Conductor-like Screening Model-segment Activity Coefficient Research Articles

Phase behavior of sodium and potassium salts in their aqueous solutions: Experiment and computational thermodynamics

AbstractWith the rapid development of the semiconductor industry, the demand for ultraclean and high‐purity electronic chemicals, especially ultrapure water as a general solvent for cleaning semiconductor chips, has increased dramatically. The distillation process is a good choice for large‐scale production of ultrapure water that can be used to clean semiconductor chips, but there is a lack of basic thermodynamic theory for removing ionic impurities. In this work, the temperature and vapor–liquid phase composition of sodium and potassium salts aqueous solutions at vapor–liquid equilibrium (VLE) were investigated by experiments. The microstructure of each inorganic salt aqueous solution was explored by molecular dynamics simulation and quantum chemical calculation, and the interaction between each ion and water molecule was analyzed. A volatilization mechanism of inorganic salts was proposed, and it was found that the volatilization of inorganic salts in an aqueous solution was affected by the strength of interaction between the dissociated anions and cations and water molecules. Finally, the conductor‐like screening model segment activity coefficient (COSMO‐SAC) model predicted the VLE values of inorganic salt aqueous solutions. The prediction at low concentrations (xs < 0.06) was in good agreement with the experimental data.

Screening of ionic liquids and deep eutectic solvents for the extraction of persistent organic pollutants from edible oils and fat

Presence of persistent organic pollutants (POPs) like polychlorinated-p-dibenzodioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in edible oils poses risk to human health. Ionic liquids (ILs) and deep eutectic solvents (DESs) are novel combinatorial solvents with a proven record of extraction of such persistent organic pollutants (POPs). However, the large possibility of such combinatorial solvents necessitates an a-priori screening strategy to select the best possible ILs and DESs. Therefore, a Conductor like Screening Model Segment Activity Coefficient (COSMO-SAC) based framework has been employed to extract 27 POPs (6 PCDDs, 9 PCDFs, 12 PCBs) from five types of edible oil and animal fat by ILs and DESs. The screening will create such a list and based on that experimentation can be performed. There are five different types of oils and fats such as sunflower oil, soya lecithin, rapeseed oil, fish oil, and milk fat that are selected as potential sources of PCDD/Fs and PCBs. A combination of 58 cations and 39 anions which will yield 2262 types of IL and 217 types of DESs with the proportional combination of 24 HBAs and 62 HBDs are considered. Infinite dilution activity coefficient (IDAC) and solubility are calculated based on COSMO-SAC modelling and a set of ILs and DESs are screened as a potential extractant for POPs. The study aims to select the most suitable green solvents to extract these POPs from edible oils to render them safe for consumption.

A comprehensive study of the water stability of eutectic solvents using COSMO-SAC

The water stability of deep eutectic solvents (DESs) is an important factor because the preferential interaction with water of one or both DESs precursors may change the nature of the solvent and impact its performance. In this work, Conductor-like Screening Model-Segment Activity Coefficient (COSMO-SAC) was applied to investigate the stability of both hydrophilic and hydrophobic eutectic solvents (ESs) in the presence of water. With this objective, an initial computational evaluation of all possible combinations of ES composed by twenty-two different hydrogen bond acceptors (HBA) and forty-four hydrogen bond donors (HBD) at three different molar ratios of HBA: HBD (2:1, 1:1, and 1:2) was carried. The results revealed that the hydrophobic ESs based on tetraalkyl -ammonium salts, terpenes and fatty acids as HBA and fatty alcohols and fatty acids as HBD are the DESs with higher water stability. Therefore, four different groups of eutectic solvents, namely menthol: fatty alcohol, menthol: fatty acid, fatty acid: fatty acid and fatty acid: fatty alcohols were selected to evaluate the COSMO-SAC predictions using water activity measurements. It is shown that a good agreement was obtained between the calculated and the experimental results and that the hydrophobicity of the eutectic solvents controls its water stability. A thermophysical characterization of the eutectic solvents studied is also reported.

