Conductor-like Screening Model For Real Solvents Research Articles

Solid–Liquid Equilibrium in Co-Amorphous Systems: Experiment and Prediction

In this work, the solid-liquid equilibrium (SLE) of four binary systems combining two active pharmaceutical ingredients (APIs) capable of forming co-amorphous systems (CAMs) was investigated. The binary systems studied were naproxen-indomethacin, naproxen-ibuprofen, naproxen-probucol, and indomethacin-paracetamol. The SLE was experimentally determined by differential scanning calorimetry. The thermograms obtained revealed that all binary mixtures investigated form eutectic systems. Melting of the initial binary crystalline mixtures and subsequent quenching lead to the formation of CAM for all binary systems and most of the compositions studied. The experimentally obtained liquidus and eutectic temperatures were compared to theoretical predictions using the perturbed-chain statistical associating fluid theory (PC-SAFT) equation of state and conductor-like screening model for real solvents (COSMO-RS), as implemented in the Amsterdam Modeling Suite (COSMO-RS-AMS). On the basis of the obtained results, the ability of these models to predict the phase diagrams for the investigated API-API binary systems was evaluated. Furthermore, the glass transition temperature (Tg) of naproxen (NAP), a compound with a high tendency to recrystallize, whose literature values are considerably scattered, was newly determined by measuring and modeling the Tg values of binary mixtures in which amorphous NAP was stabilized. Based on this analysis, erroneous literature values were identified.

A-Priori screening of deep eutectic solvent for enhanced oil recovery application using COSMO-RS framework

This study investigates the potential of Deep Eutectic Solvent (DES) in Enhanced Oil Recovery (EOR) via interfacial tension (IFT) reduction mechanism. The effectiveness of 217 DES in the IFT reduction mechanism that ultimately assist in EOR is investigated via COnductor-like Screening MOdel for Real Solvent (COSMO-RS) theory and the sigma moment model. Genetic algorithm (GA) is employed to estimate the constants of COSMO-RS theory and sigma moment model. IFT prediction of representative Omani heavy crude oil in 217 DES in the brine system is reported and analyzed at the mole fraction of DES in brine ranging from 1 × 10-3 to 5 × 10-1 with variation in temperature from 298.15 K to 353.15 K. The highest and the lowest values thus obtained for IFT are 560.8 and 0.2 mN/m. There are 26 DESs capable of reducing IFT by more than 50%, while another 10 DESs show a reduction capability of more than 75%. The optimum concentration of DES to maximize IFT reduction is further analyzed.

Ionic Liquid-Based Green Emulsion Liquid Membrane for the Extraction of the Poorly Soluble Drug Ibuprofen

Ibuprofen (Ibf) is a biologically active drug (BADs) and an emerging contaminant of concern (CECs) in aqueous streams. Due to its adverse effects upon aquatic organisms and humans, the removal and recovery of Ibf are essential. Usually, conventional solvents are employed for the separation and recovery of ibuprofen. Due to environmental limitations, alternative green extracting agents need to be explored. Ionic liquids (ILs), emerging and greener alternatives, can also serve this purpose. It is essential to explore ILs that are effective for recovering ibuprofen, among millions of ILs. The conductor-like screening model for real solvents (COSMO-RS) is an efficient tool that can be used to screen ILs specifically for ibuprofen extraction. The main objective of this work was to identify the best IL for the extraction of ibuprofen. A total of 152 different cation-anion combinations consisting of eight aromatic and non-aromatic cations and nineteen anions were screened. The evaluation was based upon activity coefficients, capacity, and selectivity values. Furthermore, the effect of alkyl chain length was studied. The results suggest that quaternary ammonium (cation) and sulfate (anion) have better extraction ability for ibuprofen than the other combinations tested. An ionic liquid-based green emulsion liquid membrane (ILGELM) was developed using the selected ionic liquid as the extractant, sunflower oil as the diluent, Span 80 as the surfactant, and NaOH as the stripping agent. Experimental verification was carried out using the ILGELM. The experimental results indicated that the predicted COSMO-RS and the experimental results were in good agreement. The proposed IL-based GELM is highly effective for the removal and recovery of ibuprofen.

