title: Transformation of acetaminophen using manganese dioxide-mediated oxidative processes: reaction rates and pathways.
abstract: This study investigates the oxidative transformation kinetics of acetaminophen (APAP) by δ-MnO2 under different conditions. APAP was rapidly oxidized by δ-MnO2 with the generation of Mn(2+). The measured APAP reaction rate considerably increased with an increase in initial δ-MnO2 and APAP concentration, but decreased as pH increased. The APAP reaction rate also increased with an increase in temperature. The addition of inorganic ions (Mn(2+), Ca(2+), and Fe(3+)) and substituted phenols (guaiacol, caffeic acid, and p-coumaric acid) as co-solutes remarkably decreased the transformation rate of APAP. The UV-Vis absorption spectra exhibited the π → π* transition, typical for aromatic rings. In addition, the intensity of the absorption peak gradually improved with increasing reaction time, suggesting that APAP can polymerize to form oligomers. Moreover, the secondary mass spectra of the dimers elucidated that the dimers were formed by the covalent bonding of phenol aromatic rings. Moreover, the higher-degree oligomers were formed by the coupling polymerization of phenolic and anilidic groups of dimers. These results are useful in understanding the fate of APAP in natural systems.
authors: School of Chemistry and Environment, South China Normal University, Universities Town, Guangzhou 510006, PR China.
authors: Hong
authors: H
authors: Xiao
authors: Haiyan
authors: H
authors: Song
authors: Hongqin
authors: H
authors: Xie
authors: Wei
authors: W
authors: Huang
authors: Jun
authors: J
authors: Tan
authors: Jianzhong
authors: J
authors: Wu
mesh_terms: D000082:Acetaminophen / Q000737:chemistry* / Q000302:isolation & purification*; D002118:Calcium / Q000737:chemistry; D019281:Dimerization; D006863:Hydrogen-Ion Concentration; D007477:Ions / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D007700:Kinetics; D008345:Manganese / Q000737:chemistry; D017895:Manganese Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry*; D019800:Phenol / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D012989:Soil Pollutants / Q000302:isolation & purification; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000302:isolation & purification; D018508:Water Purification / Q000379:methods
chemical_list: D007477:Ions; D017895:Manganese Compounds; D010087:Oxides; D011108:Polymers; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D019800:Phenol; D000082:Acetaminophen; D008345:Manganese; D007501:Iron; D010100:Oxygen; D002118:Calcium; C016552:manganese dioxide