title: Chlorination of parabens: reaction kinetics and transformation product identification.
abstract: The reactivity and fate of parabens during chlorination were investigated in this work. Chlorination kinetics of methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), and butylparaben (BuP) were studied in the pH range of 4.0 to 11.0 at 25 ± 1 °C. Apparent rate constants (kapp) of 9.65 × 10-3M-0.614·s-1, 1.77 × 10-2M-1.019·s-1, 2.98 × 10-2M-0.851·s-1, and 1.76 × 10-2M-0.860·s-1for MeP, EtP, PrP, and BuP, respectively, were obtained at pH 7.0. The rate constants depended on the solution pH, temperature, and NH4+concentration. The maximum kappwas obtained at pH 8.0, and the minimum value was obtained at pH 11.0. The reaction rate constants increased with increasing temperature. When NH4+was added to the solution, the reaction of parabens was inhibited due to the rapid formation of chloramines. Two main transformation products, 3-chloro-parabens and 3,5-dichloro-parabens, were identified by GC-MS and LCMS-IT-TOF, and a reaction pathway was proposed. Dichlorinated parabens accumulated in solution, which is a threat to human health and the aqueous environment.
authors: Department of Municipal Engineering, School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei, 230009, China.
authors: Qianhui
authors: Q
authors: Mao
authors: Institute of Animal Husbandry and Veterinary Medicine, Beijing Academy of Agriculture and Forestry Sciences, Beijing, 100097, China.
authors: Feng
authors: F
authors: Ji
authors: Department of Municipal Engineering, School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei, 230009, China.
authors: Wei
authors: W
authors: Wang
authors: Chemistry Department, Delaware State University, Dover, DE, 19901, USA.
authors: Qiquan
authors: Q
authors: Wang
authors: Department of Municipal Engineering, School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei, 230009, China.
authors: Zhenhu
authors: Z
authors: Hu
authors: Department of Municipal Engineering, School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei, 230009, China. sjyuan@hfut.edu.cn.|State Key Laboratory of Pollution Control and Resource Reuse, Nanjing University, Nanjing, 210046, China. sjyuan@hfut.edu.cn.
authors: Shoujun
authors: S
authors: Yuan
mesh_terms: D064751:Ammonium Compounds / Q000737:chemistry; D002713:Chlorine / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D054879:Halogenation; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008956:Models, Chemical; D010226:Parabens / Q000737:chemistry*; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D060753:Water Quality
chemical_list: D064751:Ammonium Compounds; D010226:Parabens; D014874:Water Pollutants, Chemical; C012313:ethyl-p-hydroxybenzoate; C038091:butylparaben; D002713:Chlorine; C015358:methylparaben; C006068:propylparaben
keywords: Chlorination; Kinetics; Mechanism; Parabens; Pathway; Transformation products