aqueous solutions of this ionic liquid were found to have positive values. Also, small and negative value of

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1 CHAPTR-2 RIW

2 Densities, speeds of sound, and electrical conductances were easured by Shekaari et al., 28 for aqueous solutions of roo teperature ionic liquid, 1-hexyl-3-ethyl-iidazoliu broide, [hi][br] at T = ( to 38.15) K and atospheric pressure followed by the calculation of apparent olar volues,, isentropic copressibilities, s, apparent olar isentropic copressibilities, and olar conductivities, Λ. Redlich-Mayer equation was used for liiting apparent olar quantities which dictated that (ion + solvent) interactions were prevailing in the studied syste. Liiting apparent olar expansibility values for aqueous solutions of this ionic liquid were found to have positive values. Also, sall and negative value of 2 2 ( / T ) were found which indicated the ionic liquid to be a structure P breaker. Structural interactions and clathrate foration ight be occurring into the systes indicated by isentropic copressibility isothers which intersected approxiately at a concentration = ol kg 1. The ion association constant, Ka values increased upon increasing teperature depicted the extent of increasing ion association with increasing teperature. Siilar treatent was given to the aino acid + ionic Liquid [bi][br] + water ixtures at K by the author (Shekari and Jebali, 21 a ). The authors had also studied densities and electrical conductances of aino acids, glycine, L- alanine and L-valine in aqueous ionic liquid, 1-hexyl-3-ethyliidazoliu broide [hi][br] solutions have been easured at K (Shekari and Jebali, 21 b ). The apparent olar volues, infinite dilution apparent olar volues, and the standard partial olar volues of transfer, tr of the aino acids fro water to the aqueous ionic liquid solutions were calculated. The results had shown that both and tr in the glycine + [hi][br] + H2O syste increased with increasing ionic liquid concentrations and decreased in the cases L-alanine and L-valine systes. The values were used to estiate the contribution of the charged end groups (NH 3, COO ), CH2 group and other alkyl chain of the aino acids. Then, association constant, Ka, liiting olar conductivies, Λ were deterined using the olar conductivities of [hi][br] in aqueous aino acids solutions. Shekari and Jebali, 21 c reported the densities, viscosities, and refractive indices of glycine, L-alanine, and L-valine in aqueous solutions of an ionic liquid, 1-propyl-3- ethyliidazoliu broide [pi][br] at K. Then, apparent olar volues,, viscosity B-coefficients, and olar refractions of these ixtures. The standard partial olar 27

3 volues, and standard partial olar volues of transfer, 28 tr were deterined and had been interpreted in ters of solute + solvent interactions. The hydrophobic interactions were found to predoinate in L-alanine and L-valine solutions. Linear correlation for both and the viscosity B-coefficient with the nuber of carbon atos in the alkyl chain of the aino acids were coputed which helped to estiate contribution of the charged end groups (NH 3, COO ), the CH2 group, and other alkyl chains of the aino acids. The viscosity and olar refractivity results were used to confir the conclusions obtained fro voluetric properties. Shekari and Jebali, 211 reported apparent olar volues,, standard partial olar volues,, transfer partial olar volues, tr and hydration nuber, n H calculated fro the easured densities of aino acids (glycine, L-alanine and L-valine) in aqueous ionic liquid, 1-hexyl-3-ethyliidazoliu chloride, [hi]cl solutions at T = K. The olar conductivities were reported. With the help of cosphere odel, the trend of tr was interpreted in ters of solute-solvent interactions. For glycine, the hydration nuber was found to be decreasing with an increase in [hi]c] concentrations owing to the dehydrating effect of [hi][cl] with the charged centre of the zwitterions of the glycine. The liiting olar conductivity, Λ and ion association constants, Ka for the ixtures studied, decreased with the olality of aino acid. It was attributed to the interaction of [hi]cl with the aino acids and increasing viscosity of the binary ixture. Fang and Ren, 213 easured densities for the ixtures containing glycine, L-arginine, and L-phenyalanine with 1-ethyl-3-ethyliidazoliu broide, [ei][br] at T = ( and 38.15) K. Using the experiental data, apparent olar volue, and standard partial olar volue,, standard partial olar volue of transfer, tr were coputed. The tr values were found negative for glycine, L-alanine, and L-phenylalanine but positive for L-arginine. Also, the standard partial olar volue of transfer values increased linearly with increase in teperature and concentration of ionic liquid. The results proved beneficial in understanding the biological processes between head and side chain groups of aino acids and aqueous ionic liquid solution. The authors (Heintz et al., 22) had also reported therodynaic properties of ixtures of alkanes, alkylbenzenes, alkenes, linear and branched alcohols, acetone, acetonitrile, ethyl acetate, alkyl ethers and chloroethanes in the ionic liquid 1-ethyl-3-ethyl-iidazoliu bis (trifluoroethyl-sulfonyls) iide and 1,2 diethyl-3-ethyl-iidazoliu bis

