Chemistry. — ''Observations about hydration under the influence o f 

 Colloidal Catalysers and hoiu to account for this process" . 

 By Prof. J. BöKSEKEN and Mr. H. W. Hofstede. 



(Communicated in the meeting of June 30, 1917). 



Some time ago ^) we performed and described a number of hjdrations 

 with the aid of colloidal catalysers. At the same time we gave an 

 outline of what might be expected during the development of this process, 

 and what we shall therefore observe in measuring the absorption of 

 the hydrogen, viz: 



The hydrogen and the matter to be reduced will pass from the 

 gas-space into the liquid medium, then they will pass one or more 

 layers covering the atoms of the catalyser and finally they will 

 coalesce. Hence we first observe a succession of diffusion-processes, 

 before the catalytic-chemical reaction enters. It was assumed that 

 the rapidity of the latter process is always considerably greater than 

 that of the former, so that the observed rapidity of absorption, 

 would seem to refer to a diffusion-process. 



The assumption of the all-surpassing velocity of the catalytic- 

 chemical process is arbitrary ; the rapidity will of course depend 

 on the nature of the catalyser. But we have been guided in the first 

 place by the consideration that the action of platina-metals on some 

 of the processes brought about by them is exceedingly great indeed, 

 so that few thousandths millimol are sufficient to bring molecular 

 quantities to a fairly rapid chemical change. 



It appears then that we want far greater quantities of catalyser, 

 say from 50—100 millimol, to reach the result, obtained in the 

 observations made. So it is obvious that we must rather look for 

 the cause of that very moderate velocity in the possibility, that of 

 these 50 — 100 millimol only a very small part can be reached at 

 the same time by the reacting substances, than to suppose that the 

 process of these particular reactions is such an extraordinarily 

 slow one. 



In my opinion the very potent catalytic action of the metal-atoms 

 results from the nature of these atoms themselves. Owing to their 



1) Recueil 35 260 (1916). 



