Effect of the Alkyl Chain Length of the Cation on the Interactions between Water and Ammonium-Based Ionic Liquids: Experimental and COSMO-RS Studies

Varadhi Govinda, T. Vasantha, Imran Khan, Pannuru Venkatesu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)


To improve the understanding of the molecular interactions of water with tetraalkyl ammonium-based ionic liquids (ILs) such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide, thermophysical properties such as density (ρ), speed of sound (u), viscosity (n) and refractive index (nD) were measured and a computational study using COSMO-RS was performed. The derived properties such as excess volumes (VE), deviation in isentropic compressibilities (Δκs), deviation in viscosities (Δ), and deviation in refractive indices (ΔnD) under the same experimental conditions for these systems were also estimated. The observed VE and Δκs values are negative over the entire composition of ILs at all investigated temperatures, whereas Δ and ΔnD values are positive under the same experimental conditions. These results reveal that the ammonium-based ILs significantly affect the intermolecular interactions between the solvent molecules. The computational study allows a qualitative analysis of the results in terms of the ion-dipole interactions, ion-pair formation, and hydrogen bonding between ammonium-based ILs and water.

Original languageEnglish
Pages (from-to)9013-9026
Number of pages14
JournalIndustrial and Engineering Chemistry Research
Issue number36
Publication statusPublished - Sept 16 2015
Externally publishedYes

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering

Cite this