COSMO-RS Calculations Research Articles

Structural models of the keratin derivatives. An approach to its solubility and processability

Small-size models of keratin constituent units and products of its decomposition are proposed and computed to i) reproduce the interaction patterns that hold the macromolecule structure and its behavior under different reaction media and physico-chemical conditions; ii) estimate the energy of interactions that support the tridimensional structure of the protein, and consequently, the energy requirements to break it. To create these models and evaluate their performance, quantum-chemical, COSMO, and COSMO-RS calculations were performed. They seem to be capable to support process simulations during the conceptual design and optimization of operations and processes to transform the raw keratin into products of higher added value. Besides, proper analyses using these models demonstrated that the cleavage of the disulfide bonds is the primary condition to break the macromolecule but additionally, the intramolecular H-bond network should be dissociated enabling the intramolecular interaction with the chemicals used to dissolve and regenerate the keratin.

Unveiling Solubilization Mechanisms of Natural Deep Eutectic Solvents in Triazole Fungicides: COSMO-RS Calculations and Screening for Eco-Friendly, High-Efficiency Pesticide Systems

Unveiling Solubilization Mechanisms of Natural Deep Eutectic Solvents in Triazole Fungicides: COSMO-RS Calculations and Screening for Eco-Friendly, High-Efficiency Pesticide Systems

COSMO-RS-based assessment of thermodynamic tools in predicting the polar and non-polar solvents efficiency in vegetable oil extraction.

One of the prevalent methods for evaluating separation performance is to predict the interactions of solvent and solute molecules. The infinite dilution activity coefficient, Gibbs free energy, and sigma profiles provided insights into the solubilization of a solute and revealed the intensity of the solution's molecular interactions. The effective thermodynamic tools (infinite dilution activity coefficient, Gibbs free energy) were evaluated for predicting the efficiency of 18 polar and non-polar organic solvents in rubber seed oil (RSO) extraction. An infinite dilution activity coefficient was computed to evaluate the solubility of the rubber seed oil model compound (linoleic acid) in the organic solvents. Gibbs free energy was evaluated to show the energy change associated with the molecules mixing process and forecast the miscibility of linoleic acid molecules in the solvents. Moreover, the study examined the sigma profiles and sigma surfaces of organic solvents and linoleic acid to acquire a deeper insight into their similarities and how they interact molecularly. According to the computational prediction and experimental verification, the thermodynamic properties of Gibbs free energy and activity coefficient proved to be highly effective tools for screening polar and moderately polar solvents, predicting the molecular interactions with solute. Whereas the sigma profile and sigma surface were found to be the most efficient tools for evaluating the efficacy of non-polar solvents. Solvents with moderate polarity, such as tetrahydrofuran and diethyl ether, as well as non-polar solvents like pentane, heptane, and n-hexane, proved to be effective and favorable for oil extraction, resulting in the highest oil yields of approximately 27.0%. Overall, the COSMO-RS method demonstrates its utility in estimating the solubility of RSO in organic solvents, enabling early identification of the most effective solvent. The initial geometry optimization of every component was conducted through density functional theory (DFT) using TmoleX software. A single-point density functional theory (DFT) computation using Becke Perdew 86 (BP86) and the Triple-Zeta Valence Potential (TZVPD) was performed to produce.cosmo files. COSMO-RS calculations were performed by applying the parameterization file BP_TZVPD_FINE_19.ctd using COSMOthermX software. The practical extraction of oil from plant seeds was performed using a sonicator bath to verify the accuracy of the COSMO-RS predictions.

Aromas: Lovely to Smell and Nice Solvents for Polyphenols? Curcumin Solubilisation Power of Fragrances and Flavours.

Natural aromas like cinnamaldehyde are suitable solvents to extract curcuminoids, the active ingredients found in the rhizomes of Curcuma longa L. In a pursuit to find other nature-based solvents, capable of solving curcumin, forty fragrances and flavours were investigated in terms of their solubilisation power. Aroma compounds were selected according to their molecular structure and functional groups. Their capabilities of solving curcumin were examined by UV-Vis spectroscopy and COSMO-RS calculations. The trends of these calculations were in accordance with the experimental solubilisation trend of the solubility screening and a list with the respective curcumin concentrations is given; σ-profiles and Gibbs free energy were considered to further investigate the solubilisation process of curcumin, which was found to be based on hydrogen bonding. High curcumin solubility was achieved in the presence of solvent (mixtures) with high hydrogen-bond-acceptor and low hydrogen-bond-donor abilities, like γ- and δ-lactones. The special case of DMSO was also examined, as the highest curcumin solubility was observed with it. Possible specific interactions of selected aroma compounds (citral and δ-hexalactone) with curcumin were investigated via 1H NMR and NOESY experiments. The tested flavours and fragrances were evaluated regarding their potential as green alternative solvents.

