Prediction of Melting Points for Ionic Liquids

Trohalaki, Steven; Pachter, Ruth

doi:10.1002/qsar.200430927

Cited by 74 publications

(61 citation statements)

References 25 publications

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“…The enthalpic correction to the total gas-phase energy from statistical thermodynamics (H g *) was calculated by the program freeh (as implemented in TURBOMOLE) at the BP86/SV(P) level using Equation (15), in which H g is the total gas phase enthalpy, E SCF the total SCF energy, E ZP the zero-point energy, and n i the i-th vibrational frequency. …”

Section: Methodsmentioning

confidence: 99%

“…An additional contribution would arise from the release of surface energy, which scales with the solvent-accessible surface (Ŝ ) of a molecule. As we move from the lattice to the gas phase, there will also be a direct contribution stemming from H g *, the enthalpic correction to the total energy as defined in Equation (15) in the Computational Methods section (with T = 298.15 K). Thus, the resulting expression is as shown in Equation (12).…”

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confidence: 99%

“…Where multiple references for one compound existed, the average of the determined values was used and the estimated experimental error was calculated by using Equation (18) for Equation (4). If the ion pair was used instead of the single ions for the calculation of H g * according to Equation (15) in the Computational Methods section, the error of the equation dropped by only 10 %, which does not justify the very time-consuming optimization of the ion pair. Experimental and calculated values are given in Table S5 in the Supporting Information.…”

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confidence: 99%

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Going Full Circle: Phase‐Transition Thermodynamics of Ionic Liquids

Preiss

Verevkin

Koslowski

et al. 2011

Chemistry A European J

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We present the full enthalpic phase transition cycle for ionic liquids (ILs) as examples of non-classical salts. The cycle was closed for the lattice, solvation, dissociation, and vaporization enthalpies of 30 different ILs, relying on as much experimental data as was available. High-quality dissociation enthalpies were calculated at the G3 MP2 level. From the cycle, we could establish, for the first time, the lattice and solvation enthalpies of ILs with imidazolium ions. For vaporization, lattice, and dissociation enthalpies, we also developed new prediction methods in the course of our investigations. Here, as only single-ion values need to be calculated and the tedious optimization of an ion pair can be circumvented, the computational time is short. For the vaporization enthalpy, a very simple approach was found, using a surface term and the calculated enthalpic correction to the total gas-phase energy. For the lattice enthalpy, the most important constituent proved to be the calculated conductor-like screening model (COSMO) solvation enthalpy in the ideal electric conductor. A similar model was developed for the dissociation enthalpy. According to our assessment, the typical error of the lattice enthalpy would be 9.4 kJ mol(-1), which is less than half the deviation we get when using the (optimized) Kapustinskii equation or the recent volume-based thermodynamics (VBT) theory. In contrast, the non-optimized VBT formula gives lattice enthalpies 20 to 140 kJ mol(-1) lower than the ones we assessed in the cycle, because of the insufficient description of dispersive interactions. Our findings show that quantum-chemical calculations can greatly improve the VBT approaches, which were parameterized for simple, inorganic salts with ideally point-shaped charges. In conclusion, we suggest the term "augmented VBT", or "aVBT", to describe this kind of theoretical approach.

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Going Full Circle: Phase‐Transition Thermodynamics of Ionic Liquids

Preiss

Verevkin

Koslowski

et al. 2011

Chemistry A European J

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“…The crystallization and melting of a PIL should depend on the packing properties of the ions and their pairwise interactions. 44 For the ethylammonium based PILs, the main focus of this paper, the general trend is increasing T m with increasing molecular mass density, Figure 2. It must be noted that there is some scatter in the data.…”

Section: Resultsmentioning

confidence: 93%

Prediction of Macroscopic Properties of Protic Ionic Liquids by Ab Initio Calculations

et al. 2007

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We have systematically investigated combinations of anions and cations in a number of protic ionic liquids based on alkylamines and used ab initio methods to gain insight into the parameters determining their liquid range and their conductivity. A simple, almost linear, relation of the experimentally determined melting temperature with the calculated volume of the anion forming the ionic liquid is found, whereas the dependence of the melting temperature with increasing cation volume goes through a minimum for relatively short side chain length. On the basis of the present results, we propose a strategy to predict the nature of protic ionic liquids in terms of low vapor pressure and conductivity. Comparisons with previously reported strategies for prediction of melting temperatures for aprotic ionic liquids are also made.

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“…Trohalaki et al built separate models for thirteen bromides, thirteen nitrates, and seven nitrocyanamide salts of 1,2,4-triazolium cations. [24] Novelty is related with the application of Quantum-Chemical RHF/6-31G** theory for computing the optimised structures of the melts in the gas phase. Then CODESSA was used to derive the model by best multi-linear regression or heuristic method.…”

Section: Reports On Modelling Melting Point For Ionic Liquidsmentioning

confidence: 99%