4 (trifluoroethylsulfonyls) iide by gas chroatography fro T = K, keeping the ionic liquid as stationary phase. Later, partial olar excess enthalpies at infinite dilution, H i of solutes in ionic liquid were derived fro the teperature dependence of liiting activity coefficients. Heintz et al., 25 a, Heintz and erevkin, 25 b, Heintz et al., 26 a easured the activity coefficients at infinite dilution i for alkanes, alkenes, alkylbenzenes, alkenes and linear and branched C1-C6 alcohols, esters and aldehydes in the ionic liquids 1- ethyl-3-butyl-iidazoliu bis(trifluoroethylsulfonyl) iide at T = K, 1-ethyl- 3-octyl-iidazoliu tetrafluoroborate at T= K and 1-hexyl-3-ethyliidazoliu bis(trifluoroethylsulfonyl) iide at T = K. The authors had also calculated activity coefficients at infinite dilution, i for alkanes, alkylbenzenes, alkenes and linear and branched C1-C6 alcohols, esters and aldehydes in the ionic liquids 1-ethyl-3-octyliidazoliu tetrafluroborate and 1-ethyl-3-butyl-iidazoliu bis(trifluoroethylsulphonyl) iide by gas chroatography fro T= K, keeping the ionic liquid as stationary phase. For all the solutes, data points were obtained. Later, partial olar excess enthalpies at infinite dilution,, H i of solutes in ionic liquid were derived fro the teperature dependence of liiting activity coefficients. In continuation of his studies, activity coefficients for hydrocarbons, alcohols, esters, aldehydes in Triethylbutylaoniu bis(trifluoroethylsulfonyl) iide (Heintz et al., 26 b ) were also presented. asiltsova et al., 26 easured the activity coefficients of aliphatic and aroatic esters and benzylaine in 1-ethyl-3-ethyliidazoliu bis(trifluoroethylsulfonyl) iide. The aporliquid equilibria of binary ixtures containing the high boiling solutes (diethyl adipate, ethyl benzoate, and benzylaine) with the ionic liquid 1-ethyl-3-ethyliidazoliu bis(trifluoroethylsulfonyl) iide [ei][ntf2] were studied using the transpiration ethod. L easureents were carried out over the whole concentration range at teperatures between 298 K and 318 K. and activity coefficients ( i ) of these solvents in the ionic liquid were deterined fro these data and are correlated by the NRTL equation. Andreatta et al., 29 a deterined the densities, viscosities, and refractive indices for binary and ternary ixtures of ethanol, ethyl acetate, and 1-octyl-3-ethyl-iidazoliu bis(trifluoroethylsulfonyl)iide at T = K and atospheric pressure. Then, excess olar volues, viscosity and olar refraction changes of ixing were calculated which were later fitted to the Redlich-Kister polynoial equation. The adjustable paraeters and the 29

5 standard deviations between experiental and calculated values were also reported. The author gave siilar treatent to the ixtures, ethyl acetate + ethanol + 1-octyl-3-ethyliidazoliu bis(trifluoroethylsulfonyl)iide) (Andreatta et al., 29 b ), ethyl acetate + ethanol + 1-butyl-3-ethyl-iidazoliu bis(trifluoroethylsulfonyl)iide (Andreatta et al., 21 a ), isopropyl acetate + isopropanol + 1-octyl-3-ethyl-iidazoliu bis(trifluoroethylsulfonyl)iide (Andreatta et al., 21 b ), and isopropyl acetate + isopropanol + 1-butyl-3-ethyl-iidazoliu (Andreatta et al., 211). bis(trifluoroethylsulfonyl)iide The density, and speed of sound, u for the binary systes were easured at , 33.15, 38.15, and K under atospheric pressure by Bahadur and Deenadalyalu, 213. The binary systes contained the ionic liquid (IL): ethyltrioctylaoniubis(trifluoroethylsulfonyl)iide [oa] + [Tf2N]. The binary systes were [oa] + [Tf2N] + ethyl acetate or ethanol. The apparent olar volue, and the apparent olar isentropic copressibility, was evaluated fro the experiental density and speed of sound data, respectively. A Redlich-Mayer equation was fitted to the apparent olar volue and apparent olar isentropic copressibility data. The partial olar volue, and partial olar isentropic copressibility, of the binary ixtures were also calculated at each teperature. The partial olar volue indicates that the interolecular interactions for (IL + ethanol) are stronger than for (IL + ethyl acetate) at all teperatures and for both systes increases with an increase in teperature. The values of the infinite dilution apparent olar expansibility,, decreases with an increase in teperature. The isentropic copressibilities, s 3 increase with an increase in teperature for both binary systes. The positive values of for both binary systes can be attributed to the predoinance of solvent intrinsic copressibility over the solute intrinsic effect. Dohnal et al., 214 studied two ionic liquids (ILs), naely 1-butyl-1-ethylpyrrolidiniu dicyanaide [bpyr][dca] and 1-ethyl-3-ethyliidazoliu thiocyanate [ei][scn] as agents for the separation of the ethyl acetate + ethanol azeotropic ixture by extractive distillation. The isotheral vapor-liquid equilibria of the ternary systes with the ILs and all the constituting binary subsystes were easured and the effect of IL additives on the separation factor was studied with the help of two HSGC ethods. The HSGC ethodology developed presented distinct advantages copared to conventional dynaic easureents using recirculation stills. Several activity coefficient odels were tested. Both [bpyr][dca]

6 and [ei][scn] increased considerably the ethyl acetate/ethanol separation factor, breaking the azeotropic behavior at rather low levels of IL ole fractions (>.43 and.87, respectively). The ionic liquid used in the study outperfored other ILs for the current purpose. Pereiro et al., 26 presented the densities and refractive indices of the pure ionic liquid (IL) [hi[[pf6] at teperature range fro T = ( to ) K for density and fro T = ( to ) K for refractive index. Using the experiental density data, the coefficient of theral expansion of IL was calculated. The densities and refractive indices of binary ixtures involving diethyl carbonate (DMC), diethyl carbonate (DC), acetone, 2- butanone, 2-pentanone, ethylacetate, ethylacetate, and butylacetate + [hi][pf6] were easured at T = K and atospheric pressure. Later, excess olar volues, changes of refractive index on ixing were calculated. Also, the iscibility of IL with different organic solvents and (liquid + liquid) equilibriu (LL) data of binary ixture IL + DC was deterined experientally. The authors also published siilar work on (liquid + liquid) equilibria involving ionic liquids {1,3-diethyliidazoliu ethyl sulfate [i][meso4], {2-propanol + ethyl acetate + 1-butyl-3-ethyliidazoliu hexafluorophosphate [bi][pf6] and {2-propanol + ethyl acetate + 1-hexyl-3-ethyliidazoliu hexafluorophosphate [hi][pf6] to separate the azeotropic ixture ethyl acetate and 2- propanol (Pereiro and Rodríguez, 27 a ), [bi][pf6] (1-butyl-3-ethyl iidazoliu hexafluorophosphate), [hi][pf6] (1-hexyl-3-ethyliidazoliu hexafluorophosphate), [oi][[pf6] (1-ethyl-3-octyliidazoliu hexafluorophosphate), and [i][ch3so4] (1,3-diethyliidazoliu ethyl sulfate) with 2-butanone, ethyl acetate, and 2-propanol (Pereiro et al., 27 b ). Pereiro and Rodríguez, 28 reported the results of study on the use of the two ionic liquids as an extraction solvent in the separation of the azeotropic ixture of hexane with ethyl acetate. xperiental densities, speeds of sound, and refractive indices of the binary ixtures of ethyl acetate + hexane or + 1-hexyl-3-ethyliidazoliu hexafluorophosphate [hi][pf6] fro T=( to 33.15) K. Then, excess olar volue, changes of refractive index on ixing, and deviations in isentropic copressibility were calculated. Liquid-liquid equilibria (LL) were deterined for the ternary systes hexane + ethyl acetate + IL at K and atospheric pressure. Fro the tie-line data, the values of selectivity and distribution ratio were derived. xperiental liquid-liquid equilibria data was accurately correlated with the NRTL and UNIQUAC equations. 31