Predicting absolute aqueous solubility by applying a machine learning model for an artificially liquid-state as proxy for the solid-state.

In this study, we use machine learning algorithms with QM-derived COSMO-RS descriptors, along with Morgan fingerprints, to predict the absolute solubility of drug-like compounds. The QM-derived descriptors account for the molecular properties of the solute, i.e., the solute-solute interactions in an artificial-liquid-state (super-cooled liquid), and the solute-solvent interactions in solution. We employ two main approaches to predict solubility: (i) a hypothetical pathway that involves melting the solute at room temperature T = T¯ ([Formula: see text]) and mixing the artificially liquid solute into the solvent ([Formula: see text]). In this approach [Formula: see text] is predicted using machine learning models, and the [Formula: see text] is obtained from COSMO-RS calculations; (ii) direct solubility prediction using machine learning algorithms. The models were trained on a large number of Bayer in-house compounds for which water solubility data is available at physiological pH of 6.5 and ambient temperature. We also evaluated our models using external datasets from a solubility challenge. Our models present great improvements compared to the absolute solubility prediction with the QSAR model for the artificial liquid state as implemented in the COSMOtherm software, for both in-house and external datasets. We are furthermore able to demonstrate the superiority of QM-derived descriptors compared to cheminformatics descriptors. We finally present low-cost alternative models using fragment-based COSMOquick calculations with only marginal reduction in the quality of predicted solubility.

Microwave enhancement of extractions and reactions in Liquid-Liquid biphasic systems

Microwaves (MWs) are a powerful technology for electrifying chemical processing and can enable selective heating, which is impossible in conventional systems. This effect was recently ascribed to enhancing liquid–liquid reactive extractions in biomass derivative chemistry. Expanding upon prior research that showcased MW-induced temperature gradients and their optimization, this study delves into the impact of these gradients on extraction using a combination of experiments and simulations. The findings illustrate that the colder organic phase enforced by the MW heating leads to alterations in solute partitioning and phase behavior. Partitioning can be further tuned by adding salts or by carefully selecting solvents, as demonstrated via COSMO-RS calculations. The colder organic phase also leads to Rayleigh instabilities and active buoyancy-driven mixing. These effects, measured experimentally and simulated in COMSOL, can greatly enhance mass transfer rates in liquid–liquid systems. Under conditions reported in the literature, the MW enhancement to reactive extractions is minimal. Conditions that may lead to more impressive extractions and reactive extractions are suggested. Additionally, it's observed that temperature gradients retard byproduct formation.

Toluene absorption from laboratory to industrial scale: An experimental and theoretical study

Toluene is a typical example of aromatic volatile organic compounds (VOCs), and its elimination makes a significant contribution to reducing air pollution. The treatment of gaseous effluents can be achieved by solvent absorption. This work aims to evaluate, for the first time, the removal of toluene from laboratory scale to industrial scale using a new heat and mass exchanger and to elucidate the absorption mechanism at molecular level. The vapor–liquid partition coefficient (K) and the absorption capacity were determined for three industrially available solvents, benzyl alcohol, acetic acid and propylene glycol, and their water mixtures. In addition, several absorption/desorption cycles were also used to regenerate the absorbent on a laboratory scale. An up to 488-fold lower K value was obtained for benzyl alcohol. The effect of water addition to the studied solvents on the partition coefficient confirmed a decreasing VOC absorption with increasing amount of water. However, the overall results show that the water/benzyl alcohol mixture (60:40 wt%) has interesting absorption capacities, close to some organic solvents, and therefore a high potential for the treatment of industrial air polluted with toluene. This phenomenon was further explained by COSMO-RS calculation and molecular dynamics. It was found that magnitude of interaction energy for absorbent-toluene (−63.3 kJ/mol) with 60 wt% water is slightly smaller than that of pure benzyl alcohol (−71.76 kJ/mol). Moreover, benzyl alcohol has the most negative Gibbs free energy of solvation value for toluene compared to other absorbents under study. The reason for the enhanced toluene absorption is the significant π–π interaction between benzyl alcohol and toluene. The results obtained at different scales were in good agreement with each other.

