Details

Autor(en) / Beteiligte

• Sexton, Andrew J
• Rochelle, Gary T

Titel

Reaction Products from the Oxidative Degradation of Monoethanolamine

Ist Teil von

• Industrial & engineering chemistry research, 2011-01, Vol.50 (2), p.667-673

Ort / Verlag

Washington, DC: American Chemical Society

Erscheinungsjahr

2011

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Aqueous monoethanolamine (MEA) at concentrations of 5 and 7 M was degraded with 100 mL/min of 98% O2/2% CO2 (98 mL/min O2), with oxygen mass transfer achieved by vortexing in a low-gas-flow degradation apparatus. Degraded samples were analyzed by ion chromatography (IC) and high-pressure liquid chromatography (HPLC) with evaporative light scattering detection (ELSD) for oxidative degradation products. In a high-gas-flow apparatus, 7.5 L/min of 83% N2/15% O2/2% CO2 (1125 mL/min O2) was sparged through a mechanically agitated 5 M MEA solution. A Fourier transform infrared (FTIR) analyzer collected continuous gas-phase data. Formate (HCOO−), hydroxyethyl formamide (HEF), and hydroxyethyl imidazole (HEI) account for 92% of degraded carbon at low-gas-flow conditions and 18−59% of degraded carbon at high-gas-flow conditions. Oxalate (C2O4 2−), oxamide (C2H4N2O2), glycolate (HOCH2COO−), acetate (CH3COO−), carbon monoxide (CO), ethylene (C2H4), formaldehyde (CH2O), and acetaldehyde (CH3CHO) are oxidation products in lower concentrations. Ammonia (NH3), HEF, and HEI account for 84% of degraded nitrogen at low-gas-flow conditions and 83−92% at high-gas-flow conditions. Nitrogen oxides (NO x ), present in lower concentrations, are stripped from solution at high-gas-flow conditions and retained in the degraded solution at low-gas-flow conditions and oxidized to nitrite/nitrate (NO2 −/NO3 −). A comparison of product rates to MEA losses shows that 25−50% of products remain unaccounted for in unknown HPLC peaks. Oxygen consumption rates vary from 1 to 2 mM/h, whereas the overall oxygen stoichiometry is 0.75 mol of O2/mol of MEA degraded.