Liquid–liquid phase equilibria in nicotine (aqueous) solutions

• Published in: Fluid phase equilibria 2011-11, Vol.310 (1), p.198-206
• Main Authors: Grozdanic, Nikola D., Najdanovic-Visak, Vesna, Kijevcanin, Mirjana Lj, Serbanovic, Slobodan P., Nunes da Ponte, Manuel, Visak, Zoran P.
• Format: Article
• Language: English
• Subjects: Chemistry; Exact sciences and technology; General and physical chemistry; Ionic liquid; Liquid-liquid equilibria; Liquid–liquid equilibrium; Nicotine; Phase equilibria; Polyethylene glycol; Sustainable solvents
• ISSN: 0378-3812; 1879-0224
• DOI: 10.1016/j.fluid.2011.08.022

► The work improves comprehension of complex nicotine (aqueous) solutions. ► Promotion of possible sustainable, ionic-liquid based tunable solvents for nicotine. ► Cheap salts, NaCl and Na 3PO 4, trigger strong demixing in nicotine aqueous solutions. ► Very small quantities of NaCl and Na 3PO 4 required for demixing in aqueous nicotine. ► Ionic liquid ECOENG 212 ® is both co- and anti-solvent in aqueous nicotine solutions. Liquid–liquid equilibria were measured for solutions containing: (1) nicotine, and one of the solvents PEG 200 or ethyl-lactate, and the ionic liquid 1-ethyl-3-methylimidazolium ethyl sulphate (ECOENG 212 ®); (2) a (nicotine + water) mixture of close to critical composition and one of the co-solvents PEG 200, or glycerol, or ethyl-lactate; and (3) a (nicotine + water) mixture and one of the salts ECOENG 212 ®, or sodium chloride, or sodium phosphate. The objective of these measurements was to assess the possibility of using environmentally friendly solvents for extraction/separation of nicotine from its (aqueous) solutions. PEG 200, glycerol and ethyl-lactate proved to be good co-solvents of nicotine in water. On the other hand, the inorganic salts Na 3PO 4 and NaCl showed remarkable salting-out effects in nicotine aqueous solutions, achieved using very small quantities of these salt. The effects of the ionic liquid (molten salt) ECOENG 212 ®, were, however, much more complex. Depending on its concentration in the solvent, it exhibited either a co-solvent (salting-in) effect or an anti-solvent one. This behaviour is very interesting both from the fundamental and the applications point of view.