Iron-Catalyzed Oxidative Deconstruction of Polyethylene Terephthalate to Terephthalic Acid under O_(2)

It is urgent to recycle polyethylene terephthalate(PET)effectively,since it is the most consumed synthetic polyester and its improper disposal has caused significant environmental pollution.The existing chemical recycling methods highly rely on the nucleophilic substitutions and hydrogenative depolymerizations,which typically require the use of excess of nucleophiles,excess strong acids or bases,expensive metal catalysts,and explosive gas atmosphere.Here,we demonstrate a mild and efficient protocol for oxidative depolymerization of PET to terephthalic acid using only an O2 balloon.Terephthalic acid can be recycled from PET-containing materials including a series of plastic products in daily life.The employing of relatively low loading of iron complex,the most earth-abundant transition metal,as the catalyst and the preliminary results on the large-scale reaction using 38 g of PET waste demonstrate the practical feasibility of this degradation method.This method can be also applicable for selective degradation of PET from mixed plastics.This work represents a rare example of a selective oxidative depolymerization and demonstrates the great potentials of such a concept in polyester recycling.