7 In the work perfored by Zhu et al., 211 the excess olar volue, and excess logarithic viscosity, (lnη) for the binary ixtures of 1-hexyl-3-ethyliidazoliu tetrafluoroborate ([C6i][BF4]) with butanone, ethyl acetate, butylaine, and tetrahydrofuran were deterined fro density and viscosity easureents in the whole coposition range at T = K. The excess olar volue, were found to have negative values but those of (ln η ) were positive over the whole range of concentration. The values exhibited their iniu at the ionic liquid ole fraction of.3, and (lnη ) values exhibited a axiu at the sae coposition. The excess olar volue values followed the order: tetrahydrofuran > butanone > ethyl acetate > butylaine for the binary systes, whereas the values of (ln η) decreased in the order: tetrahydrofuran > butylaine > ethyl acetate > butanone. The results were interpreted in ters of ion-dipole interaction, packing efficiency, hydrogen bonding, and the ion-pairs existing aong ionic liquid. Wang et al., 25 reported the experiental data of densities and viscosities for the ixtures of the ionic liquid 1-butyl-3-ethyliidazoliu hexaflurophosphate, [C4i][PF6], with acetone, 2-butanone, 3-pentanone, cyclopentanone and ethyl acetate at K followed by the coputation of excess olar volues,, and excess logarith viscosities, (lnη ). The excess olar volue values were found negative but those of (lnη) were positive. Also, a iniu in and a axiu in (lnη) were observed at about the sae ole fraction of the ionic liquid (x =.3) for all the ixture investigated. Cobined with the data reported in literature, the effects of the [PF6] and [BF4] anions were copared and discussed in ters of the ion-dipole interactions of the cations of the ionic liquids with the organic copounds as well as their influence on the association of [C4i] + and [PF6] in the ionic liquid. Naydenov and Bart, 29 presented the ternary liquid-liquid equilibria for four systes containing an alcohol (1-propanol or 1-butanol) or acetic acid + ester + the ionic liquid 1- ethyl-3-ethyliidazoliu hydrogen sulfate at (313.2 ±.5) K headspace gas chroatography. The effect of the alkyl chain on the alcohol and ester on the phase equilibria for these systes containing reactants and products of esterification reactions was investigated. xcept the syste ester and IL, all were of type I. The effect of alkyl chian length on alcohol and ester iiscibilities regions was discussed. The author (Naydenov and 32

8 Bart, 27) also reported LL easureents on systes containing acidic ionic liquid (IL) + ethylacetate + ethanol or acetic acid and discussed the effect of alkyl chain length. Li et al., 212 reported the vapor-liquid equilibriu (L) and liquid-liquid equilibriu (LL) of the ternary syste of ethyl acetate + ethanol + 1-ethyl-3-ethyliidazoliu acetate, together with the vapor-liquid-liquid equilibriu (LL) for the binary syste of ethyl acetate + IL. The experiental L, LL, and LL data were correlated by the nonrando two-liquid (NRTL) equation and the calculated results agreed with the experiental results satisfactorily. Zhang et al., 213 reported the isobaric vapor-liquid equilibriu (L) data for the binary ixtures containing (propyl acetate + n-pentanol), (propyl acetate + 1-ethyl-1-butanol), and (propyl acetate + 3-ethyl-1-butanol) at 11.3 kpa using an equilibriu still. The seiepirical ethods of Herington were used to test the therodynaic consistency of the experiental data. The NRTL, Wilson, and UNIQUAC odels were used to correlate the activity coefficients. Cai et al., 211 a presented the vapor-liquid equilibriu (L) data for ethanol + ethyl acetate + 1-octyl-3-ethyliidazoliu hexafluorophosphate at 11.3 kpa. The experiental L data was correlated by the non-rando two-liquid (NRTL) activity coefficient odel and the binary paraeters were obtained. The ionic liquid [oi][pf6] produced a notable salting-out effect which enhanced the relative volatility of ethanol to ethyl acetate. The effect of IL on ethanol + ethyl acetate syste was copared with that of o-xylene. The author (Cai et al., 211 b ) also easured the (L) and (LL) data for the ternary syste of ethyl acetate + ethanol + 1-ethyl-3-ethyliidazoliu acetate and treated the data siilarly. The experiental easureents of density in the teperature interval, T= ( to ) K, the speed of sound and osotic coefficients at K for aqueous solution of 1-ethyl-3- ethyliidazoliu broide [ei][br], and osotic coefficients at K for aqueous solutions of 1-butyl-3-ethyliidazoliu chloride [bi][cl] in the dilute concentration region were carried out by Gardas et al., 28. Then copressibilities, expansivity, apparent and liiting olar properties, internal pressure, activity, and activity coefficients for [ei][br] in aqueous solutions were coputed. Hydration nuber and the osotic second virial coefficients of ionic liquids were calculated fro the activity data which was also copared with that obtained fro Debye-Hückel and Pitzer odels. Partial olar entropies of [bi][cl] have been calculated and the distance of the closest approach of ions is estiated using the activity data for ILs in aqueous solutions and is copared with that of 33

