Depolymerization of poly(2,6-dimethyl-1,4-phenylene oxide) under oxidative conditions

Kei Saito, Toru Masuyama, Kenichi Oyaizu, Hiroyuki Nishide

研究成果: Article査読

28 被引用数 (Scopus)


Depolymerization of an engineering plastic, poly(2,6-dimethyl-1, 4-phenylene oxide) (PPO), was accomplished by using 2,6-dimethylphenol (DMP) under oxidative conditions. The addition of an excess amount of DMP to a solution of PPO in the presence of a CuCl/pyridine catalyst yielded oligomeric products. When PPO (Mn = 1.0 × 104, M w/Mn = 1.2) was allowed to react with a sufficient amount of DMP, the molecular weight of the product decreased to Mn = 4.9 × 102 (Mw/Mn = 1.5). By a prolonged reaction with the oxidant, the oligomeric product was repolymerized to produce PPO essentially identical to the starting material, making the oligomer useful as a reusable resource. During the depolymerization reaction, an intermediate phenoxyl radical was observed by ESR spectroscopy. Kinetic analysis showed that the rate of the oxidation of PPO was about 10 times higher than that of DMP. These results show that a monomeric phenoxyl radical attacks the polymeric phenoxyl to induce the redistribution via a quinone ketal intermediate, leading to the substantial decrease in the molecular weight of PPO, which is much faster than the chain growth.

ジャーナルChemistry - A European Journal
出版ステータスPublished - 2003 9 5

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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