Screening method and mechanism of ionic liquid as extractant in fuel extraction desulfurization process

AbstractBackgroundIn the production of ultra‐low sulfur fuels, the use of extraction processes to remove sulfides from the fuel has various advantages. The selection of a suitable extractant is key to the extraction process. Ionic liquids (ILs) are known as green solvents and are designable, but there is a wide variety. In this study, an IL screening method was developed based on a conductor‐like screening model‐segment activity coefficient (COSMO‐SAC) model and a fuzzy comprehensive evaluation model. In addition, the feasibility of the method was verified by fuel extraction desulfurization experiments. Finally, the separation mechanism was explored through intermolecular interactions.ResultsIn this study, suitable extractants were screened from 2400 ILs with 24 anions and 100 cation combinations. Based on the results of the fuzzy comprehensive evaluation model, five ILs were selected; 1‐hexyl‐3‐methylimidazolium hexafluorophosphate ([HMIM][PF6]) was selected as the extractant and the single desulfurization rate could reach 72.74%. After four desulphurization experiments, the sulfur content in the model oil decreased from 1200 to 6.98 μg/g. The interaction energy difference between [HMIM][PF6] + BT and [HMIM][PF6] + OC (ΔE = ‐12.8662 kJ·mol−1) is higher than those of the other four extractants.ConclusionThe feasibility of the screened method was verified by the extraction desulfurization experiment. [HMIM][PF6] was selected as the most suitable extractant. Furthermore, by analyzing the weak interaction between ILs and benzothiophene (BT) and n‐octane (OC), it was found that weak hydrogen bonds (HBs) and π–π interactions between [HMIM][PF6] and BT play important roles in the extraction process. © 2022 Society of Chemical Industry (SCI).

Ionic liquid derived novel deep eutectic solvents as low viscous electrolytes for energy storage

This work investigates a newly emerging class of solvents to be used as alternatives to or complementarily with ionic liquid (IL) electrolytes. Three novel deep eutectic solvents (DESs) comprised of the hydrogen bond donors (HBDs), namely N-Methylacetamide (NMAc) and formamide, were formulated with three variants of the methyl imidazolium-based ionic liquids (ILs) as hydrogen bond acceptors (HBAs). ILs consisting of 1-butyl-3-methyl imidazolium ([BMIM]) cation with anions namely methanesulphonate ([MeSO3]), bis(trifluoromethylsulfonyl)imide ([Tf2N]), and hexafluorophosphate ([PF6]) were used as hydrogen bond acceptors. Initially, the eutectic points of the DESs were estimated using a quantum chemical-based thermodynamic model, namely Conductor like Screening Model-Segment Activity Coefficient (COSMO-SAC). The calculated melting points of the DESs were determined to be markedly lower than those of both the constituent components. Further, physical and chemical characterization was done on the synthesized DESs. The viscosities (<20 cp) were found to be significantly lower than those of conventionally used pure room temperature ILs, and ionic conductivities (>5 mS/cm) were found to be appreciably higher than those of the corresponding constituent ILs. Thermogravimetric analysis revealed negligible mass loss up to 80–100 °C. Linear scan voltammetry (LSV) was employed to determine the electrochemical stable potential window (ESPW) of the solvents with a glassy carbon (GC) electrode. LSV provided electrochemical stabilities in the range of 3.8–4 V for all three studied deep eutectic solvents, comparable to pure ILs and far higher than the potential windows of mixtures of ILs and organic solvents, a blend commonly used as electrolytes.

