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In the present work, the thermochemistry of solution, solvation, and hydrogen bonding of cyclic amides in proton acceptor (B) and proton donor (RXH) solvents were studied. The infinite dilution solution enthalpies of δ-valerolactam, N-methylvalerolactam, ε-caprolactam, and N-methylcaprolactam were measured at 298.15 K. The solvation enthalpies of cyclic amides were calculated based on the measured solution enthalpies and sublimation/vaporization enthalpies from literature. The enthalpies of hydrogen bonding between cyclic amides and proton acceptor and donor solvents were then calculated as a difference between the total solvation enthalpy and the non-specific contribution. The latter was estimated via two different approaches in proton donor and proton accepting solvents. The effect of the cycle size on the strength of hydrogen bonding of the cyclic amides in solution is discussed.

The present work is devoted to the thermochemical study of solvation of ionic liquids (IL) in benzene. The solution enthalpies of 1-ethyl-3-methylimidazolium tricyanomethanide [EMIM][C(CN)3], 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4], 1-hexyl-3-methylimidazolium hexafluorophosphate [HMIM][PF6], 1-octyl-3-methylimidazolium tetrafluoroborate [OMIM][BF4], 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [EMIM][NTf2], 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM][NTf2] and 1-butyl-3-methylimidazolium trifluoromethanesulfonate [BMIM][TfO] in benzene were measured. The solvation enthalpies of imidazolium-based IL were calculated. Molar refractions of imidazolium-based IL form literature data on density and refractive indexes of IL were also calculated. The linear correlation between solvation enthalpy and molar refraction of IL was observed. This correlation can be used to calculate the vaporization enthalpy of imidazolium-based IL from solution calorimetry data. [ABSTRACT FROM AUTHOR]

Abstract The thermochemical study of hydrogen bonding of organic solutes in 1-methylimidazolium bis(trifluoromethylsulfonyl)imide ([MIM][NTf 2 ]) was carried out. Activity coefficients at infinite dilution of organic compounds in [MIM][NTf 2 ] were measured by gas-liquid chromatography at different temperatures between 303.15 and 343.15 K. The solution enthalpies of organic solutes in [MIM][NTf 2 ] were determined from the temperature dependence of activity coefficients in the same systems. Solution enthalpies of solutes (propanol-1, meta -cresol, acetone, acetonitrile, diethyl ether, tetrahydrofuran, dichloromethane, trichloromethane, pyrrole) in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM][NTf 2 ] were measured by using high-precision solution calorimetry. The hydrogen bond enthalpies of organic solutes in [MIM][NTf 2 ] and [BMIM][NTf 2 ] were calculated using a previously developed method. The hydrogen bond enthalpies of organic solutes in the protic ionic liquid [MIM][NTf 2 ] were compared with the values in the aprotic ionic liquid [BMIM][NTf 2 ], as well as with those in the molecular solvent pyrrole. The hydrogen bond enthalpies of proton acceptor molecules in [MIM][NTf 2 ] differ significantly from zero unlike in [BMIM][NTf 2 ]. Hydrogen bond enthalpies of proton acceptor molecules in [MIM][NTf 2 ] and pyrrole are close. Graphical abstract Unlabelled Image Highlights • Activity coefficients of organic solutes in [MIM][NTf 2 ] at five temperatures were measured. • The hydrogen bond enthalpies of proton acceptor solutes in [MIM][NTf 2 ] were determined. • Solution enthalpies of solutes in [BMIM][NTf 2 ] were measured by solution calorimetry. • The N H fragment of [MIM][NTf 2 ] and pyrrole exhibits similar proton donor ability. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The solution enthalpies of water in ionic liquids were measured. • The specific interaction enthalpies of water and methanol in ionic liquids were calculated. • The specific interactions enthalpies of water and methanol in ionic liquids are treated as 2:1. Abstract The thermochemical study of hydrogen bonding of water with different proton acceptor ionic liquids was carried out. Along with the available experimental data, the solution enthalpies of water in [BMIM][TfO], [BMIM][BF 4 ] and [BMIM][PF 6 ] were measured. The hydrogen bonding enthalpies of water with various ionic liquids were determined by using previously developed method of solvation enthalpy separation into the nonspecific solvation enthalpy and the specific solute-solvent interaction enthalpy (hydrogen bonding). The findings indicate the formation of a complex, where one molecule of water is bound to two molecules of ionic liquids. Similarly, hydrogen bonding enthalpies of methanol with the same proton acceptor ionic liquids were determined. [ABSTRACT FROM AUTHOR]

