13. Photofragmentation of Dibenzyl Ketone in the Presence of Tetramethylpiperidine Derivatives. Studies on Light Stabilizer Mechanisms

Article abstract of DOI:10.1002/hlca.19800630114

The interaction of selected tetramethylpiperidine derivatives with radicals arising from the Norrish-type I cleavage of dibenzyl ketone under oxygen was studied.Product analyses and kinetic studies showed that the investigated sterically hindered piperidine derivatives have a pronounced effect on both the nature and distribution of the products of photolysis of dibenzyl ketone in the presence of oxygen.Observations indicated that the phenylperacetoxyl radical is formed as an intermediate during irradiation and that is interacts with additives used.Possible mechanism of the reactions studied are discussed.The observation that oxidation of an isolated duoble bond by radicals formed in dibenzyl ketone photolysis under oxygen is strongly inhibited in the presence of the studied sterically hindered amines is discussed in the light of the results presented. the findings are considered in realtion to the problem of polymer stabilization.