Aromatic volatile organic compounds absorption with phenyl‐based deep eutectic solvents: A molecular thermodynamics and dynamics study

AbstractThe suitability of phenyl‐based deep eutectic solvents (DESs) as absorbents for toluene absorption was investigated by means of thermodynamic modeling and molecular dynamics (MD). The thermodynamic models perturbed‐chain statistical associating fluid theory (PC‐SAFT) and conductor‐like screening model for real solvents (COSMO‐RS) were used to predict the vapor–liquid equilibrium of DES–toluene systems. PC‐SAFT yielded quantitative results even without using any binary fitting parameters. Among the five DESs studied in this work, [TEBAC][PhOH] consisting of triethyl benzyl ammonium chloride (TEBAC) and phenol (PhOH), was considered as the most suitable absorbent. Systems with [TEBAC][PhOH] had lowest equilibrium pressures of the considered DES–toluene mixtures, the best thermodynamic characteristics (i.e., Henry's law constant, excess enthalpy, Gibbs free energy of solvation of toluene), and the highest self‐diffusion coefficient of toluene. The molecular‐level mechanism was explored by MD simulations, indicating that [TEBAC][PhOH] has the strongest interaction of DES–toluene compared to the other DESs under study. This work provides guidance to rationally design novel DESs for efficient aromatic volatile organic compounds absorption.

Redox Potentials with COSMO-RS: Systematic Benchmarking with Different Databases.

Recent techniques of computational electrochemistry can yield redox potentials with accuracy as good as 0.1 V. Yet, many such methods are not universal, easy to use, or computationally efficient. Herein, we provide a systematic benchmarking of a relatively cheap and straightforward computational approach for fairly accurate computations of redox potentials. It is based on a combination of the conductor-like screening model for real solvents (COSMO-RS) and the density functional theory (DFT). The benchmarking is done with databases covering diverse redox systems, including transition-metal aquacomplexes and various organic and inorganic compounds. In addition, we also present our own test set aiming at maximum chemical diversity and maximum range of redox potential values. We assess the performance of the fairly efficient computational protocol combining the COSMO-RS with the BP86 DFT functional. This is done by calibrating it against different high-level state-of-the-art techniques, in particular, polarizable continuum model (PCM) connected to composite G3(MP2,CC)(+) method, domain-based pair natural orbital implementation of coupled cluster theory, or complete basis set CBS-QB3 method. We also elaborate on the absolute reduction potential value of standard hydrogen electrode to be used with COSMO-RS, and we propose the value of approx. 4.4 V. The COSMO-RS/BP86-D3(BJ) combination outperforms other methods on a wide range of redox systems. However, we show that its accuracy is based on a balanced error cancelation and, therefore, it cannot be further systematically improved. As a result, the proposed procedure represents a pragmatic choice for large-scale screening, yet it could be combined with more advanced methods for detailed studies.

Use of Tunable Copolymers in Aqueous Biphasic Systems for Extractive Bioconversion Aimed at Continuous Fructooligosaccharide Production