This work is devoted to the quantitative study of hydrogen bond formation of N -alkyl substituted ionic liquids with proton acceptor and proton donor organic solvents. 1-Butyl-3-methylimidazolium bis (trifluoromethanesulfonyl)imide [BMIM][NTf 2 ], 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF 4 ], 1-butyl-3-methylimidazolium trifluoromethanesulfonate [BMIM][TfO], 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF 6 ], triethylsulfonium bis (trifluoromethylsulfonyl)imide [Et3S][NTf 2 ], 1-butyl-3-methylimidazolium tricyanomethanide [BMIM][TCM], 1-hexyl-3-methylimidazolium tetrafluoroborate [HMIM][BF 4 ] were investigated by solution calorimetry and FTIR-spectroscopy techniques. The stretching vibration region of C O group of 2-pentanone in mixture with N -alkyl substituted ionic liquid in inert solvent carbon tetrachloride was analyzed at different concentrations of components for the estimation of proton donor ability of ionic liquids. Also, the stretching vibration region of the OH-group of methanol was studied in a ternary system carbon tetrachloride (inert solvent), methanol (proton donor) and N -alkyl substituted ionic liquid for the estimation of proton acceptor ability of ionic liquids. The hydrogen bond enthalpy of methanol in ionic liquids was calculated using data of measured solution enthalpies and data extracted from the literature. The frequency shifts of the OH-group of methanol induced by intermolecular interactions within ionic liquids in a carbon tetrachloride solution were compared with the hydrogen bonding enthalpies of methanol with ionic liquids. A linear relationship between the frequency shifts of the OH-groups and hydrogen binding enthalpies of methanol in ionic liquids were found. According to measured FTIR-spectroscopy data, the N -alkyl substituted ionic liquids analyzed in this work possess weak proton donor properties, and at the same time their proton acceptor ability (basicity) is much higher and shows dependency on anion structure. [ABSTRACT FROM AUTHOR]

In this work thermochemistry of solvation of mono-, di-, tri- and tetra-substituted benzenes in 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF 4 ]) ionic liquid was studied. Enthalpies of solution at infinite dilution of 34 substituted benzenes in [BMIM][BF 4 ] were measured at 298.15 K using solution calorimetry technique. Based on the experimental and literature data enthalpies of solvation of 36 substituted benzenes in [BMIM][BF 4 ] were calculated. It was shown that enthalpies of solvation of substituted benzenes in [BMIM][BF 4 ] are independent on the mutual position of subtituents and dipole moment of molecules. Group contribution scheme for prediction of enthalpies of solvation of substituted benzenes was applied. Values of methyl- (CH 3 ), tert -butyl- ( tert -C 4 H 9 ), bromo- (Br), iodo- (I), amino- (NH 2 ), methoxy- (OCH 3 ), dimethylamino- (N(CH 3 ) 2 ), methylcarboxylate- (COOCH 3 ) group contributions to the enthalpies of solvation in [BMIM][BF 4 ] were derived and compared with molecular solvents. Solvation enthalpies of substituted benzenes in [BMIM][BF 4 ] calculated through group contribution scheme were in good agreement with experimental data. [ABSTRACT FROM AUTHOR]

