Conductor-like Screening Model For Real Solvents Research Articles

Resolving unknown isomers of emerging per- and polyfluoroalkyl substances (PFASs) in environmental samples using COSMO-RS-derived retention factor and mass fragmentation patterns

Chromatographic retention factors (k) and mass spectral fragmentation patterns of per- and polyfluoroalkyl substances (PFASs) were determined using the optimized parameters in liquid chromatography with tandem high-resolution mass spectrometry (LC-HRMS) analysis. Characteristic fragment ions obtained at various collision energies (MS2 fragmentation) were used to determine the structures of newly discovered (emerging) PFASs detected from industrial effluent and surface water samples. Moreover, COnductor-like Screening MOdel for Realistic Solvents (COSMO-RS) derived octanol-water partition coefficients (Kow), along with mean isotropic polarizabilities calculated from Density Functional Theory (DFT), of known PFASs were plotted against their experimental k values (kexp) to obtain a multivariable regression model that can be used to predict k values of unknown PFASs. The k values of different structural isomers of unknown PFASs were calculated and compared to kexp. The predicted k value for the isomer that matches the MS2 fragmentation observed was found to be within 4.2 % of kexp. This study demonstrates the applicability of an approach that combines the observed MS2 fragmentation patterns and k values, together with computationally-derived log Kow and polarizabilities, in assigning the structures of unknown PFASs at environmentally relevant conditions when no reference standards are available.

Ultrasound and deep eutectic solvents: An efficient combination to tune the mechanism of steviol glycosides extraction

Ultrasound-assisted extraction is widely recognized as an eco-friendly technique due to low solvent consumption and time extraction as well as enhanced extraction efficiency with respect to conventional methods. Nevertheless, it would be convenient to avoid the usually used organic solvents to reduce the environment pollution. In this regard, Deep Eutectic Solvents (DES) represent nowadays a green and sustainable alternative for the extraction of bioactive compounds from natural sources. In this study, an efficient extraction of stevioside and rebaudioside A from Stevia rebaudiana coupling ultrasound with DES was developed. A solvent screening was performed using the predictive approach COnductor-like Screening MOdel for Real Solvent (COSMO-RS). The effect of three independent variables, namely % of water, temperature, and sonication amplitude, were investigated by the response surface methodology (RSM). Comparing ultrasound-assisted extraction (UAE) with conventional extraction, it has been demonstrated that the amount of steviol glycosides through UAE is almost three times higher than that obtained by the conventional method. Possible physicochemical factors involved in the UAE mechanism were discussed.

Systematic Green Solvent Selection for the Hydroformylation of Long-Chain Alkenes

When selecting solvents, not only thermodynamic criteria but also environmental, health, and safety (EHS) properties should be considered. To this end, we present a fully automated solvent selection approach for the homogeneous catalyzed hydroformylation of 1-decene in a temperature-dependent thermomorphic multicomponent system (TMS) using the conductor-like screening model for real solvents (COSMO-RS). The state-of-the-art TMS uses N,N-dimethylformamide (DMF) as the catalyst carrier, which is developmentally toxic, thereby demanding replacement. In order to evaluate the EHS properties holistically, 30 predictive EHS models for 15 different properties are considered in the solvent selection framework, as well as the reliability of the predictions. From a database containing approximately 7800 molecules, the most promising candidates are identified. The best solvent among them, diethyl sulfoxide (DESO), is predicted as outperforming DMF as a catalyst solvent in the hydroformylation. The evidence suggests that DESO may be a broadly applicable environmentally benign substitute solvent for DMF.

Bifunctional Imidazole-Benzenesulfonic Acid Deep Eutectic Solvent for Fructose Dehydration to 5-Hydroxymethylfurfural

Imidazole (Im) and benzenesulfonic acid (BSA) formed deep eutectic solvents (DESs) were used as acidic catalyst and solvent for the dehydration of fructose to 5-hydroxymethylfurfural (5-HMF). The DES formation involved an acid–base neutralization to produce equimolar salt from BSA and Im, and subsequent interaction between equimolar salt as hydrogen bond acceptor and excessive BSA as hydrogen bond donor. The BSA-rich DES [Im:1.5BSA] with a 1:1.5 molar ratio of Im:BSA and 10% dosage exhibited high catalytic activity for fructose dehydration with a 5-HMF yield of 90.1% at 100 °C after a very short reaction time (3 min). The bifunctionality of [Im:1.5BSA] for promoting reaction rates and catalytic activity of fructose dehydration has been identified by tuned acidity of DESs and hydrogen bond interaction among fructose, 5-HMF, and DESs demonstrated by conductor-like screening model for real solvents (COSMO-RS) theory.

