

 catalyst. 



temp. 0° 1 mol diph. I2V2 mol. anh. 



temp. 20° 1 mol. diph. I2V2 mol anh. 



temp. 30° 1 mol diph. I2V2 mol. anh. 



temp. 40° 1 mol. diph. I2V2 mol anh. 



Taking into consideration that in the first table the converted 

 quantities are so small, the most probable values of the reaction 

 constants are respectively; 0,0021-0,0070—0,0124—0,0209 and 

 0,0384. 



1) Diss. Delft 1922. 