In this work thermochemistry of solution and solvation of mono- and di-substituted chloro- and nitro-benzenes in 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIM][TfO]) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][NTf2]) ionic liquids was studied. Enthalpies of solution at infinite dilution of benzene, chlorobenzene, nitrobenzene, 1,2-, 1,3-, 1,4-dichlorobenzenes, 1,2-, 1,3-, 1,4-dinitrobenzenes, 1-chloro-2-nitrobenzene, 1-chloro-3-nitrobenzene, and 1-chloro-4-nitrobenzene in three ionic liquids were measured at 298.15 K. On the basis of experimental data enthalpies of solvation of substituted benzenes in ionic solvents were calculated. Values of Cl and NO 2 group contributions to the enthalpies of solvation were derived and compared with molecular solvents. Enthalpies of solvation of each series of dichlorobenzenes, chloronitrobenzenes and dinitrobenzenes in studied ionic liquids are equal and do not depend on the mutual position of substituents. This fact shows that dipole moment does not affect the enthalpy of solvation of organic solutes in ionic liquids. Enthalpies of solvation of disubstituted benzenes in ionic liquids calculated through group contribution approach were in good agreement with experimental data. [ABSTRACT FROM AUTHOR]

In this work the thermodynamics of intermolecular interactions for imidazolium based ionic liquids in solutions of proton donor solvent chloroform and proton acceptor solvent tetrahydrofuran was studied using solution calorimetry technique. Enthalpies of solution of 1-ethyl- and 1-butyl-3-methylimidazolium based ionic liquids with tetrafluoroborate, methylsulfate, ethylsulfate, butylsulfate, dicyanoamide, trifluoromethanesulfonate, thiocyanate anions were measured in two solvents over concentration range 0.18-3.60 mmol kg −1 at 298.15 K. Enthalpies of transfer from tetrahydrofuran to chloroform derived from experimental data were exothermic for all studied ionic liquids. Proton acceptor scale of ionic liquids as solutes was proposed on the basis of thermochemical data. Enthalpy of hydrogen bonding of ionic liquids with proton donor solvent chloroform increases in the range of anions [BF 4 ] − < [SCN] − < [TfO] − < [N(CN) 2 ] − < [AlkSO 4 ] − . At the same time these values remain constant for ILs with different length of alkyl group in cations and anions. Thermochemical proton acceptor scale of ILs in solution correlates well with COSMO-RS hydrogen-bonding energies in equimolar cation–anion pairs of ILs. [ABSTRACT FROM AUTHOR]

• The comparative analysis the solvation enthalpies of organic solutes in ionic liquids and molecular solvents was carried out. • The effects of the solute structure on the solvation enthalpy in ionic liquids are close to the molecular solvents. • The relative place of ionic liquids among other solvents in terms of intermolecular interactions was determined. The present review is devoted to the critical analysis of literature and own data on the solution and solvation enthalpies of nonelectrolytes in ionic liquids. The analysis is based on the concept of the relationship between the structure of the solute molecules and the intermolecular solute–solvent interactions. It was shown that the contribution of the solvophobic effect to the solvation enthalpy of nonelectrolytes in ionic liquid is insignificant. Despite the ion–dipole solvent–solvent interactions in the ionic liquids, the contribution of polar solute–solvent interactions to the solvation enthalpy of is also negligible. Based on data on the solvation enthalpies of aromatic and heteroaromatic derivatives in ionic liquids, an additive scheme for calculating the corresponding solvation enthalpies is proposed. Previously developed approaches to dividing the solvation enthalpy into the contributions from the nonspecific solvation and specific interactions have been applied to ionic liquids. The enthalpies of the solute–solvent hydrogen bonding were determined. In each of the cases considered above, a comparison with the data on the solvation enthalpies of the same non-electrolytes in benzene and N,N -dimethylformamide was made in order to determine the relation of ionic liquids to common solvents. It was shown that the structure effects of dissolved nonelectrolyte molecules on their solvation enthalpy in ionic liquids do not differ significantly from the ordinary solvents. [ABSTRACT FROM AUTHOR]

In the present work thermochemistry of intermolecular interactions of organic compounds in solutions of imidazolium based ionic liquids (ILs) has been studied using solution calorimetry method. Enthalpies of solution at infinite dilution of non-polar (alkanes, aromatic hydrocarbons) and polar (alcohols, amides, and etc.) organic solutes in two ionic liquids 1-butyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium trifluoromethanesulfonate were measured at 298.15 K. The scale of van der Waals interactions of imidazolium based ILs has been proposed on the basis of solution enthalpies of n -alkanes in their media. The effect of the cation and anion structure of ILs on the enthalpies of solvation was analyzed. Enthalpies of hydrogen bonding of organic solutes with imidazolium based ILs were determined. It has been shown that these values are close to zero for proton acceptor solutes. At the same time, enthalpies of hydrogen bonding of proton donor solutes with ionic liquids are increased depending the anion: tetrafluoroborate ≈ bis(trifluoromethylsulfonyl)imide < 2-(2-methoxyethoxy)ethyl sulfate < trifluoromethanesulfonate. Enthalpies of van der Waals interactions and hydrogen bonding in the solutions of imidazolium based ionic liquids were compared with the same data for molecular solvents. [ABSTRACT FROM AUTHOR]

