Quantum chemical calculations and in situ infrared spectroscopy were applied to analyze the role of CO₂ activation by aprotic heterocyclic anion ionic liquids (AHA-ILs) in its reaction with propylene oxide to form propylene carbonate. Two AHA-ILs with remarkably different behavior as CO₂ chemical absorbent were considered: triethyl(octyl)-phosphonium indazole, [P₂₂₂₈][Inda], and triethyl(octyl)-phosphonium 2-cyanopyrrol-1-ide [P₂₂₂₈][2-CNPyr]. The structure and energy of reaction intermediates were predicted by Density Functional Theory (DFT) method, observing that CO₂ and AHA-IL reaction form an anionic carbamate that promotes a nucleophilic attack on the propylene oxide, causing the ring opening with negligible energy barrier. Later intramolecular cyclization occurs, followed by the AHA-IL regeneration and propylene carbonate production, both requiring appreciable activation energy. The proposed reaction mechanism were experimentally validated by ATR-FTIR measurements, identifying the characteristic signals of reactants, products and intermediate species. Finally, the reaction using the AHA-ILs [P₂₂₂₈][Inda] and [P₂₂₂₈][2-CNPyr] was followed over time using operando ATR-FTIR technique at different operating conditions (temperature and catalyst concentration). A close relationship between the performance of AHA-IL as CO₂ chemical absorbent and CO₂ conversion catalyst is revealed, opening opportunities for the efficient application of AHA-ILs in intensified process of CO₂ capture and utilization.

应用量子化学计算和原位红外光谱技术分析了质子惰性杂环阴离子液体（AHA-ILs）与环氧丙烷反应生成碳酸亚丙酯对CO ₂活化的作用。考虑了两种行为与CO ₂化学吸收剂具有显着不同的AHA-IL ：三乙基（辛基）-吲唑[P ₂₂₂₈ ] [Inda]和三乙基（辛基）-2-氰基吡咯-1-ide [P ₂₂₂₈ ] [2-CNPyr]。通过密度泛函理论（DFT）方法预测反应中间体的结构和能量，观察到CO ₂与AHA-IL反应形成阴离子氨基甲酸酯，该氨基甲酸酯促进对环氧丙烷的亲核攻击，从而导致开环，而能垒可忽略不计。后来发生分子内环化，接着是AHA-IL再生和碳酸亚丙酯的生产，两者都需要相当大的活​​化能。通过ATR-FTIR测量对所提出的反应机理进行了实验验证，确定了反应物，产物和中间物种的特征信号。最后，在不同的操作条件（温度和催化剂浓度）下，使用操作性ATR-FTIR技术随时间追踪使用AHA-IL [P ₂₂₂₈ ] [Inda]和[P ₂₂₂₈ ] [2-CNPyr]的反应。AHA-IL作为CO的性能之间存在密切关系揭示了₂种化学吸收剂和CO ₂转化催化剂，为在强化CO ₂捕集和利用过程中有效应用AHA-ILs提供了机会。