Kinetics and mechanisms of reactions of penta-O-acetyl-N-chloro-N-methylglucamine with model water contaminants.

摘要

Penta-O-acetyl-N-chloro-N-methyl-glucamine (NCMGE) was shown to be a potentially useful germicidal agent. The main objective of this work was to study the utility of NCMGE in water treatment by assessing the reactivity of NCMGE towards model water contaminants and comparing the reactivity of NCMGE to that of currently used water chlorinating agents, such as hypochlorous acid and monochloramine. Acetone, dichloroacetone, and p-cresol were used as model water contaminants.;While hypochlorous acid reacted with acetone in a zero-order manner with respect to HOCl concentration, NCMGE did not react with acetone at all. The formation of trihalomethanes, which are undesirable chlorination by-products with potential health risks, is thought to involve the chlorination of a methyl group ;The reaction of NCMGE with dichloroacetone was found to be fifty times slower than the reaction of monochloramine with dichloroacetone under the same conditions. The time needed for the disappearance of 20% (t;The reactivity of NCMGE against the sulfhydryl group was studied using N-acetylcysteine. The active chlorine of NCMGE disappeared immediately in presence of N-acetylcysteine, even at one to one molar ratio. This might explain the germicidal activity of NCMGE despite its low chemical reactivity.;The kinetics of reactions of HOCl, NCMGE, and several N-chloro-dialkylamines with p-cresol were studied. NCMGE was found to be the slowest in its reaction with p-cresol. Phenolic materials are implicated in the formation of trihalomethanes and other chlorination by-products. Thus, the slow reaction of NCMGE with p-cresol is of great significance. It indicates that NCMGE will generate less chlorination by-products.;The different chemical reactivity of HOCl and NCMGE towards p-cresol was used to investigate the chemical stability of penta-O-acetyl-N-methylglucamine (NMGE), the parent compound of NCMGE. The data showed that NMGE undergoes a rapid O ;The previous results suggest that NCMGE might has a potential as a practical and safe disinfectant.