Gas solubility in long‐chain imidazolium‐based ionic liquids

The gas solubility in 1‐dodecyl‐3‐methylimidazolium [C₁₂MIM] based ionic liquids (ILs) was measured at temperatures (333.2, 353.2, and 373.2) K and pressures up to 60 bar for the first time. The popular UNIFAC‐Lei model was successfully extended to long‐chain imidazolium‐based IL and gas (CO₂, CO, and H₂) systems. The free volume theory was used to explain the gas solubility and selectivity in imidazolium‐based ILs by calculating the fractional free volume and free volume by the COSMO‐RS model. Furthermore, the excess enthalpy of gas‐IL system was concerned to provide new insights into temperature dependency of gas (CO₂, CO, and H₂) solubility in ILs. The experimental data, calculation, and theoretical analysis presented in this work are important in gas separations with ILs or supported ionic liquid membranes. © 2017 American Institute of Chemical Engineers AIChE J, 63: 1792–1798, 2017     

Prediction and screening of solubility of pharmaceuticals in single‐ and mixed‐ionic liquids using COSMO‐SAC model

In this work, we investigated the prediction of solubility (x_d) of drug molecules in single‐ and mixed‐ionic liquid (IL) solutions using the COSMO‐SAC activity coefficient model. In particular, the effect of dissociation of IL on solubility is examined. The prediction accuracy is found to be 91% in x_d (root‐mean‐square deviation in ln x_d is 0.65) for a total of 442 data points with solubility ranging from 0.93 to 2.84 × 10^?4 (mole fraction) and temperature ranging from 248.9 to 488.3 K. The solubility of drug is found not sensitive to the treatment of dissociation of IL in the calculations. The method is used to determine the solubility of paracetamol in 2624 single IL made from combination of 82 cations and 32 anions. The solubility of paracetamol can vary by 4 orders of magnitude in different ILs, indicating that this is a powerful method for screening for solvents with desired solubility power. The solubility of a drug in binary IL solution can be significantly higher or lower than those in pure IL components. For the 3,441,376 binary IL mixtures, about 8% of the mixtures exhibit higher solubility for paracetamol and 6% exhibit lower solubility. Our results indicate that mixing ILs can be a viable approach for tuning drug solubility. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3096–3104, 2017     

Electrical,mechanical, structural,and thermal behaviors of polymeric gel electrolyte membranes of poly(vinylidene fluoride‐co‐hexafluoropropylene) with the ionic liquid 1‐butyl‐3‐methylimidazolium tetrafluoroborate plus lithium tetrafluoroborate

Polymeric gel electrolyte membranes based on the polymer poly(vinylidene fluoride‐co‐hexafluoropropylene) [P(VdF–HFP)] with different weight percentages of the ionic liquid (IL) 1‐butyl‐3‐methylimidazolium tetrafluoroborate plus 0.3M lithium tetrafluoroborate (LiBF₄) salt were prepared and characterized by scanning electron microscopy, X‐ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared (FTIR) spectroscopy, complex impedance spectroscopy, pulse echo techniques, and Vickers hardness (H) testing. After the incorporation of the IL plus the salt solution in the P(VdF–HFP) polymer, the melting temperature, glass‐transition temperature (T_g), degree of crystallinity, thermal stability, elastic modulus (E), and hardness (H) gradually decreased with increasing content of the IL–salt solution as a result of complexation between the P(VdF–HFP) and IL. This was confirmed by FTIR spectroscopy. A part of the IL and LiBF₄ were found to remain uncomplexed as well. The ionic conductivity (σ) of the polymeric gel membranes was found to increase with increasing concentration of the IL–salt solution. The temperature‐dependent σs of these polymeric gel membranes followed an Arrhenius‐type thermally activated behavior. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41456.     

Chemical modification of chloromethylated polystyrene with pyridylazo‐β‐naphthol

Chloromethylated polystyrene was chemically modified through alkylation of pyridylazo‐β‐naphthol (PAN) in the presence of a phase‐transfer catalyst. The chemical modification was achieved through O‐alkylation as well as N‐alkylation of PAN, leading to formation of polymer‐supported quaternary ammonium salt in the latter case. Both types of a polymer‐supported PAN moiety were detected by FTIR spectroscopic analysis. The complexation behavior of the polymer‐supported PAN as an ion‐exchanger toward some metal ions was studied. Thermogravimetric and differential thermogravimetric analyses data were used to study the kinetics of the thermal decomposition process of the ion‐exchanger. Some thermodynamic parameters for the ion‐exchanger were calculated by applying the rate theory of the first‐order reaction. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 3044–3048, 2000     