9 X-ray data analysis in the solid phase. It was interpreted that the concentration dependence for aqueous solutions of IL can be accounted for hydrophobic hydration of ions and that the IL exhibited coulobic interactions as well as hydrophobic hydration for both the cations and anions. An attept was ade by Toé et al., 29 to understand the interolecular interactions existing aong aqueous ILs and bioolecules. The liquid liquid equillibria was studied for aqueous 1-butyl-3-ethyliidazoliu tricynoethane and aino acids. arious factors such as polarity, size, and charge distribution of aino acids were found to influence solubility effects and have been explained in ters of refined odels. The salting in and salting out phenoenon resulted by the ost proinent interaction aong water-aino acid side chain, IL-aino acid side chain and water-il interactions which is further decided by the relative affinities of bioolecules towards water, or IL cation and anion. Classical olecular dynaics siulation studies were carried out upon aino acids (glycine, alanine, valine, isoleucine, and glutaic acid) and ionic liquid {1-butyl-3-ethyliidazoliu bis(trifluoroethyl) sulfonyl iide} in aqueous edia to understand the underlying olecular level echaniss by Toé et al., 212. The results provided a coprehensive coverage of factors involved in solubility phenoenon observed in [IL + aino acid+ water] systes such as agnitude, direction and strength of interaction which finally depends upon interactions of IL cation, IL anion, and water with aino acids. The density, and speed of sound, u for the binary systes (ethanol + ethyl acetate) and (ethanol + ethyl acetate or ethyl acetate) were easured at , 33.15, and K and at atospheric pressure by Bahadur et al., 214 in this work whereas the syste (ethanol + ethyl acetate) had been studied in literature. Then, apparent olar volue,, isentropic copressibility, s, and apparent olar isentropic copressibility, were calculated using density and speed of sound data respectively. The liiting apparent olar volue,, and liiting apparent olar isentropic copressibility,, were found by extrapolation to infinite dilution using the Redlich-Mayer equation. The liiting apparent olar volue was used to obtain inforation about interactions aong solute-solvent and solute-solute. Finally, apparent olar expansibility, and Hepler's constant, ( 2 2 / T ) P, isobaric theral expansion coefficient, P 34 were also calculated. Positive values for all binary systes could be attributed to the predoinance of solvent intrinsic copressibility over the solute intrinsic effect.

10 Sastry et al., 23 reported new experiental data of densities at T = ( to K), viscosities, speeds of sound, relative perittivities at T = ( and K for the binary ixtures of alkyl (ethyl, ethyl, butyl, and isoayl) acetates + glycols (ethylene, diethylene, triethylene, and propylene) as a function of coposition. The deviations in excess olar volues and exess isentropic copressibilities were calculated and fitted to Redlich-Kister type equation. Grunberg-Nissan McAllister, and Auslander equations correlated the ixture viscosities efficiently. A qualitative analysis of the deviation and excess functions was ade to evaluate the nature and type of bulk state interactions. The at K for binary ixtures of n-alkanols CnH2n+1OH (fro n = 2 to n = 1) with ethyl and propyl acetates were reported by Ortega et al., All the excess volues were found positive over the entire concentration range, with increasing linearly with the length of the alkanol chain. Suitable equations were fitted to the data for each ixture. Densities and viscosities were easured by Nika et al., 1996 for the binary ixtures of ethyl acetate with linear and branched alkanols (C1-C4) at T = (298.15, 33.15, and 38.15) K. The experiental density, and viscosity, η values were used to calculate the excess olar volue, and viscosity deviation, Δη. Later, the and Δη values were fitted to a Redlich-Kister polynoial equation. In a study perfored by Canosa et al., 1998 the viscosities were easured for the binary ixtures of ethyl acetate + (ethanol, or ethanol, or propanol, or 2- propanol, or 1- butanol), and ethanol + (ethanol, or 1-propanol, or 2-propanol, or 2-butanol) and their viscosity deviations were evaluated at T = K and atospheric pressure over the entire range of coposition. Several sei-epirical relations were proposed to estiate the dynaic viscosity of ixtures, and results are copared with the experiental data. The UNIFAC-ISCO group contribution ethod, Lobe s volue fraction exponential odel, and the group contribution therodynaic viscosity odel (GC-UNIMOD) were used to predict the dynaic viscosity of the binary ixtures under investigation. Densities, viscosities and speeds of sound of binary ixtures of ethanol, propan-1-ol, butan-1-ol and pentane-1-ol with n-butyl acetate were easured over the entire range of coposition in the teperature interval T= ( ) K and atospheric pressure by Hasan et al., 211. Fro the experiental densities, viscosities and speeds of sound, the excess olar volues, copressibility,, deviations in viscosity, Δη and deviations in isentropic s were calculated. The excess olar volues and deviations in isentropic 35

11 copressibility were found to be positive for all the binary systes, while deviations in viscosities were negative for all of the binary ixtures. The excess olar volues, deviations in viscosity, and deviations in isentropic copressibility were fitted to Redlich-Kister type polynoial equation. FTIR and 1 H-NMR studies of these ixtures were also reported into the study. Qin et al., 1993 calculated excess olar volues fro the easured densities of binary ixtures of five alkanols (ethanol, ethanol, 1-propanol, 1-butanol, and 1-pentanol) with n- alkyl acetates (ethy, ethyl, propyl, butyl, and pentyl acetates) and with two ketones (acetone and 2-butanone) at 2 C over the whole coposition range. For a particular alcohol, the / value decreased upon increasing the size of carbonyl copound and for a given 1 2 carbonyl copound, it increased with the length of alkanol. The / 1 2 values were found soehow for systes containing ethyl acetate coponent. The systes containing ethanol were found to display different copositional dependency as copared to other alcohols. Lladosa et al., 21 reported the vapor-liquid equilibriu (L) data for the ternary systes ethanol + 2-butanone + butyl propionate and 2-propanol + 2-butanone + butyl propionate and soe of their constituent binary systes: ethanol + butyl propionate and 2-butanone + butyl propionate at 11.3 kpa. Positive deviations fro Raoult s law for ethanol + butyl propionate syste were observed. However, the syste 2-butanone + butyl propionate didn t show any deviation fro ideal behavior. Using Wilson, nonrando two-liquids, and universal quasicheical odels, the activity coefficients of the solutions were correlated as a function of ole fraction. arious therodynaic consistency tests were perfored and the binary L data easured in the present study passed the tests. It was concluded that Butyl propionate could be considered an effective agent for the separation of the azeotropic ixtures ethanol + 2-butanone and 2-propanol + 2-butanone by extractive distillation. Wang et al., 214 deterined the isobaric (vapor + liquid) equilibriu (L) data for the binary syste ethanol + 2-butyl alcohol and the quaternary syste ethyl acetate + ethanol + 2-butyl alcohol + 2-butyl acetate at P = kpa in a odified Rose still. The L data was found therodynaic consistent using the Herrington ethod. It was correlated by the Wilson and NRTL equations respectively, which were used to predict the L data of the quaternary syste. Wilson and NRTL odels atched well with the (vapor + liquid) phase equilibriu data. 36