Aqueous biphasic systems (ABSs) based on sodium polyacrylate (NaPA), ethylene oxide/propylene oxide (EO/PO) polymers, and (EO)x-(PO)y-(EO)x triblock copolymers were prepared and applied aiming at continuous fructooligosaccharide (FOS) production and separation. EO/PO hydrophilicity/hydrophobicity balance had a significant effect on ABS formation. To develop an integrated process including the continuous enzymatic (levansucrase) production of FOSs and their purification while improving the production yield by further glucose separation, the potential of these novel polymer-based ABSs as alternative platforms was investigated. They were used for the partitioning of different carbohydrates (FOS, sucrose, d-fructose, and d-glucose) and levansucrase. Results revealed a highly polymer-dependent partition of carbohydrates and a poorly dependent one of the enzymes. Changing EO/PO and copolymers, FOS was purified with high yields (72.94–100.0%). Using polypropylene glycol 400 + NaPA 8000-based ABS, the FOS was precipitated in the interphase and separated from the other components. Pluronic PE-6800 + NaPA 8000 was identified as the best ABS for FOS continuous production and in situ purification, while minimizing levansucrase inhibition by d-glucose. This system allowed selective partition of FOSs and d-glucose toward the top phase and that of levansucrase and its substrates toward the bottom one. COnductor-like Screening MOdel for Real Solvent (COSMO-RS) suggested that ABS formation may have been due to NaPA and polymer/copolymer competition to form hydrogen bonds with water molecules. Moreover, the partition of FOSs and sugar may have been the result of a subtle balance between hydrogen bonding of sugar and polymer/copolymer and electrostatic misfit of solute with NaPA. Finally, two integrated processes were proposed to be applied with real FOS extracts obtained by chemical or enzymatic hydrolysis of inulin or by transfructosylation of concentrated sucrose solutions using bacterial levansucrases.

Robust definition and prediction of dispersive Hansen solubility parameter δD with COSMO-RS

A simple approach to predict dispersive Hansen solubility parameter δD is proposed, taking advantage of the separation of energies in the COnductor-like Screening MOdel for Realistic Solvation (COSMO-RS). The “COSMOmorph”, that is, the COSMO file(s) with all surface charge densities and dielectric energy equal to zero, allows an unambiguous splitting of energies and choice of structures and removes the requirement for the experimental existence of a homomorph. Reasonable agreement between δD of COSMOmorph and published δD for 89 solvents is obtained, with a standard deviation of 1.0 MPa1/2. Note that perfect agreement is not expected due to the shortcomings of the historical method.

Intermolecular Interactions of Edaravone in Aqueous Solutions of Ethaline and Glyceline Inferred from Experiments and Quantum Chemistry Computations.

Edaravone, acting as a cerebral protective agent, is administered to treat acute brain infarction. Its poor solubility is addressed here by means of optimizing the composition of the aqueous choline chloride (ChCl)-based eutectic solvents prepared with ethylene glycol (EG) or glycerol (GL) in the three different designed solvents compositions. The slurry method was used for spectroscopic solubility determination in temperatures between 298.15 K and 313.15 K. Measurements confirmed that ethaline (ETA = ChCl:EG = 1:2) and glyceline (GLE = ChCl:GL = 1:2) are very effective solvents for edaravone. The solubility at 298.15 K in the optimal compositions was found to be equal xE = 0.158 (cE = 302.96 mg/mL) and xE = 0.105 (cE = 191.06 mg/mL) for glyceline and ethaline, respectively. In addition, it was documented that wetting of neat eutectic mixtures increases edaravone solubility which is a fortunate circumstance not only from the perspective of a solubility advantage but also addresses high hygroscopicity of eutectic mixtures. The aqueous mixture with 0.6 mole fraction of the optimal composition yielded solubility values at 298.15 K equal to xE = 0.193 (cE = 459.69 mg/mL) and xE = 0.145 (cE = 344.22 mg/mL) for glyceline and ethaline, respectively. Since GLE is a pharmaceutically acceptable solvent, it is possible to consider this as a potential new liquid form of this drug with a tunable dosage. In fact, the recommended amount of edaravone administered to patients can be easily achieved using the studied systems. The observed high solubility is interpreted in terms of intermolecular interactions computed using the Conductor-like Screening Model for Real Solvents (COSMO-RS) approach and corrected for accounting of electron correlation, zero-point vibrational energy and basis set superposition errors. Extensive conformational search allowed for identifying the most probable contacts, the thermodynamic and geometric features of which were collected and discussed. It was documented that edaravone can form stable dimers stabilized via stacking interactions between five-membered heterocyclic rings. In addition, edaravone can act as a hydrogen bond acceptor with all components of the studied systems with the highest affinities to ion pairs of ETA and GLE. Finally, the linear regression model was formulated, which can accurately estimate edaravone solubility utilizing molecular descriptors obtained from COSMO-RS computations. This enables the screening of new eutectic solvents for finding greener replacers of designed solvents. The theoretical analysis of tautomeric equilibria confirmed that keto-isomer edaravone is predominant in the bulk liquid phase of all considered deep eutectic solvents (DES).