A deep insight into the structure-solubility relationship and molecular interaction mechanism of diverse flavonoids in molecular solvents, ionic liquids, and molecular solvent/ionic liquid mixtures

The dissolution behavior and structure-solubility relationships of diverse flavonoids in various solvent systems, including the pure molecular solvents, pure ionic liquids (ILs), and molecular solvent/IL mixtures, are investigated in conjunction with experiments as well as quantum chemical and COSMO-RS calculations. The dissolution of flavonoids is a complex process. The dissolution difference of various flavonoids is ascribed to the synergistic influence of multiple factors, including the structure and planarity of the diverse flavonoid molecules, the extent of delocalization, the type, number, and position of functional groups, properties of the various solvents, and inter/intramolecular interactions. The planarity of flavonoid molecules is usually the most critical of these factors. The degree of nonplanarity of flavonoids follows the order flavanone > isoflavone > flavone > flavonol, which basically coincides with the solubility ranking of diverse flavonoids. Additionally, the type, number, and position of functional groups capable of forming hydrogen bonds also significantly affect flavonoid dissolution in solvents. The dissolution sequence of different flavonoids in various solvents varies with the structure and configuration of flavonoids. Of all the investigated solvents, flavonoid compounds are the least soluble in water because of their hydrophobicity, and they are most easily soluble in ILs with higher HBA basicity due to solute–solvent hydrogen-bond interactions, such as [Bmim]Ac and [Bmim]NO3. Adding ILs into molecular solvents or water has a significantly enhanced solubilization effect for the poorly soluble flavonoid compounds. In addition, water can act as an effective antisolvent, allowing for efficient recovery of flavonoids and ILs.

Novel copper desorption from a functionalized fly ash adsorbent using 1,1,1-trifluoro-2,4-pentanodione in ionic liquid [bmim][Tf2N]: Experimental and quantum chemistry calculations

In the context of the current environmental issues and the need to consolidate effective efforts according to the criteria of a circular economy, adsorption of copper from water with functionalized materials has shown high performance at low cost. However, desorption requires high amounts of acid and base to regenerate the functionalized material. In order to overcome this drawback, this work proposes an alternative desorbing phase based on a specific extractant for copper 1,1,1-trifluoro-2,4-pentanodione (TFA) dissolved in the ionic liquid (IL) 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. In this way, adsorption experiments were carried out using adsorbent fly ash, modified with a mesoporous siliceous material, and functionalized with 3-aminopropyl-triethoxysilane (APS). Under the operating conditions of this study, the best desorption performance was achieved using the lowest functionalization percentage of the absorbent material. The desorption percentage reached 45% after 200 min of contact with a stirred solution of TFA 0.2 [M] in IL. This percentage can be increased to around 70% through a second contact with fresh desorbing phase. Meanwhile, the conventional desorption technique with nitric acid showed faster kinetics and a slightly higher desorption percentage close to 50%. In turn, the final pH of the adsorbent slightly decreased when the proposed desorbing phase was used, representing an advantage over the use of acid. Additionally, it was possible to decrease the amount of desorbing phase allowing the concentration of copper. The COSMO-RS calculations indicate that a more hydrophobic IL could increase desorption percentage.

Highly efficient catalyzed by imidazolium-based dual-sulfonic acid functionalized ionic liquids for liquid phase Beckmann rearrangement: experiments and COSMO-RS calculations