12 Xiao et al., 213 reported the isobaric vapor-liquid equilibriu (L) data for the quaternary syste ethyl acetate + ethanol + isopropanol + isopropyl acetate and the constituent binary syste ethyl acetate + isopropyl acetate at 11.3 kpa. The rest of binary systes L data was obtained fro the literature. According to Herington analysis, the easured experiental data were found to be therodynaically consistent. arious odels like Wilson, NRTL and UNIQUAC activity coefficient odels were used to correlate the experiental binary data. The three odels with their best-fitted paraeters were used for the prediction of quaternary vapor liquid equilibriu. Later, a coparison of perforances was ade. The NRTL odel yielded a good prediction for the quaternary syste fro the paraeters of the correlated binary systes. Wang et al., 25 b used iidazoliu based ionic liquids [bi][pf6], [hi][pf6], [hi][bf4] and [oi][bf4] used as alternative solvents for the recovery of soe aino acids (L-tryptophan, L-phenylalanine, L-tyrosine, L-leucine and D-valine) fro aqueous edia. The logarith of partition coefficients, log (PIL/W), of the aino acids correlated well with the hydrophobicity of the aino acids. It indicated the iportance of the aino acid s hydrophobic effect as a driving force for their partition into a particular ionic liquid. The partition coefficients decreased with increasing ph in the range of ph < pk1, but increased with increasing solubility of water in ionic liquid phases. Strong electrostatic interactions between cationic for of the aino acids and anion of the ionic liquids were accounted for the higher extraction degree at low phs. The ionic liquid with BF4 anion had uch higher extraction efficiency for the aino acids than those with PF6 anion because of the stronger effective charge in BF4. Preliinary results indicated that [hi][bf4] and [oi][bf4] ionic liquids ight be adapted to liquid-liquid recovery process of soe aino acids fro aqueous edia. Also, L-tryptophan could be effectively separated fro ferentation broth in a ultiple step process using Ionic liquid, [hi][bf4] as an extractant. Doínguez-Pérez et al., 21 studied aqueous biphasic systes (ABS) coposed by hydrophilic ILs and ainoacids to obtain new evidences regarding their ABS foration ability and their capacity for the extraction of specific bioolecules. On the basis of the IL cation 1-butyl-3-ethyliidazoliu, the IL anion influence on ABS foration was assessed through its cobination with tetrafluoroborate, triflate, and dicyanaide anions, with different aino acids. Ternary phase diagras alongwith tie-lines fored by these aqueous solutions were easured at T = 298 K and atospheric pressure. The ability of aino acids to for ABS followed the order: l-lysine d,l-lysine HCl > l-proline. Later, the extraction 37

13 capability of the studied ABS was evaluated through their application to the extraction of bioolecules. Cheng et al., 26 easured the vapor-liquid equilibriu (L) data for the ternary ixture of carbon dioxide, 1-propanol and propyl acetate at T = 38.2, 313.2, and K, and at pressures ranging fro 4 to 1 MPa using a static type phase equilibriu apparatus with visual sapphire windows. New L data for CO2 in the ixed solvent was presented. These ternary L data at elevated pressures were also correlated using either the odified Soave- Redlich-Kwong or Peng-Robinson equation of state (OS), and by eploying either the van der Waals one-fluid or Huron-idal ixing odel which correlated satisfactorily. The results showed that at T = K and 1 MPa, 1-propanol ight be separated fro propyl acetate into the vapor phase at the entire concentration range in the presence of high pressure CO2. Costa et al., 29 reported the liquid-liquid equilibriu (LL) data for the syste water + n- butyl acetate + 1-propanol at T = K and atospheric pressure. The densities, viscosities, and surface tensions were easured. Also, the liquid interfacial tensions of the conjugate phases located in the isotheral binodal curve were deterined. The UNIFAC ethod was used to predict the experiental tie-line data and it was correlated using the epirical ethod of Other and Tobias, and the ethod of Pick et al. was applied for binodal data correlation. The olar volues, 38, dynaic viscosity, η and the surface tension, of the binary systes were correlated in ters of coposition using rational functions. Later, binary pair additivity and a rational function were considered for the ternary contributions to describe the ternary syste. Dong et al., 25 deterined the excess olar enthalpies of five binary systes for ethyl acetate and (1-propanol, 2-propanol, 1-butanol, 2-butanol, and 1-pentanol) at T = ( and 38.15) K and p = (5. and1.) MPa using a high-pressure flow-ixing isotheral calorieter. The sooth values of with the experiental results. H calculated by Redlich-Kister equation were copared Ortega et al., 199 a reported the vapor-liquid equilibriu data at kpa for (ethyl acetate (1) + ethanol (2) or + 1-propanol (2). The results were copared with those predicted by UNIFAC and ASOG ethods. Then, the foration of azeotrope was reported. Both ethods predicted the vapor phase coposition well. The author (Ortega et al., 199 b ) also reported isobaric vapor-liquid equilibriu of ethyl butanoate with ethanol and 1- propanol binary systes. In succession, he reported the L data for isobutylalkanol and an alkyl (ethyl to butyl) alkanoate (ethanoate to butanoate) (Ortega et al., 1999),

