Liquid-liquid equilibrium data have been reported for aqueous two-phase
systems formed by imidazolium-based ionic liquids, 1-hexyl-3-methylimidazolium chloride, and 1-butyl-3-methylimidazolium dicyanamide, with
inorganic salts,K2HPO4 and K3PO4. The binodal curves were fitted to a
three parameter equation and the tie line length was calculated.PHYSICAL CHEMISTRY 2014: 12th International Conference on Fundamental and Applied Aspects of Physical Chemistry;Belgrade (Serbia),22-26 September, 201

Dimitrijević, A.

Trtić-Petrović, Tatjana M.

Liquid-liquid equilibrium data have been reported for aqueous two-phase
systems formed by imidazolium-based ionic liquids, 1-hexyl-3-methylimidazolium chloride, and 1-butyl-3-methylimidazolium dicyanamide, with
inorganic salts,K2HPO4 and K3PO4. The binodal curves were fitted to a
three parameter equation and the tie line length was calculated.Physical chemistry 2014: 12th International Conference on Fundamental and Applied Aspects of Physical Chemistr

Repository of the Vinča Nuclear Institute (VinaR)

     PHYSICAL CHEMISTRY 2014  12th International Conference on Fundamental and Applied Aspects of Physical Chemistry          The Conference is dedicated to the 25. Anniversary of the Society of Physical Chemists of Serbia            September 22-26, 2014  Belgrade, Serbia   II   ISBN 978-86-82475-30-9 Title: PHYSICAL CHEMISTRY 2014 (Proceedings) Editors: Ž. Čupić and S. Anić Published by: Society of Physical Chemists of Serbia, Studenski trg 12-16, 11158, Belgrade, Serbia Publisher: Society of Physical Chemists of Serbia For Publisher: S. Anić, President of Society of Physical Chemists of Serbia Printed by: “Jovan” Priting and Publishing Company; 200 Copies; Number of pages: 6+ 441; Format: B5; Printing finished in September 2014.  Text an Layout: “Jovan”  Neither this book nor any part may be reproduced or transmitted in any form or by any means, including photocopying, or by any information storage and retrieval system, without permission in writing from the publisher.  200 - Coppy priting    IV  PHYSICAL CHEMISTRY 2014  12th International Conference on  Fundamental and Applied Aspects of Physical Chemistry     Organized by The Society of Physical Chemists of Serbia  in co-operation with   Institute of Catalysis Bulgarian Academy of Sciences   Boreskov Institute of Catalysis of Siberian Branch of the Russian Academy of Sciences  Faculty of Physical Chemistry, University of Belgrade, Serbia  Institute of Chemistry Technology and Metallurgy,  University of Belgrade, Serbia  Vinča Institute, University of Belgrade, Serbia  Institute of General and Physical Chemistry, Serbia    Faculty of Pharmacy, University of Belgrade, Serbia    VInternational Organizing Committee  Chairman:  S. Anić (Serbia) Vice-chairman:  M. Gabrovska (Bulgaria)                             V. A. Sadykov  (Russia)  Members: N. Cvjetičanin (Serbia), S. N. Blagojević (Serbia), M. Daković (Serbia), T. Grozdić (Serbia), D. Jovanović (Serbia), M. Kuzmanović (Serbia), D. Marković (Serbia), J. Marković-Dimitrić (Serbia), B. Milosavljević (USA), M. Mojović (Serbia), N. Ostrovski (Serbia), I. Pašti (Serbia), M. Petković (Serbia), A. Popović-Bjelić (Serbia),  B. Simonović (Serbia), D. Stanisavljev (Serbia),  B. Šljukić (Serbia), N. Vukelić (Serbia), V. Vukojević (Sweden)  International Scientific Committee  Chairman:  Ž. Čupić (Serbia) Vice-chairmans: V. N. Parmon (Russia)                                   S. Rakovsky (Bulgaria) Members: B. Adnađević (Serbia), S. Anić (Serbia), A. Antić-Jovanović (Serbia), G. Bačić (Serbia), A. Kelarakis (Greece), R. Cervellati (Italy), V. Dondur (Serbia), Ivan Gutman (Serbia), S. D. Furrow (USA), K. Hedrih (Serbia), M. Jeremić (Serbia), A. V. Knyazev (Russia), Lj. Kolar-Anić (Serbia), V. Kuntić (Serbia), Z. Marković (Serbia),  S. Mentus (Serbia), Š. Miljanić (Serbia), M. Perić (Serbia), M. Plavšić (Serbia), D. M. F. Santos (Portugal), G. Schmitz (Belgium), I. Schreiber (Czech), P. Sevčik (Slovakia), B. C. Simionescu (Romania), N. Stepanov (Russia), D. Todorović (Serbia), M. Trtica (Serbia), V. Vasić (Serbia), D. Veselinović (Serbia)   Local Executive Committee  Chairman:              S. Blagojević Vice-chairmans:    A. Ivanović-Šašić  Members: P. Banković,  N. Bošnjaković, J. Dostanić,  A. Đerić, A. Ignjatović, A. Jović, N. Jović-Jovičić, D. Lončarević, J. Krstić, J. Maksimović, V. Marković, M. Milenković, S. Maćešić, V. Marković, B. Nedić, N. Potkonjak, D. Ranković, M. Stević, M. Žunić, M. Ristić,          PHYSICAL CHEMISTRY 2014  A-14-P   109PHASE DIAGRAM OFTHE SELECTED AQUEOUS TWO-PHASE SYSTEMS BASED ON IONIC LIQUIDS  A.Dimitrijević and T.Trtić-Petrović  Laboratory of Physics, Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, Belgrade, Serbia. (daleksandra@vinca.rs)   ABSTRACT Liquid-liquid equilibrium data have been reported for aqueous two-phase systems formed by imidazolium-based ionic liquids, 1-hexyl-3-methyl-imidazolium chloride, and 1-butyl-3-methylimidazolium dicyanamide, with inorganic salts,K2HPO4 and K3PO4. The binodal curves were fitted to a three parameter equation and the tie line length was calculated.  INTRODUCTION Aqueous two-phase systems (ATPSs) exploit the incompatibility between aqueous solutions forming two phases [1]. ATPSs have consisted of two mutually incompatible salts or polymer, one of them kosmotropic or water-structuring, and the other chaotropic or water-destructuring, in the presence of water. Each phase contains mainly one of the compounds and a small amount of the other [2]. In the recent years, ionic liquids (ILs) have shown to be an attractive alternative to polymers in the formation of ATPSs due to their potential use as green solvents and as possible replacement for traditional volatile organic compounds [3]. Ionic liquids are salts with their ions poorly coordinated and which are liquid at temperatures below 100°C. As a new kinds of green solvents, ILs have unique properties such as negligible vapor pressure, wide liquid temperature range, non-flammability, enhanced thermal and chemical stability, tunable chemical structures, good electrical conductivity and improved solvation ability for a large matrix of compounds [3]. This makes ILs attractive as novel extractants for various metal ions and organic compounds (e.g., amino acids, dyes, proteins) [4]. Gutowski et al. demonstrated that addition of inorganic salt to aqueous solutions of ionic liquids can also cause liquid-liquid demixing and induce the formation of ATPSs.[5] The phase diagram, comprised binodal curve and tie-lines, provides information about: the concentration of phase forming components required to form two phases, the concentration of phase components in top and bottom phases and the ratio of phase volume. Coordinates for all potential        PHYSICAL CHEMISTRY 2014  A-14-P   110systems will lie on a tie line, which connects two nodes on the binodal and represents the final concentration of phase components in top and bottom phases. Moving along the tie line coordinates, the systems denoted will have different total compositions and volume ratios, but with the same final concentration of phase components in the top and bottom phases. [4] The aim of this study was forming of phase diagrams for two targeted hydrophilic ILs and determination of their tie lines. These results represent the first step of applying ATPS for extraction.  EXPERIMENTAL The ionic liquids used in this work were 1-hexyl-3-methylimidazolium chloride, [C6mim]Cl and 1-butyl-3-methylimidazolium dicyanamide, [C4mim][N(CN)2] with a stated purity of >99 wt % and supplied by Iolitec.Inorganic salts, 30 % solution of K2HPO4or K3PO4in deionized water. The phase diagram was determinated by the cloud-point method at room temperature. A known amount of IL was weight into a test tube and an appropriate volume of the salt was added dropwise into the test tube while shaking. By appearance of turbidity, the total mass of the added salt was calculated. The weight percentages