Highly efficient separation of benzene + cyclohexane mixtures by extraction combined extractive distillation using imidazolium-based dicationic ionic liquids

Benzene (BEN) and cyclohexane (CYH), which have very close boiling points and a binary azeotrope, are the most difficult binary components in the separation of aromatic and non-aromatic hydrocarbons. This study further explored the separation mechanism and industrial application prospects of BEN ​+ ​CYH mixtures separated by a dicationic ionic liquid (DIL) [C5(MIM)2][NTf2]2 based on experimental research. The calculation results of the Conductor-like Screening model Segment Activity Coefficient (COSMO-SAC) model show that selectivity and solvent capacity of the DIL are significantly improved. The effects of different anions and cations on the microstructure distribution and diffusion behavior of BEN ​+ ​CYH system were investigated by quantum chemistry (QC) calculations and molecular dynamics (MD) simulations. The results indicate that the anion [NTf2]− has low polarity, uniform charge distribution, and a dual role of hydrogen bonding and π-π bonding, and the cation [C5(MIM)2]2+ has stronger interaction with BEN and higher selectivity than conventional cations. The liquid-liquid extraction and extractive distillation (LLE-ED) process using an optimized 65 mol/mol DIL ​+ ​35 mol/mol H2O mixed solution as the extractant was proposed, which solved the problem of low product purity in the LLE process and high energy consumption in the ED process. Under the best operating conditions, the purity of CYH product was 99.9%, the purity of BEN product was 99.6%, the recovery rate of BEN reached 99.9%, and the recovery rate of DIL reached 99.9%. The heat-integrated LLE-ED process reduced total annual cost by 21.6%, and reduced CO2 emissions by 48.0%, which has broad industrial application prospects.

Extractive Distillation with Ionic Liquids To Separate Benzene, Toluene, and Xylene from Pyrolysis Gasoline: Process Design and Techno-Economic Comparison with the Morphylane Process

Aromatic/aliphatic separation stands as a challenge for both industry and academia. More and more efforts are being made to improve energy-demanding technologies based on liquid–liquid extraction or extractive distillation processes. Recently, ionic liquid-based technologies devoted to separating benzene, toluene, and xylene from pyrolysis gasoline have been evaluated, and extractive distillation showed more potential than liquid–liquid extraction in terms of separation performance and global energy requirements. In this work, extractive distillation with ionic liquids is completely evaluated from solvent selection to rate-based process design and compared with the Morphylane benchmark process. The ILUAM database is explored through a validated COSMO/Aspen methodology to understand the impact of the ionic liquid nature on the extractive distillation operation. A parametric study focused on the extractive distillation column (EDC) is conducted for preliminary set initial guesses to design task. The final issue is centered on rigorously designing the ionic liquid-based and Morphylane processes at commercial specifications. Two different ionic liquid-based process configurations are evaluated based on the opportunities that the use of ionic liquids enables. The new process configuration working with [emim][TCM] reduces the energy costs and capital expenditures associated with the Morphylane process by 67 and 63%, respectively, along with a reduction in the solvent costs, confirming it as a cleaner alternative. In addition, a parametrization of the Cubic Plus Association equation of state (CPA EoS) obtained from the regression of experimental vapor–liquid–liquid equilibrium data is also used to simulate the EDC in equilibrium and rate-based mode. Both models provide similar results, confirming the ability of the conductor-like screening model–segment activity coefficient model as an a priori tool and the reliability of the CPA EoS as a regressive alternative to describe these kinds of complex multicomponent systems.

A solvent loss study for the application of solvent extraction processes in the pharmaceutical industry

Liquid – liquid extraction (LLE) processes have been widely applied to extract active pharmaceutical compounds (APCs) from plant materials at both the laboratory and industrial-scale. The approach to modify the aqueous phase with small molecule organic modifiers has been used to increase the solubility of APCs in the aqueous phase. This work investigates the solvent loss for 18 LLE systems, including three aqueous phase modifiers (methanol, ethanol and acetone), three traditional volatile organic compounds (VOCs) solvents (xylene, methyl isobutyl ketone (MIBK) and n-heptane) and three green solvents (d-limonene, α-pinene and p-cymene) with the aim of identifying the most suitable solvents for cannabinoid extraction from cannabis tissues. The solvent selection screening using COnductor-like Screening MOdel - Segment Activity Coefficient (COSMO-SAC) modelling was investigated. The loss of modifier into organic solvents generally increases as the original modifier concentration in aqueous solution increases. Methanol and ethanol are preferred for use in pharmaceutical LLE processes with volume fractions in organic phases at equilibrium of ≤ 0.02 v/v and ≤ 0.06 v/v, respectively. The organic solvent loss into the alcoholic aqueous phase at ≤ 0.8 v/v alcohol/water aqueous phase is negligible. MIBK and acetone are not suitable for pharmaceutical LLE processes with the presence of the modifier. Both Hanson solubility parameters (HSPs) and COSMO-SAC modelling show good agreement with the experimental outcomes.

