Huang I-Shou, Li Jia-Jen, Tsai Ming-Kang
Department of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan.
Molecules. 2016 Dec 23;22(1):8. doi: 10.3390/molecules22010008.
A classical force field approach was used to characterize the solvation dynamics of high-density CO₂(g) by monoethanolamine (MEA) at the air-liquid interface. Intra- and intermolecular CO₂ and MEA potentials were parameterized according to the energetics calculated at the MP2 and BLYP-D2 levels of theory. The thermodynamic properties of CO₂ and MEA, such as heat capacity and melting point, were consistently predicted using this classical potential. An approximate interfacial simulation for CO₂(g)/MEA(l) was performed to monitor the depletion of the CO₂(g) phase, which was influenced by amino and hydroxyl groups of MEA. There are more intramolecular hydrogen bond interactions notably identified in the interfacial simulation than the case of bulk MEA(l) simulation. The hydroxyl group of MEA was found to more actively approach CO₂ and overpower the amino group to interact with CO₂ at the air-liquid interface. With artificially reducing the dipole moment of the hydroxyl group, CO₂-amino group interaction was enhanced and suppressed CO₂(g) depletion. The hydroxyl group of MEA was concluded to play dual but contradictory roles for CO₂ capture.
采用经典力场方法表征了单乙醇胺（MEA）在气液界面处对高密度CO₂（g）的溶剂化动力学。根据在MP2和BLYP-D2理论水平计算的能量对分子内和分子间的CO₂与MEA势能进行了参数化。使用该经典势能一致地预测了CO₂和MEA的热力学性质，如热容和熔点。对CO₂（g）/MEA（l）进行了近似界面模拟，以监测受MEA氨基和羟基影响的CO₂（g）相的消耗。与本体MEA（l）模拟相比，在界面模拟中明显发现了更多的分子内氢键相互作用。发现在气液界面处，MEA的羟基更积极地靠近CO₂并超过氨基与CO₂相互作用。通过人为降低羟基的偶极矩，增强了CO₂-氨基相互作用并抑制了CO₂（g）的消耗。得出结论，MEA的羟基在CO₂捕获中起双重但相互矛盾的作用。