Enrichment of surface oxygen functionalities on activated carbon for adsorptive removal of sevoflurane

Activated carbons have been reported to be useful for adsorptive removal of the volatile anaesthetic sevoflurane from a vapour stream. The surface functionalities on activated carbons could be modified through aqueous oxidation using oxidising solutions to enhance the sevoflurane adsorption. In this study, an attempt to oxidise the surface of a commercial activated carbon to improve its adsorption capacity for sevoflurane was conducted using 6 mol/L nitric acid, 2 mol/L ammonium persulfate, and 30 wt per cent (wt%) of hydrogen peroxide (H2O2). The adsorption tests at fixed conditions (bed depth: 10 cm, inlet concentration: 528 mg/L, and flow rate: 3 L/min) revealed that H2O2 oxidation gave desirable sevoflurane adsorption (0.510 ± 0.005 mg/m2). A parametric study was conducted with H2O2 to investigate the effect of oxidation conditions to the changes in surface oxygen functionalities by varying the concentration, oxidation duration, and temperature, and the Conductor-like Screening Model for Real Solvents (COSMO-RS) was applied to predict the interactions between oxygen functionalities and sevoflurane. The H2O2 oxidation incorporated varying degrees of both surface oxygen functionalities with hydrogen bond (HB) acceptor and HB donor characters under the studied conditions. Oxidised samples with enriched oxygen functionalities with HB acceptor character and fewer HB donor character exhibited better adsorption capacity for sevoflurane. The presence of a high amount of oxygen functional groups with HB donor character adversely affected the sevoflurane adsorption despite the enrichment of oxygen functional groups with HB acceptor character that have a higher tendency to adsorb sevoflurane.

Theoretical and Economic Evaluation of Low-Cost Deep Eutectic Solvents for Effective Biogas Upgrading to Bio-Methane

This paper presents the theoretical screening of 23 low-cost deep eutectic solvents (DESs) as absorbents for effective removal of the main impurities from biogas streams using a conductor-like screening model for real solvents (COSMO-RS). Based on thermodynamic parameters, i.e., the activity coefficient, excess enthalpy, and Henry’s constant, two DESs composed of choline chloride: urea in a 1:2 molar ratio (ChCl:U 1:2), and choline chloride: oxalic acid in a 1:2 molar ratio (ChCl:OA 1:2) were selected as the most effective absorbents. The σ-profile and σ-potential were used in order to explain the mechanism of the absorptive removal of CO2, H2S, and siloxanes from a biogas stream. In addition, an economic analysis was prepared to demonstrate the competitiveness of new DESs in the sorbents market. The unit cost of 1 m3 of pure bio-methane was estimated to be in the range of 0.35–0.37 EUR, which is comparable to currently used technologies.

Prediction of Electrical Conductivity of Deep Eutectic Solvents Using COSMO-RS Sigma Profiles as Molecular Descriptors: A Quantitative Structure–Property Relationship Study