Multiscale molecular simulations for the solvation of lignin in ionic liquids

Lignin, the second most abundant biopolymer found in nature, has emerged as a potential source of sustainable fuels, chemicals, and materials. Finding suitable solvents, as well as technologies for efficient and affordable lignin dissolution and depolymerization, are major obstacles in the conversion of lignin to value-added products. Certain ionic liquids (ILs) are capable of dissolving and depolymerizing lignin but designing and developing an effective IL for lignin dissolution remains quite challenging. To address this issue, the COnductor-like Screening MOdel for Real Solvents (COSMO-RS) model was used to screen 5670 ILs by computing logarithmic activity coefficients (ln(γ)) and excess enthalpies (HE) of lignin, respectively. Based on the COSMO-RS computed thermodynamic properties (ln(γ) and HE) of lignin, anions such as acetate, methyl carbonate, octanoate, glycinate, alaninate, and lysinate in combination with cations like tetraalkylammonium, tetraalkylphosphonium, and pyridinium are predicted to be suitable solvents for lignin dissolution. The dissolution properties such as interaction energy between anion and cation, viscosity, Hansen solubility parameters, dissociation constants, and Kamlet–Taft parameters of selected ILs were evaluated to assess their propensity for lignin dissolution. Furthermore, molecular dynamics (MD) simulations were performed to understand the structural and dynamic properties of tetrabutylammonium [TBA]+-based ILs and lignin mixtures and to shed light on the mechanisms involved in lignin dissolution. MD simulation results suggested [TBA]+-based ILs have the potential to dissolve lignin because of their higher contact probability and interaction energies with lignin when compared to cholinium lysinate.

Predicting liquid-liquid phase separation in ternary organic-organic-water mixtures.

Liquid-liquid phase separation (LLPS) affects the water uptake of aerosol particles in the atmosphere through Kelvin and Raoult effects. This study investigates LLPS in ternary mixtures containing water and two organic compounds, using a conductor-like screening model for real solvents (COSMO-RS). COSMO-RS found LLPS in all of the studied mixtures containing water and proxies for primary and secondary organic aerosol (POA and SOA, respectively), due to the limited solubility of the hydrophobic POA proxies in water. The computations predict additional three-phase states in some of the SOA-POA-water mixtures at relative humidity (RH) close to 100%, which was not observed in experiments, likely due to the relatively low RH (90%) used in the experiments. A computational method, such as COSMO-RS, allows for the estimation of new information on mixing states and mixtures that cannot be accessed experimentally. Comparison with experiments can also provide insight into which types of compounds may be present in SOA. Additionally, the possibility of LLPS can be assessed faster with rough estimates rather than by computing the whole phase diagram.

Measurement and prediction of isothermal vapor–liquid equilibrium of α-pinene + camphene/longifolene + abietic acid + palustric acid + neoabietic acid systems

The vapor-liquid equilibrium (VLE) data of α-pinene + camphene + [abietic acid + palustric acid + neoabietic acid] and α-pinene + longifolene + [abietic acid + palustric acid + neoabietic acid] systems at 313.15 K, 333.15 K and 358.15 K were measured by headspace gas chromatography (HSGC). These data was compared with the predictions value by Conductor-like screening model for realistic solvation (COSMO-RS). Moreover, the calculated data of COSMO-RS and NRTL（Nationally Recognized Testing Laboratory） models showed good agreement with the experimental data. It was found that the three resin acids inhibits the volatility of α-pinene, camphene and longifolene and resulted in the decrease of total pressure. Moreover, H E (HB) contributes the most to the excess enthalpy and the hydrogen bonding interaction is the dominant intermolecular force of α-pinene, camphene and longifolene with the three resin acids. In addition, the geometric structures optimization and binding energy were obtained by the DFT to further illustrate the hydrogen bonding interaction and the effects of the addition of the three resin acids on the isothermal VLE.

