title: Verification of competitive kinetics technique and oxidation kinetics of 2,6-dimethyl-aniline and o-toluidine by Fenton process.
abstract: The competitive kinetics technique is shown to be a useful and reliable tool for determining rate constants. Regardless of the conditions of the reaction and the operation mode, the intrinsic second-order rate constants of 2,6-dimethyl-aniline and hydroxyl radicals were 1.65 × 10(10), 1.60 × 10(10), and 1.71 × 10(10)M(-1)s(-1) in the absence of SiO(2) under complete-mix conditions, in the presence of SiO(2) under complete-mix conditions, and in a fluidized-bed Fenton reactor with SiO(2) as the media, respectively, demonstrating that the rates are comparable under a variety of reaction conditions. The average intrinsic second-order rate constant of o-toluidine and hydroxyl radicals obtained in a homogeneous system under various conditions was 7.36 × 10(9)M(-1)s(-1), indicating that o-toluidine is less susceptible to hydroxyl radicals than 2,6-dimethyl-anilne. Hydroxyl radicals primarily attacked the amine group rather than the methyl group of the o-toluidine to form o-cresol and 2-nitrotoluene, which sequentially transformed to carboxylic acids including acetic, oxalic, lactic, and maleic acids after the collapse of the benzene ring.
authors.affiliation: Department of Environmental Engineering, Faculty of Engineering, King Mongkut's University of Technology Thonburi, National Center of Excellence for Environmental and Hazardous Waste Management, Pracha-u-tid Road, Bangmod, Thungkru, Bangkok 10140, Thailand. jin.ano@kmutt.ac.th
authors.forename: Jin
authors.initials: J
authors.lastname: Anotai
authors.forename: Nacorn
authors.initials: N
authors.lastname: Panchanawaporn
authors.forename: Nonglak
authors.initials: N
authors.lastname: Boonrattanakij
authors.forename: Ming-Chun
authors.initials: MC
authors.lastname: Lu
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D002264:Carboxylic Acids; D006861:Hydrogen Peroxide; D017665:Hydroxyl Radical; D007501:Iron; D007700:Kinetics; D008962:Models, Theoretical; D010084:Oxidation-Reduction; D014052:Toluidines / Q000737:chemistry*
chemical_list: D000814:Aniline Compounds; D002264:Carboxylic Acids; C045076:Fenton's reagent; D014052:Toluidines; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide; D007501:Iron; C023650:aniline