This work presents the development of molecular-based mathematical models for the prediction of electrical conductivity of deep eutectic solvents (DESs). Two new quantitative structure–property relationship (QSPR) models based on conductor-like screening model for real solvent (COSMO-RS) molecular charge density distributions (Sσ-profiles) were developed using the data obtained from the literature. The data comprise 236 experimental electrical conductivity measurements for 21 ammonium- and phosphonium-based DESs, covering a wide range of temperatures and molar ratios. First, the hydrogen-bond acceptors (HBAs) and hydrogen-bond donors (HBDs) of each DES were successfully modeled using COSMO-RS. Then, the calculated Sσ-profiles were used as molecular descriptors. The relation between the conductivity and the descriptors in both models has been expressed via multiple linear regression. The first model accounted for the structure of the HBA, the HBD, the molar ratio, and temperature, whereas the second model additionally incorporated the interactions between the molecular descriptors. The results showed that by accounting for the interactions, the regression coefficient (R2) of the predictive model can be increased from 0.801 to 0.985. Additionally, the scope and reliability of the models were further assessed using the applicability domain analysis. The findings showed that QSPR models based on Sσ-profiles as molecular descriptors are excellent at describing the properties of DESs. Accordingly, the obtained model in this work can be used as a useful guideline in selecting DESs with the desired electrical conductivity for industrial applications.

Phenylacetonitrile (C6H5CH2CN) Ionic Liquid Blends as Alternative Electrolytes for Safe and High-Performance Supercapacitors.

The increasing need in the development of storage devices is calling for the formulation of alternative electrolytes, electrochemically stable and safe over a wide range of conditions. To achieve this goal, electrolyte chemistry must be explored to propose alternative solvents and salts to the current acetonitrile (ACN) and tetraethylammonium tetrafluoroborate (Et4NBF4) benchmarks, respectively. Herein, phenylacetonitrile (Ph-ACN) has been proposed as a novel alternative solvent to ACN in supercapacitors. To establish the main advantages and drawbacks of such a substitution, Ph-ACN + Et4NBF4 blends were formulated and characterized prior to being compared with the benchmark electrolyte and another alternative electrolyte based on adiponitrile (ADN). While promising results were obtained, the low Et4NBF4 solubility in Ph-ACN seems to be the main limiting factor. To solve such an issue, an ionic liquid (IL), namely 1-ethyl-3-methylimidazolium bis [(trifluoromethyl)sulfonyl] imide (EmimTFSI), was proposed to replace Et4NBF4. Unsurprisingly, the Ph-ACN + EmimTFSI blend was found to be fully miscible over the whole range of composition giving thus the flexibility to optimize the electrolyte formulation over a large range of IL concentrations up to 4.0 M. The electrolyte containing 2.7 M of EmimTFSI in Ph-ACN was identified as the optimized blend thanks to its interesting transport properties. Furthermore, this blend possesses also the prerequisites of a safe electrolyte, with an operating liquid range from at least −60 °C to +130 °C, and operating window of 3.0 V and more importantly, a flash point of 125 °C. Finally, excellent electrochemical performances were observed by using this electrolyte in a symmetric supercapacitor configuration, showing another advantage of mixing an ionic liquid with Ph-ACN. We also supported key structural descriptors by density functional theory (DFT) and COnductor-like Screening Model for Real Solvents (COSMO-RS) calculations, which can be associated to physical and electrochemical properties of the resultant electrolytes.

High-Voltage Electrical Discharges in Green Extractions of Bioactives from Oregano Leaves (Origanum vulgare L.) Using Water and Ethanol as Green Solvents Assessed by Theoretical and Experimental Procedures

Development of green extractions of natural compounds is an ongoing challenge for researches. The aim of the study was to evaluate the extraction of bioactive compounds (BACs) from oregano combining an experimental procedure with a theoretical approach using two computational simulation methods, Hansen solubility parameters (HSP) and conductor-like screening model for real solvents (COSMO-RS) software. In this study, the high-voltage electrical discharge-plasma (HVED) was used as one of new promising green extraction techniques. Optimization of processing extraction parameters (argon and nitrogen for generation of plasma, voltage―15 kV, 20 kV, and/or 25 kV), frequency (100 Hz), pulse duration (400 ns), and treatment time (3 and 9 min) was done using software STATGRAPHICS. Oregano extracts were prepared by pharmacopoeia, 1 g per 50 mL of solvents (water or aqueous ethanol (25 and 50% v/v) treated by HVED. Extraction process was controlled by analytical methods (determination of total phenolic compounds (TPC); antioxidant properties by electronic paramagnetic resonance (EPR), 2,2-diphenyl-2-picrylhydrazyl (DPPH) free radical assay; near-infrared (NIR) spectroscopy; and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) characterization of phenolic compounds, and changes during and after extraction process were investigated. Process follows six principles of green extractions. Theoretical results were in line with experimental for solvent selection; ethanol had higher potential of solubility of BACs than water. Results showed that HVED, as a green extraction method, confirmed high potential for extraction of BACs from oregano with increased yield of individual BACs and TPC in obtained extracts and increased antioxidant activity, compared with untreated samples.

