354 



(for instance bv lowering llie temperalure) similar coumponnds have 

 often been met with and it was imagined that the explanation of 

 the catalytic phenomena had thns been fonnd. 



Now, however, it is evident that the explanation is not given liy 

 the formation of these compounds, but shonld be found before the 

 formation and that the best catalysts will be those whose dissociation 

 equilibrium extends over as large as possible a region of tempera- 

 ture and pressure, without any compounds being formed. 



3. In this manner, ascending by the inductive niediod from the 

 special case of the reaction of Friedkl and Crafts (Böeseken) and 

 descending by the deductive method from the general principle of 

 reciprocity (H. J. Pkins), we have come to the conclusion that 

 the catalytic action is situated in the pre-stage of the chemical 

 union. 



It is evident that with this result no explanation has been fonnd 

 in the sense that nov/ everything is completely elucidated. 



Yet, in my opinion, owing to the sharper detinition of the con- 

 ceptions the whole held is easier to survey (Pkins I.e.) and the 

 special cases are more readily understood, also a fundament has 

 been given on which we can pursue our researches with a greater 

 certainl) . 



These in view of the further elucidation will have to move in 

 two directions. 



1st. It must be ascertained, as has been already done in some 

 cases (I.e.), in how far the ctiange in velocity is connected with the 

 shifting of the catalyst and activated bonds in the dissociation region. 



With this may be coupled systematic researches as to the most 

 suitable catalysts for specified reactions, (for instance on metals which 

 are in a rapidly setting in dissociation-equilibrium simultaneously 

 with N.J and H., at a low temperature in view of the ammonia 

 synthesis; or on carbonates which in view of the ketone synthesis 

 from acids according to Sabatiek and Sendekens must, at about 

 300°, be with those acids in the same favourable conditions). 



2"^'. Those catalytic actions must be investigated where very small 

 energy shiftings are concerned ; to this appertain in the tirst place 

 the photocatalytic phenomena. 



The lirst series of researches are of a more direct practical result; 

 the second series, on the other hand, are of a more penetrating 

 nature, the object being to attack the catalytic phenomena in their 

 last recess. 



Delft, June 1914. 