14 isobaric vapor-liquid equilibria and excess quantities for binary ixtures of an ethyl ester + tert-butanol (Ortega et al., 23), ethyl esters + tert-butanol (Ortega et al., 24), butyl esters + tert-butyl alcohol (Ortega et al., 25), and alkyl esters + tert-butyl alcohol: (Ortega et al., 26). Susial et al., 1989 reported the isobaric vapor-liquid equilibriu easureents for the binary ixtures of ethyl propanoate-ethanol and ethyl propanoate-propan-1-ol at kpa. The systes were found to deviate fro the ideality and therodynaically consistent and the ixture was found to for azeptrope at x = y =.483 and T= K. Later, suitable equations were used to fit the data copared with the values predicted by UNIFAC and ASOS odels. The author also treated the data of ethyl propanoate + isobutyl alcohol (Susial et al., 1993 a ) and propanoate + n-butyl alcohol (Susial et al., 1993 b ) siilarly. Susial et al., 21 also deterined vapor-liquid equilibriu (L) data for ethyl acetate + ethanol binary syste at (.1,.5, and.7) MPa using a stainless-steel ebullioeter in which both phases were recirculated. The operating procedure was based on the Cottrell pup principle. The liquid ixture was placed in an inverted double-walled vessel and heated. Using the data previously studied by various authors, the equipent perforance was verified. The experiental data was tested with the point-to-point test of an Ness, eploying the progra of Fredenslund. The results were consistent. Siilarly, the author studied the (L) data for isobutyl Acetate + ethanol and isobutyl acetate + 1-propanol (Susial et al., 212 a ), propyl Acetate and isobutyl acetate with ethanol or 2-propanol (Susial et al., 212 b ), isobutyl acetate + ethanol, + 1-propanol or + 2-propanol (Susial et al., 212 c ) and binary Systes of ethyl acetate, ethyl acetate, and propyl acetate with 1-propanol (Susial et al., 213) Blanco and Ortega, 1996 reported the isobaric vapor-liquid equilibriu data at kpa for the binary systes ethanol + ethyl ethanoate, +ethyl propanoate, and +ethyl butanoate. All ixtures showed positive deviations fro ideality but ethanol + ethyl ethanoate and ethanol + ethyl propanoate showed a iniu teperature azeotrope. Later, the results were tested for therodynaic consistency and correlated with several equations. The results were copared with the predictions of the ASOG and UNIFAC ethods. The author (Blanco and Ortega, 1998) also treated the binary ixtures of ethanol and ethyl esters siilarly. Dhanalakshi et al., 213 investigated the separation of the nonaqueous azeotropic systes ethyl acetate-ethanol and ethyl acetate-ethanol with 13 cations and 27 anions as entrainers to identify suitable ionic liquids using the COSMO-RS odel. It is observed that the cations best suited are iidazoliu > pyridiniu > ethyl pyrrolidiniu > octyl quinoliniu. The 39

15 lengthening of the alkyl chain of cations was also studied as well as whether the shorter the alkyl chain, the better is the separation. It was also noticed that the efficacy of the anions is in the order [OAc] > [Cl] > [DHP]. It was seen that the influence of anions is ore significant on the behavior of ionic liquid solvation in alcohols. The effects of polarity, excess free energy, and excess enthalpy are addressed on nonaqueous systes containing ionic liquids. It is suggested that [ei][oac], [ei][cl], and [ei][dhp] can be used as proising entrainers for practical applications of ester-alcohol separation. Berúdez-Salguero et al., 211 easured the densities,, refractive indices, n D, speeds of sound, u and surface tensions, σ for the aqueous binary solutions of partially iscible 2- ethyl-1-propanol, cyclopentanone, cyclohexanone, cyclohexanol, and ethyl acetoacetate at the teperature of K and atospheric pressure over the ole fraction range reaching the solubility liit in the aqueous phase. Isentropic copressibilities, deterined by eans of the Laplace equation, have been calculated fro the easured experiental data. To analyze the behavior of surface tensions, the extended Languir (L) odel was used. Gao et al., 29 presented the data on excess olar enthalpies of five binary systes for ethyl acetoacetate + (1-butanol, + 2-butanol, + 1-pentanol, + water, and + ethyl acetate) at T = (298.15, , , , and ) K and p =.1 MPa using a flow-ixing isotheral icrocalorieter. Upon increasing the teperature and the olecular size of the alcohols, excess olar enthalpies increased. The Redlich-Kister equation was used to correlate the experiental data. Siilarly, the author (Gao et al., 211) reported the excess olar enthalpies for four binary systes of ethyl acetoacetate + (ethanol, + ethanol, + 1- propanol, and + 2-propanol) at T = (288.2, 298.2, 313.2, and 328.2) K and p = 11.3 kpa. Sheu and Tu, 26 a easured the refractive indices and surface tensions for binary ixtures of six flavor esters (ethyl acetoacetate, ethyl isovalerate, ethyl benzoate, benzyl acetate, ethyl salicylate, and benzyl propionate) with ethanol over the whole coposition range at T = (288.15, , 38.15, and ) K and atospheric pressure. Refractive indices and surface tensions were easured using a digital Abbe-type refractoeter and Wilhely-plate ethod respectively. Fro the experiental data, deviations in the refractive index Δ n D and deviations in the surface tension Δσ fro volue fraction average for the binary ixtures were derived. The binary data of Δ n D and Δσ was correlated as a function of ole fraction using the Redlich-Kister equation. The author (Sheu and Tu, 26 b ) also reported the densities and viscosities for six binary ixtures fored by the flavor esters (ethyl acetoacetate, ethyl isovalerate, ethyl benzoate, benzyl acetate, ethyl salicylate, and benzyl 4

16 propionate) with ethanol at T = (288.15, , 38.15, and ) K and atospheric pressure. Then, the excess olar volue, and deviations in the viscosity fro ole fraction average, Δη for the binary ixtures were coputed and were correlated to Redlich- Kister equation. Later, kineatic viscosities were correlated using the McAllister's ultibody interaction odels. Nika et al., 1998 reported the densities and viscosities for the binary ixtures of ethyl acetate with linear and branched alkanols (C1-C4) at T = (298.15, 33.15, and 38.15) K. Then, the experiental density, and viscosity, η values were used to calculate the excess olar volue, and viscosity deviation, Δη. The and Δη values were fitted to Redlich-Kister polynoial. Montón et al., 25 presented the new consistent vapor-liquid equilibriu data for the binary systes isobutyl alcohol (IBA) + isobutyl acetate (IBAc) and tert-butyl alcohol (TBA) + tert-butyl acetate (TBAc) at 2 and 11.3 kpa. The IBA + IBAc syste deviated positively fro ideal behavior. It was described as syetric solution and presented azeotrope at both pressures. The TBA + TBAc syste also deviated positively fro ideal behavior and presented azeotrope only at 2 kpa. The activity coefficients and boiling points of the solutions were correlated with their coposition by the Wilson, UNIQUAC, NRTL and Wisniak-Tair equations. Muñoz et al., 25 a deterined the consistent vapor-liquid equilibriu (L) data at 11.3 kpa for the ternary syste isobutyl alcohol (IBA) + isobutyl acetate (IBAc) + butyl propionate (BUP) and two constituent binary systes: IBA + BUP and IBAc + BUP. The positive deviation were found fro Raoult's law for IBA + BUP syste and no deviation for IBAc + BUP syste were exhibited. The activity coefficients of the solutions were correlated with its coposition by the Wilson, NRTL, UNIQUAC odels. The ternary syste was well predicted fro binary interaction paraeters. IBA-IBAc binary azeotrope was eliinated by BUP. The significant change of phase equilibria behavior was observed which indicated that the solvent was an effective agent for that azeotrope ixture separation. The binary L data easured in this study passed the therodynaic consistency test reported in the literature and phase behavior was well predicted using the paraeters obtained fro binary data. The author gave siilar treatent to the ternary syste of isobutyl alcohol + isobutyl acetate + 1-hexanol and the binary systes isobutyl alcohol + 1-hexanol, isobutyl acetate + 1-hexanol at 11.3 kpa (Muñoz et al., 25 b ). 41