Assessing Viability of Soybean Oils to Remove Hydrogen Sulfide from Natural Gas

A combination of in silico and benchtop experiments was implemented to assess how soybean oils could remove hydrogen sulfide (H₂S)—a corrosive and toxic impurity—from natural gas. The development of hydraulic fracturing (i.e., fracking) in the United States has increased both the use of and interest in natural gas, but natural gas extracted via fracking is often highly concentrated with H₂S. The present work is a proof-of-concept study to evaluate the viability of conventional and high-oleic soybean oils to extract H₂S. The conductor-like screening model for real solvents (COSMO-RS) was used to predict the partition coefficient (Kₘₒd) of the target molecule (H₂S) between the liquid (soybean oil) and gas phases. These predicted Kₘₒd values were below 0.0005 at temperatures ranging from 10 to 100 °C at atmospheric pressure; Kₘₒd values approaching 0 are indicative of near-complete removal of the H₂S from the gas. Experiments showed Kₑₓₚ values below 0.2 in biphasic gas/oil systems at residence times <15 min. Isotherm models demonstrated the saturation limits of the soybean oils as compared with water and heptane. This proof-of-concept study employs a novel use of soybean oils as biosolvents for sweetening natural gas, and they have potential for high-impact application in soybean and natural gas industries.

Silver(I) Dicyanonitrosomethanide, Ag[ONC(CN)2] Complex as Catalyst for the Selective Oxidation of Styrene to Benzaldehyde

Silver(I) dicyanonitrosomethanide, Ag[ONC(CN)2] represent a 3D interwoven coordination polymer organization in which all the donor atoms of the functional groups of ONC(CN)2- are coordinated to the Ag(I). Oxidation of styrene utilizing H2O2 as an oxidant in acetonitrile (CH3CN) was used as a model reaction to investigate the catalytic potential of the Ag(I) complex. The CH3CN was chosen as the solvent based on the data collected from Conductor like Screening Model for Real Solvents (COSMO-RS) study. The data indicate that the Ag[ONC(CN)2] complex was compatible and soluble in CH3CN. Different parameters such as styrene:H2O2 molar ratio, reaction time, catalyst mass, and reaction temperature were studied. Highest styrene conversion (36%) with 100% selectivity towards benzaldehyde (BZ) was achieved when 25 mg catalyst, 1:1 styrene to H2O2 molar ratio were used. The reaction was carried out at 303 K for 3 h. The catalytic conversion of styrene to BZ is proposed to take place via [Ag-H2O2] adduct with styrene oxide (StO) as an intermediate. Molecular Electrostatic Potential (MEP) shows that the Ag atom has the highest probability to coordinate with the oxygen atom of H2O2. The MEP data confirms the proposed mechanism.

Extensive Evaluation of Performance of the COSMO-RS Approach in Capturing Liquid–Liquid Equilibria of Binary Mixtures of Ionic Liquids with Molecular Compounds

A conductor-like screening model for real solvents (COSMO-RS) is presented as a predictive thermodynamic tool for estimating the liquid–liquid equilibrium (LLE) phase diagrams of the binary systems...