Ionic liquid-based deep eutectic solvents as novel solvent-cum-catalyst media for thermal dehydrogenation of chemical hydrides

The current work explores the usage of novel synthesized Deep Eutectic Solvent (DES) as a catalyst cum solvent media for the thermal dehydrogenation of chemical hydrides, namely Ammonia Borane (AB) and Ethylene diamine bisborane (EDAB). In the first instance, the quantum chemistry based COSMO-SAC (COnductor like Screening MOdel Segment Activity Coefficient) model was used for the selection of the pertinent solvent. 1-Butyl-3-methylimidazolium methanesulfonate: Imidazole ([BMIM][MeSO3]:[Im]) turned out to be an ideal eutectic mixture with the highest predicted solubility with amine boranes. The DES was synthesized by combining the Hydrogen Bond Acceptor (HBA), namely 1-Butyl-3-methylimidazolium methanesulfonate and Imidazole as Hydrogen Bond Donor (HBD) at a molar ratio of 1:2 and T = 70 °C. The formation of DES was confirmed by recording the NMR spectra. Further, the thermal dehydrogenation study was performed at a vacuum of 4 × 10−2 mbar (gauge pressure) of AB/DES and EDAB/DES systems at 105 °C, where a hydrogen equivalent of 1.40 and 2.55 was produced, respectively. The residual samples were further analyzed through 1H NMR analysis for the reaction mechanism and to confirm the role of Ionic Liquid-based DES as catalyst cum solvent media.

Low- to Room-Temperature Dehydrogenation of Dimethylamine Borane Facilitated by Ionic Liquids: Molecular Modeling and Experimental Studies

A novel low- and room-temperature dehydrogenation of dimethylamine borane (DMAB) is being reported using hydrogen sulfate-based ionic liquids (ILs), namely, 1-ethyl-3-methylimidazolium hydrogen sulfate ([EMIM][HSO4]) and 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM][HSO4]). The ILs are selected from a pool of potential ILs using a conductor-like screening model-segment activity coefficient (COSMO-SAC) model, and the dehydrogenation is performed at 0, 15, and 25 °C and a high vacuum of 4 × 10–2 mbar gauge pressure. The dehydrogenated products are characterized with 1H and 11B NMR. 1H NMR characterization reveals the structural integrity of ILs after the dehydrogenation. The 11B NMR characterization reveals the evolution of −BH2 and B═N moieties during dehydrogenation. Based on the 11B NMR study, the IL-assisted intramolecular and intermolecular dehydrogenation mechanism has been proposed. The intramolecular dehydrogenation pathway of dehydrogenation is proposed at 0 °C, and the intermolecular dehydrogenation pathway is at 15 and 25 °C. Formation of DMAB dimers has been confirmed for the intermolecular dehydrogenation pathway; on the contrary, DMAB does not oligomerize as other amine boranes. The interaction energy calculations reveal a greater stability of DMAB in [EMIM][HSO4] than in [BMIM][HSO4] IL. The anionic moiety of ILs is found to be the prominent pathway for the hydrogen bond interaction with protic and hydridic moieties of DMAB. It confirms the dominant role with respect to the selection of anion in hydrogen production.