Experimental investigation and thermodynamic modeling of cannabidiol solubility in plant oils and hydrophobic eutectic systems

Cannabidiol (CBD) is one of the most important cannabinoids found in hemp plants, having numerous applications in the pharmaceutical and food industries. Due to its low solubility in water, CBD is usually supplied in hydrophobic solvents. The present work investigated the solubility of CBD in ten plant oils and various systematically designed hydrophobic eutectic systems (ESs). The CBD solubility was found to correlate with the molecular weight and structure of the oils and ES constituents. CBD was more soluble in medium-chain triglyceride oils than in oils containing long-chain unsaturated fatty acids. Moreover, the CBD solubility was found to be higher in ESs than in oils. The conductor-like screening model for realistic solvents (COSMO-RS) was then applied to estimate the CBD solubility in oils and ESs. COSMO-RS did not provide satisfactory predictions of the CBD solubility in oils, possibly because oils were regarded as simple mixtures of fatty acids. On the other hand, COSMO-RS predicted well the CBD solubility in ESs. This work showed that newly-designed hydrophobic ESs could be alternative green solvents for CBD formulation and extraction.

Solubility Study of Lignin Monomeric Compounds in Deep Eutectic Solvents for Biomass Waste Pre-treatment

Lignin is a complex polymer class formed from the cell wall, it is an organic polymer with a variety of biological aspects and industrial applications. Deep eutectic solvent (DES) has been introduced as a green solvent to dissolve lignin from lignocellulosic biomass. DESs typically have low vapor pressure, high heat stability, low toxicity and biodegradation which are the ideal features for lignocellulosic biomass pre-treatment. In this work, Conductor-like Screening Model for Real Solvents (COSMO-RS) was used to determine the suitable DESs for lignin degradation. The performance of the selected DESs was tested on lignin monomeric compounds, commercial lignin and the actual biomass of oil palm empty fruit bunch (OPEFB). Three DESs were used to test its lignin dissolution capability, i.e. choline chloride:urea (ChCl:Ur) (1:2), choline chloride:glycerol (ChCl:Gly) (1:2) and choline chloride:glucose ( ChCl:Glu) (1:1). The saturation points of dissolving each lignin type were determined for each DES. It was experimentally found that ChCl:Ur (1:2) could dissolve more lignin than ChCl:Gly (1:2) and ChCl:Glu (1:1). This work shows the possibility of using DES to dissolve lignin structures for biomass pretreatment and utilization.

An achieved strategy for magnetic biochar for removal of tetracyclines and fluoroquinolones: Adsorption and mechanism studies

In this study, poplar wood biochar modified with Fe3O4 (MPBC) was prepared using poplar wood as carbon source applied to remove tetracyclines and fluoroquinolones. The adsorption behavior was investigated by batch experiments, and a series of characterization techniques were used to study the corresponding mechanism. Characterizations indicated that pore filling, electrostatic interactions, π-π interaction, surface complexation, and hydrogen bond contributed to the adsorption of antibiotics on MPBC. Most importantly, the thermodynamic experiment results showed that the adsorption capacity of MPBC for tetracyclines (70.28–89.58 mg⋅g−1) was significantly higher than fluoroquinolones (35.54–60.31 mg⋅g−1), which was further explained by hydrogen bond interactions calculated from Conductor-like screening model for real solvents (COSMO-RS). In addition, the adsorption between MPBC and antibiotics was favorable at lower ionic strengths and neutral conditions. Conclusively, this study could provide a promising approach to controlling the pollution of tetracyclines and fluoroquinolones.

