Spin Trapping as Applied to Radicals Produced by the Thermal Decomposition of Di-t-butyl Diperoxyoxalate (DBPO) in Aromatic Hydrocarbons

Di-t-butyl diperoxyoxalate (DBPO) was allowed to decompose at 40 °C in benzene and xylenes, and transient radicals were trapped by some nitroso compounds. By means of an ESR simulation technique, the trapped radicals were assigned. In benzene, t-butoxyl radicals were trapped. Exceptionally, when 1,3,5-tri-t-butyl-2-nitrosobenzene(1) was used, methoxyl radicals were trapped first, but the ESR signals changed with time and methyl radicals were finally trapped. In xylenes, monomethylbenzyl radicals were exclusively trapped by 1 and 2,4,6-trimethyl-l-nitrosobenzene(2). The hyperfine coupling constant (hfcc) of β-hydrogens exhibited a negative temperature dependence for adducts formed between 1 and benzyl radicals(1-BZ), while for adducts formed between 2 and benzyl radicals(2-BZ), a positive one.