In the present work, the thermochemistry of solution, solvation, and hydrogen bonding of cyclic amides in proton acceptor (B) and proton donor (RXH) solvents were studied. The infinite dilution solution enthalpies of δ-valerolactam, N-methylvalerolactam, ε-caprolactam, and N-methylcaprolactam were measured at 298.15 K. The solvation enthalpies of cyclic amides were calculated based on the measured solution enthalpies and sublimation/vaporization enthalpies from literature. The enthalpies of hydrogen bonding between cyclic amides and proton acceptor and donor solvents were then calculated as a difference between the total solvation enthalpy and the non-specific contribution. The latter was estimated via two different approaches in proton donor and proton accepting solvents. The effect of the cycle size on the strength of hydrogen bonding of the cyclic amides in solution is discussed. [ABSTRACT FROM AUTHOR]

This work is devoted to the study of hydrogen bond formation ability of ionic liquids. The proton donor abilities of pyrrolidinium-based ionic liquids with common anion bis(trifluoromethylsulfonyl)imide ([NTf 2) and a range of cations, i.e. 1-Methyl-1-ethylpyrrolidinium [MEPyr][NTf 2 , 1-Methyl-1-propylpyrrolidinium [MPrPyr][NTf 2 , 1-Methyl-1-butylpyrrolidinium [MBPyr][NTf 2 , 1-Methyl-1-octylpyrrolidinium [MOPyr][NTf 2 were studied by FTIR spectroscopy. The proton acceptor abilities of several ionic liquids (1-Butyl-3-methylimidazolium bis (trifluoromethanesulfonyl)imide [BMIM][NTf 2 , 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF 4 , 1-butyl-3-methylimidazolium trifluoromethanesulfonate [BMIM][TfO], 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF 6 , triethylsulfonium bis (trifluoromethylsulfonyl)imide [Et 3 S][NTf 2 , 1-butyl-3-methylimidazolium tricyanomethanide [BMIM][TCM], 1-hexyl-3-methylimidazolium tetrafluoroborate [HMIM][BF 4) were studied by both FTIR and solution calorimetry techniques. The hydrogen bond enthalpies of pyrrole in various ionic liquids were calculated. A linear correlation between frequency shifts of H-bonded NH-group of pyrrole in ionic liquids and hydrogen bond enthalpies of pyrrole in the same ionic liquids was found. The obtained correlation for ionic liquids was compared with molecular organic solvents. Unlabelled Image • The pyrrolidinium-based ILs cannot form hydrogen bond with proton donor molecules. • The hydrogen bond enthalpy of pyrrole in ionic liquids was calculated by solution calorimetry. • The frequency shifts of NH-group of pyrrole in ionic liquids were measured by FTIR-spectroscopy. • Linear correlation between frequency shifts of H-bonded OH-group of pyrrole in complexes with ionic liquids was found. [ABSTRACT FROM AUTHOR]

In this work solution enthalpies of aromatic compounds and their halogen derivatives in 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF 4 ], 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide [BMIM][NTf 2 ], 1-butyl-3-methylimidazolium trifluoromethanesulfonate [BMIM][TfO] were measured by solution calorimetry method. The solvation enthalpies of aromatic compounds and their halogen derivatives in ionic liquids were calculated. Based on experimentally measured solvation enthalpies and calculated non-specific solvation enthalpy the contribution of the solvophobic effect on the solvation enthalpy of dissolved molecules in ionic liquids was demonstrated to be negligible. The correlation between solvation enthalpies of the aromatic compounds and their halogen derivatives in ionic liquids and solute molecules polarizability parameter was found. Also, a comparison of relationships between solvation enthalpy and molar refractions in ionic liquids and molecular solvents was made. Unlabelled Image • Solution enthalpies of solutes in ionic liquids were measured by solution calorimetry. • Non-specific solvation enthalpies of solutes in ionic liquids were calculated. • Contribution of solvophobic effect on solvation enthalpy were determined. • Correlation between solvation enthalpies of aromatic compounds and their halogen derivatives in ionic liquids was found. [ABSTRACT FROM AUTHOR]