A production technique with the high yield and environmentally friendly process need be developed for ε-Caprolactam (CPL) in the chemical industry. This technology is highly desired to design and synthesize high−performance catalysts for liquid phase Beckmann rearrangement of cyclohexanone oxime (CHO) to CPL. In this work, 3-methyl-1-(propyl-4-sulfonyl) imidazolium methanesulfonate ([PHSO3MIM][MSA]) with highly efficient and excellent yield is synthesized successfully. When the optimum molar ratio of ZnCl2 over [PHSO3MIM][MSA] was 0.02, it exhibits the high selectivity (94%) of CPL at 90 °C for 1 h. Interestingly, Fourier-transform infrared (FT-IR) investigations show that the functional Brønsted−Lewis acidic types of ionic liquids (ILs) are formed by the uniformly distributed ZnCl2 and [PHSO3MIM][MSA]. In addition, the hydrogen bond (H-bond) is formed between CHO and ILs. After ten reaction cycles, no significant structure changes are observed in the recovered [PHSO3MIM][MSA]·ZnCl2. The solubilities of ILs are predicted by using COSMO-RS model, the results show that [PHSO3MIM][MSA] is a promising candidate for the liquid phase Beckmann rearrangement of CHO into CPL. Finally, a theoretical model of the H-bond interactions between ILs and CHO is further confirmed to support the advance of reaction mechanism. A feasible way is provided for the CPL production technique in the liquid phase Beckmann rearrangement reaction.

Highly efficient separation of phenolic compounds from low-temperature coal tar by composite extractants with low viscosity

• Imidazolium IL-solvent composite extractants were applied for separation of phenolic compounds from oil. • The suitable composite extractants were identified by COSMO-RS calculation and viscosity determination. • [Emim][HSO 4 ]:EG (1:2) was selected due to its high phenol extraction efficiency, low oil entrainment, and low viscosity. • The separation mechanism was investigated by σ -profile, σ -potential, and FT-IR. Highly efficient separation of phenolic compounds from low-temperature coal tar (LTCT) is significant in the industry. In this work, composite extractants composed of imidazolium-based ionic liquids (ILs) and solvents were used to separate phenolic compounds from model oil and LTCT. First, the COSMO-RS model was used to screen composite extractants that combined the infinite dilution thermodynamic indexes and liquid–liquid equilibria (LLE) calculations. Meanwhile, the separation mechanism was analyzed by σ -profile and σ -potential. Then, the reliability of the COSMO-RS model was validated by LLE experiments and FT-IR. The viscosity of composite extractants with high separation performance was further determined. Among the composite extractants, 1-ethyl-3-methyl-imidazolium hydrogen sulfate ([emim][HSO 4 ])/ethylene glycol (EG) was selected as the most suitable extractant in the separation process. The m -cresol extraction efficiency and cumene entrainment were 98.1% and 8.3%, respectively, at a [emim][HSO 4 ]:EG molar ratio of 1:2, a temperature of 25 ℃, and a composite extractant: model oil mass ratio of 1:1. Moreover, the viscosity of [emim][HSO 4 ]:EG (1:2) was only 51.8 cP at 25 ℃ and decreased by 95.6% compared with pure [emim][HSO 4 ], which enhanced the mass transfer in the separation process. The [emim][HSO 4 ]:EG (1:2) could be regenerated and reused without significant reduction in separation performance. Finally, [emim][HSO 4 ]:EG (1:2) was applied to separate phenolic compounds from LTCT with a phenol extraction efficiency of more than 99.9% and a neutral oil entrainment of 8.3%, providing a promising prospect for the separation of phenolic compounds.

Accelerating Solvent Selection for Type II Porous Liquids.

Type II porous liquids, comprising intrinsically porous molecules dissolved in a liquid solvent, potentially combine the adsorption properties of porous adsorbents with the handling advantages of liquids. Previously, discovery of appropriate solvents to make porous liquids had been limited to direct experimental tests. We demonstrate an efficient screening approach for this task that uses COSMO-RS calculations, predictions of solvent pKa values from a machine-learning model, and several other features and apply this approach to select solvents from a library of more than 11,000 compounds. This method is shown to give qualitative agreement with experimental observations for two molecular cages, CC13 and TG-TFB-CHEDA, identifying solvents with higher solubility for these molecules than had previously been known. Ultimately, the algorithm streamlines the downselection of suitable solvents for porous organic cages to enable more rapid discovery of Type II porous liquids.

Highly Efficient Catalyzed by Imidazolium-Based Dual-Sulfonic Acid Functionalized Ionic Liquids for Liquid Phase Beckmann Rearrangement: Experiments and Cosmo-Rs Calculations

Highly Efficient Catalyzed by Imidazolium-Based Dual-Sulfonic Acid Functionalized Ionic Liquids for Liquid Phase Beckmann Rearrangement: Experiments and Cosmo-Rs Calculations

Nanoscopic study on carvone-terpene based natural deep eutectic solvents.

