Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

The effect of six N,N'-disubstituted 1,4-phenylenediamines (I) and four derivatives of 1,4-benzoquinonediimine (II) on the photo-oxidation of tetralin, squalane and squalene at 35 °C and radiation 300-400 nm was investigated by oxygen uptake measurements. Due to irradiation, the antioxidant effectiveness of I is so restricted that the induction period did not appear in any of the photo-oxidized hydrocarbons. On the other hand, however, owing to the presence of I, there is a strong retardation of the photo-oxidation of hydrocarbons connected with the transformation of I in the oxidized hydrocarbon to II. Benzoquinonediimines are able to scavenge radicals involved in the propagation step and provide a screening effect. The retardant efficiency of II was proved by model investigation. Hence, II play a pronounced role in the mechanism of photo-oxidation of hydrocarbons stabilized with I.