A series of nine different known ionic liquids or low melting salts was synthesised and purified. They are composed of the [NTf₂]^– (bis(trifluoromethane)sulfonimide), [OTf]^– (trifluoro‐methane‐sulfonate), or [B(CN)₄]^– (tetracyanidoborate) anion and [Ph₄P]⁺ (tetraphenylphosphonium), [Ph₃BzP]⁺ (triphenylbenzyl phosphonium), [ⁿBu₄P]⁺ (tetra‐ⁿbutylphosphonium), [ⁿBuPh₃P]⁺ (tri‐phenyl‐ⁿbutylphosphonium), [ⁿBu₄N]⁺ (tetra‐ⁿbutylammonium), or the [PPN]⁺ (bis(triphenylphosphine)iminium) cation. Precise vapour pressure data and enthalpies of vaporisation were measured using the Quartz Crystal Microbalance (QCM) method and evaluated. Structure‐property relations are established using the obtained data as well as literature known data of ILs with alkyl‐substituted imidazolium cations. It turns out that ILs with the tetracyanidoborate anion have even higher values of the enthalpy of vaporisation than those with the common [NTf₂]⁻ or [OTf]⁻ anion and therefore are even less volatile.

中文翻译：

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追随 August Michaelis 的脚步：极低挥发性离子液体的合成和热力学

合成并纯化了一系列九种不同的已知离子液体或低熔点盐。它们由 [NTf ₂ ] ^–（双（三氟甲烷）磺酰亚胺）、[OTf] ^–（三氟甲磺酸根）或 [B(CN) ₄ ] ^–（四氰基硼酸根）阴离子和 [Ph ₄ P] ⁺组成(四苯基鏻)、[Ph ₃ BzP] ⁺ (三苯基苄基鏻)、[ ⁿ Bu ₄ P] ⁺ (四正^丁基鏻)、[ ⁿ BuPh ₃ P] ⁺ (三苯基正^丁基鏻)、[ ⁿ Bu ₄ N ] ⁺ (四正^丁基铵)，或 [PPN] ⁺ (双(三苯基膦)亚胺) 阳离子。使用石英晶体微天平 (QCM) 方法测量精确的蒸气压数据和蒸发焓并进行评估。使用获得的数据以及具有烷基取代的咪唑鎓阳离子的离子液体的文献已知数据建立了结构-性质关系。事实证明，具有四氰基硼酸根阴离子的离子液体比具有常见的[NTf ₂ ] ^-或[OTf] ^-阴离子的离子液体具有更高的汽化焓值，因此挥发性更低。