Terpene-based natural deep eutectic solvents (NADES) formed by using carvone as the hydrogen bond acceptor and a series of organic acids including tartaric, succinic, malic, and lactic acids as hydrogen bond donors are studied using a combination of molecular simulation methods. Density functional theory was used to study small molecular clusters and the topological characterization of the intermolecular forces using the atoms-in-a-molecule approach. Close-range interactions between the optimized carvone bases eutectic solvents between carbon dioxide have been studied for potential utilization of these solvents for gas capture purposes. Furthermore, COSMO-RS calculations have been carried out for the carbon dioxide solubilization performance of NADES compounds and to obtain s-profiles to infer the polarity and H-bond forming ability of the studied solvents. On the other hand, molecular dynamics simulations were carried out to analyze the bulk liquid properties and their relationship with relevant macroscopic properties (e.g., density or thermal expansion). Last but not least, relevant toxicity properties of the studied systems were predicted and reported in this work. The reported results provide the characterization of environmentally friendly NADES and show the suitability of carvone for advanced applications as carbon dioxide solubilizers.

Screening of alternative solvent ionic liquids for artemisinin: COSMO-RS prediction and experimental verification

Organic solvents are usually used to extract artemisinin from Artemisia annua L., and they can also be the solvents for the subsequent purification or derivatization to produce compounds with more efficient antimalarial effect. However, these solvents are volatile, explosive and toxic. The designable material ionic liquids (ILs) are alternative solvents to replace traditional ones. In this work, a reliable method for screening ILs with high solvation capability for artemisinin was developed. The infinite dilution activity coefficients of artemisinin in 903 ILs, composed by 43 cations and 21 anions, were calculated by COSMO-RS, and the results implied that the solubility of artemisinin in ILs mainly depends on the anions. Solubilities of artemisinin in 14 representative ILs were tested, and the results were in good accordance with those obtained in COSMO-RS calculation. The stability of artemisinin in some typical ILs was also studied, which indicated that this drug was stable in [EMIM][BF4], [EMIM][CF3Ac], [EMIM][NTF2], [BPY][NTF2], [EMIM][SCN], and [EMIM][Ac]. The excess enthalpy analysis demonstrated that artemisinin interacted with ILs mainly through hydrogen bond. Extraction of artemisinin using the optimal IL indicated that more artemisinin could be extracted from the leaves when compared with petroleum ether (254.73 mg/mol IL vs. 14.16 mg/mol solvent), further verifying accuracy of the simulation results. Therefore, structures of ILs with high solvation capacity for artemisinin can be obtained by the COSMO-RS method.

Evaluation of solvate and co-crystal screening methods for CL-20 containing energetic materials

ABSTRACT The difficulty synthesizing new co-crystals has made the development of efficient methods for screening co-formers a high priority. Co-crystals have been realized as a new generation of materials with tuneable solubility, stability, and performance. Energetic co-formers have exceptionally weak intermolecular interactions making selection of co-crystallization method and parameters critical to forming a true co-crystal. COSMO-RS calculations coupled with the COSMOtherm software suite were used to screen common solvents and co-formers for CL-20. The predicted favorable solvates and co-crystal formers were compared to experimentally confirmed solvates and co-crystals to assess the accuracy of the COSMO method for CL-20-based materials. It was found that screening solvents using excess enthalpy and solvent cavity volume were able to predict experimentally confirmed CL-20 solvates. Co-crystal formation was difficult to predict using the COSMO method, highlighting the importance of entropy and solid-state interactions. The selection of good solvents is perhaps the best method for maximizing entropy. Understanding the dependence on entropy for energetic-energetic cocrystal formation coupled with an accurate method for screening co-crystal formation allows for intelligent design of co-crystallization methods.

Molecular Transport across Oil-Brine Interfaces Impacts Interfacial Tension: Time-Effects in Buoyant and Pendant Drop Measurements.