of both ILs and salt were calculated by measuring the weights of both ILs and the salt. The sequential addition of water and salt was repeated until sufficient data points for constructing the phase diagram were obtained [6]. The binodal curve was fitted applying following equation:    [1] where Y and X are the concentrations (in w/w%)of IL and salt, respectively [7]. The fitting was performed using “Tablecurve 5.01” program. The tie lines were experimentally determined through the relationship between the weight of the top phase and the overall weight by lever-arm rule. The tie line length (TLL) for different salt and IL compositions were calculated according to:   [2] The symbols T and B refer to the top (IL-rich) and bottom (salt-rich) phases.  RESULTS AND DISCUSSION A sufficiently high concentration of inorganic salts added in an aqueous solution of hydrophilic IL can cause phase separation a salt-reach bottom phase which is in equilibrium with Il-reach top phase. The first step in designing of ABSs is forming of phase diagram for the investigated system. The experimental phase diagrams for two investigated IL/salt        PHYSICAL CHEMISTRY 2014  A-14-P   111systems([C6mim]Cl/ K2HPO4 and [C4mim][N(CN)2]/ K3PO4are presented in Figure 1.                               Figure 1. Phase diagramsof (i)[C6mim]Cl/K2HPO4 and (ii) [C4mim][N(CN)2]/K3PO4systems  The data were fitted according to the empirical relationships of Merchuk (Eq. 1), and the parameters for this equation as determinated by least-squares regression of the cloud point data are shown in Table 1. Literature results confirmed that the method can satisfactorily correlate binodal curves and determinated tie lines in these systems. TLL wasexperimentally determined for each system and given in Table 2. 0 5 10 15 20 25 30 35 40010203040506070 Ionic liquid (% w/w)Salt (% w/w)(i)0 2 4 6 8 10 12 14 16 18 2001020304050 Ionic liquid (% w/w)Salt (% w/w)       PHYSICAL CHEMISTRY 2014  A-14-P   112 Table 1. Correlation parameters used in Eq. 1 to describe the binodals. System A B C R [C6mim]Cl/K2HPO4 4.45364 -3.33576 10-5 -.033085 0.99904 [C4mim][N(CN)2]/K3PO4 4.44272 -1.73984 10-4 -0.40424 0.99905  Table 2. Tie-line lengths for IL+Salt systems  System IL Salt TLL 1 [C6mim]Cl+K2HPO4 27.5 17.6 45.129 2 [C4mim] [N(CN)2] 7.9 29.1 32.481  CONCLUSION The phase diagrams of ATPS for two imidazolium-based ILs were determinated by cloud point method at 298K. The binodal curves were fitted to the Merchuk equation, and tie-line lengths were determinated. The results showed that the empirical equation is satisfactory for correlating the investigated systems [7]. It can be seen that [C6mim]Cl/K2HPO4 system has greater ability to promote ATPS than [C4mim][N(CN)2]/K3PO4 system.  ACKNOWLEDGEMENT  We acknowledge the support to this work provided by the Ministry of Education and Science of Serbia through project Physics and Chemistry with Ion Beams, No. III 45006.  REFERENCES [1] J. A. Asenjo, B. A. Andrews, Journal of Chromatography A, 2011, 1218, 8826-8835. [2] F. J. Deive, A. Rodríguez, The Journal of Chemical Thermodynamics 2012, 54, 272-277. [3] S. Shahriari, C. M. Neves, M. G. Freire, J. o. A. Coutinho, The Journal of Physical Chemistry B 2012, 116, 7252-7258. [4] Z. Li, Y. Pei, H. Wang, J. Fan, J. Wang, TrAC Trends in Analytical Chemistry 2010, 29, 1336-1346. [5] K. E. Gutowski, G. A. Broker, H. D. Willauer, J. G. Huddleston, R. P. Swatloski, J. D. Holbrey, R. D. Rogers, Journal of the American Chemical Society 2003, 125, 6632-6633. [6] L. Sheikhian, M. Akhond, G. Absalan, Journal of Environmental Chemical Engineering 2014, 2, 137-142. [7] S. L. Mistry, A. Kaul, J. Merchuk, J. Asenjo, Journal of Chromatography A 1996, 741, 151-163. 

Phase diagram ofthe selected aqueous twophase systems based on ionic liquids

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Phase diagram ofthe selected aqueous twophase systems based on ionic liquids

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