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[Display omitted] Stimuli-responsive lyogels are considered to be smart materials due to their capability of undergoing significant macroscopic changes in response to external triggers. Due to their versatile and unique properties, smart lyogels exhibit great potential in various applications such as drug delivery or actuation processes. While Poly-N-isopropylacrylamide (pNIPAM) is widely known as a thermo-responsive material, it also shows significant solvent-responsive swelling behavior. For the systems tested, polar solvents induce strong swelling due to hydrogen bonding with the amide group, nonpolar solvents lead to significant shrinkage of the lyogels. The aim of this study is to investigate and to model this behavior for future application in chemical or biochemical reactors. As a current area of research, incorporating smart lyogel technology into (bio-)chemical reactors facilitates the development of smart reactor systems. Applying thermodynamic modelling with the gE model COSMO-RS on the monomer or oligomers of pNIPAM, the correlation between solvent-polymer interactions and the degree of swelling can be observed. pNIPAM derivatives exhibit low infinite dilution activity coefficients (IDACs) in polar solvents with large degrees of swelling, while displaying an increase of IDACs in nonpolar solvents. Hydrogen bonds dominate the swelling behavior of lyogels not only in pure solvents but also in mixtures of solvents with varying polarity. Even in mixtures containing high amounts of nonpolar solvents, large degrees of swelling were observed due to the uptake of the polar solvent in the lyogel matrix. This effect can be observed in binary solvent mixtures but also in representative mixtures along an esterification reaction with varying carboxylic chain length of alcohol and carboxylic acids. [ABSTRACT FROM AUTHOR]

In this study, we introduce openCOSMO-RS 24a, an improved version of the open-source COSMO-RS model parameterized using quantum chemical calculations from ORCA 6.0, leveraging a comprehensive dataset that includes solvation free energies, partition coefficients, and infinite dilution activity coefficients for various solutes and solvents mainly at 25 °C. This is the first version of the model also capable of predicting solvation free energies based on ORCA calculations. Additionally, we develop a Quantitative Structure-Property Relationships model to predict molar volumes of the solvents, an essential requirement for predicting solvation free energies and partition coefficients from structure alone. Our results show that openCOSMO-RS 24a achieves an average absolute deviation of 0.45 kcal mol1 for solvation free energies, 0.76 for the logarithm of the partition coefficients, and 0.51 for the logarithm of infinite dilution activity coefficients, demonstrating improvements over the previous openCOSMO-RS 22 parameterization and comparable results to COSMOtherm 24 BP-TZVP. The user interface was extended to be able to use it as solvation model directly from within ORCA 6.0 or from the command line to provide researchers with a robust tool for applications in chemical and materials science. [ABSTRACT FROM AUTHOR]

In this work, the derivation of a general expression for the residual entropy for quasi-chemical models – including modern COSMO-RS/SAC – is shown. This expression is equivalent to equations that had to be assumed or postulated in previous works. More interestingly, it allows to unravel order (or non-randomness) in pure compounds and mixtures in a very detailed way. It is possible to investigate the entropic contribution of every possible pair of molecular surface segments, without relying on any lattice or coordination number. Different types of mixtures are very well explained by modern quasi-chemical models, including polar, apolar, and associating compounds showing positive, negative, and s-shaped excess entropy. Finally, it is shown that these models are unable to precisely represent some aqueous mixtures — the assumption of pairwise additive interactions is apparently too limited in those cases. [Display omitted] [ABSTRACT FROM AUTHOR]

• Flash points of binary and ternary mixtures of ethanol, hydrocarbon, and esters. • Mixtures with ethanol exhibited non-ideal behavior. • A drastic decrease in FP value was observed with a small addition of ethanol. • COSMO-RS and UNIFAC models aided in surrogate selection for biodiesel. • Measuring and modeling flash point enhances safe handling of jet fuels. The flashpoint (FP) holds significant importance in the fire risk mitigation and prevention strategies within the fuel industry, specifically when considering biojet blends. This property directly impacts the safety aspects associated with the handling and transportation of biojet fuel, moreover the FP of biojet blends exhibits variability based on the specific type of biofuel utilized and the percentage incorporated into the blend. Hence, it is crucial to employ a precise model for the estimation of the FP in newly developed biojet blends, ensuring compliance with safety standards governing their handling and transportation. Determination and modeling of such property is important, considering that the presence of other compounds (e.g. ethanol, esters) in a fuel mixture can change its FP. This study emphasized the sensitivity of fuels' FP regarding ethanol concentration and the applicability of activity coefficient models to predict the FP of mixtures. The FP of mixtures containing ethanol, hydrocarbons (dodecane, tetradecane and hexadecane) and esters (methyl palmitate, ethyl palmitate and biodiesel) as aviation fuel surrogates were experimentally determined from 0.0 to 1.0 molar fraction range for both binary and ternary mixtures, totalizing 11 binary mixtures and 5 ternary mixtures. For all system, an abrupt decrease in the FP temperature was observed with small additions of ethanol. The FP drop is less expressive for the binary mixtures formed by hydrocarbon esters, due to the similarities between the compounds and FP of the pure compounds. Besides, the Liaw's approach combined with UNIFAC, UNIFAC-Dortmund, UNIQUAC, and NRTL models as well as COSMO-RS, were used to calculate the FP data of the studied mixtures, resulting in global root-mean-square deviations (RMSD) with an average deviation ranging from 0.24 K to 12.03 K. The predictions provided by all models were more accurate than the ideal approach (RMSD = 17.42 K) for the studied mixtures. These results highlight the significance of accounting for non-ideal effects when estimating FP data for such systems. Additionally, the COSMO-RS model and UNIFAC proved to be an advantageous model to predict the shape of the FP curve and helped the selection of suitable surrogates for the biodiesel system and provide essential information for accurate process safety and fire risk assessment in the biojet fuel industry. Synopsis : Flash Point of ester, long-chain hydrocarbons and ethanol were measured to provide the data for the development of new formulations of Biojet fuels. [Display omitted] [ABSTRACT FROM AUTHOR]

Deep eutectic solvents (DES) present interesting properties, mostly connected to their solvation ability, and have been subject to much research in the recent past. Currently, the discovery of new eutectic solvents is accomplished by experimentally measuring the eutectic point of random systems, often using choline chloride as a hydrogen bond acceptor. In this work, the eutectic temperatures of new choline chloride-based eutectic systems were experimentally assessed. These data, along with other previously reported in the literature, were used to evaluate a method based on COSMO-RS to predict the eutectic temperature of choline-chloride based mixtures. The predictive methodology herein developed allows for the quick scanning of a large matrix of systems in order to identify those more promising to be in the liquid state at a given temperature. To validate this method, the eutectic temperature of pharmaceutical drug mixtures was predicted and, then, assessed experimentally, showing that COSMO-RS is useful in the design of liquid drug-based formulations. [ABSTRACT FROM AUTHOR]

