US EPA

3384550 

Journal Article 

Ozone Promotes Chloropicrin Formation by Oxidizing Amines to Nitro Compounds 

Mccurry, DL; Quay, AN; Mitch, WA 

2016 

1 

Environmental Science & Technology
ISSN: 0013-936X
EISSN: 1520-5851 

American Chemical Society 

50 

3 

1209-1217 

English 

26752338 

10.1021/acs.est.5b04282 

WOS:000369471300016 

Chloropicrin formation has been associated with ozonation followed by chlorination, but the reaction pathway and precursors have been poorly characterized. Experiments with methylamine demonstrated that ozonation converts methylamine to nitromethane at ∼100% yield. Subsequent chlorination converts nitromethane to chloropicrin at ∼50% yield under the conditions evaluated. Similarly high yields from other primary amines were limited to those with functional groups on the β-carbon (e.g., the carboxylic acid in glycine) that facilitate carbon-carbon bond cleavage to release nitromethyl anion. Secondary amines featuring these reactive primary amines as functional groups (e.g., secondary N-methylamines) formed chloropicrin at high yields, likely by facile dealkylation to release the primary nitro compound. Chloropicrin yields from tertiary amines were low. Natural water experiments, including derivatization to transform primary and secondary amines to less reactive carbamate functional groups, indicated that primary and secondary amines were the dominant chloropicrin precursors during ozonation/chlorination. Ozonation followed by chlorination of the primary amine side chain of lysine demonstrated low yields (∼0.2%) of chloropicrin, but high yields (∼17%) of dichloronitrolysine, a halonitroalkane structural analogue to chloropicrin. However, chloropicrin yields increased and dichloronitrolysine yields decreased in the absence of hydroxyl radical scavengers, suggesting that future research should characterize the potential occurrence of such halonitroalkane analogues relative to natural radical scavenger (e.g., carbonate) concentrations. 

Amines; Amino acids; Chlorination; Condensation reactions; Ozone; Ozone water treatment; Ozonization; Scavenging; Carbon-carbon bond cleavage; Hydroxyl radicals; Natural radical scavengers; Nitro compounds; Primary and secondary amine; Reaction pathways; Secondary amines; Structural analogue; Insecticides; amine; chloropicrin; nitro derivative; ozone; amine; chlorinated hydrocarbon; chloropicrin; methane; methylamine; nitro derivative; nitroalkane; nitromethane; ozone; water; carboxylic acid; chlorination; chloropicrin; concentration (composition); hydroxyl radical; ionic composition; nitrogen compound; oxidation; ozone; reaction kinetics; research work; Article; chemical structure; chlorination; concentration at steady-state; dealkylation; derivatization; mass fragmentography; mineralization; molecular weight; oxidation; ozonation; reaction analysis; analogs and derivatives; chemistry; halogenation; oxidation reduction reaction; procedures; water management; Amines; Halogenation; Hydrocarbons, Chlorinated; Methane; Methylamines; Nitro Compounds; Nitroparaffins; Oxidation-Reduction; Ozone; Water; Water Purification