CATALYSIS. 



35 



The progress of the reaction can be determined by measuring the nitrogen 

 set free. The following figures explain the results: 



V 



As 77 for the different acids and different quantities of acid is the same, then 

 the velocity coefficient is here also proportional to the concentration of the H ions. 



As the catalytic action of acids is caused by the H ions, so are the 

 catalytic properties of bases due to the OH ions. The first determined 

 case of this kind was the transformation of hyoscyamine into the stable 

 a tr opine. 1 



KOELICHEN 2 has studied a specially pretty case of the catalytic action of 

 OH ions in the decomposition of diacetonalcohol into acetone : 



CH 3 .CO.CH 2 .C(CH3) 2 .OH=2CH3.CO.CH 3 . 



The reaction is reversible, and from the following table it is seen that the 

 velocity constant for various concentrations of the same catalyst remains the same 

 as well as by using different bases. 



Catalyst. Cone, of the 



Catalyst. 



Piperidine 0. 1090 



Triethylamine 0.4900 



Ammonia . 5500 



Tetraethylammonium / . 0760 

 hydroxide j 0.0076 



Sodium hydroxide < ' ~ 



Velocity 

 Constant. 



0.038 

 0.036 

 0.038 

 0.037 

 0.037 

 0.036 

 0.035 



By this a rule which VAN'T HOFF and OSTWALD 3 proved by thenno- 

 dynamic means, is substantiated, namely, that the equilibrium at con- 

 stant temperature does not change with the quantity and kind of catalyst 

 when the catalyst is not changed by the reaction. 



Among other kinds of ions which act as catalysts we must mention (1) iodine 

 ions, which decompose H 2 2 in proportion to their concentration, 4 and (2) cyan- 



1 Ber. d. d. chem. Gesellsch., 21, 2777 (1888). 



2 Zeitschr. f. physik. Chem., 33, 129 (1900). 



3 Van't Hoff, Vorlesimgen, 1, 211. 



4 Walton, Zeitschr. f . physik. Chem., 47, 185, 1904. 



