Intermediate distributions and primary yields of phenolic products in nitrobenzene degradation by Fenton's reagent.
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.
Carlos
Luciano
L
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.
Fabbri
Debora
D
Capparelli
Alberto L
AL
Prevot
Alessandra Bianco
AB
Pramauro
Edmondo
E
Einschlag
Fernando S García
FS
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
C045076:Fenton's reagent; D009578:Nitrobenzenes; D010636:Phenols; D014874:Water Pollutants, Chemical; D006861:Hydrogen Peroxide; D007501:Iron; C036077:nitrobenzene