Open AccessDensity and Solvation Effects of Imidazolium Based Ionic Liquids in Propylene Carbonate
Author(s) -
Anastasiia V. Riabchunova,
Victoria M. Karabtsova,
Oleg N. Kalugin,
V Karazіn
Publication year - 2018
Publication title -
vìsnik harkìvsʹkogo nacìonalʹnogo unìversitetu. serìâ hìmìâ
Language(s) - English
Resource type - Journals
eISSN - 2220-6396
pISSN - 2220-637X
DOI - 10.26565/220-637x-2018-31-02
Subject(s) - ionic liquid , propylene carbonate , solvation , hexafluorophosphate , chemistry , bromide , tetrafluoroborate , ionic radius , partial molar property , solvation shell , molar volume , analytical chemistry (journal) , inorganic chemistry , ion , thermodynamics , aqueous solution , electrolyte , organic chemistry , physics , electrode , catalysis
The results of densimetry investigation of the solutions of 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4), hexafluorophosphate (BMIMPF6) and bromide (BMIMBr) in propylene carbonate (PC) at 298.15, 318.15, 338.15 and 358.15 К are presented and discussed in terms of apparent partial molar volumes and solvation contribution. Density measurements were carried out using the vibrational tube densitometer Mettler Toledo DM 50 with accuracy ± 3∙10-5 g/cm3.The limiting partial molar volumes of investigated ionic liquids in PC were obtained from density experiment using Masson equation and divided into ionic contributions. Limiting partial molar volumes of BMIMBF4, BMIMPF6 and BMIMBr in PC slightly increase with the increase of temperature. The limiting partial molar volumes of BMIM+ cation obtained from three ionic liquids with different anions was found to have the same value, 115 cm3/mol at 298.15 K.The intrinsic volume of BMIM+ cation estimated from quantum chemical calculations at the M062X/6‑311++G(d,p) theory level exceeds one obtained from density experiment indicating that solvation of cation has a negative contribution to the volume of ion in propylene carbonate.In order to investigate the microscopic structure of the BMIM+ solvation shell in PC, molecular dynamics simulation of the infinitely dilute solution was carried out in the NVT ensemble at 298.15 K. The results of the simulation reveal that 5-6 PC molecules forming the first solvation shell penetrate into the inner space of the cation, which agrees with the results of a density experiment treatment. From the analysis of the cation-solvent site-site radial distribution functions and the running coordination numbers it was established that the most probable coordination center of PC molecule is carbonyl oxygen.