(355n) Mixtures of Amino Acid Salts and Ethylene Glycol for CO2 Capture
AIChE Annual Meeting
Tuesday, November 9, 2021 - 3:30pm to 5:00pm
In this study, natural DESs made from a choline cation and series of amino acid anions (glycine, alanine, proline, and phenylalanine) were mixed with ethylene glycol to yield CO2-reactive solvents. The melting points of the mixtures were measured using differential scanning calorimetry. The resulting phase diagrams indicate eutectic behavior. These solvents were tested for CO2 capacity at various CO2 partial pressures in nitrogen (400 ppm CO2 to 100% CO2 at 1 bar). Choline amino acids show very slow CO2 uptake because they are extremely viscous (>1000 cP). Therefore, dilution with an active solvent such as ethylene glycol improves mass transport of CO2 while maintaining a high CO2 capacity. The CO2 absorption mechanism of these solvents was assessed via quantitative 13C-NMR. These eutectic solvents are made entirely from natural materials that are significantly cheaper and easier to synthesize than most ILs.