17 Tovar et al., 1997 easured the density for the binary ixtures of ethyl acetate [CH3COOCH2CH3] and glyes [CH3O(CH2CH2O)nCH3, n =1, 2, 3, and 4] and dibutyl ether [(CH3CH2CH 2 CH2)2O] at T = (278.15, , and 38.15) K and atospheric pressure using Kyoto lectronics DA-21 vibrating-tube densieter. The excess olar volue was calculated using the experiental density values. Also, the excess olar isobaric heat capacities were deterined using icro DSC II differential scanning calorieter for the binary ixtures of ethyl acetate with glyes (n =2, 4) and dibutyl ether at T = K. Pal and Kuar, 21 studied the excess olar volues, and viscosities, η for the binary liquid ixtures of polyether + ethyl acetate (C3H6O2), ethyl acetate (C4H8O2), and propyl acetate (C5H1O2)) as a function of coposition at the teperatures of , 38.15, and K and atospheric pressure over the entire range of coposition. The polyethers used in the study were 2,5,8-trioxanonane, and 2,5,8,11-tetraoxadodecane. Fro these results, the deviations of the viscosity, Δη fro a ole fraction average and excess free energies of activation of viscous flow, ΔG were calculated and discussed in ters of olecular interactions between the coponents of the ixtures. Furtherore, activation enthalpies, ΔH, entropies, ΔS of viscous flow and their variation with concentration were discussed. xcess olar volues, and viscosities for the binary ixtures of tetraethylene glycol diethyl ether with ethyl acetate, ethyl acetate, and propyl acetate at (298.15, 38.15, and ) K and atospheric pressure were reported by Pal and Kuar, 2. Fro the easured data, deviations in viscosity, and excess free energies of activation of viscous flow have been coputed and these quantities were used to interpret olecular interactions existing aong solution. Furtherore, activation enthalpies, and entropies of viscous flow have been evaluated and their variation with concentration is discussed. A short coparative study with results for ixtures with esters and polyethers was also been furnished Ainabhavi et al., 1994 reported the densities, speeds of sound, and sheer viscosities for the ixtures of diethylene glycol diethyl ether with ethyl acetate, ethyl acetate, ethyl benzoate, or diethyl succinate are easured as a function of ole fraction at teperatures, T = (298.15, 33.15, 38.15, , and ) K. Then, the values of these properties were fitted to a power series equation involving both teperature and the ole fraction of the binary ixture. The experiental values of the ixtures and pure liquids were used to calculate excess olar volue,, changes in isentropic copressibility, s, changes in refractivity, R and changes in viscosity, for the ixing process. Later, these results were fitted to the Redlich-Kister polynoial relation to estiate the binary coefficients. The 42

18 specific acoustic ipedance factor of the liquids was calculated to find a possible atch of their values with that of sea water, and the potential applications of these liquids as sonar transducer fill fluids have been investigated. The refractive index and density values of the ixtures were used to test the accuracy of the available refractive index ixing relationships in predicting the binary refractive index data. iscosity results were also analyzed by using the viscosity equations of MacAllister, Heric, and Auslaender. Density, viscosity, and refractive index at , and speed of sound at K for the binary ixtures of ethyl acetate + ethylene glycol or + poly (ethylene glycol) were reported by Ainabhavi et al., Then, excess olar volue, viscosity,, deviations in, olar refractivity, R, speed of sound, u, and isentropic copressibility, s, were coputed. Finally the results were fitted to Redlich-Kister type equation and binary coefficients and standard errors were calculated. Ainabhavi et al., 1993 presented the densities, viscosities, refractive indices, and speed of sound at , and K for the binary ixtures of ethyl acetoacetate with ethyl alcohol, ethyl alcohol, 1-propanol, 2-propanol, 2-ethyl-1-propanol, 1-butanol,1- pentanol, 1-hexanol, 1-heptanol and 2-octanol. xcess olar volues, excess olar refractions, viscosity deviations and isentropic copressibility deviations were calculated. Later, fitting of results using polynoial relation was perfored to estiate the coefficients and standard errors. The experiental and calculated quantities were used to interpret the interolecular interactions. The density and sound velocity of the solutions of roo teperature ionic liquid 1-butyl-3- ethyliidazoliu broide, [bi][br] in water, ethanol, and ethanol were easured at T = ( to ) K at atospheric pressure by Zafarani-Moattar and Shekaari, 25. Apparent olar volue and the apparent olar isentropic copressibility were coputed and fitted to a Redlich+Mayer type equation. Then, apparent olar volue and apparent olar isentropic copressibility of the solutions at the infinite dilution were also been calculated at all studied teperatures which indicated ionic liquid + solvent interactions in water were stronger than the alcoholic solutions. An intersection point in isothers of isentropic copressibility was observed for aqueous solutions which was indicative of structural interactions and clathrate foration. Tshibangu et al., 211 synthesized the ionic liquid, 1-butyl-3-ethyliidazoliu broide [bi][br] and characterized. Density and viscosity easureent for the ionic liquid with water, ethanol, ethanol, acetonitrile and acetone were carried out at roo teperature. The 43

