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Highlights: [•] 10 pyrazines issued from MEA degradation were identified and quantified. [•] A new analytical method based on HS-SPME and GC–MS was developed. [•] A mechanism was proposed to explain pyrazines formation. [•] Toxicity of pyrazines was assessed with TOPKAT and DEREK SARs. [•] Identified pyrazines are currently not indicating toxicological concern. [Copyright &y& Elsevier]

Abstract: Post-combustion CO2 capture based on CO2 absorption by aqueous amine solutions is the most mature gas separation technology. A main problem is amine degradation due to heat, CO2, O2, NO x and SO x . This review proposes to make a critical survey of literature concerning degradation, to list degradation products and to discuss mechanisms proposed by authors. Benchmark molecule is monoethanolamine (MEA) but diethanolamine (DEA), N-methyldiethanolamine (MDEA), piperazine (PZ) and 2-amino-2-methylpropan-1-ol (AMP) are also studied. Uses of other amines and amine blends are also considered. In the case of MEA, ammonia, N-(2-hydroxyethyl)-piperazin-3-one (HEPO) and N-(2-hydroxyethyl)-2-(2-hydroxyethylamino) acetamide (HEHEAA) are the main identified degradation products in pilot plants. Among lab studies, the most cited degradation products are ammonia, carboxylic acids, N-(2-hydroxyethyl)-formamide (HEF), N-(2-hydroxyethyl)-acetamide (HEA) and N-(2-hydroxyethyl)-imidazole (HEI) for oxidative degradation, and oxazolidin-2-one (OZD), N-(2-hydroxyethyl)-ethylenediamine (HEEDA) and N-(2-hydroxyethyl)-imidazolidin-2-one (HEIA) for thermal degradation. Numerous degradation products have been identified but some are still unknown. A lot of degradation mechanisms have been proposed but some are missing or need proofs. SO x and NO x effects are still few examined and much work remains to be done concerning volatile degradation products potentially emitted to atmosphere: their identification and their formation mechanisms need further investigations. [Copyright &y& Elsevier]