The effect of the cation aromaticity upon the thermophysical properties of piperidinium- and pyridinium-based ionic liquids

Ionic liquids and deep eutectic solvents for lignocellulosic biomass fractionation

“…40,84,98 The viscosity of an IL widely depends on the combination of cation and anion or impurities present, their effects are well studied in literature. 71,40,84,99,100 For example, the presence of very low concentrations of chloride drastically increases the viscosity, whereas the presence of water significantly reduces the viscosity. 101,102,103,104,105,106 DESs exhibit relatively high viscosities (> 100 mPa•s at ambient temperature).…”

Wettability and corrosion of [NTf2] anion-based ionic liquids on steel and PVD (TiN, CrN, ZrN) coatings

“…Coutinho et al [20,[24][25][26][27][28][29][30][31][32] found that surface tension in a couple of imidazolium-based IL series decreases with an increase in the cation side alkyl chain length up to hexyl and thus defined the CACL (critical alkyl chain length). On the other hand, surface tension remained almost constant for ILs with aliphatic moieties longer than the obtained CACL.…”

Synthesis and properties of novel ammonium-based room-temperature gemini ionic liquids

“…The p-p interactions in pyridinium GIL were expected to provide higher resistance to shear stress due to a more rigid IL structure and bulk distribution; the results, however, showed the opposite, with lower viscosity for the pyridinium GIL, since the p-p interactions will also lend a more rigid ring structure and induce a more organized bulk distribution compared with the more exible piperidinium ring, resulting in a relatively exible structure and a greater entanglement of the rings in the liquid phase. 40 The viscosities of GILs are higher than those of the monocationic analogues reported in the literature. 18,41 The viscosity of the pure GILs decreases sharply at low temperature when the temperature is increased, while it decreases smoothly at high temperature (see Fig.…”