Molecular structure design ionic liquids

Analysis of supramolecular structures in ionic liquids Supramolecular assemblies are the molecular base for some of the unique properties of ILs. Therefore, the knowledge of the nature, type, and strength of these structures [23] is a prerequisite for a deeper understanding of ILs as well as for the tailor-made design of new compounds. The most important noncovalent interactions responsible for the formation of such a structure are C-H hydrogen bonds [25]. Other interactions encompass the formation of clusters by ion pairing, which can be found, for example, in chloroaluminates [12]. 

Nanotechnological approaches will lead to defined structures on the molecular level by implementing active side groups or isolated particles as well as by crosslinking via side chains. Specially designed chemicals such as ionic liquids (ILs) allow the immobilisation and as a consequence the defined disfribution of active particles such as catalysts. These kinds of chemicals can also be used to functionalise inorganic structures such as zeolites or molecular sieves. 

In summary, designing low melting, low viscosity ionic liquids is a challenging task because several molecular features contribute. Additionally some molecular features, like ion pairing, enhance the mobility of the ions only over a selected range before their influence show a reversed effect. Therefore, semiemperical and quantitative structure-property relationship (QSPR) approaches seem to be a good choice to estimate melting points or... 

An ionic liquid also has vast possibilities because the hquid properties as a solvent can be altered by designing the molecular structure. There are a few reports of enzymatic ring-opening polymerization in ionic liquids. The hpase-catalyzed polymerization of e-CL was carried out in ionic solvents, such as the l-butyl-3-methyl-imidazolium salts [169]. In order to establish the compatibihty of enzymes with ionic liquids, the hpase-catalyzed transesterification of 2-hydroxymethyl-1,4-benzodioxane was studied [170]. 

The updated application of the ionic liquid in the synthesis of inorganic nanomaterials was briefly outlined. The main emphasis of the outline was a focus on the preorganized structure of the ionic liquid as template effect for inorganic nanomaterials. The particular strength of ionic liquids is their virtually unlimited flexibility of anions and cations combinations. As the cation or anion in the ionic liquid can be tailored by functional substitutes, the size and size distribution of the ionic liquid-stabilized metal nanopartides can be easily controlled too. In case ionic liquid phase behavior, chemical composition, and reactivity are also considered, ionic liquids provide a flexible toolbox for the fabrication of inorganics with various (and variable) properties simply by designing the appropriate precursor. These precursors are entities which are defined molecularly, which can be well characterized and studied as the transformation to the inorganic proceeds. 

Due to the fact that the physical dimensions of the flow structures in microfluidic systems are in the micro-scale, the Reynolds numbers characterizing fluid-flow in microfluidic systems are well below the critical value for turbulence and the flow regime is, consequently, laminar (Pohar Plazl, 2008). Therefore, micromixers in microfluidic systems rely on molecular diffusion. In general, micromixers used for ionic liquid synthesis are designed in such a way that their internal flow geometries reduce diffusion distances. Some examples of micromixers used for ionic liquid synthesis are shown in Figure 3. 

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