( 618 ) 



difficulty) unite with the reacting molecules, but forms a kind of 

 solid solution. Carbon tetrachloride which forms no compound with 

 aluminium chloride is certainly attacked by benzene in presence of 

 that catalyst not less easily than benzoyl chloride which does form 

 an additive product; whilst also the chlorine atom in the acid chloride 

 is certainly not less "mobile" than that of CC1 4 . 



Gustavson imagines that the formation of compounds, such as 

 C„H 8 (C 2 H 6 ) 8 A1 2 C1 6 is necessary for the action of C 3 H 6 C1 on benzene; 

 these were separated from the bottom liquid layer which forms 

 during the action of C 2 H B C1 on benzene and aluminium chloride ; 

 if, however, the formation of this layer is prevented as much as 

 possible, the yield of ethylated benzene improves. Therefore I do 

 not call its formation necessary. That it may act favourably perhaps 

 is because the catalyst and also the two reacting molecules are 

 soluble in the same, thus allowing them to react on each other in 

 concentrated solutions. 



As has been observed above, there is something unsatisfactory 

 in assuming intermediate reactions in order to explain catalytic 

 phenomena. I will try to explain this matter more clearly. 



As is known, we may express the reaction velocity of a condition 



impelling force . , . . 



change by the ratio: — in which the impelling 



resistance 



force for that change in condition possesses a definite value which 



a catalyst cannot alter in the least; the resistance, however, is 



dependent on intluences for the greater part unknown. Therefore, 



the resistance must be lessened by the catalyst and the question to 



be solved is: "On what does this decrease in resistance depend?" 



If we suppose that intermediate reactions take place we divide 

 the process into a series of others of which each one considered by 

 itself is propelled by a force less impelling than the total change; 

 the resistance of each of those division processes must, therefore, 

 be much less, and the question then becomes: How is it that those 

 intermediate reactions proceed much more rapidly than the main 

 reaction? which is in fact nothing else but a circumlocution of the 

 first question : how is it that the catalyst decreases the original 

 resistance? Therefore, by assuming intermediate products, we have 

 not been much enlightened, on the contrary we have made the 

 problem more intricate, because, instead of having to account for a 

 single increase of velocity, we have to look for that of at least two. 



I call to mind the theory of Ostwald who supposes each process 

 to be a succession of condition changes, which will be all possible 

 if they occur with potential diminution. If, however, the first of those 