Abstract In this work a new method for inclusion of pressure effects in COSMO-type activity coefficient models is proposed. The extension consists in the direct combination of COSMO-SAC and lattice-fluid ideas by the inclusion of free volume in form of holes. The effort when computing pressure (given temperature, volume, and mole numbers) with the proposed model is similar to the cost for computing activity coefficients with any COSMO-type implementation. For given pressure, computational cost increases since an iterative method is needed. This concept was tested for representative substances and mixtures, ranging from light gases to molecules with up to 10 carbons. The proposed model was able to correlate experimental data of saturation pressure and saturated liquid volume of pure substances with deviations of 1.16% and 1.59%, respectively. In mixture vapor-liquid equilibria predictions, the resulting model was superior to Soave-Redlich-Kwong with Mathias-Copeman α -function and the classic van der Waals mixing rule in almost all cases tested and similar to PSRK method, from low pressures to over 100 bar. Good predictions of liquid-liquid equilibrium were also observed, performing similarly to UNIFAC-LLE, with improved responses at high temperatures and pressures. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Abstract The new predictive electrolyte model COSMO-RS-ES is evaluated and refined for the calculation of solubilities of salts in mixed solvent systems. It is demonstrated that the model is capable of predicting solid-liquid equilibria at 25 °C for ammonium and alkali metal salts quite accurately in a wide variety of solvent mixtures. Furthermore, through the introduction of Gibbs free energies of transfer of single ions it is shown that the model performance can be improved even further. This new data type also allows for an ion-specific way of evaluating the model for the first time. For some systems when calculating the solubility, larger deviations are observed, but for the vast majority of systems the model delivers good predictions. This shows that COSMO-RS-ES is a valuable tool for calculation of phase equilibria in electrolyte systems especially when the scarcity of data impede the application of models that require a higher number of parameters. Highlights • Predictive calculation of solubilities of salts in mixed solvents possible. • Inclusion of Gibbs free energies of transfer of ions into training set. • New thermodynamic data leads to improved model. [ABSTRACT FROM AUTHOR]

A computational approach is presented for prediction of cellulose solubilities in ionic liquids (ILs) based on COSMO-RS (Conductor-like Screening Model for Real Solvents). Thermodynamically stable molecular structures were optimized from 2D structures of cellulose and ILs following specific force-field based search of conformation lowest in energy and quantum chemical optimizations of molecular geometry. The thermodynamic property of logarithmic activity coefficient (lnγ) and excess enthalpy (H E ) were calculated by COSMO-RS based on the COSMO molecular surfaces of cellulose and ILs to qualitatively predict the ability of ILs for cellulose dissolution. To evaluate the method, four sets of ILs were used to calculate lnγ and H E based on four different cellulose models. The goodness-of-fit of linear regressions between the experimental cellulose solubilities and the calculated lnγ and H E shows that lnγ is more reliable than H E for prediction of the dissolving power of ILs to dissolve cellulose. However, H E is more suitable for prediction of the dissolution ability of halogen-based ILs. Moreover, all the cellulose models gave comparably good prediction results regarding of the dissolving power of ILs based on the calculated lnγ, but the cellobiose model was identified as the optimal model due to the relatively higher prediction ability (R 2 ) across different IL datasets. The approach is time efficient and robust, which provides a novel method for large-scale screening of ILs for cellulose dissolution. [ABSTRACT FROM AUTHOR]

In this study, the densities of formaldehyde (FA) + water (H 2 O) binary systems with formaldehyde fractions ( x F A ) of 0.05–0.27 at temperatures ( T ) of 293.15, 298.15, and 313.15 K were measured at 0.1 MPa, as well as those of a formaldehyde + water + methanol (MeOH) ternary system with x F A of 0.05–0.27 and x M e O H of 0.09–0.64. A thermodynamic model was combined with the conductor-like screening model for real solvents (COSMO-RS) coupled with a chemical reaction equilibrium and mass balance to describe the species distribution in the above solutions containing poly (oxymethylene) glycols ((HO(CH 2 O) n H, MG n n  ≥ 1) and poly (oxymethylene) hemiformals (CH 3 O(CH 2 O) n H, HF n , n  ≥ 1) produced by the reactions of FA with H 2 O and MeOH, respectively. The densities and volumes of these unknown oligomers, MG n and HF n , were computed by the COSMO-RS method and were correlated with the polymerization degree, n , and temperature, T . Furthermore, the densities of the FA + H 2 O and FA + H 2 O + MeOH solutions were calculated based on the species distribution and COSMO-RS simulations, which reproduced the experimental data well. Finally, the excess molar volumes of the FA + H 2 O and FA + H 2 O + MeOH systems were studied for the first time. [ABSTRACT FROM AUTHOR]

In this research, a prediction method for the vapor-liquid equilibrium compositions of the propylene-propane mixture by the combined use of the COSMO-RS method and the Peng-Robinson equation of state is examined. Employing the van der Waals (VdW) mixing rule, the average deviations from this method for both the pressures and vapor phase compositions are no more than 0.62% and 0.75%, respectively. The average deviations for the relative volatility and tray efficiency are 0.93% and 5.52%, respectively. This method successfully describes the relative volatility of this system is not only related to the temperature but also dependent on the propylene mole fraction at low temperatures and high propylene concentrations. The density, excess molar volume and surface tension data are listed. The calculations explain the irregular phenomenon of the relative volatility. The results show that the non-ideality of this system comes from the dispersions between the components dominates the bulk liquid properties at low temperatures and high propylene concentrations. [ABSTRACT FROM AUTHOR]

In the presented study, COSMO-RS sigma moments were utilized in a nonlinear multivariate QSPR model for the estimation of the temperature dependent surface tension of various ionic liquids in wide surface tension (15.5–65.1 mN m −1 ) and temperature (268–533 K) range. The developed model is supposed to be a generally applicable, robust and accurate method for the prediction of ionic liquid's surface tension. 880 data points ensure its reliability, which values were used to establish, validate and test the method. An artificial neural network was developed, optimized and used as regression model. The prediction power of the proposed model was validated with an external data set, with a squared correlation coefficient R 2  = 0.97 and a mean absolute error MAE = 1 mN m −1 . The estimation ability of the model was compared against widely known methods. Furthermore, the factor sensitivity analyses of the utilized molecular descriptors allowed shedding light on the intermolecular basis of ionic liquid's surface tension. Results showed that the kind of skewness of the sigma profile, the electrostatic interaction energy and the hydrogen bonding acceptor function play the most important roles in the formation of ionic liquid's surface tension. [ABSTRACT FROM AUTHOR]

