[maass-russell] OXONIUM COMPOUND 263 



Table III 



It can be seen that the curve is continuous and reaches a point 

 representing a composition 23 per cent alcohol. Now, a compound 

 ether-hydrobromide-alcohol would have a composition 22-9 per cent 

 alcohol, and the continuity of the curve shows that it could not have 

 been isolated here. 



These results are in agreement with the recent ideas upon the 

 relation M^hich the formation of molecular compounds bears to chemical 

 reactions, according to which the interaction of two substances is 

 preceded by their association in a molecular complex. The example 

 given by Baumé^ is quite analagous in characteristics to the one ob- 

 served above. He showed the probability that the catalysis of ester 

 formation by the presence of an acid is due to the formation of a ter- 

 molecular compound between the organic acid, the alcohol and the 

 catalytic acid., By additions of methyl alcohol to the oxonium com- 

 pound propronic acid-hydrochloric acid he obtained a freezing point 

 curve having a definite maximum at a point corresponding to a com- 

 pound propronic acid-hydrochloric acid-methyl alcohol. The pro- 

 pronic acid and the methyl alcohol do not combine, but each unites 

 with the halogen acid, and the three together combine as a preliminary 

 stage to a reaction between the two organic substances. The parallel- 

 ism between the two is completed by recalling the reaction whereby, 

 if ether be heated for some hours in a sealed tube with dilute hydro- 

 chloric acid, an equilibrium is established in the reaction represented 

 by the following equation : 



C2H5OC2H5 + H2O = 2C2H5OH. 2 

 It is evident from this work that here, too, as in the reaction 

 investigated by Baume, the acid may function as an intermediary by 



1 Comptes Rendus 55426. 



^ Bernsthen, Organic Chemistry, pp. 84, 85 (Eng. Ed.) 