Design and evaluation of polarity controlled and recyclable deep eutectic solvent based biphasic system for the polarity driven extraction and separation of compounds

Deep eutectic solvent (DES) based extraction methods have promising applications in extracting and separating compounds from plants. In this study, a polarity controlled biphasic extraction system consisting of a hydrophilic DES phase (Hexafluoroisopropanol-choline chloride: HFIP-ChCl) and a hydrophobic DES phase (Menthol-tricaprylylmethylammonium chloride: Menthol-N8881Cl) was constructed. The DES based biphasic system was successful in the simultaneous extraction and separation of high polarity compounds, such as chlorogenic acid (CHA), quercetin (QUE) and anthocyanidins (ANT), and a low polarity compound artemisinin(ART), from Artemisia annua Leaves in a single step by the polarity driven recognition targets. By adjusting the mole ratio of the component in each DES phase, the HFIP-ChCl(1:1)/Menthol-N8881Cl(2:1) biphasic system showed the best extraction and separation performance. A conductor-like screening model for real solvents (COSMO-RS) was used to monitor and analyze the changes in the surface polarity dynamics of each DES. The results showed that the non-polar intensity increased from 11.89 to 21.06 Å2 with increasing proportion of HFIP in HFIP-ChCl and the non-polar intensity weakened from 16.47 to 10.01 Å2 with increasing proportion of Menthol in Menthol-N8881Cl. This model can be efficient for screening suitable DESs in a DES based biphasic extraction system to accommodate compounds with a range of polarities. Supported by the model and experimental data of the DES based biphasic system, 6.21 mg/g ART was transferred to the upper layer (Menthol-N8881Cl with 2:1 mol ratio) and 7.89 mg/g CHA, 5.5 mg/g QUE, and 8.9 mg/g ANT were transferred to the lower layer (HFIP-ChCl with 1:1 mol ratio) under the optimal condition (15/1 solvent/solid ratio, 40 °C extraction temperature, 1:1 vol ratio and 30 min extraction time). Therefore, the polarity controlled DES based biphasic extraction system was used to expand the application of DESs in the extraction and separation of bioactive compounds with various polarities.

Extraction of pyridine from n-alkane mixtures using methyltriphenylphosphonium bromide-based deep eutectic solvents as extractive denitrogenation agents

In our previous work, we showed that phosphonium-based deep eutectic solvents (DESs) are good candidates for the extractive denitrogenation of oil fuels. In particular, pyridine was successfully extracted from n-hexane and n-heptane via liquid-liquid extraction. The extraction using ‘methyltriphenylphosphonium bromide and ethylene glycol’ DES yielded high distribution ratios and selectivities of pyridine. In this work, two phosphonium-based DESs were prepared, the first one was a “binary DES” composed of methyltriphenylphosphonium bromide and glycerol and the second one was a “ternary DES” composed of methyltriphenylphosphonium bromide, glycerol, and ethylene glycol. One objective was to assess the extraction properties of the DESs for pyridine from n-alkanes. Another objective of this work was to study the influence of n-alkane chain length on the extraction performance. Thus, the oil models selected were n-hexane/pyridine, n-heptane/pyridine, and n-octane/pyridine. First, the prepared DESs were characterized for their water content, density, viscosity, and the degradation temperatures. Then the solubility of n-hexane, n-heptane, n-octane, and pyridine in the DESs was measured at 298.2 K and 1.01 bar. Afterward, the liquid-liquid equilibrium (LLE) data of the pseudo-ternary systems {n-alkane + pyridine + DES} were determined at a temperature of 298.2 K and a pressure of 1.01 bar. The consideration of a pseudo-ternary system was validated by showing that none of the DES constituents appears in the n-alkane-rich phase “the raffinate”.The solute distribution ratios and the selectivities were calculated from the experimental LLE data and compared to our previous work and some relevant literature. Furthermore, the LLE data were correlated with the non-random two-liquid (NRTL) model using ASPEN Plus. There was good agreement between the calculated experimental results. Finally, the COnductor like Screening MOdel for Real Solvents (COSMO-RS) model was used to predict the ternary tie lines for the studied systems. Based on the good distribution ratios and selectivities obtained, the studied DESs can be considered as potential solvents for extractive denitrogenation processes.

