552 



Specific atomic group) occurs as a component, will be a catalyst 

 in the sense of Ostwald. 



B -^ C A ^ D 



n n 



A B 



The above symbols represent this explanation from which we gather 

 that the change of tlie free energy in so far as it concerns the catalyst 

 approaches in the pure catalysis to zero and wherewith we also wish 

 to express that the catalyst is in fact more a change of condition 

 than a substance. 



In the positive catalytic action tlie equilibrium A f^ B will set in 

 much more rapidly than the reaction B-» C or A — s>-D and thus 

 cause or accelerate the same. 



Hence an ideal catalyst, according to this deduction and in connexion with 

 Ostwald's definition, is a substance which undergoes with one of the to be 

 activated substances ior bonds) such reciprocal action that in the latter 

 system the thermodynamic potential and chemical resistance simultaneously 

 approach to zero. 



As it concerns here particularly the bond that is being activated, 

 the other molecule will also be more or less intiuenced ; this we 

 notice immediately when we reinember that intramolecular displace- 

 ments come under the same point of view. 



Hence, we will obtain the maximal catalytic action when, with 

 the catalyse (for instance B) we approach as closely as possible the 

 catalytic stage in regard to A as well as D. 



The chlorination of benzene again presents us with a suitable 

 meaning example to elucidate the intention of this thesis. 



Both chlorine and benzene are in regard to A\C\^ in the catalytic 

 stage; they are both rendered active without forming a compound. 



As soon as we replace benzene by nitrobenzene the action ceases 

 at the ordinary temperature because AICI^ forms a solid combination 

 with nitrobenzene so that these two are, in regard to each other, 

 not in the catalytic stage and because AICI3 cannot any longer 

 acti\ate the chlorine simultaneously. 



At a h'gher temperature the chlorination starts; we may assume 

 that the system AlCl^ NO.^C^ R.^ is then again approaching the 

 catalytic stage. 



It is, however, self-evident that a case like the chlorination of 

 benzene is rarely met with ; as presumably somewhat similar cases 

 I mention : all ionreactions in acjueons solutions ; the union of 

 hydrogen and oxygen and the decomposition of hydrogen peroxide 