Guggenheim proposed a theoretical expression for the combinatorial entropy of mixing of unequal sized and linear and branched molecules to improve the Flory-Huggins model. Later the combinatorial activity coefficient equation, which was derived from Guggenheim's model, was applied in the UNIQUAC, UNIFAC, and COSMOSAC models. Here we derive from Guggenheim's entropy theory a new function for the number of nearest neighbors of a compound in a multicomponent mixture for which the knowledge of the coordination number and a reference area are not needed. This new relation requires only the mole, volume and surface fraction of the compounds in the mixture. The benefit of the new relation is that both the combinatorial and the residual term in the aforementioned models can be made lattice-independent. We demonstrate that the proposed relation simplifies the Staverman-Guggenheim combinatorial model and can be applied with success to the UNIQUAC and COSMOSPACE model in the description of vapor-liquid phase equilibria and excess enthalpy. We also show that the new expression for the number of nearest neighbors should replace the relative surface area and the number of surface patches in the residual part of the UNIQUAC and the COSMOSPACE model, respectively. As a result a more rigorous version of the UNIQUAC and the COSMOSPACE model is obtained. This could serve as a better basis for predictive models like UNIFAC, COSMO-RS and COSMOSAC. [ABSTRACT FROM AUTHOR]

A new COSMO-RS based electrolyte model (COSMO-RS-ES) was applied to the prediction of the solubility of CO 2 in aqueous MDEA solutions. For this purpose, the model was combined with the Soave-Redlich-Kwong equation of state to describe the gas phase non-ideality. First, it was shown that the model can successfully describe the phase equilibria in the CO 2 + water, as well as in alkanolamine + water systems. Using a region specific interaction parameter for the amine, the accuracy of the model for the prediction of the phase equilibrium in alkanolamine + water systems was further improved. Additionally, a detailed investigation of different amine + water systems based on the calculation of the partial molar enthalpies and entropies provided valuable insights on the properties of the systems. The description of the ternary CO 2 + MDEA + H 2 O system was successful after a readjustment of selected interaction energy equations of the model using few parameters. The model was then applied to the prediction of the species distribution as well as the prediction of the partial pressure of CO 2 at low gas loading. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) have been proposed as promising extractants to broaden the potential utility of liquid–liquid extraction process for lithium, but developing an attractive IL from numerous available ILs remains challenging. In this work, a rapid preliminary predicting and screening method based on COSMO-RS was proposed. The design strategy was to collocate anions that had intensive affinity to lithium ion with high hydrophobic cations. Based on it, a series of candidate ILs were prepared and characterized by 1 H and 13 C NMR spectroscopy, including [P 4444 ]-based and [N 4444 ]-based ILs with phosphate, phosphinate and long-chain carboxylate anions. The further extraction experiments indicated that the tetrabutylammonium mono-2-ethylhexyl(2-ethylhexyl)phosphate ([N 4444 ][EHPMEH]) had the highest Li + extraction efficiency. The extraction mechanism was investigated by slope analysis method and ATR-IR spectroscopy. It was determined that every Li + associated with 1.33 molecule [N 4444 ][EHPMEH] to form the extracted species. The stripping study showed that the Li + was able to be stripped by only 0.5 mol/L HCl without additional agents. The extraction experiments of Li + from multi-metal-ion solution were also carried out, and the distribution ratio of Li + was nearly twice those of Na + , K + , and Rb + , indicating that [N 4444 ][EHPMEH] was available to separate lithium ion from the other alkali metal ions. [ABSTRACT FROM AUTHOR]

Enantiomeric ratios for the esterification reaction of 2-phenylpropionic acid with 1-octanol catalyzed by immobilized Candida antarctica lipase B in sixteen organic solvents have been measured. Correlation equations that relate the enzyme enantioselectivity with the van der Waals volume (V w ), the van der Waals area (A w ), and the Hildebrand solubility parameters (δ 2 ) of the solvents were obtained, and they were compared with linear solvation energy relationship (LSER) correlation equations, which relates the enzyme enantioselectivity with polarity, acidity, basicity, and Hildebrand solubility parameters of the solvents. Statistical analysis of the experimental data for the esterification reaction investigated here as well as for seven other reactions taken from the literature showed that the pure solvent V w , A w and δ 2 parameters, sufficiently describe the dependence of enzyme enantioselectivity on the properties of the solvent, yielding better results than the LSER equations that use one more parameter. Furthermore, the enzyme enantioselectivity has been related to the infinite dilution activity coefficients of substrates in the solvent, which are predicted by the COSMO-RS model. It is shown that the predicted by COSMO-RS ratios of infinite dilution activity coefficients of the two enantiomers can be used to correlate satisfactorily the enantiomeric ratios. [ABSTRACT FROM AUTHOR]

Gas hydrate forms in oil and gas pipelines under low temperature and high pressure which result in flow assurance issues. To solve this, ionic liquids are introduced to act as dual inhibitors. Currently, the main method of studying the performances of ionic liquids is by conducting sometimes laborious experiments. Trial and error method as well as selection through literature are often employed in choosing the appropriate ionic liquids for gas hydrate inhibition. These methods are costly and probabilistic. In this work, Conductor-Like Screening Model for Real Solvents (COSMO-RS) software is used to pre-screen ionic liquids based on the fundamental property of the ionic liquid-hydrate system. The main energy that affects ionic liquid inhibition ability was found to be the hydrogen bonding energy (E HB ). Results showed that increasing anion E HB improves inhibition ability while increasing cation E HB decreases the inhibition ability. Studies on the hydrogen bonding energies for double salt ionic liquids showed that the combination of chloride [Cl − ] and hydrogen sulphate [HSO 4 ] as the anion has high hydrogen bonding energy. The introduction of the hydroxyl group [OH − ] in the cation increased the hydrogen bonding energy between anion and water. The proposed ionic liquids for experimental tests are [EMIM][Cl][HSO 4 ], [OH-EMIM] [Cl] and [OH-EMIM][HSO 4 ]. [ABSTRACT FROM AUTHOR]

The reported experimental data for the separation of aromatic from aliphatic compounds using green solvents is growing exponentially. This paper surveys the existing data and presents a critical review that helps clarifying the major findings, identifies shortcomings and provides some recommendations. The comparison between deep eutectic solvents (DESs) and both ionic liquids (ILs) and classical organic solvents for this challenging separation is also presented based on experimental selectivity and distribution ratio data. This comparison confirms the capability of DESs to effectively extract aromatic compounds and shows that DESs can compete with ILs and even outclass them in some cases. Moreover, our comprehensive literature survey has revealed that in many cases the use of DESs yields to a minimum cross-contamination between the two phases. This will undeniably facilitate the separation procedure and thus reduce the cost of the separation process. On the other hand, the performance of COSMO-RS to predict ternary liquid-liquid equilibrium diagrams for systems including DESs is also evaluated in this work for all available data. COSMO-RS was able to reproduce the experimental tie-lines with a good accuracy in many cases. Therefore, it represents a cost-effective and time-saving screening tool to evaluate the extraction performance of the unlimited number of possible salt/complexing agents' combinations. [ABSTRACT FROM AUTHOR]