Computational Screening and Experimental Validation on Multicomponent Crystals of a New Class of Janus Kinase (JAK) Inhibitor Drug with Improved Solubility

Developing multicomponent crystal forms, especially cocrystals and salts, is becoming a promising pathway to improve the solubility and bioavailability of drugs. Herein, new multicomponent crystals of SHR0302, a new generation of Janus Kinase (JAK) inhibitor that suffers from poor solubility, were developed based on a cooperative approach of computational and experimental coformer screenings. Virtual screening methods, including the conductor-like screening model for realistic solvents (COSMO-RS) and molecular complementary (MC) analysis, were employed to predict the binding affinity between SHR0302 and selected coformers. The developed screening method was capable of reducing the screening database to 30 coformers from a total of 42 proposed coformers. The proof-of-concept experimental screening study was performed to demonstrate the efficiency of computational screening, wherein three new multicomponent crystalline forms were found and fully characterized by powder X-ray diffraction, thermal analysis, and IR and 1H-NMR spectroscopy. Further, the measurements of the solubility property of these new multicomponent crystal forms reveal an apparent promotion compared with the drug alone. Finally, the receiver operator characteristic (ROC) curve was used to assess the prediction performance of the COSMO-RS model. It was found that the established screening model can effectively shorten the experimental screening time and efforts.

Ab initio calculation based solvent system selection in silico for counter-current chromatography: Separation of resibufogenin glycosylation products

In this study, a strategy based on COSMO-RS (Conductor-like Screening Model for Real Solvents) with a constrained optimization calculation was developed for ab initio calculation based solvent system selection in silico for counter-current chromatography. The separation of resibufogenin glycosylation products was selected as an example to show its practicability. The selected solvent system in silico gave the K values consistent with the experimentally measured data (RMSD=0.2861) and the glycosylation products, namely Resibufogenin-3-O-β-D-glucoside (R-G) and Resibufogenin-3-O-β-D-glucosyl (1→2)-β-D-glucoside (R-2G), were successfully separated by HSCCC.

Development of Natural Hydrophobic Deep Eutectic Solvents for Precombustion CO2 Capture

Hydrophobic deep eutectic solvents (DESs) have been designed as effective solvents for precombustion CO2 capture by using a conductor-like screening model for real solvents (COSMO-RS). Reliable CO2 solubilities in various compounds and binary solvents were estimated. We have developed new DESs from 38 selected, nature-derived, hydrophobic, and CO2 affinitive compounds. The possibilities of any two of these substances to form DESs were assessed from predicted activity coefficients, followed by an estimation of the CO2 solubilities of the theoretically feasible DESs. 58 promising hypothetical DESs were screened out. Subsequently, eight DESs were successfully prepared and characterized. Most of these DESs have a density larger than 1.0 g/mL at 298.15 K. The DESs have a similarly low volatility as decanoic acid–menthol (1:2) and are thermally stable below 420 K. Vanillin-4-oxoisophorone (1:3) and methyl salicylate-4-oxoisophorone (1:1) have been identified to be very promising for precombustion capture, showing comparable CO2 solubility and viscosity to the well-known, conventionally used Selexol solvent.

Screening of ionic liquids as green entrainers for ethanol water separation by extractive distillation: COSMO-RS prediction and aspen plus simulation