Effect of added ionic liquids on the solubility and viscosity of dilute ionomer solutions in tetrahydrofuran

Solubility and viscosity behaviors of three ionomers with comparable ion contents of ca 6 mol%, i.e. poly(methyl methacrylate) sodium salt, sulfonated polystyrene calcium salt and sulfonated polystyrene sodium salt, were studied in a low‐polarity solvent, i.e. tetrahydrofuran (THF), containing an ionic liquid (IL). Upon addition to THF, the IL disrupts ionic aggregates to form a homogeneous solution and increases viscosity, because the IL disrupts intramolecular ionic aggregates at dilute concentration. Among eight ILs of the imidazolium family studied, 1‐ethyl‐3‐methylimidazolium trifluoromethanesulfonate performs best. The effectiveness of ILs for disrupting ionic aggregates is discussed in terms of the structures of ionomers and ILs. © 2017 Society of Chemical Industry     

Computer‐aided design of ionic liquids as solvents for extractive desulfurization

Although ionic liquids (ILs) have been widely explored as solvents for extractive desulfurization (EDS) of fuel oils, systematic studying of the optimal design of ILs for this process is still scarce. The UNIFAC‐IL model is extended first to describe the EDS system based on exhaustive experimental data. Then, based on the obtained UNIFAC‐IL model and group contribution models for predicting the melting point and viscosity of ILs, a mixed‐integer nonlinear programming (MINLP) problem is formulated for the purpose of computer‐aided ionic liquid design (CAILD). The MINLP problem is solved to optimize the liquid‐liquid extraction performance of ILs in a given multicomponent model EDS system, under consideration of constraints regarding the IL structure, thermodynamic and physical properties. The top five IL candidates preidentified from CAILD are further evaluated by means of process simulation using ASPEN Plus. Thereby, [C₅MPy][C(CN)₃] is identified as the most suitable solvent for EDS. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1013–1025, 2018     

Exploration on polypropylene carbonate polymer for gel polymer electrolyte preparation and dye‐sensitized solar cell application

Gel polymer electrolytes (GPEs) with incorporation of polypropylene carbonate (PPC) polymer and different weight percentages of sodium iodide (NaI) salt are prepared. Ethylene carbonate and propylene carbonate are used as plasticizers. The maximum ionic conductivity of 2.01 mS cm^?1 is achieved at room temperature. Temperature‐dependent ionic conductivity study is performed. The GPEs are studied for structural properties using Fourier transform infrared (FTIR). The FTIR analysis confirms that complexation between PPC and NaI has occurred. By using GPEs, dye‐sensitized solar cells (DSSC) are fabricated under the one Sun light intensity. The highest energy conversion efficiency of 6.38% is achieved with incorporation of 60 wt % of NaI. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45091.     

Kinetic Monte Carlo simulation for homogeneous nucleation of metal nanoparticles during vapor phase synthesis

We present a free‐energy driven kinetic Monte Carlo model to simulate homogeneous nucleation of metal nanoparticles (NPs) from vapor phase. The model accounts for monomer‐cluster condensations, cluster–cluster collisions, and cluster evaporations simultaneously. Specifically, we investigate the homogeneous nucleation of Al NPs starting with different initial background temperatures. Our results indicate good agreement with earlier phenomenological studies using the Gibbs# free energy formulation from Classical Nucleation Theory (CNT). Furthermore, nucleation rates for various clusters are calculated through direct cluster observations. The steady‐state nucleation rate estimated using two different approaches namely, the Yasuoka‐Matsumoto (YM) and mean first passage time (MFPT) methods indicate excellent agreement with each other. Finally, our simulation results depict the expected increase in the entropy of mixing as clusters approach the nucleation barrier, followed by its subsequent drastic loss after the critical cluster formation resulting from first‐order phase transitions. © 2017 American Institute of Chemical Engineers AIChE J, 63: 18–28, 2018     

Resolved‐particle fixed bed CFD with microkinetics for ethylene oxidation

The incorporation of an ethylene oxidation microkinetic model into fixed‐bed CFD is studied using two different approaches. The first is based on mapping pre‐calculated reaction rates into quadratic splines under steady‐state conditions without any further assumptions or simplification of the elementary steps. The second approach uses conventional reaction engineering assumptions such as quasi‐equilibrium (QE) and hybrid steady state (HSS) to reduce the kinetic model and generate lumped rate expressions. Both kinetic models are implemented for illustrative resolved‐particle CFD simulations in a randomly packed bed of 120 spheres. It is shown that the QE and HSS assumptions are not valid throughout the range of reacting conditions. Comparison of the temperature and species profiles for these two approaches shows that the strong gradients inside the bed cause significant deviations in the reduced model compared to using the splines method with full microkinetics, which produces accurate results without increasing the computational time. © 2016 American Institute of Chemical Engineers AIChE J, 63: 87–94, 2017     

