1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU)/imine, DBU/imide DESs were designed and synthesized as CO₂ trapping agents. Toward this end, the optimal absorption temperature and the maximum absorption capacity were determined. It was found that ionicity is a key factor to affect the absorption capacity of CO₂. Combined with the ionicity calculation, a new CO₂ capture mechanism has been proposed. HBD in DES can be divided into two parts. One can undergo proton transfer, obeying anion 2:1 absorption, whereas the other, without proton transfer, is amine 1:1 absorption. The degree of proton transfer in DES determines the ionicity and affects the absorption performance. The DFT calculation results confirmed this mechanism by micro perspective. DBU/2-Pyrrolidinone and DBU/Oxazolidinone were proved to be good CO₂ trapping agents with high absorption capacity, being 1.064 mol CO₂/mol DES and 0.827 mol CO₂/mol DES, respectively, and excellent recyclability when the mole ratio of HBA:HBD is 2:1.

中文翻译：

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新的基于 DBU 的 DES 捕获二氧化碳：离子性和吸收能力之间的关系

1,8-二氮杂双环[5.4.0] undec-7-ene (DBU)/亚胺、DBU/酰亚胺DESs被设计和合成为CO ₂捕集剂。为此，确定了最佳吸收温度和最大吸收能力。发现离子性是影响CO ₂吸收能力的关键因素。结合离子度计算，新的 CO ₂提出了捕获机制。DES 中的 HBD 可分为两部分。一种可以进行质子转移，服从阴离子 2:1 吸收，而另一种没有质子转移，是胺 1:1 吸收。DES中质子转移的程度决定了离子性并影响吸收性能。DFT 计算结果从微观角度证实了这种机制。DBU/2-吡咯烷酮和DBU/恶唑烷酮被证明是良好的CO ₂捕集剂，具有高吸收能力，分别为1.064 mol CO ₂ /mol DES和0.827 mol CO ₂ /mol DES，当摩尔比为HBA:HBD 为 2:1。