Thermodynamic Properties and Intermolecular Interactions of a Series of N-Butylammonium Carboxylate Ionic Liquids

Abstract

A series of new N-butylammonium carboxylate ionic liquids (N-butylammonium formate, N-butylammonium acetate, N-butylammonium propionate, and N-butylammonium butyrate) were synthesized by a one-step method and characterized. The thermodynamic properties such as surface tension, density, electrical conductivity, and dynamic viscosity of the ILs were measured as functions of temperature. Important parameters such as molecular volume, crystal energy, thermal expansion coefficient, standard molar entropy, and the surface properties are estimated by the empirical equations. The Vogel−Fulcher−Tamman (VFT) equation is used to explore the dependence of electrical conductivities and dynamic viscosities on temperature. The relationship between the molar conductivity and the fluidity of the ILs was examined through the use of Walden plots. To describe intermolecular interactions of the N-butylammonium carboxylate ILs, the optimized structures and energetics of ILs are calculated by DFT calculations. The calculated energies showed that the increase in the interaction energies between the ion clusters is the same as the trend of experimental viscosities.

Protic Amine Carboxylic Acid Ionic Liquids Additives Regulate α‐FAPbI3 Phase Transition for High Efficiency Perovskite Solar Cells

“…[ 41 ] The broad band in the 3250–2500 cm −1 range represents the characteristic ammonium structure. [ 42 ] For the BAFa, the asymmetric stretching vibration of COO − peak shifts to 1567 from 1587 cm −1 , [ 43 ] indicating an interaction between the formate and Pb 2+ . The results of 13 C‐NMR spectra and FTIR spectra confirm the establishment of O…Pb bond via chelation between Pb 2+ and butyrate/formate anions, [ 38 ] meanwhile these strong interactions can passivate the undercoordinated Pb 2+ at the grain boundaries and surface of perovskite films.…”

Relationship between Structure and Properties of Nonstoichiometric Protic Ionic Liquids: n-Butylammonium Butyrate System

“…In panel a, the differences in densities from experiments and MD simulations are smaller than 1% except 3.1% for pure BuNH 2 , corresponding to x (PrCOOH) = 0. Some data from the literature are also plotted (green circles). − Composition dependence of ionic conductivity (c) from experiments and self-diffusion coefficients (d) of ions and excess molecules obtained in MD simulations at 298 K.…”