Development of high-efficient absorbents for ammonia (NH₃) to improve the quality of atmosphere and ecological environment has gained interest among scholars. Ionic liquids (ILs) with unique properties have been reported as potential solvents for NH₃ uptake to avoid many problems troubling the traditional NH₃ capture technology. In this study, six protic ethanolamine-based ILs (PILs) were synthesized for efficient and reversible NH₃ uptake, with the initial idea of constructing multiple binding sites to enhance the absorption ability for NH₃. The physical properties and NH₃ absorption performance in these PILs were investigated and analysized on the basis of molecular structures. The results demonstrated that the preferred [EtAN][SCN] had suitable viscosity of 78.18 mPa.s and molality capacity up to 0.296 and 0.0802 g NH₃/g PILs at 100.0 and 4.5 kPa NH₃ pressure, respectively. Such absorption ability was higher than all the reported absorbents related with ILs. ¹H NMR spectroscopy illustrated that the outstanding absorption ability was originated from multiple hydrogen-bonding interactions between acidic proton, hydroxyl group and thiocyanate with NH₃. The absorption enthalpy of −35.5 kJ/mol was further calculated according to the absorption capacity at low NH₃ pressure under corresponding temperatures. In short, present PILs exhibited attractive absorption ability, excellent recyclability, low absorption enthalpy, and competitive selectivity of NH₃/CO₂. Present work can provide instructive idea for designing PILs in NH₃ recovery and separation application.

开发高效氨（NH ₃）吸收剂以改善大气和生态环境质量引起了学者们的兴趣。据报道，具有独特性质的离子液体 (IL) 可作为 NH ₃吸收的潜在溶剂，以避免困扰传统 NH ₃捕获技术的许多问题。在本研究中，合成了六种基于质子乙醇胺的 ILs (PILs) 以实现高效和可逆的 NH ₃吸收，最初的想法是构建多个结合位点以增强对 NH ₃的吸收能力。物理性质和NH ₃基于分子结构研究和分析了这些 PIL 的吸收性能。结果表明，优选的[EtAN][SCN]在100.0和4.5kPa NH ₃压力下分别具有78.18mPa.s的合适粘度和高达0.296和0.0802g NH ₃ /g PILs的摩尔浓度容量。这种吸收能力高于所有报道的与ILs相关的吸收剂。¹ H NMR光谱表明，优异的吸收能力源于酸质子、羟基和硫氰酸盐与NH ₃之间的多重氢键相互作用。根据低NH ₃吸收容量进一步计算-35.5 kJ/mol的吸收焓相应温度下的压力。简而言之，目前的 PILs 表现出有吸引力的吸收能力、优异的可回收性、低吸收焓和 NH ₃ /CO _{2 的}竞争选择性。目前的工作可为设计用于NH ₃回收和分离应用的PIL 提供指导思想。