The physicochemical properties and structure of alkylammonium protic ionic liquids of RnH4-nNX (n = 1–3) family. A mini–review

CuCl2诱导咪唑离子液体水凝胶的相变

“…离子液体是一种由阴阳离子组成， 在较低温度下 呈液态的离子化合物。 离子液体具有很多独特的物理 化学性质，如熔点低、不易燃、蒸气压低、稳定性好、 电导率高、电化学窗口宽、可循环使用等 [1][2][3][4] 。除此 之外， 离子液体还可以通过阴阳离子组分改变以及结 构的设计，获得独特的性质以及特殊的功能 [5][6][7][8] ，这 些优势使得离子液体成为了近十年来研究的热点。 作为极具应用前景的绿色溶剂， 研究离子液体体 系的相行为等物理化学性质、 分子间相互作用和微观 结构等对离子液体应用研究有着重要的意义与价值 [9][10][11][12] 。近年来，越来越多的研究关注到离子液体与其 它物质组成的复杂流体中分子聚集与微观结构 [13][14][15] 。 Li 等人 [16] 利用拉曼光谱和红外光谱研究了 FeCl3 在 C4mimCl 离子液体中的存在状态， 研究结果表明离子 液体和 FeCl3 存在很强的相互作用，形成缔合结构。 Firestone 等人 [17] 通过研究 1-癸基-3-甲基咪唑溴盐离 子液体中水分子的聚集行为， 制备出离子凝胶。 SAXS 等表征手段研究表明，通过调节体系中的水含量，可 以形成层状、二维六角形或三维立体的结构。Kang 等人 [18] 发现无机盐可以在一定程度上改变离子液体 体系的相行为。无机盐 CaCl2 和 MgCl2 诱导离子液体 OmimCl 水溶液形成凝胶，无机盐阳离子与离子液体 中的 Cl -具有很强的相互作用，能够使得 Cl -围绕在无 机盐阳离子四周，进而使 Omim + 阳离子发生重排产 生有序结构形成凝胶。除此之外，很多研究表明，离 子液体与表面活性剂 [19,20] 、 离子液体与超临界二氧化 碳 [21,22] 等体系也可以形成不同类型的聚集体， 这些新 型的体系在化学反应、 材料制备等应用上具有显著的 优势 [23][24][25] [26] 。IR 光谱结果 与 SAXS、电导率结果相一致。…”

Alkylimidazolium Protic Ionic Liquids: Structural Features and Physicochemical Properties

“…The melting temperatures of the studied protic ILs with 1R3HIm cations are higher, in most cases, than the T m value of the corresponding aprotic ILs with a 1R3MeIm cation but lower than the melting temperatures of alkylammonium PILs with a R n H 4-n N (n = 1-3) cation. [72] The melting temperatures are basically determined by the structural properties of the PIL cation and anion as well as by the strength of their interaction. [73] A decrease in the ion-ioninteraction energy, distortion of the ion symmetry, and large volume of the ions of high conformational flexibility together lower the melting temperature.…”

Cholinium amino acid-based ionic liquids

“…The problem with these substances is that their degree of ionicity and their ability to transport charge are very dependent upon the tendency of the involved molecular species to bind the proton. The correlation between quantities such as pK a and proton affinities of the acid and base involved and the ensuing ionization degree and conductive properties of the fluid has been the subject of a great number of research activities, but it still eludes a simple generalization (Shmukler et al 2020). The ChAAILs in which the AA anions have an additional protic function on the side chains and where the additional protons are mobile and give rise to the aforementioned tautomerization reactions might provide an exemplar ionized medium where fast charge transfer could be achieved by proton diffusion (Adenusi et al 2020b) and point toward the development of novel conducting media (Adenusi et al 2020a).…”