Power generation from waste heat: Ionic liquid‐based absorption cycle versus organic Rankine cycle

AbstractAspen Plus® simulations using the Peng‐Robinson (PR‐EOS) and the COSMO‐SAC models were performed to study absorption power cycles (APCs) using mixtures of R‐134a with two ionic liquids, [C2C1im][Tf2N] or [C6C1im][Tf2N], and compared against an R‐134a organic Rankine cycle (ORC) operating under similar conditions. The PR‐EOS results were in agreement with calculations from a PR model fitted to the R‐134a + IL experimental phase equilibrium data. The APCs have similar efficiencies and outperform the ORC by 3%–46%, with the largest differences observed when operating with lower grade (lower TH) heating sources, lower quality cooling (higher TL), and lower subcooling in the pump inlet stream. The PR‐EOS and the Conductor‐like Screening Model Segment Activity Coefficient (COSMO‐SAC) results follow similar trends, but numerical discrepancies are observed in the cycle efficiencies and stream flow rates and compositions due to differences in solubilities and enthalpy changes between both models, suggesting that improvements are needed to increase the accuracy of COSMO‐SAC for these systems.

A priori prediction of complex liquid-liquid-liquid equilibria in organic systems using a continuum solvation model.

Liquid-liquid-liquid equilibria (LLLE) is usually observed in many industrial processes primarily linked to enhanced oil recovery techniques. However their measurements are complex and so are their computations. An inherently predictive tool is often useful for elucidating their distribution ratios and phase compositions. In the present work, the phase behavior of nine ternary and two quaternary LLLE systems were predicted employing the quantum chemical based COnductor like Screening MOdel-Segment Activity Coefficient (COSMO-SAC) model. The methodology namely, Rachford-Rice LLLE (RRL3E) algorithm and Henley-Rosen LLLE (HRL3E) algorithm were used to predict the triphasic compositions in each system. In the RRL3E approach, the triphasic systems were assumed into two co-existing biphasic liquid-liquid equilibria systems, whereas in the HRL3E approach, all three phases were considered to be in equilibrium with each other simultaneously. Apart from predicting the local compositions, the HRL3E algorithm was also used to predict the individual phase splits and phase fractions of the LLLE region. Average overall root mean square deviation (rmsd (%)) values considering all 42 datasets and corresponding to 414 data points were recorded as 4.65% and 4.83% using the RRL3E and HRL3E algorithms respectively. Further, the RRL3E algorithm was extended to correlate the LLLE data for all systems using the Genetic Algorithm (GA) based NRTL (GA-NRTL) and UNIQUAC (GA-UNIQUAC) models.

A Brief Review of the Prediction of Liquid–Liquid Equilibrium of Ternary Systems Containing Ionic Liquids by the COSMO-SAC Model

The selection of the extractant is an important consideration for the design of liquid–liquid extraction processes. Researchers are paying more attention to a priori predictions of liquid–liquid equilibria. The predictive and fully open-source thermodynamic model COSMO-SAC (conductor-like screening model-segment activity coefficient) uses quantum chemical calculations for calculating activity coefficients and thermodynamic properties. Through a brief review of the recent advances of COSMO-SAC in predicting liquid–liquid equilibrium of ionic liquid systems, this work assessed the accuracy of prediction for different chemical family combinations and generated directions for future improvement.

Reactive insights into the hydrogen production from ammonia borane facilitated by phosphonium based ionic liquid

The current work presents a mechanistic insight of hydrogen production from ammonia borane (AB) facilitated by the phosphonium based ionic liquid (IL), trihexyl(tetradecyl)phosphonium bis (2,4,4-trimethylpentyl) phosphinate ([TDTHP][Phosph]). Prior to experiments, the IL was screened from a pool of 11 phosphonium ILs with the infinite dilution activity coefficients (IDAC) values as predicted by conductor like screening model segment activity coefficient (COSMO-SAC) theory. Thereafter, a dehydrogenation experiment of AB/[TDTHP][Phosph] was carried out at 105 °C and 4×10-2 mbar of gauge pressure, which yielded 2.07 equivalent hydrogen production. At higher temperature, the 11B NMR characterization shows the suppression of induction period at 105 °C and appearance of borohydride anion after 1 min of dehydrogenation. Further, time-resolved characterization of AB/[TDTHP][Phosph] at 105 °C confirmed the appearance of polymeric aminoborane after 10min with a subsequent formation of polyborazylene. HR-MS characterization coupled with 1H resonance spectrum confirmed structural integrity of IL. The dual characterization of NMR and HR-MS led us to propose a dehydrogenation mechanism of AB/[TDTHP][Phosph] system.