Separation of azeotropic mixtures is a topic of great industrial interest. In this work, liquid-liquid extraction using deep eutectic solvents (DESs) is explored to separate binary azeotropic mixtures of ethanol and n -hexane, n -heptane or n -octane. Ten DESs were screened using the COSMO-RS approach by predicting the activity coefficient at infinite dilution, γ ∞ of ethanol and n -alkanes in each DES. Then, three DESs were selected for experimental validation where Tetrabutylammonium bromide/Levulinic acid (TBAB/LA) with a molar ratio (1:2) gave the best extractive performance for all systems. Ternary liquid-liquid extraction experiments were conducted at room temperature with this DES. It was found that the tie-lines of all systems have positive slopes, indicating that a small amount of solvent is required to extract ethanol. Moreover, the distribution ratio and selectivity values are all greater than unity and the DES was not detected in the raffinate phase which indicate minimal cross-contamination between extract and raffinate phases. Finally, COSMO-RS predictions of the ternary tie-lines were in excellent agreement with experimental data, with an average RMSD value of 1.65%. The experimental data were also successfully correlated with NRTL model with an average RMSD value of 1.50%. [ABSTRACT FROM AUTHOR]

In this experimental work, the phase boundaries of TMAOH + H 2 O + CH 4 and TMAOH + H 2 O + CO 2 hydrates are measured at different concentrations of aqueous TMAOH solution. The temperature-cycle (T-cycle) method is applied to measure the hydrate equilibrium temperature of TMAOH + H 2 O + CH 4 and TMAOH + H 2 O + CO 2 systems within the ranges of 3.5–8.0 MPa and 1.8–4.2 MPa, respectively. Results reveals that, TMAOH acts as a thermodynamic inhibitor for both gases. In the presence of 10 wt% of TMAOH, the inhibition effect appears to be very substantial for CO 2 with an average suppression temperature (ΔŦ) of 2.24 K. An ample inhibition influence is observed for CH 4 hydrate at 10 wt% with ΔŦ of 1.52 K. The inhibition effect of TMAOH is observed to increase with increasing TMAOH concentration. Confirmed via COSMO-RS analysis, the TMAOH inhibition effect is due to its hydrogen bonding affinity for water molecules. Furthermore, the calculated hydrate dissociation enthalpies in both systems revealed that TMAOH does not participate in the hydrate crystalline structure. [ABSTRACT FROM AUTHOR]

The availability of property data is one of the major bottlenecks in the development of chemical processes and products, often requiring time-consuming and expensive experiments or limiting the chemical space to a small number of known molecules. This bottleneck has been the motivation behind the continuing development of predictive property models. For the property prediction of novel molecules, group contribution methods have been groundbreaking. In recent times, machine learning has joined the more established property prediction models. However, even with recent successes, the integration of physical constraints into machine learning models remains challenging. Physical constraints are vital to many thermodynamic properties, such as the Gibbs-Dunham relation, introducing an additional layer of complexity into the prediction. Here, we introduce SPT-NRTL, a natural language processing model to predict thermodynamically consistent activity coefficients and provide NRTL parameters for easy use in process simulations.SPT-NRTL can be classed as an advanced group contribution model that uses characters of the SMILES code as atom groups and then dynamically constructs higher-order groups. The results show that SPT-NRTL achieves higher accuracy than UNIFAC in the prediction of activity coefficients across all functional groups and is able to predict many vapor–liquid-equilibria with near experimental accuracy, as illustrated for multiple exemplary mixtures. To ease the application of SPT-NRTL, NRTL-parameters of 100 000 000 mixtures are calculated with SPT-NRTL and provided online. [ABSTRACT FROM AUTHOR]

Pairwise interacting surface models, like COSMO-RS and COSMO-SAC, are getting popular in the prediction of activity coefficients when experimental data is scarce. In this work an alternative derivation of the COSMO-SAC model is presented and pair contact probabilities as well as nonrandom factors are compared with classic models. By using these probabilities one can readily calculate the system internal energy (or enthalpy). The case of temperature dependent interaction energies and the potential inconsistencies in this case are discussed in detail. Many properties of the resulting equations are discussed, including the issue of distinguishable or indistinguishable segment types. An accompanying open-source code favoring readability over efficiency is also provided. [ABSTRACT FROM AUTHOR]

In this study, a thermodynamic model was combined with the conductor-like screening model for real solvents (COSMO-RS), coupled with chemical reaction equilibrium and mass balance, for describing the phase behavior and complex chemical equilibrium in the ternary system of formaldehyde–water–methanol at temperatures between 323 and 383 K. To the best of our knowledge, this is the first time accurate and reasonable predictions were made for the species distribution and vapor–liquid equilibrium (VLE). Meanwhile, the σ-profiles and σ-potential were employed to interpret the molecular interaction in the system. Compared to the extrapolation method, COSMO therm implementation was preferred here for the prediction of the vapor pressures of methylene glycol (MG) and hemiformal (HF). Furthermore, the maximum partition coefficient for formaldehyde in the dilute formaldehyde–water–methanol mixture at low temperature was discussed. [ABSTRACT FROM AUTHOR]

The isobaric vapor-liquid equilibria of the binary 1-propanol + water, 2-propanol + water, and 2-methyl-2-propanol ( tert -butanol) + water systems were predicted using the conductor-like screening model for realistic solvation (COSMO-RS) method. The phase behavior of the 1-propanol/2-propanol/ tert -butanol + water + piperazine-based Good’s buffer systems were predicted. The effect of piperazine-containing Good’s buffers, 2-[4-(2-hydroxyethyl)piperazin-1-yl]alkanesulfonic acid, as mass-separating agents on the separation of proponals from water were discussed. The influence of alkyl chain length between the zwitterion end groups, R = methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl was evaluated. Further, the effect of 4-(2-hydroxyethyl)piperazine-1-(2-hydroxypropane sulfonic acid) was also evaluated. Piperazine-based Good’s buffers are expected to be effective mass-separating agents to have practical application in the separation of propanol from water. [ABSTRACT FROM AUTHOR]

When selecting ionic liquid (IL) as solvent for extraction processes, the cation alkyl chain length is an important structural variation, while research particularly concerning its effect is lacking. In this work, the effect of cation alkyl chain length on the liquid-liquid equilibria of {IL + thiophene + heptane}, an example for extractive desulfurization, was systematically investigated. The COSMO-RS model was employed to calculate the distributional coefficient (β ∞ ) and selectivity (S ∞ ) at infinite dilution for thiophene of the combinations of 17 cations and 63 anions. Two different anion-dependent tendencies of the β ∞ with increasing the cation alkyl chain length were identified and analyzed by COSMO-RS theory. To verify the scarcely-reported decreasing β ∞ with longer cation alkyl chain, acetate ([OAc] − ) was selected as representative and liquid-liquid equilibria {[C n MIM][OAc] + thiophene + heptane} (n = 2, 4, 6, 8) were experimentally determined, which validate the anion-dependency and demonstrate the highest extraction performance of [C 2 MIM][OAc]. [ABSTRACT FROM AUTHOR]

