Abstract: The oxidation of polymethyl acrylate(PMA) and its model compound methyl 2-methylbutyrate with molecular oxygen in dark have been studied.The experimental results showed that the two esters could form a contact charge transfer complex(CCT)with O₂ respectively.When O₂ was bubbled to solution of ester and kept for several hours and then N₂ was bubbled to the solution again,the UVabsorption of the CCTcould not completely disappear and a remaining peak was formed, and the strength of the remaining peak increased with the increasing of time.It indicated that the new compound was produced,and CCT played an important role in the oxidation of the two esters with O₂.Furthermore from IR and NMR spectra it was found that the hydroperoxide was formed at the a-Cof methyl 2-methylbutyrate.As well as the unsaturated methyl 2-methylbutenate which was produced in the further oxidation of methyl 2-methylbutyrate with O₂.

Key words: Polymethyl acrylate(PMA), 2-Methylbutyrate(MMB), Contact charge transfer complex(CCT), Initial oxidation