Ionic Liquid Facilitated Dehydrogenation of tert-Butylamine Borane.

The current work reports ionic liquid (IL) facilitated dehydrogenation of tert-butylamine borane (TBAB) at 90 and 105 °C. For the screening of potential IL solvent, solubility predictions of TBAB in ILs were performed by the conductor-like screening model segment activity coefficient (COSMO-SAC) model. The COSMO-SAC model predicted a logarithmic infinite dilution activity coefficient of −6.66 and −7.31 for TBAB in 1-butyl-3-methylimidazolium acetate [BMIM][OAc] and trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate [TDTHP][Phosph], respectively. Hydrogen (1.95 equiv) was seen to release from TBAB/[BMIM][OAc] at 105 °C, whereas TBAB/[TDTHP][Phosph] produced 1.63 equiv of hydrogen after 360 min of dehydrogenation. The proton nuclear magnetic resonance (1H NMR) characterization of TBAB/IL systems revealed the structural integrity of ILs during dehydrogenation. Further characterization through the boron NMR (11B NMR) technique disclosed the time-resolved formation and stability of the starting compound, intermediate boron moieties, and product distribution. The 11B NMR characterization also revealed the fact that the TBAB/[TDTHP][Phosph] mixture dehydrogenates via bimolecular addition of TBAB by forming borohydride anion (−BH4–). It was seen to oligomerize with the subsequent addition of TBAB in the oligomer chain. For the TBAB/[BMIM][OAc] system, the 11B NMR characterization could not identify the borohydride anion but confirmed a faster formation of the B=N moiety when compared to the TBAB/[TDTHP][Phosph] system. On the basis of the NMR characterization, IL-facilitated dehydrogenation mechanism of TBAB is proposed.

Prediction of solid-liquid-gas equilibrium for binary mixtures of carbon dioxide + organic compounds from approaches based on the COSMO-SAC model

Six predictive approaches based on the Peng-Robinson (PR) equation of state (EOS), conductor-like screening model segment activity coefficient (COSMO-SAC), and mixing rules were applied to model solid-liquid-gas equilibrium for 21 binary mixtures of CO2 and an organic compound. The accuracy of these approaches in predicting equilibrium temperatures at given pressures (635 experimental data with T=220∼413.97K and P=0.05∼48.35MPa), liquid phase compositions, and liquid molar volumes was examined and compared to provide an overview on their performance. The recently developed PR+COSMO-SAC EOS was found to be most accurate, with deviations of 6.25K in temperature, 0.071 in liquid mole fraction, and 21% in liquid molar volume. The performance of these models can be very different for the solid containing different functional groups. Nevertheless, the PR+COSMO-SAC EOS could provide useful a priori predictions with only input of experimental heat of fusion and melting temperature of the solid.

Experimental Insights into the Thermal Dehydrogenation of Ethylene Diamine Bisborane Using Allyl-Based Ionic Liquids

This work reports the use of allyl-based imidazolium cations for dehydrogenation of ethylene diaminebisborane (EDAB) at three different temperatures, namely, 95, 105, and 115 °C, under vacuum. The allyl-based ionic liquid (IL) was selected by using the infinite dilution activity coefficient (IDAC) as predicted from the COSMO-SAC (COnductor-like Screening MOdel–Segment Activity Coefficient) model. Based on the results of the COSMO-SAC model, the following allyl-based ILs were used for experimentation: 1-allyl-3-methylimidazolium dicyanamide ([AMIM][N(CN)2]), 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([AMIM][Tf2N]), and 1-allyl-3-methylimidazolium bromide ([AMIM][Br]). The highest amount of hydrogen (3.25 equiv) was measured from the EDAB/[AMIM][Br] system at 115 °C. Gas chromatography was conducted to confirm that the gas released was pure hydrogen. To better understand the reaction mechanism of EDAB dehydrogenation, the Reactive Force Field (ReaxFF) method was employed. Further analyse...