Unlimited number of permutations with respect to cation and anion combinations of ionic liquids as well as large number of existed azeotropic mixtures cause experimentally impossibility to screen all of possible systems of these compounds. Therefore, predictive models have been developed as COnductor-like Screening MOdel for Real Solvents (COSMO-RS) – an a priori predictive method independent of experimental data, which only requires the information is the molecular structure of the compounds. In this work, COSMO-RS model has been used in prediction of activity coefficients at infinite dilution of about 60 different organic solutes and water in 12 ionic liquids as well as ternary liquid–liquid equilibrium in 13 systems: (ionic liquid + methanol + heptane), (ionic liquid + thiophene + heptane) and (ionic liquid + benzothiophene + heptane). The model predictions are compared with experimental data (obtained in previously in our laboratory) in order to evaluate the accuracy of COSMO-RS model in phase equilibrium prediction of this kind of systems. [ABSTRACT FROM AUTHOR]

Due to the large number of different surfactant and solute molecules used in micellar solutions, it is important to have predictive models for micelle-water partition equilibrium. The relative new method COSMOmic, an extension of COSMO-RS, can predict thermodynamic data by taking the anisotropy of a system into account. For this purpose, it needs the structure of the system in atomistic resolution. In previous studies, atomic distributions were obtained from self-assembly molecular dynamics (MD) simulations. In this work MD simulations starting from pre-assembled micelles are used to receive atomic distributions. These simulations are more efficient than self-assembly simulations with respect to system size and simulation time and allow the detailed study of micelle size/structure influences on solute partitioning. For the first time a wide range of aggregation numbers for different types of surfactants are investigated. More than 90 different micelles structures were obtained for six different surfactants: SDS (sodium dodecyl sulfate), CTAB (cetyltrimetylammonium bromide), C 12 E 10 , Brij35 (C 12 E 23 ), Triton X-114 and Triton X-100 with initial aggregation numbers between 20 and 160. These were investigated with respect to micelle size, micelle shape, surfactant concentration and simulation time. To examine the prediction quality of COSMOmic, experimental data was collected and 36 micelle-water partition coefficients for C 12 E 10 , Triton X-100 and Brij35 were measured. In total more than 370 experimental partition coefficients were used to validate the calculations. The results show that the calculations are in good agreement with the experimental data and that they are better than predictions from methods that do not take the micelle structure into account (pseudo phase approach). In this context, small spherical micelles are proven to be more efficient while larger more ellipsoidal micelles show a higher probability to result in outliers. Therefore, this article provides a guideline for the development of averaged atomic distributions as input for COSMOmic. [ABSTRACT FROM AUTHOR]

In biotechnological processes, salts might be present during reaction steps and in downstream processes. Salts are known to have a strong impact on phase equilibria of aqueous systems. In this work, the liquid–liquid equilibria (LLE) of ternary salt/MIBK/water mixtures were measured at 298.15 K and 1 bar up to the salt solubility limit. The salts studied in this work were NaCl, LiCl, KCl, NaNO 3 , LiNO 3 , Na 2 SO 4 , CH 3 COONa, and CH 3 COOLi. From these LLE measurements it was found that a high amount of salt is dissolved in the aqueous phase whereas only a very small amount of salt was detected in the MIBK phase. Further, the salting-out behavior of MIBK from the aqueous phase upon addition of different salts was investigated to study ion-specific effects. Two ion-specific models, ePC-SAFT and an extended version of COSMO-RS for electrolytes were used for modeling the binary system MIBK/water and ternary salt/MIBK/water systems. In case of the COSMO-RS based approach, the modeling results were fully predictive. In contrast, ion-specific binary interaction parameters between MIBK and ions were fitted to experimental LLE data of the ternary systems salt/MIBK/water when using ePC-SAFT. The results show that the COSMO-RS based approach allows for predicting the salt influence on LLE with acceptable accuracy, whereas ePC-SAFT allows for almost quantitative correlations of experimental data. [ABSTRACT FROM AUTHOR]

We herein present a quantum chemical method for predicting the thermodynamic properties of a reactive formaldehyde + water system. The TURBOMOLE program was used to obtain the σ profiles of poly(oxymethylene) glycol oligomers produced via a series of chemical reactions in aqueous solution. The conductor-like screening model for real solutions (COSMO-RS) method, in combination with chemical equilibrium constants and the mass balance equation obtained using MATLAB, was successfully used to calculate the activity coefficients of all compounds in the liquid. Based on NMR data from the literature along with the obtained activity coefficients, we modified the thermodynamic chemical equilibrium constant K n ∗ for glycol formation. Finally, we estimated the vapor–liquid equilibrium and distribution of oligomers (MG n , n ≥ 1) in the formaldehyde-water solution. The COSMO-RS method was thus proven to be an efficient tool to study formaldehyde-containing aqueous solutions, and can be used as a basis for other similar reactive systems. [ABSTRACT FROM AUTHOR]

The adsorption isotherms of two new ionic liquids (4-tert-butyl-1-propylpyridinium bromide: IL1 and (4-ter-butyl-1-(2 carboxyethyl) pyridinium bromide: IL2) and ibuprofen (2-[4-(2-methylpropyl) phenyl] propanoic acid: IBP) on an activated carbon cloth were studied at 286, 298 and 313 K. Experimental adsorption isotherms were simulated by a single energy monolayer model using statistical physics, allowing to determine the number of molecules per site ( n ), the density of receptor sites ( N M ) and the concentration at half saturation ( c 1/2 ). Simulation results suggested that two adsorbates were docked per receptor sites of the activated carbon cloth surface. As a function of temperature, the study of the monolayer adsorbed quantity has indicated that the adsorption process is exothermic. The magnitudes of the estimated adsorption energies have indicated that IBP and ILs have been physisorbed on the adsorbent. The conductor-like screening model for real solvents (COSMO-RS) was applied to calculate three specific interaction energies of ILs and IBP with a graphene layer, i.e., the electrostatic misfit energy (E MF ), the hydrogen-bonding energy (E HB ) and the Van der Waals energy (E vdW ). The COSMO-RS model has proved that the interaction of all the three studied adsorbates with a graphene layer mainly depends on the Van der Waals contribution. The highest interaction energies of IL2 and IBP with the carbon surface have been explained by the additional contribution of hydrogen bond attributed to the presence of a carboxyl group on these molecules. [ABSTRACT FROM AUTHOR]

