title: Intermediate distributions and primary yields of phenolic products in nitrobenzene degradation by Fenton's reagent.
abstract: Nitrobenzene thermal degradation was investigated using the Fenton reagent in different experimental conditions. Reaction products were analyzed by HPLC, GC-MS, LC-MS and IC. The products obtained at different nitrobenzene conversion degrees show that degradation mainly involves successive hydroxylation steps of the aromatic ring and its subsequent opening followed by oxidation of corresponding aliphatic compounds. Our results show as primary reaction products: 4-nitrophenol, 3-nitrophenol, 2-nitrophenol, phenol and 1,3-dinitrobenzene, indicating that both hydroxylation and nitration reactions are involved. The formation of phenolic products can be explained by postulating an initial step of HO() addition to nitrobenzene ring. The mechanisms of primary reaction pathways are discussed and a detailed kinetic analysis to obtain the true primary yields of phenolic products is proposed. The relative yields observed for nitrophenol isomers do not follow the expected orientation according to deactivating characteristics of the nitro group but significantly depend on Fe(+2), Fe(+3), H(2)O(2) and O(2) concentrations. The understanding of the effect of reaction conditions on the relative product distribution benefits the application of Fenton and Fenton-like systems to waste water treatment.
authors.affiliation: Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CCT-La Plata-CONICET, Departamento de Química, Facultad de Ciencias Exactas, UNLP. La Plata, Diagonal 113 y 64, Casilla de Correo 16 Sucursal 4, Código Postal 1900, Argentina.
authors.forename: Luciano
authors.initials: L
authors.lastname: Carlos
authors.forename: Debora
authors.initials: D
authors.lastname: Fabbri
authors.forename: Alberto L
authors.initials: AL
authors.lastname: Capparelli
authors.forename: Alessandra Bianco
authors.initials: AB
authors.lastname: Prevot
authors.forename: Edmondo
authors.initials: E
authors.lastname: Pramauro
authors.forename: Fernando S García
authors.initials: FS
authors.lastname: Einschlag
mesh_terms: D006861:Hydrogen Peroxide / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D008956:Models, Chemical; D009578:Nitrobenzenes / Q000032:analysis* / Q000737:chemistry; D010084:Oxidation-Reduction; D010636:Phenols / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D018508:Water Purification / Q000379:methods
chemical_list: C045076:Fenton's reagent; D009578:Nitrobenzenes; D010636:Phenols; D014874:Water Pollutants, Chemical; D006861:Hydrogen Peroxide; D007501:Iron; C036077:nitrobenzene