Electrical Conductances of 1‑Butyl-3-propylimidazolium Bromide and 1‑Butyl-3-propylbenzimidazolium Bromide in Water, Methanol, and Acetonitrile at (308, 313, and 318) K at 0.1 MPa
Sumanta Gupta, Amritendu Chatterjee, Sajal Das, and Basudeb Basu
Department of Chemistry, North Bengal University, Darjeeling 734013, India
Department of Chemistry & Biochemistry, Presidency University, 86/1 College Street, Kolkata 700 073, India ABSTRACT: Two ionic liquids (ILs), 1-butyl-3-propyl imidazolium bromide ([BPim][Br]) and 1-butyl-3-propyl benzimidazolium bromide ([BPbim][Br]), have been synthesized from their appropriate imidazole and benzimidazole precursors and were characterized by NMR spectroscopic technique. Their electrical conductances have been measured as a function of their concentrations in water, methanol, and acetonitrile at three diﬀerent temperatures. The limiting molar conductances (Λ0), the association constants (KA), and the values of the association diameters (R) of these ILs have been obtained by analysis of the conductance data using the Fuoss conductance equation. These ILs have been found to remain unassociated in water and methanol, whereas these exhibit slight ionic association in acetonitrile within the investigated temperature range. The temperature elevation causes an increase in their limiting molar conductances in the three solvents under investigation. The IL cations [BPim]+ and [BPbim]+ exist as unsolvated species in aqueous solutions, whereas substantial solvation was noticed for the [BPim]+ ion in methanol and acetonitrile solutions.
Ionic liquids (ILs) constitute a group of molten organic electrolytes whose chemical and physical properties could be conveniently engineered by judicious choice of their anions, cations, and the substituents. They possess speciﬁc properties, for example, negligible