Looking for a better knowledge concerning water and ionic liquids (ILs) interactions, a systematic study of the activity coefficients of water in pyridinium, pyrrolidinium and piperidinium-based ILs at 298.2 K is here presented based on water activity measurements. Additionally, the study of the structural effects of the pyridinium-based cation is also pursued. The results show that non-aromatic ILs are interacting more with water than aromatic ones, and among the ortho, meta and para isomers of 1-butyl-methylpyridinium chloride, the ortho position confers a more hydrophilic character to that specific IL. The physical-chemistry of the solutions was interpreted based on dissociation constants, natural bond orbitals and excess enthalpies providing a sound basis for the interpretation of the experimental observations. These results show that hydrogen bonding controls the behavior of these systems, being the anion-water one of the most relevant interactions, but modulated by the anion–cation interactions. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) with cyano-functionalized anions are a set of fluids that are still poorly characterized despite their remarkably low viscosities and potential applications. Aiming at providing a comprehensive study on the influence of the number of –CN groups through the surface tension and surface organization of ILs, the surface tensions of imidazolium-based ILs with cyano-functionalized anions were determined at atmospheric pressure and in the (298.15–343.15) K temperature range. The ILs investigated are based on 1-alkyl-3-methylimidazolium cations (alkyl = ethyl, butyl and hexyl) combined with the [SCN] - , [N(CN) 2 ] − , [C(CN) 3 ] − and [B(CN) 4 ] − anions. Although the well-known trend regarding the surface tension decrease with the increase of the size of the aliphatic moiety at the cation was observed, the order obtained for the anions is more intricate. For a common cation and at a given temperature, the surface tension decreases according to: [N(CN) 2 ] − > [SCN] − > [C(CN) 3 ] − > [B(CN) 4 ] - . Therefore, the surface tension of this homologous series does not decrease with the increase of the number of –CN groups at the anion as has been previously shown by studies performed with a more limited matrix of ILs. A maximum in the surface tension and critical temperature was observed for [N(CN) 2 ]-based ILs. Furthermore, a minimum in the surface entropy, indicative of a highly structured surface, was found for the same class of ILs. All these evidences seem to be a result of stronger hydrogen-bonding interactions occurring in [N(CN) 2 ]-based ILs, when compared with the remaining CN-based counterparts, and as sustained by cation-anion interaction energies derived from the Conductor Like Screening Model for Real Solvents (COSMO-RS). [ABSTRACT FROM AUTHOR]

The quantum chemically based conductor-like screening model for realistic solvation COSMO-RS is a rather general method for predicting the chemical potentials – and thus the activity coefficients – of almost arbitrary molecules in almost any dense pure or mixed liquid. Originally it was developed for the prediction of partition coefficients and Henry’s law constants which are important in environmental and life science, almost all of them involving the aqueous phase. Partitioning between organic phases, as essential in many chemical engineering applications, was considered only in later stages. Therefore, the solvent water had and still has a great importance in the parameterization and validation of COSMO-RS with the result, that aqueous solvation in generally is well described. In this article, we review the performance of COSMO-RS for aqueous solvation, discuss some problems arising for this special fluid, i.e., water, and review some recent extension of COSMO-RS to p K a prediction, electrolyte systems, and aqueous interfaces. [ABSTRACT FROM AUTHOR]

• The hydrotropic effect of IL and salts on the aqueous solubility of artemisinin was studied. • Sodium salicylate increase the artemisinin solubility 750 fold compared to pure water. • Apolarity and hydrogen-bond acceptor character of hydrotrope are important for solubility enhancement. • Solvatochromic parameters of the hydrotrope aqueous solutions were measured. • Accurate empirical correlations are proposed to describe the solubility enhancement. Artemisinin is an antimalarial substance very sparingly soluble in water. In the attempt to identify environmental-friendly and non-toxic aqueous-based solvents to extract it from Artemisia annua L., the solubility of artemisinin in aqueous solutions of different hydrotropes was measured at 303.2 K, for hydrotrope concentrations up to 5 M. The ability of the studied hydrotropes for enhancing the artemisinin solubility increases in the following order: Na[N(CN) 2 ] < Na[SCN] < [Chol][Van] < [Chol][Gal] < [N 4,4,4,4 ]Cl < [Chol][Sal] < [P 4,4,4,4 ]Cl < Na[Sal], with Na[Sal] allowing an increase in the solubility of 750 fold compared to pure water. The COSMO-RS model and experimental Kamlet-Taft solvatochromic parameters were applied to connect the solubility enhancement with solvent properties. At low hydrotrope concentration, the solubility increases with the decreasing of the difference between the Apolar Factors of the hydrotrope and artemisinin, while for higher hydrotrope concentration, the hydrogen-bond acceptor character of the hydrotrope seems to have an impact on the solubility enhancement. Even if some mechanistic understanding is still to unfold, quantitatively the empirical correlations of solubility enhancement with the hydrotrope concentration and the solvatochromic parameters show very high accuracy. In particular, 93% of the change on the artemisinin solubility enhancement could be explained using the hydrotrope concentration and two combined solvatochromic parameters (α β and π * 2) as explaining variables. [ABSTRACT FROM AUTHOR]

The computation of solvation energies has many uses in several fields, such as design of separation processes, pharmacology and drug-design, and kinetic modeling. These applications require thermodynamic models capable of accurately predicting solvation energies, accounting for the temperature dependency of this property, and which are fast and robust. Within this framework, we compared two COSMO-based continuum solvation models (COSMO-RS and COSMO-SAC-dsp) with two versions of predictive cubic equations of state well-acknowledged for their efficiency (PSRK and UMR-PRU). For this purpose, a large experimental set of 57,000 datapoints extracted from the COMPSOL databank was considered. Comparisons between computed and experimental data were performed for Gibbs solvation energy and, for the first time in the literature, for both entropy and enthalpy of solvation simultaneously. For simpler binary mixtures, in which hydrogen bonding does not take place, all models were capable of providing accurate predictions, with average absolute deviations below 0.3 kcal/mol regarding the solvation Gibbs energy. For more complex associating mixtures, COSMO-RS showed the best correlation between experimental and calculated data, especially for aqueous systems; among EoS, it is observed that the PSRK model offers the best accuracy. [Display omitted] [ABSTRACT FROM AUTHOR]

Partial solvation parameters (PSP) are molecular descriptors sharing features with the widely used Abraham’s LSER molecular descriptors and Hansen’s Solubility Parameters. The present work attempts to place PSPs in an equation-of-state framework so that they can be used over an extended range of external temperature and pressure in a consistent manner. In such a framework, the external temperature and pressure dictates the density of the system which, in turn, changes PSPs. In addition, such a framework provides with operational definitions of PSPs which are most useful for their determination from a variety of experimental data. The alternative ways of expressing hydrogen-bonding interactions via PSPs is discussed. The predictive potential of this new approach is also discussed. [ABSTRACT FROM AUTHOR]

The solvent effect on the equilibrium position of the esterification reaction of tyrosol with ( R )-(+)-α-lipoic acid (RLA) catalyzed by Novozym 435 ® ( Candida antarctica lipase B immobilized on macroporous acrylic resin), in organic solvents and ionic liquids of various polarities has been experimentally examined. The solubilities of tyrosol in these organic solvents and ionic liquids have been also measured. It is shown that there is a correlation between the solubility of tyrosol in the reaction medium and the conversion yield of the reaction. Actually, high substrate solubility leads to a low conversion yield, with the higher conversion yields observed for the hydrophobic ionic liquids where tyrosol solubility is lower. Furthermore, tyrosol solubilites in the organic solvents and ionic liquids used for the enzymatic reactions of tyrosol with RLA have been measured, while the application of COSMO-RS model resulted to satisfactory predictions. Finally, the prediction of the solvent effect on the equilibrium position of esterification reactions has been investigated. The COSMO-RS model was used to calculate the activity coefficients of the chemical species involved in various reactions, carried out in different solvents. When applicable, the UNIFAC model has been also employed for comparison purposes. It is shown that the COSMO-RS method can be successfully applied for solvent selection with general applicability both for organic solvents and ionic liquids as well as in any kind of substrates. [ABSTRACT FROM AUTHOR]

