„1075 
dx 
as KX Caich X CBC, H,SO,Cl.ALCH 
In solution of one of the active molecules, the velocity of reaction 
is therefore proportional to the quantity of the other molecule, in 
so far as this has united with the catalyst, as well as with the 
total quantity of the catalyst. 
The part thereof which during the reaction passes to the sulphon : 
AICI,BrO,H,SO,Cl + C,H, = HCI + BrC,H,S0,C,H, AlCl, 
although not capable of rendering the acid chloride active must 
retain its catalystic activity in other respects. 
We may explain this by assuming that AICI, renders active the 
benzene, with which it forms no compound, never mind whether the 
catalyst is united to the sulphonchloride or to the sulphon *). 
If the above relation is correct, the addition of an equivalent 
amount of sulphon to the catalyst before or during the reaction must 
either prevent or stop the same, because one of the necessary mole- 
cules cannot, or no longer, be rendered active. 
From Table Vlla and b this appears really to be the case. 
TABLE Vlla and 6. 
b 
MEL =0. tn; siiphonchtoride=0.1 n. a Een Le 
sulphon = 0.1 n. become homogeneous. 
t (a—x)103 t | ais 
0 99.2 0 83.6 
180 99.3 155 83.9 
500 99.8 435 83.6 
1200 . 85,5 
[f on the other hand our explanation is correct, an excess of AICI,, 
which cannot then be paralysed either by the sulphonchloride or by 
the sulphon, must exert a perceptibly stronger action. For we have 
assumed that the catalyst renders active the benzene also and it 
will do this undoubtedly better still when it is in looser combination ; 
this is also confirmed by the experiment. (Table VIII). 
1) It is possible and even probable that the action of the AICl, does undergo a 
slight change; the course of the constant (see table I) might be partly attributed 
to this. 