Enhancement of bio-oil derived chemicals in aqueous phase using ionic liquids: Experimental and COSMO-SAC predictions using a modified hydrogen bonding expression

In this work the commercial hydrophobic imidazolium based ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][TF2N]) was investigated for the extraction of acetic acid and furfural from aqueous solution. The liquid–liquid equilibrium (LLE) data for the ternary mixture of [BMIM][TF2N] (1)+acetic acid (2)+water (3) and [BMIM][TF2N] (1)+furfural (2)+water (3) were experimentally determined at T=298.15K and atmospheric pressure. The two phase region for acetic acid system was smaller as compared to the furfural system. The distribution co-efficient and selectivity values were greater than unity which indicates easier extraction of acetic acid and furfural from aqueous phase. The selectivity values for furfural were of two orders of magnitude greater than acetic acid. The experimental results were then correlated with the thermodynamic activity coefficient models namely NRTL and UNIQUAC models. The root mean square deviation (RMSD) obtained in NRTL and UNIQUAC models for both the systems were in the range of 0.26–0.75%. Thereafter a continuous probability distribution function for screening charge density has been used to obtain the interaction due to the hydrogen bonding term in conductor like screening model-segment activity coefficient (COSMO-SAC). This implementation gave RMSD values of 2.9% and 2.2% for IL–acetic acid–water and IL–furfural–water systems, respectively.

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Vapor-Liquid equilibrium (VLE) data involving alcohols and hydrocarbons are relevant to the gas and oil industry. Under certain circumstances, for instance, in the determination of the distribution of components between phases in equilibrium, and physical properties of the fluids in reservoirs, the predictions from the available models for hydrocarbon systems in the presence of flow-assurance additives, such as alcohols, are, at times, insufficient. This study used the Conductor-like Screening Model-Segment Activity Coefficient (COSMO-SAC) to predict liquid phase activity coefficients for the description of VLE of seven binary systems containing alcohols and hydrocarbons, at low and high pressures (10-2500kPa), and under temperatures ranging from 298-400K. The COSMO SAC has a relatively simple mathematical form and can be easily incorporated into a process simulation software. COSMO-SAC model predictions in this work showed average absolute relative deviation (AARD) values ranging from 5.0% to 13.8%.

Kinetics of the Synthesis of 1‐Alkyl‐3‐methylimidazolium Ionic Liquids in Dilute and Concentrated Solutions

ABSTRACTThe kinetics of the reactions of 1‐methylimidazole with iodoethane, 1‐iodobutane, 1‐bromobutane, 1‐bromohexane, 1‐bromooctane resulting in the formation of corresponding 1‐alkyl‐3‐methylimidazolium halide ionic liquids in acetonitrile and cyclopentanone solutions has been studied in a wide range of concentrations and degrees of conversion. The studied reactions were found to follow the SN2 rate law in the dilute solutions. The significant deviations from the simple SN2 rate law observed at higher concentrations of the reactants were assigned to the concentration dependence of activity coefficients for the reactants and the transition states. The experimental data were processed with the conductor‐like screening model–segment activity coefficient (COSMO‐SAC) model and the Scatchard–Hildebrand equation. The latter was found to provide somewhat better description of the experimental results; however, the former has a wider predictive ability. The Arrhenius activation energies and the activation enthalpies were calculated for the investigated systems. The rate constants at infinite dilution were obtained for a large number of 1‐haloalkane + 1‐methylimidazole + solvent systems with the use of the COSMO‐SAC model. It was demonstrated that the rate constants of the studied reactions in various non‐hydrogen‐bonding solvents can be estimated from a correlation with the Hildebrand solubility parameter.