The ionic liquid tetrabutylphosphonium 1H-tetrazole-1-acetate, [P_4,4,4,4][TetrazC₁COO], appears as promising for the selective and reversible absorption of SO₂ at low pressures and in the presence of CO₂. The ionic liquid reversibly reacts with SO₂ and to a minor extent with CO₂ as shown by high-pressure NMR analysis. High absorption capacities were measured for SO₂ at pressures below 1 bar using an isochoric saturation technique, the CO₂ being measured in a gravimetric microbalance. We could calculate one of the highest SO₂/CO₂ selectivity reported so far. Contrary to previously reported ionic liquids, the solutions have lower viscosities, as inferred by the diffusivities measured by NMR, than that of the pure absorbent─a clear advantage for practical usages. Molecular dynamics simulations using validated polarizable force fields allow for a molecular understanding of the physical absorption of both acidic gases and how they impact of the microscopic structure of the liquid. Ab initio calculations provide estimates of the energetics of chemical absorption in line with the experiments confirming that the regeneration of the absorbent can be done at mild conditions of temperature and pressure.

中文翻译：

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稳定的羧酸鏻离子液体改善了 SO2 可逆和选择性吸收


离子液体四丁基鏻 1H-四唑-1-乙酸盐，[P _4,4,4,4 ][TetrazC ₁ COO]，似乎有望用于选择性和可逆吸收 SO ₂ 。高压 NMR 分析表明，离子液体与 SO ₂ 发生可逆反应，并在较小程度上与 CO ₂ 发生反应。使用等容饱和技术在低于 1 bar 的压力下测量 SO ₂ 的高吸收能力，在重力微天平中测量 CO ₂ 。我们可以计算出迄今为止报道的最高 SO ₂ /CO ₂ 选择性之一。与之前报道的离子液体相反，根据 NMR 测量的扩散率推断，该溶液的粘度低于纯吸收剂，这在实际应用中具有明显的优势。使用经过验证的极化力场进行分子动力学模拟可以从分子角度理解酸性气体的物理吸收以及它们如何影响液体的微观结构。从头计算提供了化学吸收能量的估计，与实验一致，证实吸收剂的再生可以在温和的温度和压力条件下进行。