A molecular screening of 64 ionic liquids (IL’s) for the solubility of monosaccharides such as d -(+)-Glucose, d -(+)-Xylose, d -(−)-Fructose and d -(+)-Galactose were performed by continuum solvation model (COSMO-RS) over the temperature range of 303.15–373.15 K. The IL data set consisted of 31 cations and 23 anions comprising of cations such as imidazolium, ammonium, pyridinium, pyrrolidinium, phosphonium, sulfonium and piperidinium. The imidazolium and ammonium based IL’s gave the highest solubility for cations possessing lesser number of carbon side chains. Based on the screening studies, the following two IL’s were chosen: 1-ethyl-3-methylimidazolium thiocyanate ([EMIM][SCN]) and Tris(2-hydroxyethyl)methyl ammonium methylsulfate [TMA][MeSO 4 ] to experimentally study the solubility of monosaccharides in the two IL’s. The experimentally obtained solid–liquid equilibria (SLE) values were then compared with COSMO-RS predicted values. The root mean square error (RMSE) values of monosaccharides such as d -(+)-Glucose, d -(+)-Xylose, d -(−)-Fructose and d -(+)-Galactose in [EMIM][SCN] were 3.11%, 3.12%, 2.32% and 1.83% respectively while the corresponding figures in [TMA][MeSO 4 ] is 1.47%, 1.20%, 2.94% and 0.70%. The overall solubility ranking in two IL’s was: d -(−)-Fructose > d -(+)-Xylose > d -(+)-Glucose > d -(+)-Galactose. [ABSTRACT FROM AUTHOR]

Knowledge concerning the solubility of ginger bioactive compounds in hot compressed water (HCW) is important for designing an extraction process with water as a green solvent. The solubilities of 6-gingerol and 6-shogaol in hot compressed water are calculated using the conductor-like screening model for real solvent (COSMO-RS) method to study the potential of water as a solvent. The comparison indicates that the calculated solubility is at a higher concentration for the binary system of 6-gingerol + water and 6-shogaol + water when compared to the HCW extraction. This illustrates the performance of the HCW extraction, which has not reached the equilibrium condition, and gives an opportunity to explore the options for further improving the process. The availability as well as the thermo-labile nature of the bioactive compounds are factors that must be considered for the improvement of HCW as a solvent. The solubilities of 6-gingerol and 6-shogaol in aqueous ethanol solutions are also calculated by the COSMO-RS method to study the entrainer effect of ethanol. The calculations with ethanol as entrainer indicate that the molecular cavity and contact interaction are changed so as to increase the solubilities. Based on the calculations, the suitable amount of ethanol as an entrainer is estimated to be 0.02 mole fraction for both 6-gingerol and 6-shogaol with an improved solubility of 1.86 and 1.76 times, respectively. In general, the addition of the entrainer will improve the recovery and operating parameters at a milder operating condition. This approach may be applied to other bioactives and will further strengthen the use of water as a solvent in natural extracts. [ABSTRACT FROM AUTHOR]

The model COSMO-RS (Conductor-like screening model for realistic solvation) is based on the approximation of molecular interactions by the interactions of surface segments from the molecular cavities. These segment interactions are functions of the segment properties i.e. descriptors, with the most important descriptor being the screening charge density. Whereas the inclusion of further descriptors can lead to improved accuracy for the models predictions, it also increases the computational demand due to the growth of the central nonlinear equation system of COSMO-RS. In this work, we present an algorithm that efficiently allows the introduction of further segment descriptors at moderate size increase of the central equation system. It is included into our implementation of COSMO-RS, which is provided as open source code and will be named openCOSMO-RS in the future. Different parameterizations of the model are performed, implementing an RDKit/ORCA based workflow for the required quantum chemical calculations. In this way, the implementation is open for evaluation and refinement for a large range of academic users. [ABSTRACT FROM AUTHOR]

Succinic acid has been considered a promising chemical building block that can be bio-produced using renewable resources. However, one of the biggest challenges in the bioproduction of this acid is the extraction and purification process. Currently, to extract and improve the purity of the produced succinic acid, a liquid-liquid extraction using organic solvents and extractants is performed. In this work, a liquid-liquid extraction of succinic acid from a model fermentation solution of Yarrowia lipolytica yeast broth (succinic acid + glycerol + water) is studied. The liquid-liquid extraction was carried out using hydrophobic phosphonium-based ionic liquids as extractants, for a 1:1 phase-volume ratio during 24 h at two different temperatures (298.15 K and 310.15 K) measuring the differences in the concentration of succinic acid and glycerol in the aqueous feed phase after 24 h to quantify the extraction percentage and, the succinic acid / glycerol selectivity. To obtain the succinic acid /water selectivity, the water concentration in the IL phase was calculated using Karl Fischer titration. With an extraction percentage of 78.4% for succinic acid and, a selectivity of 103 and 157 respectively for succinic acid /water and succinic acid /glycerol at 310.15 K, the best studied ionic liquid was [P 6,6,6,14 ][PHOS] being 10 times higher than octanol, which is commonly used as a comparative conventional solvent. On the other hand, a molecular simulation of liquid-liquid extraction generated in COSMO-RS, allowed to validate the experimental results, also indicating that the strong hydrogen bond interactions of [P 6,6,6,14 ][PHOS] and succinic acid were responsible for the excellent values obtained. Finally, the dissolved succinic acid in the organic phase was easily removed with an ultra-pure water striping using liquid-liquid extraction at 298.15 K for 40 min with a 1:1 phase-volume ratio. [ABSTRACT FROM AUTHOR]

The purpose of our study was to select the most effective ionic liquid (IL) extraction solvents for NdCl 3 and DyCl 3 using a theoretical conductor-like screening model for real solvents (COSMO-RS) based on quantum chemistry and the statistical thermodynamics of predefined NdCl 3 -IL and DyCl 3 -IL systems. The thermodynamics of the extraction process were predicted with the COSMO-RS method. NdCl 3 and DyCl 3 were considered in 4400 different ILs. As predicted, the chemical potential values of both NdCl 3 and DyCl 3 decreased significantly in systems with ILs based on the cation of dodecyl-dimethyl-3-sulfopropylammonium and the anions of bis(2,4,4-trimethylpentyl) phosphinate, decanoate, and benzoate. Considering the calculated physicochemical properties of the ILs containing these specific ions, the most effective IL extraction solvents for liquid–liquid extraction of the salts were selected. Experiments confirmed the high extraction efficiency of the ionic liquids chosen based on the COSMO-RS predictions. The COSMO-RS approach can be applied before extensive experimental tests to quickly screen the affinity of any rare earth element (REE) for a large number of IL systems, if only the physical dissolution of the REEs is considered. [ABSTRACT FROM AUTHOR]

