Amine degradation in CO2 capture. 2. New degradation products of MEA. Pyrazine and alkylpyrazines: Analysis, mechanism of formation and toxicity

Amine degradation in post-combustion CO2 capture is a main problem because of its consequences on process units and the potential impact of degradation products on environment. Ethanolamine (MEA) is the benchmark amine for this application. Although MEA degradation has been intensively studied, some degradation products are still unidentified. In this article, new degradation products of MEA are reported: pyrazine and 9 alkylpyrazines. A new analytical method based on HS-SPME and GC-MS was developed to identify and quantify the 10 pyrazines present in two pilot plant samples. A mechanism for their formation was proposed. The toxicity of these molecules was assessed based on available toxicological data and, when the information was not sufficient, a computational approach was used: TOPKAT and DEREK SARs. LD50, skin and eye irritancy potential, genotoxicity and reproductive effects were assessed. The study showed that the ten identified pyrazines are currently not indicating toxicological concern at the level of intake estimated at 0.2-120 μg/day in Europe.