Influence of the cation partner on levulinate ionic liquids properties

Dielectric Study of Tetraalkylammonium and Tetraalkylphosphonium Levulinate Ionic Liquids

“…Therefore, stronger ionic interaction means a lower value of f ε and as a consequence, a lower value of f M ( ) and, hence, lower dc conductivity, a behavior that characterizes the experimental data of [N 8881 ]Lev IL. This is in accordance with a recent work [ 48 ]. The viscosity values and the related activation energy of both ILs [ 48 ], suggest that [N 8881 ]Lev has stronger interactions between anion–cation pairs than [P 8881 ]Lev.…”

“…Data for ion conductivity of [N 8881 ]NTf 2 IL reported in the literature [ 25 ] are plotted as crosses in Figure 3 , along with current results. Considerably lower ion conductivity values were obtained for [N 8881 ]Lev compared to [N 8881 ]NTf 2 in accordance with the higher viscosity measured for the former (at 298 K 1019 mPas [ 48 ] and 620 mPas [ 4 ], respectively). Interestingly, the same values for ionic conductivity were found for [N 8881 ]NTf 2 and [P 8881 ]Lev although lower viscosity values were measured for the latter (at 298 K 620 mPas [ 4 ] and 366 mPas [ 48 ], respectively).…”

“…Considerably lower ion conductivity values were obtained for [N 8881 ]Lev compared to [N 8881 ]NTf 2 in accordance with the higher viscosity measured for the former (at 298 K 1019 mPas [ 48 ] and 620 mPas [ 4 ], respectively). Interestingly, the same values for ionic conductivity were found for [N 8881 ]NTf 2 and [P 8881 ]Lev although lower viscosity values were measured for the latter (at 298 K 620 mPas [ 4 ] and 366 mPas [ 48 ], respectively). The lower conductivity values from that expected according to its viscosity obtained for [P 8881 ]Lev, could be understood in terms of enhanced ion association in this IL compared to [N 8881 ]NTf 2 .…”

“…The fact that the reported results refer to IL systems with cations having different lengths of alkyl chains and different anions than those studied here indicates that this is a general trend. Higher values of ionic conductivity found for [P 8881 ]Lev compared to [N 8881 ]Lev can be understood in terms of lower viscosity and T g values found for the former [ 48 ]. In the inset of Figure 3 the logarithm of molar conductivity was plotted as a function of the logarithm of inverse viscosity, known as a Walden plot [ 35 , 49 ].…”

“…Molar conductivity was calculated as , where M is the molecular weight and ρ the density. For the calculations, ρ values obtained for the same systems reported in [ 48 ] were used. The Walden plot was used for the determination of the relationship between ionic conductivity and viscosity as well as for a qualitative description of ILs regarding their ion association.…”