Double salt ionic liquids based on 1-ethyl-3-methylimidazolium acetate and hydroxyl-functionalized ammonium acetates: strong effects of weak interactions

Author(s)

Pereira, Jorge F. B. ^{[1, 2]} ; Barber, Patrick S. ^{[2, 3]} ; Kelley, Steven P. ^{[2, 4]} ; Berton, Paula ^[4] ; Rogers, Robin D. ^{[2, 4, 5]}

Affiliation

^[1] Univ Estadual Paulista UNESP, Sch Pharmaceut Sci, Dept Bioproc & Biotechnol, Campus Araraquara, BR-14800903 Araraquara, SP - Brazil

^[2] Univ Alabama, Dept Chem, Box 870336, Tuscaloosa, AL 35487 - USA

^[3] Earlham Coll, 801 Natl Rd W, Richmond, IN 47374 - USA

^[4] McGill Univ, Dept Chem, 801 Sherbrooke St West, Montreal, PQ H3A 0B8 - Canada

^[5] 525 Solut Inc, 720 2nd St, Tuscaloosa, AL 35401 - USA

• Document type: Journal article
• Source: Physical Chemistry Chemical Physics; v. 19, n. 39, p. 26934-26943, OCT 21 2017.
• Web of Science Citations: 8

Abstract

The properties of double salt ionic liquids based on solutions of cholinium acetate ({[}Ch]{[}OAc]), ethanolammonium acetate ({[}NH3(CH2)(2)OH]{[}OAc]), hydroxylammonium acetate ({[}NH3OH]{[}OAc]), ethylammonium acetate ({[}NH3CH2CH3]{[}OAc]), and tetramethylammonium acetate ({[}N(CH3)(4)]{[}OAc]) in 1-ethyl3- methylimidazolium acetate ({[}C(2)mim]{[}OAc]) were investigated by NMR spectroscopy and X-ray crystallography. Through mixture preparation, the solubility of {[}N(CH3)(4)]{[}OAc] is the lowest, and {[}Ch]{[}OAc] shows a 3-fold lower solubility than the other hydroxylated ammonium acetate-based salts in {[}C(2)mim]{[}OAc] at room temperature. NMR and X-ray crystallographic studies of the pure salts suggest that the molecular-level mechanisms governing such miscibility differences are related to the weaker interactions between the -NH3 groups and {[}OAc](-), even though three of these salts possess the same strong 1 : 1 hydrogen bonds between the cation -OH group and the {[}OAc](-) ion. The formation of polyionic clusters between the anion and those cations with unsatisfied hydrogen bond donors seems to be a new tool by which the solubility of these salts in {[}C(2)mim]{[}OAc] can be controlled. (AU)

• FAPESP's process: 14/16424-7 - Optimization and scale-up of liquid-liquid extraction process with ionic liquids (ILs) as a sustainable tool for the separation of the anti-leukemia biopharmaceutical L-asparaginase (ASPase)
• Grantee: Jorge Pereira
• Support Opportunities: Research Grants - Young Investigators Grants