Ionic liquids (ILs) have been demonstrated as promising alternatives to conventional entrainers in separation of azeotropic mixtures mostly investigating phase equilibrium and process design scenarios. However, proper selection of ILs for a specific task always remains challenging. Hence a simulation tool, i.e. conductor like screening model for real solvents (COSMO-RS) was applied to address this challenge. Furthermore, screened ILs were simulated as entrainers for ethanol water separation by extractive distillation. The current study also aims to demonstrate a systematic approach to retrofit existing processes, by employing ILs as green entrainers. Screening of twenty-five (25) ILs was carried out using COSMO-RS to select suitable ILs as green entrainers based on activity coefficient, capacity and selectivity. Results illustrated that tetramethylammonium chloride ([TMAm][Cl]) due to its strong hydrogen bonding ability was found to be the best ILs entrainer. Moreover, in order to reduce the operating costs without compromising desired product purity (ethanol purity ≥99.5% in top product), the selected ILs (8 kg/h) in a mixture with ethylene glycol (72 kg/h) were simulated using Aspen plus v.11. The simulation results revealed that by combining tetramethylammonium chloride (2 kg/h) with ethylene glycol (78 kg/h) reduced 7.26 tons of CO2 emissions/year through heat integration by saving 1.49*108 kJ/year energy besides minimizing operating costs. In conclusion, the systematic selection of ILs as green entrainers in combination with ethylene glycol and then the appropriate simulation of the whole system will ultimately reduce the cost of the separation process and reduce the emission of greenhouse gases as well utilization of toxic conventional entrainers.

Ionic liquid assisted nanocellulose production from microcrystalline cellulose: Correlation between cellulose solubility and nanocellulose yield via COSMO-RS prediction

The use of ionic liquids (ILs) in nanocellulose (NC) production from cellulosic materials has gained significant interest due to the intrinsic physical solubility of cellulosic materials in many ILs. However, given the numerous possible cation–anion combinations, selecting potential candidates from thousands of ILs for NC production is rather difficult. In addition, NC yield depends on the types of ILs and their capability in dissolution of cellulosic materials. In this study, we investigate NC production from microcrystalline cellulose (MCC) using various ILs as a reaction medium. Firstly, the prediction of MCC solubility in 300 ILs (15 cations and 20 anions) was obtained by deploying the conductor-like screening model for real solvents (COSMO-RS) which has emerged as a reliable and promising tool for solvents screening based on the dominant interactions of H-bonds, misfits, and Van der Waals energies of the fluid mixture. Experimental measurement of NC production from MCC in six ILs, namely [Emim][OAc], [Bmim][OAc], [Bmim][Cl], [Emim][HSO4], [Bmim][HSO4], and [Hmim][HSO4], was conducted. Based on the logarithmic activity coefficient prediction at infinite dilution, there was a negative correlation between cellulose solubility and experimental NC yield obtained. [Hmim][HSO4] IL showed the highest nanocellulose yield (65%) due to a relatively weaker H-bonding ability with cellulose. Moreover, the multiparameter scale of the Kamlet-Taft of six ILs revealed that the increase in alkyl side chain length of the IL cation resulted in a decrease of hydrogen bonding acidity, which contributed to higher NC yield. The quantitative prediction of COSMO-RS, coupled with the experimental study, can therefore be utilized to screen, and classify the potential ILs to prepare nanocellulose.

Nonideality and cocrystal formation in l-menthol/xylenol eutectic systems

Nonideality and cocrystal formation affect the solid–liquid equilibria (SLE) in eutectic systems. This study investigates the influence of the molecular structure of xylenol (dimethylphenol) isomers on the nonideality and cocrystal formation in eutectic systems containing l-menthol and five different xylenol isomers. Differential scanning calorimetry and powder X-ray diffraction analyses were employed to comprehend the SLE phase diagram of the studied systems. l-Menthol did not form cocrystals with xylenol isomers having a methyl group at position 2. In contrast, two cocrystals were observed in the l-menthol/3,4-xylenol systems at 1:2 and 2:1 ratios, and one cocrystal was observed in the 1:1 l-menthol/3,5-xylenol system. The liquid phase of all systems showed a strong negative deviation from ideality, except the l-menthol/2,6-xylenol eutectic system, which exhibited a near-ideal behavior. The nonideality of the liquid phase was modeled using the conductor-like screening model for realistic solvation (COSMO-RS) using TZVP and TZVPD_FINE parameterizations, finding that COSMO-RS can reasonably describe the liquid phase nonideality and predict the SLE phase diagram of simple eutectic systems and systems with cocrystal formation.