The buoyant drop method is a ubiquitous tool for addressing phenomena at the liquid-liquid interface via the determination of the interfacial tension (IFT) between two immiscible phases. Here, the focus is on how electrolytes (in an aqueous phase) and carboxylic acids (in a decane phase) impact the interfacial layer between the two phases. The IFT measurement provides a single number, which is not fulfilling when it comes to deducing information about a complex multiparameter system. Furthermore, the temporal evolution of IFT does not always reach a steady-state value on a time scale, which is realistic to use for comparative studies. We have investigated the temporal evolution of IFT in a series of experiments with varying compositions of the decane-carboxylic acid phase and the brine phase. The results show that there are at least two opposing effects in play. For water-soluble acids, the IFT initially increases with time until a turnover point is reached from where there is a gradual decay. The IFT at the turnover point is close to that of the pure water-decane system. For a poorly water-soluble acid, the IFT shows a much smaller increase and the turnover happens much faster. For a water-soluble acid, there is a high degree of sensitivity toward the electrolyte; it determines the position (in time) of the IFT peak and the steepness of the subsequent decay. Now, if the phases are reversed, that is, by placing a drop of brine in the decane-surfactant phase, the IFT decreases with time regardless of the acid and with little impact of the electrolyte and its concentration in the brine. We propose an explanation for the observed behavior (supported by COSMO-RS calculations), which is based on diffusion in and out of the two phases, solubility, and interfacial reactivity (i.e., aggregation between electrolytes and carboxylic acids).

Theoretical prediction of selectivity in solvent extraction of La(III) and Ce(III) from aqueous solutions using β-diketones as extractants and kerosene and two imidazolium-based ionic liquids as diluents via quantum chemistry and COSMO-RS calculations

This study proposes a theoretical method based on DFT and COSMO-RS calculations to predict selectivity in the solvent extraction (SX) of lanthanum(III) and cerium(III), by using β-diketones as the extractant and kerosene or imidazolium-based ionic liquids (ILs) as the diluent. To calculate the selectivity, the model requires three important pieces of information: the extraction stoichiometry, the type and structure of the extractant/synergistic agent, and the diluent used in the SX process. Therefore, as the first step, the extraction stoichiometry is determined experimentally. Using these results to perform DFT and COSMO-RS calculations, thermochemical parameters allowed to calculate the selectivity. The results indicate that the theoretical selectivity trends agree closely with the experimental results even when using ILs as diluents, demonstrating the applicability of this method. It is established that the selectivity can be increased by using both β-diketones with bulky functional groups and a synergistic agent. This predictive method has immense potential as a practical tool providing valuable insights into the design of extractants and hydrophobic diluents for the selective recovery of lanthanides in industrial applications.

Prediction of CO2 chemical absorption isotherms for ionic liquid design by DFT/COSMO-RS calculations

Ionic liquids with an aprotic heterocyclic anion (AHA-ILs) is a promising family of compounds to overcome the challenge of CO2 capture. In this work, a computational methodology has been developed to predict CO2 chemical absorption isotherms in AHA-ILs without the need of experimental data. This methodology combines DFT and COSMO-RS calculations allowing the design of new chemical absorbents for CO2 capture. The CO2 physical absorption equilibrium constants (Henry's law constants), chemical equilibrium constants and reaction enthalpies were reliably predicted by proposed computational approach, by means of comparison to available experimental data of 9 different AHA-ILs. Finally, 15 newly designed AHA-ILs were evaluated to demonstrate the flexibility of the DFT/COSMO-RS tool by predicting their CO2 absorption isotherms. The evaluated absorbents compromise very different behaviors: from physical absorption to reactions completely displaced toward products at very low CO2 partial pressure, emphasizing the extremely tunable character of AHA-ILs. Current results will definitively contribute to link molecular and processes scales in the research of new CO2 capture technology based on ILs.

Stability of cellulase in ionic liquids: correlations between enzyme activity and COSMO-RS descriptors

Ionic liquids (ILs) are effective in pretreating cellulose for enhanced enzymatic saccharification, however ILs can inactivate cellulases. To guide the selection of ILs, the activity of cellulase was correlated with COSMO-RS calculations and descriptors of ILs including hydrogen bond (H-bond) basicity/acidity, polarity and ion size. Trends were deduced using an anion-series and a cation-series of ionic liquids in aqueous solutions. The activity in the cation-series was best correlated with the size of varied cations, whereas the activity in the anion-series showed a pronounced correlation to H-bond basicity and polarity of different anions. COSMO-RS was further used to predict the solubility of cellulose in ILs, which was correlated with cellulase activity on IL-pretreated cellulose. The best correlations were found between the enzyme activity in the anion-series ILs and the logarithmic activity coefficients, the H-bond energy, H-bond basicity and polarizability, underlining that the anion plays a crucial role in cellulose dissolution.