Type of Document	Master's Thesis
Author	Rule, Krista Lynn
Author's Email Address	krule@vt.edu
URN	etd-05252004-122641
Title	The Mechanisms, Products, and Kinetics of Triclosan-Free Chlorine Reactions
Degree	Master of Science
Department	Environmental Engineering
Advisory Committee	Advisor Name Title Vikesland, Peter J. Committee Chair Edwards, Marc A. Committee Member Little, John C. Committee Member
Keywords	Chlorophenoxyphenols Pharmaceutical and Personal Care Products Triclosan Free Chlorine Chlorophenols
Date of Defense	2004-05-24
Availability	restricted
Abstract The kinetics, products, and reaction pathways of triclosan/free chlorine reactions were investigated for the pH range 3.5-11. Although pH dependent speciation occurs in both triclosan and free chlorine, only the reaction between HOCl and the phenolate-triclosan was found to play a significant role in the kinetics. The second order rate constant for the reaction between phenolate-triclosan and HOCl was found to be 5.40 (±1.82) × 103 M-1s-1. Three chlorinated triclosan intermediates were tentatively identified based on mass spectral analysis. Additionally, 2,4-dichlorophenol, 2,4,6-trichlorophenol, and chloroform formed under excess free chlorine conditions. The majority of the chloroform formed during the reactions does not form via 2,4-dichlorophenol and 2,4,6-trichlorophenol oxidation. Therefore, the majority of chloroform is likely formed via the oxidation of triclosan’s phenolic ring. Based on the identified products, a reaction pathway was proposed for the oxidation of triclosan in the presence of free chlorine.
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