19 density easureents were found to decrease onotonically while viscosity easureent decreased with increase in teperature. Conductivity easureent showed increase in conductivity due to the presence of the ionic liquid in water and ethanol, and decrease in other cosolvents. Conductivity easureent of the ionic liquid and ixture of the ionic liquid in various cosolvents at different concentrations showed increase in conductivity with increase in concentration. High theral stability of IL was confired fro thero gravietric analysis (TGA) with decoposition starting at about 4 o C. González et al., 26 deterined dynaic viscosities, densities, and speed of sound for the binary ixtures of 1-ethyl-3-octyliidazoliuchloride with ethanol, ethanol, and 1- propanol at T = (298.15, , and ) K and refractive index at T = K and P =.1 MPa. Fro the data, excess olar volues, isentropic copressibility deviations, and viscosity deviations fro to K were calculated. The results were further fitted to Redlich-Kister type polynoial equation to obtain fitting paraeters and root ean square deviations. Gozález et al., 27 reported the dynaic viscosities, densities, and speeds of sound of 1- ethyl-3-ethyliidazoliu ethyl sulfate with ethanol, 1-propanol, and 2-propanol at T = (298.15, , and ) K and refractive indices at T = K and at atospheric pressure over a wide range of coposition. Then, using the experiental data, excess olar volues, excess olar isentropic copressions, and viscosity deviations for the binary systes fro T= K to T = K and refractive deviations at K were calculated. The results were fitted to Redlich-Kister equation to obtain the fitting paraeters and the root-ean-square deviations. Arce et al., 26 deterined the densities, refractive indices, speeds of sound and dynaic viscosities of 1-ethyl-3-octyliidazoliu tetrafluoroborate, [oi][bf4] in binary ixtures with ethanol, ethanol, 1-propanol and 2-propanol at K and atospheric pressure. Then, excess olar volues, olar refraction, isentropic copressibility and dynaic viscosity changes of ixing were calculated. Finally, the results were correlated to Redlich- Kister polynoial equation. Calvar et al., 26 reported the densities, refractive indices, speeds of sound and isentropic copressibilities of the ternary ixture of ethanol + water + 1-butyl-3-ethyliidazoliu chloride [bi][cl], and of the binary subsystes containing the ionic liquid at K and atospheric pressure. 44

20 Góez et al., 26 presented the densities and refractive indices of the ternary ixture ethanol + water + 1-hexyl-3-ethyliidazoliu chloride, [hi][cl] and of the binary systes containing the ionic liquids (ILs) at T= K and atospheric pressure. xperiental data was used to calculate excess olar volues and changes of refractive indices upon ixing. Finally, the data was correlated using the Redlich-Kister polynoial equation, while the Cibulka equation was applied for the ternary syste. 45

21 RFRNCS: Ainabhavi, T. M.; Aralaguppi, M. I., Harogoppad, S. B., Balundgi, R. H. (1993) J. Che. ng. Data 38:31. Ainabhavi, T. M.; Phayde, H. T. S.; Khinnavar, R. S.; Gopalakrishna, B. (1994) J. Che. ng. Data 39:251. Ainabhavi T. M.; Banerjee, K. (1998) J. Che. ng. Data 43: 852. Andreatta, A..; Arce, A.; Rodil,.; Soto, A. (29 a ) J. Che. ng. Data 54:122. Andreatta, A..; Arce, A.; Rodil,.; Soto, A. (29 b ) J. Che. Therodyn. 41:1317. Andreatta, A..; Arce, A.; Rodil,.; Soto, A. (21 a ) J. Solution Che. 39:371. Andreatta, A..; Arce, A.; Rodil,.; Soto, A. (21 b ) Fluid Phase quilib. 287:84. Andreatta, A..; Francisco, M.; Rodil,.; Soto, A.; Arce, A. (211) Fluid Phase quilib. 3:162. Arce, A.; Rodil,.; Soto, A. (26) J. Solution Che. 35:63. Bahadur, I.; Deenadayalu, N. (213) Therochi. Acta 566:77. Bahadur, I.; Deenadayalu, N.; Rajugernath D. (214) Therochi. Acta 577:87. Berúdez-Salguero, C.; Gracia-Fadrique, J.; Calvo,.; Aigo, A. (211) J. Che. ng. Data 56:3823. Blanco, A. M.; Ortega, J. (1996) J. Che. ng. Data 41:566. Blanco, A. M.; Ortega, J. (1998) J. Che. ng. Data 43:638. Cai, J.; Cui, X.; Zhang, Y.; Li, R.; Feng, T. (211 a ) J. Che. ng. Data 56:2884. Cai, J.; Cui, X.; Zhang, Y.; Li, R.; Feng, T. (211 b ) J. Che. ng. Data 56:282. Calvar, N.; González, B.; Doínguez, A.; Tojo, J. (26) J. Solution Che. 35:1217. Canosa, J.; Rodriguez, A.; Tojo, J. (1998) J. Che. ng. Data 43:417. Cheng, C.-H.; Tang, M.; Chen, Y.-P. (26) Fluid Phase quilib. 248:89. Costa, H. F.; Lourenço, H.; Johnson, I.; Gonçalves, F. A. M. M.; Ferreira, A. G. M.; Fonseca, I. M. A. (29) J. Che. ng. Data 54:2845. Dhanalakshi, J.; Sai, P. S. T.; Balakrishnan, A. R. (213) Ind. ng. Che. Res. 52: Dong, H.; Zhang, R.; Yan, W.; Li, S. (25) J. Che. ng. Data 5:197. Dohnal,.; Baránková,.; Blahut, A. (214) Che. ng. J. 237:199. Doínguez-Pérez. M.; Toé, L. I. N.; Freire, M. G.; Marrucho, I. M.; Cabeza, O.; Coutinho João A. P. (21) Sep. Purif. Technol. 72:85. Fang, S.; Ren, D-H. (213) J. Che. ng. Data 58:845. Gardas, R. L.; Dagade, D. H.; Coutinho J. A.; Patil K. J. (28) J. Phys. Che. B 112:338. Gao, H.; Wang, Y.; Yan, W. (29) J. Che. ng. Data 54: