Cl initiated reactions play an important role for the formation of carcinogenic nitrosamine in the amine oxidation. Piperazine (PZ) is considered as a potential atmospheric pollutant since it is an alternative solvent to the benchmark solvent monoethanolamine (MEA) in a leading CO2 capture technology. Here, we employed the quantum chemical method and kinetics modeling to investigate Cl-initiated atmospheric oxidation of PZ, particularly concerning the relative potential of PZ to MEA for the formation of nitrosamine. Results showed that Cl-initiated PZ reaction exclusively leads to N-center radicals (PZ-N) that mainly react with NO to produce nitrosamine in their further reaction with O2/NO. Together with reaction PZ + OH radical, the N-center radicals yield from PZ oxidation is still lower than that of corresponding reaction of MEA, consistent with previous findings only based on the reaction PZ + OH radical. However, the nitrosamine yield of PZ is higher than that of reported MEA when [NO] is &lt; 5 ppb. The unexpected high nitrosamine yield of PZ results from more favorable competition reaction of PZ-N with NO over O2 than that of MEA N-center radicals, clarifying the yield of N-center radicals should not be taken as the yield of corresponding carcinogenic nitrosamine.

Toward comprehensively evaluating the daytime potential of piperazine to form carcinogenic nitrosamines: Atmospheric oxidation of piperazine by atomic chlorine

256th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.