CO2Aggregation on Monoethanolamine: Observations from Rotational Spectroscopy

Abstract

AbstractThe initial stages of the gas‐phase nucleation between CO2and monoethanolamine were investigated via broadband rotational spectroscopy with the aid of extensive theoretical structure sampling. Sub‐nanometer‐scale aggregation patterns of monoethanolamine‐(CO2)n,n=1–4, were identified. An interesting competition between the monoethanolamine intramolecular hydrogen bond and the intermolecular interactions between monoethanolamine and CO2upon cluster growth was discovered, revealing an intriguing CO2binding priority to the hydroxyl group over the amine group. These findings are in sharp contrast to the general results for aqueous solutions. In the quinary complex, a cap‐like CO2tetramer was observed cooperatively surrounding the monoethanolamine. As the cluster approaches the critical size of new particle formation, the contribution of CO2self‐assembly to the overall stability increases.