TY - JOUR
T1 - Ozone Promotes Chloropicrin Formation by Oxidizing Amines to Nitro Compounds
AU - McCurry, Daniel L.
AU - Quay, Amanda N.
AU - Mitch, William A.
N1 - KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors thank Dr. Teng Zeng of Stanford University for experimental assistance, and Dr.Julien Le Roux (KAUST) for a helpful suggestion. D.L.M. acknowledges support from the NSFGraduate Research Fellowship Program (No. DGE-11474).
This publication acknowledges KAUST support, but has no KAUST affiliated authors.
PY - 2016/1/25
Y1 - 2016/1/25
N2 - 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.
AB - 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.
UR - http://hdl.handle.net/10754/599128
UR - https://pubs.acs.org/doi/10.1021/acs.est.5b04282
UR - http://www.scopus.com/inward/record.url?scp=84957592213&partnerID=8YFLogxK
U2 - 10.1021/acs.est.5b04282
DO - 10.1021/acs.est.5b04282
M3 - Article
C2 - 26752338
SN - 0013-936X
VL - 50
SP - 1209
EP - 1217
JO - Environmental Science & Technology
JF - Environmental Science & Technology
IS - 3
ER -