29* 
a secondary product resulting from the decomposition or hydrolysis 
of the primary peroxide by the action of water. Thus, Clover and 
Houghton ( 122 ) have observed that succinic peroxide acid is readily 
hydrolyzed by water, yielding succinic acid and hydrogen peroxide, 
in the sense of the equation — 
ch 2 cooh 
ch 2 cooh 
2 T 2H 2 0 = 2 I +H 2 0 2 . 
ch 2 cooh 
ch 2 cooh 
I 
CH 2 CO\ n 
ch!co/ 0 
Finally, Engler and Weissberg ( 164 ), have laid considerable stress 
upon the idea that dissociation or the liberation of free valences, 
both in the oxygen molecule and in the substance undergoing au- 
toxidation, are necessary for autoxidation processes, and in this way 
the}" explain the effect of heat and light in accelerating oxidations 
and also account for the ease with which unsaturated organic com- 
pounds undergo oxidation. They assume, with von Helmholtz and 
Richarz ( 208 ) and Bach ( 18 ), a partial dissociation of the oxygen mole- 
cule, resulting in the complex — O — O — , thereby enabling them to 
account for the direct addition of the whole molecule of oxygen to 
the oxidizing substance. 
In the light of these considerations the phenomenon of oxygen- 
activation is easily explained. According to Engler and his follow- 
ers it is due primarily to the oxidation of the second substance — the 
acceptor — by the peroxide (moloxide) resulting from the autoxida- 
tion of the carrier. Thus, when an autoxidizable substance, A, finds 
itself in contact with oxygen and a second oxidizable substance, B, 
the following changes would occur: 
H + 0 2 = A0 2 , 
and 
ao 2 +b=ao+bo. 
In this way a substance incapable of combining directly with 
oxygen may be oxidized through the intervention of another sub- 
stance, and a given quantity of oxygen equally distributed between 
them. To take the case of the oxidation of benzaldehyde and the 
changes which may be accomplished through the oxidation of this 
compound at ordinary temperatures in the air. When exposed to 
the air this compound is converted into benzoyl-hydrogen peroxide 
(see Baeyer and Villiger ( 33 )) — 
C 6 H 5 CHO + 0 2 = C 6 H 5 CO - O - O - H. 
If allowed to remain in contact with water, benzoyl-hydrogen per- 
oxide is hydrolyzed with the production of benzoic acid and hydro- 
gen peroxide — 
C 6 H 5 CO.O.OH + HOH = C 6 H 5 COOH + H 2 0 2 . 
