ACTION OF OXYGEN 121 



which also offers an opportunity for introduction of metal 

 in this group CH as in glutaconic ester 1 . 



C 2 H-OCOCH 2 CHCHC0 2 C 2 H 5 . 



If the organic compound contains a hydroxyl group 

 which in any case is accessible to the metals, the addition 

 of oxygen in its immediate neighbourhood, making the 

 carboxyl group 



O = C H, 



raises this faculty to a pronounced acid character. Further 

 off the oxygen increases acidity if this already exist, as 

 appears from the dissociation constants of acetic, glycollic, 

 glyoxalic, and oxalic acids. 



H 3 CCOOH HOH 2 CCOOH HOCCOOH HO 2 CCOOH 



Jf = o-ocooi8 0-000152 0000474 o-i 



(f3) Oxygen reduces basicity. Here, again, the number 

 of examples is so great that we will confine ourselves to 

 the nitrogen derivatives, especially organic. The entire 

 change from the strong base, ammonia, to the strong acid, 

 nitric, is shown in the series : 



NH 3 , NH 3 OH, N(XH, N0 3 H, 



as a result of replacement of hydrogen by oxygen. 



The same thing may be noted in organic chemistry in 

 the different characters of the amines and amides, which 

 contain the characteristic groups : 



C NH 2 and OC NH 2 , 



the introduction of oxygen in the latter causes the group 

 almost to lose its basic character. 



If the influence goes further, as in the groupings 



OCNH and OCNHCO, 



the change is still more marked, and in both cases acids 

 are formed, cyanic in the former, and acids like uric in 

 the latter. 



1 Henrich, Centralblatt, 1899, n. 701. 



