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Ag(I)‐Catalyzed Chlorination of Linezolid during Water Treatment: Kinetics and Mechanism
Author(s) -
Kulkarni Raviraj M.,
Hanagadakar Manjunath S.,
Malladi Ramesh S.,
Shetti Nagaraj P.
Publication year - 2018
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.21175
Subject(s) - chemistry , reaction rate constant , catalysis , reaction rate , kinetics , reaction mechanism , chlorine , ionic strength , order of reaction , inorganic chemistry , medicinal chemistry , aqueous solution , organic chemistry , physics , quantum mechanics
The kinetic and mechanistic study of Ag(I)‐catalyzed chlorination of linezolid (LNZ) by free available chlorine (FAC) was investigated at environmentally relevant pH 4.0–9.0. Apparent second‐order rate constants decreased with an increase in pH of the reaction mixture. The apparent second‐order rate constant for uncatalyzed reaction, e.g., k ″ app = 8.15 dm 3 mol −1 s −1 at pH 4.0 and k ″ app. = 0.076 dm 3 mol −1 s −1 at pH 9.0 and 25 ± 0.2°C and for Ag(I) catalyzed reaction total apparent second‐order rate constant, e.g., k ″ app = 51.50 dm 3 mol −1 s −1 at pH 4.0 and k ″ app. = 1.03 dm 3 mol −1 s −1 at pH 9.0 and 25 ± 0.2°C. The Ag(I) catalyst accelerates the reaction of LNZ with FAC by 10‐fold. A mechanism involving electrophilic halogenation has been proposed based on the kinetic data and LC/ESI/MS spectra. The influence of temperature on the rate of reaction was studied; the rate constants were found to increase with an increase in temperature. The thermodynamic activation parameters E a , Δ H # , Δ S # , and Δ G # were evaluated for the reaction and discussed. The influence of catalyst, initially added product, dielectric constant, and ionic strength on the rate of reaction was also investigated. The monochlorinated substituted product along with degraded one was formed by the reaction of LNZ with FAC.