• Solution enthalpies chloro- and nitro-benzenes in binary mixtures were measured. • Dipole moment of solute does not effect on solvation enthalpy in binary solvents. • Polarizability of binary solvents does not influence on solvation enthalpy. In the present work a thermochemistry of solution and solvation of mono- and di-substituted chloro- and nitrobenzenes in binary mixtures was studied. The infinite dilution solution enthalpies of 1,2-dichlorobenzene,1,4-dichlorobenzene, 1,2- dinitrobenzene, 1,4-dinitrobenzene, 1-chloro-2-nitrobenzene and 1-chloro-4-nitrobenzene in binary mixtures of benzene-cyclohexane, benzene-acetonitrile, carbon tetrachloride-acetonitrile at different molar ratios (0, 0.25, 0.50, 0.75, 1.00) solvents were measured at 298.15 K. Based on experimental data the solvation enthalpies in binary mixture were calculated. It was shown that the solvation enthalpies slightly depend on neither the location of chloro- and nitro - substituents in aromatic ring nor a composition of binary mixture. [ABSTRACT FROM AUTHOR]

• Solution enthalpies proton donors in binary solvents were measured. • The approach to evaluate the intermolecular interactions contributions of solute in binary solvent has been demonstrated. • The enthalpies of specific interaction of solute in binary solvent were calculated. The work focuses on a thermochemical study of solvation of organic non-electrolytes in various binary mixed solvents. The enthalpies of solution of pyrrole, methanol and chloroform in carbon tetrachloride – pyridine binary mixture were measured at 298.15 K. Data on solution enthalpies of solute – binary solvent for more than 350 systems has been collected. The specific and non-specific terms to the enthalpies of solvation of proton donors have been evaluated for the first time for the mixed solvent using the model previously adapted for individual solvents. [ABSTRACT FROM AUTHOR]

In present work a thermochemistry of hydrogen bond formation of proton acceptors (B) in the medium of linear ( N -methylformamide (NMF)) and cyclic (2-pyrrolidone (Py)) amides was studied. The infinite dilution solution enthalpies of nitriles, ketones, esters, ethers and amines in amides were measured at 298.15 K. Enthalpies of hydrogen bonding of proton acceptors in solution linear and cyclic amides were calculated and compared with previously determined the enthalpies of hydrogen bonding of amides in proton acceptor media. The cooperative effects of hydrogen bonding in multi-particle complexes of amides with proton acceptors were evaluated. It was shown that cooperativity coefficients were decreased with increasing the basicity of proton acceptors. [ABSTRACT FROM AUTHOR]

[Display omitted] • Solution enthalpies of linear and cyclic ethers in solvents were measured. • The enthalpies of specific interaction of solute in solvent were calculated. • The influence of number of active centers in ethers on thermochemical parameters has been discussed. In work a thermochemistry of solution, solvation and hydrogen bond formation of linear (diethyl ether and diglyme) and cyclic ethers (1,4-dioxane, 12-crown-4, 15-crown-5 and 18-crown-6) in proton acceptor and proton donor solvents were studied. The infinite dilution solution enthalpies of ethers in cyclohexane, carbon tetrachloride, benzene, ethyl acetate, N,N-dimethylformamide, dimethylsulfoxide, acetone, pyridine, chloroform and methanol were measured at 298.15 K. The solvation and hydrogen bonding enthalpies of ethers in the solvent are calculated. The influence of number of active centers in ethers on thermochemical parameters is shown. It was found that the formation of hydrogen bonds for linear and cyclic ethers with proton donors are different. [ABSTRACT FROM AUTHOR]