Removal of chlorophenols from aqueous media with hydrophobic deep eutectic solvents: Experimental study and COSMO RS evaluation

Chlorophenols have been strongly linked with health and environmental risks which includes genotoxicity, mutagenicity, carcinogenicity and histopathological alterations. These hazards are further intensified due to the prevalent usage and disposal. Hence, regulatory bodies have established tolerable limits for chlorophenols in water and air. In this study, seven different hydrophobic deep eutectic solvents (HDESs) were prepared and characterized for the liquid extraction of 3-chlorophenol (3-CP), 2-chlorophenol (2-CP) and 2,4-dichlorophenol (2,4-DCP) form wastewater. The HDESs are Menthol-Hexanoic acid 1:2, Menthol-Octanoic acid 1:2, Menthol-Decanoic acid 1:2, and Menthol-Thymol 1:1, 1:2, 1:3, 1:4. To the best of our knowledge, this is the first study to focus on the extraction of 3-chlorophenols and 2,4-dichlorophenols with these seven HDESs. The effect of different conditions such as pH (3−11), initial concentration in aqueous solution (0-1000 ppm) and the HDES/water mass ratio (1:1–1:10) on the extraction efficiency of the chlorophenols was evaluated. The experimental results showed that the HDESs have excellent extraction capacity for the chlorophenols which were studied. The extraction efficiencies were higher than 94% under the conditions investigated. The extraction capacity of the chlorophenols followed the order 3-CP > 2-CP > 2,4-DCP for the Menthol-Alkanoic acid HDESs. In addition, Conductor-like Screening Model for Real Solvents (COSMO-RS) was utilized to model the extraction process. This model provides insightful understanding of the interaction between the HDESs and the chlorophenols. In general, the COSMO RS provided good agreement with the experimental data.

Screening of ionic liquids for the extraction of biologically active compounds using emulsion liquid membrane: COSMO-RS prediction and experiments

Emulsion liquid membrane (ELM) is an effective way to recover and remove biologically active compounds, particularly drug molecules from hospital wastewater. Ionic liquid (IL)-assisted ELMs have recently been found to be efficient for recovery and removal of biologically active compounds owing to their excellent characteristics. However, the selection of potential ILs from the wide range of anion-cation combinations is quite challenging. To address this issue, the conductor-like screening model for real solvents (COSMO-RS) has emerged as a reliable tool to screen solvents based on a variety of fluid mixture properties. In this study, we screened ILs for the extraction of lactic acid as a model drug using COSMO-RS. Six cations and 20 anions were selected and combined to form 120 ILs, which were then assessed for recovery of lactic acid. The activity coefficient at infinite dilution, capacity, selectivity, performance index, and solvation energy values for all of the combinations were predicted, by which the effectiveness of each IL was evaluated. ILs without aromatic rings showed greater efficiencies than ILs containing aromatic rings. Moreover, the sulphate anion-cation combinations showed the highest capacities and selectivities. Overall, tetramethylammonium sulfate was found to be the best extractant for lactic acid. The COSMO-RS predictions were validated with experimental data, and the results showed a maximum difference of ~8.0 between the predicted and experimental values.

COSMOperm: Mechanistic Prediction of Passive Membrane Permeability for Neutral Compounds and Ions and Its pH Dependence.

We present a new and entirely mechanistic COSMOperm method to predict passive membrane permeabilities for neutral compounds, as well as anions and cations. The COSMOperm approach is based on compound-specific free energy profiles within a membrane of interest from COSMO-RS (conductor-like screening model for realistic solvation) calculations. These are combined with membrane layer-specific diffusion coefficients, for example, in the water phase, the polar head groups, and the alkyl tails of biochemical phospholipid bilayers. COSMO-RS utilizes first-principle quantum chemical structures and physically sound intermolecular interactions (electrostatic, hydrogen bond, and van der Waals). For this reason, it is unbiased toward different application scenarios, such as in cosmetics and industrial chemical or pharmaceutical industries. A fully predictive calculation of passive permeation through phospholipid bilayer membranes results in a performance of r2 = 0.92; rmsd = 0.90 log10 units for neutral compounds and anions, as compared to gold standard black lipid membrane experiments. It will be demonstrated that new membrane types can be generated by the related COSMOplex method and directly used for permeability studies by COSMOperm.

