Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Institute of Industrial Ecology and Environment, College of Chemical and Biological Engineering, Zhejiang University (Yuquan Campus), Hangzhou 310027, China.
Environ Sci Technol. 2020 Mar 17;54(6):3520-3529. doi: 10.1021/acs.est.9b06717. Epub 2020 Feb 27.
To achieve low regeneration energy consumption and viscosity, a novel amino-functionalized ionic liquid [TEPAH][2-MI] combined with organic solvents has been proposed for CO capture in this work. The results demonstrated that the absorption loading of [TEPAH][2-MI]/-propanol (NPA)/ethylene glycol (EG) was 1.72 mol·mol (28 wt %, 257 g·L), which was much higher than that of monoethanolamine/water, and the regeneration efficiency was maintained at 90.7% after the fifth regeneration cycle. The viscosities of the solution were only 3.66 and 7.65 mPa·s before and after absorption, respectively, which were significantly lower than those of traditional nonaqueous absorbents. The reaction mechanism investigated via C NMR and quantum calculations summarized that CO first reacted with the amino group of [TEPAH] to form the carbamates through the zwitterion formation and protonation process, while CO reacted with the N atom of [2-MI] to directly form the carbamate. Then, some of them further reacted with NPA and EG to form the carbonates. Moreover, N and N tautomers of [TEPAH][2-MI] could convert into each other continuously when CO was absorbed. During CO desorption, the carbamates and carbonates reacted with AFILH to decompose and released CO directly.
为了实现低再生能耗和低粘度，本工作提出了一种新型氨基功能化离子液体[TEPAH][2-MI]与有机溶剂结合用于 CO 捕集。结果表明，[TEPAH][2-MI]/异丙醇（NPA）/乙二醇（EG）的吸收负载量为 1.72mol·mol（28wt%，257g·L），远高于单乙醇胺/水，且在第五次再生循环后，再生效率仍保持在 90.7%。吸收前后溶液的粘度分别仅为 3.66 和 7.65mPa·s，明显低于传统非水吸收剂。通过 C NMR 和量子计算研究的反应机制总结出，CO 首先与[TEPAH]的氨基反应，通过两性离子形成和质子化过程形成氨基甲酸酯，而 CO 与[2-MI]的 N 原子反应直接形成氨基甲酸酯。然后，其中一些与 NPA 和 EG 进一步反应形成碳酸盐。此外，[TEPAH][2-MI]的 N 和 N 互变异构体在吸收 CO 时可以相互转化。在 CO 解吸过程中，氨基甲酸酯和碳酸盐与 AFILH 反应分解并直接释放 CO。