With COSMO-RS, interactions between molecules are described with statistical thermodynamics of interacting surface segments. Thereby, all spatial information is neglected. Hence, concerted multiple contacts of molecules, and therefore dimerization, are not captured with COSMO-RS. In this study COSMO-RS-DARE, an extension of COSMO-RS for consideration of dimerization when predicting liquid phase properties, is evaluated for binary mixtures of dimerizing carboxylic acids and nonpolar components. For this extension two new parameters are introduced. These dimerization parameters are determined for the above-mentioned mixtures. Furthermore, a generalization of these parameters for a general application to that type of systems observed in this study is investigated. For this purpose activity coefficients for the binary mixtures of carboxylic acids and nonpolar components, calculated with COSMO-RS-DARE, are fitted to activity coefficients determined using experimental data by varying the new parameters. A better description of mixtures containing a dimerizing carboxylic acid and a nonpolar component can be achieved with COSMO-RS-DARE. If the dimerization parameters are determined for a single system, this system can be described with a high accuracy. Good results are achieved also with dimerization parameters generalized for a general application. This holds for systems used to determine these parameters as well as for systems not used to determine these parameters. Therefore, it can be stated that activity coefficients calculated with COSMO-RS-DARE have a higher accuracy than activity coefficients calculated with COSMO-RS without this extension. Nevertheless, further investigations with more systems are necessary to evaluate portability of COSMO-RS-DARE to a broader range. [ABSTRACT FROM AUTHOR]

The knowledge of the liquid–liquid equilibria (LLE) between ionic liquids (ILs) and water is of utmost importance for environmental monitoring, process design and optimization. Therefore, in this work, the mutual solubilities with water, for the ILs combining the 1-methylimidazolium, [C 1 im] + ; 1-ethylimidazolium, [C 2 im] + ; 1-ethyl-3-propylimidazolium, [C 2 C 3 im] + ; and 1-butyl-2,3-dimethylimidazolium, [C 4 C 1 C 1 im] + cations with the bis(trifluoromethylsulfonyl)imide anion, were determined and compared with the isomers of the symmetric 1,3-dialkylimidazolium bis(trifluoromethylsulfonyl)imide ([C n C n im][NTf 2 ], with n = 1–3) and of the asymmetric 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C n C 1 im][NTf 2 ], with n = 2–5) series of ILs. The results obtained provide a broad picture of the impact of the IL cation structural isomerism, including the number of alkyl side chains at the cation, on the water-IL mutual solubilities. Despite the hydrophobic behaviour associated to the [NTf 2 ] − anion, the results show a significant solubility of water in the IL-rich phase, while the solubility of ILs in the water-rich phase is much lower. The thermodynamic properties of solution indicate that the solubility of ILs in water is entropically driven and highly influenced by the cation size. Using the results obtained here in addition to literature data, a correlation between the solubility of [NTf 2 ]-based ILs in water and their molar volume, for a large range of cations, is proposed. The COnductor like Screening MOdel for Real Solvents (COSMO-RS) was also used to estimate the LLE of the investigated systems and proved to be a useful predictive tool for the a priori screening of ILs aiming at finding suitable candidates before extensive experimental measurements. [ABSTRACT FROM AUTHOR]

Abstract: Aiming at the evaluation of the impact of the ionic liquids (ILs) cation symmetry on their phase behaviour, in this work, novel mutual solubilities with water of the symmetric series of [C n C n im][NTf2] (with n =1–5) were determined and compared with their isomeric forms of the asymmetric [C n C1im][NTf2] group. While the solubility of isomeric ILs in water was found to be similar, the solubility of water in ILs follows the same trend up to a maximum cation alkyl side chain length. For n ≥4 in [C n C n im][NTf2] the solubility of water in the asymmetric ILs is slightly higher than that observed in the symmetric counterparts. The thermodynamic properties of solution and solvation derived from the experimental solubility data of ILs in water at infinite dilution, namely the Gibbs energy, enthalpy and entropy were used to evaluate the cation symmetry effect on the ILs solvation. It is shown that the solubility of ILs in water is entropically driven and highly influenced by the cation size. Accordingly, it was found that the ILs solubility in water of both symmetric and asymmetric series depends on their molecular volume. Based on these findings, a linear correlation between the logarithm of the solubility of ILs in water and their molar volume is here proposed for the [NTf2]-based ILs at a fixed temperature. [Copyright &y& Elsevier]

Highlights: [•] Vapor–liquid equilibria were measured for three furfural containing binary mixtures. [•] A recirculation still, a static apparatus and a headspace gas-chromatography were used. [•] Excess enthalpies were measured at 298.15K with isothermal flow calorimeter. [•] NRTL, UNIQUAC and Wilson model parameters were optimized. [•] The UNIFAC-Dortmund and COSMO-RS models were compared to the new data. [ABSTRACT FROM AUTHOR]

Enthalpies of vaporization of a large set of ionic liquids were predicted using the COSMO-RS ion-pair approach, at T =298.15K. Comparison with currently available experimental data of different methodological origin suggests ±10kJmol−1 as a preliminary realistic expectation range for the accuracy of COSMO-RS results. The obtained results were further used to derive the Hildebrand solubility parameters of the studied ionic liquids. While energetic subtleties due to different interaction modes in given ionic combinations are reflected in the respective enthalpies of vaporizations and are described by COSMO-RS, the presented COSMO-RS results additionally support a phenomenological data differentiation on a descriptive molecular level. [ABSTRACT FROM AUTHOR]

Highlights: [•] Conformational analysis of cinnamic acid derivatives (CADs). [•] COSMO-RS solubility predictions of CADs in ILs and/or organic solvents. [•] Analysis of energy interactions (misfit, hydrogen bonding and van der Waals). [•] COSMO-RS predictions are generally qualitatively consistent with the experiments. [•] COSMO-RS is a suitable model for a priori solvent screening. [Copyright &y& Elsevier]

Abstract: In the present paper, a study on the influence of the alkyl chain length in N-alkyl-triethylammonium bis(trifluoromethylsulfonyl)imide ionic liquids, [N R,222][Tf2N] (R =6, 8 or 12), on the excess molar enthalpy at 303.15K and excess molar volume within the temperature interval (283.15–338.15K) of ionic liquid+methanol mixtures is carried out. Small excess molar volumes with highly asymmetric curves (i.e. S-shape) as a function of mole fraction composition were obtained, with negative values showing in the methanol-rich regions. The excess molar volumes increase with the increase of the alkyl-chain length of the ammonium cation of the ionic liquid and decrease with temperature. The excess enthalpies of selected binary mixtures are positive over the whole composition range and increase slightly with the length of the alkyl side-chain of the cation on the ionic liquid. Both excess properties were subsequently correlated using a Redlich–Kister-type equation, as well as by using the ERAS model. From this semipredictive model the studied excess quantities could be obtained from its chemical and physical contribution. Finally, the COSMOThermX software has been used to evaluate its prediction capability on the excess enthalpy for investigated mixtures at 303.15K and 0.1MPa. From this work, it appears that COSMOThermX method predicts this property with good accuracy of approx. 10%, providing at the same time the correct order of magnitude of the partial molar excess enthalpies at infinite dilution for the studied ILs, , and methanol, . [Copyright &y& Elsevier]