COSMO-RS predicted 1-octanol/water partition coefficient as useful ion descriptor for predicting phase behavior of aqueous solutions of ionic liquids

Abstract 1-Octanol/water partition coefficients (log P) of 450 cations and 132 anions composing ionic liquids (ILs) were estimated with the conductor-like screening model for real solvents (COSMO-RS). For each cation-anion combination mixed with water, the liquid-liquid equilibrium (LLE) compositions at T = 308.15 K and T = 373.15 K were calculated using COSMO-RS. An influence of cation and anion hydrophobicity (measured by log P) on the phase behavior of the {IL + water} mixture. Distinct domains of log P values corresponding to miscible, immiscible and partial solubility behavior, were observed, in particular those with upper and lower critical solution temperature (UCST/LCST). 18 ILs were chosen from different regions of the resulting plot. The ILs were synthesized and their LLE with water has been measured. The predicted phase behavior is in good agreement with the observed data as well as with the literature data in general. The proposed method is simple and allows for rapid and straightforward evaluation of the phase behavior of {IL + water} systems.

COSMO‐RS based ionic liquid screening for the separation of acetonitrile and ethanol azeotropic mixture

AbstractBACKGROUNDThe selection of competent entrainer is very important for separating azeotrope systems by extractive distillation. Ionic liquids (ILs) are outstanding entrainers due to their excellent properties. However, it is time‐consuming to choose suitable ILs from the huge database of anions and cations. Herein, the selectivity and viscosity of ILs were combined as double standards to select suitable ILs for the separation of acetonitrile and ethanol mixture.RESULTSThe selectivity and viscosity of 450 ILs (25 cations and 18 anions) were predicted based on Conductor‐like Screening Model for Real Solvents (COSMO‐RS). 1‐Butyl‐3‐methylimidazolium acetate [BMIM][Ac] was selected as a potential entrainer due to its higher selectivity and lower viscosity and [BMIM][Cl] was chosen as a comparison item as ILs with [Cl]− anion have separation performance next to [Ac]−‐based ILs. The vapor–liquid equilibrium (VLE) data of the acetonitrile + ethanol + ILs systems were determined at 101.3 kPa and correlated with the non‐random two‐liquid (NRTL) model. The result showed that the addition of the two ILs produced a salting‐out effect on acetonitrile and enhanced the relative volatility of acetonitrile to ethanol. Furthermore, [BMIM][Ac] exhibited better separation performance than [BMIM][Cl] and our previous reported ILs, which are consistent with the predicted results. The reduced density gradient (RDG) method indicated that hydrogen bonding dominated the interactions between ethanol and IL.CONCLUSION[BMIM][Ac] is a superior entrainer for the separation of acetonitrile–ethanol azeotrope. Compared to the previously studied ILs, there is a stronger hydrogen bond between ethanol and [BMIM][Ac]. This makes ethanol ‘bundled’ and acetonitrile more volatile, resulting in the superior separation performance of [BMIM][Ac]. © 2019 Society of Chemical Industry

Solubility parameters and solvent affinities for polycaprolactone: A comparison of methods

ABSTRACTIntrinsic viscosity measurements were used in combination with the functional solubility parameter (FSP) and Hansen solubility parameter (HSP) fitting methods to determine the solubility parameters (SPs) of polycaprolactone (PCL). Despite using only eight solvents, a simple similarity criteria approach showed that the HSPs and FSPs were good predictors of the relative solvent‐PCL affinity compared to HSPs available in the literature and SPs calculated using additive group contribution methods. Three complementary computational methodologies—Conductor‐like Screening MOdel for Real Solvents (COSMO‐RS), partial solvation parameters (PSPs), and a thermodynamic quantitative structure–property relationship (QSPR) approach—were used to substantiate the relative solvent–PCL affinities revealed by the intrinsic viscosity measurements. The solvent affinities predicted by all three techniques were in good agreement with the trend observed in the experimental intrinsic viscosity data, but the COSMO‐RS activity coefficients, ln(γPCL), were slightly superior to the PSP and thermodynamic QSPR methods, particularly when incorporating the Elbro free‐volume combinatorial correction in the COSMO‐RS calculations. As part of this study, the FSP fitting algorithm was modified to obtain the PSPs for PCL in terms of the intrinsic viscosity data, thereby, presenting a promising new way to calculate the PSPs of polymers from empirical solubility and solvent affinity data. © 2020 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48908.