Аннотация:Novel functionalized ionic liquid (IL) combining an imidazolium-based cation with branched alkyl chain bearing silyl group, 1-methyl-3-(2-methyl-3-(trimethylsilyl)propyl)imidazolium ([Si-C1-C3-mim]+), and bis(trifluoromethylsulfonyl)imide ([NTf2]–) anion was synthesized and its thermophysical properties (density, viscosity, surface tension, surface entropy and enthalpy, heat resistance and thermal stability) were studied in a wide temperature range and compared with those of ILs having linear alkyl ([Cn-mim][NTf2]) and siloxane ([(SiOSi)C1mim][NTf2]) side chains. It was found that at 25oC [Si-C1-C3-mim][NTf2] represents yellowish liquid with dynamic viscosity of 224 cP and density of 1.32 g cm-3. The presence of side branched alkyl chain with trimethylsilyl end-group prevented crystallization of IL even on cooling with as slow rate as 5oC min-1. Moreover, it led to higher viscosities and lower densities in comparison with commonly known [Cn-mim][NTf2] (n = 2-4). As surface excess enthalpy was found to be in the lower end of the usual range of values for ILs, the interactions between silyl-functionalized cation and [NTf2] anion can be considered as relatively weak.
Finally, [Si-C1-C3-mim][NTf2] was used for the preparation of polymer supported ionic liquid membranes (SILMs) and their CO2 and N2 permeation properties at 20oC and 100kPa were determined: permeability PCO2=311, PN2=12 Barrer, diffusivity DCO2=115×1012, DN2=227×1012 m2 s-1 and CO2/N2 permselectivity CO2/N2=25.3.