Gas drying with ionic liquids

The gas drying technology with ionic liquids (ILs) was systematically studied ranging from the molecular level to industrial scale. The COSMO‐RS model was first used to screen the suitable IL and provide theoretical insights at the molecular level. Toward CO₂ gas dehydration, we measured the CO₂ solubility in single [EMIM][Tf₂N] and in the [EMIM][Tf₂N] + H₂O mixture, as well as the vapor‐liquid equilibrium (VLE) of [EMIM][Tf₂N] + H₂O system, to justify the applicability of UNIFAC model. Based on the thermodynamic study, the rigorous equilibrium (EQ) stage mathematical model was established for process simulation. The gas drying experiment with IL was also performed and the water content in gas product can be reduced to 375 ppm. It was confirmed that a less flow rate of absorbent, a higher CO₂ recovery ratio and a much lower energy consumption can be achieved with IL than with the conventional triethylene glycol (TEG). © 2017 American Institute of Chemical Engineers AIChE J, 64: 606–619, 2018     

Preparation and antimicrobial activity of sulfopropyl chitosan in an ionic liquid aqueous solution

To improve the solubility and antibacterial activity of chitosan and expand its applications, we synthesized sulfopropyl chitosan (SP‐CS) with various degrees of substitution (DSs) under mild and green reaction conditions in the aqueous solution of an ionic liquid by a green process. The chemical structures of the polymers were verified by Fourier transform infrared spectroscopy and ¹H‐NMR, and the thermal stability was studied by thermogravimetric analysis. After modification, the water solubility of chitosan was improved significantly, and SP‐CS showed excellent solubility in water at neutral pH. The antibacterial activities of the SP‐CSs with various DSs were systematically studied for the first time by the Oxford cup method and optical density method. The results suggest that the antimicrobial properties of SP‐CS were enhanced by the introduction of sulfopropyl and increased with increasing DS. The application of chitosan could be expanded, and SP‐CS has the potential to be used as a water‐soluble antimicrobial. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44989.     

Polycarbonate/1‐(2‐hydroxyethyl)‐2,3‐dimethylimidazolium chloride composite membranes and short‐range chain mobility analysis

In this investigation, the incorporation of imidazolium salt, 1‐(2‐hydroxehtyl)‐2,3‐dimethylimidazolium chloride [hydemmim][Cl] within bisphenol A polycarbonate (PC) matrix and the subsequent formation of membranes via casting were studied. Characterizations that aimed to establish structure‐property correlations by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical thermal analysis, and water vapor transport (WVT) were performed. The results indicated that the presence of ionic liquid (IL) within the PC matrix significantly alter the local and macromolecular structure. The thermal stability is increased for all levels of incorporation. The plasticizing and antiplasticizing effects were observed due to the influence of the proportions of IL incorporated and of the cation's substituent chain of this IL. Distinct mechanisms of WVT were also observed in the presence of IL. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45117.     

A study on the curing kinetics of epoxy molding compounds with various latent catalysts using differential scanning calorimetry

We performed kinetic analysis in an epoxy curing system with differential scanning calorimetry (DSC) using a dynamic approach to investigate the reaction behavior of epoxy molding compounds (EMCs) according to three types of catalysts with varying latencies: triphenyl phosphine (TPP), triphenylphosphine‐1,4‐benzoquinone (TPP‐BQ), and tetraphenylphosphonium tetraphenylborate (TPP‐TPB). In dynamic approach, the well‐known model free kinetic (MFK) method was applied first to find out the variation of activation energy by the extent of conversion. By applying the MFK method, it was found that activation energy as a function of reaction conversion was nearly constant for TPP‐BQ and TPP‐TPB, but significantly reduced for TPP. By the dependence of activation energy, the model fitting method with single step reaction could be applied for TPP‐BQ and TPP‐TPB, and the nth order model was in good agreement with the MFK results. By contrast, in TPP, the reaction curve derived from MFK did not match with plot from nth order model. Isothermal curing experiments were also carried out to determine whether the assumption on kinetic predictions for the three catalysts was correct or not. As a result, TPP‐TPB and TPP‐BQ followed both MFK and nth order model. Nevertheless, TPP was more likely to follow MFK rather than nth order model. In addition, TPP‐TPB showed definitely lower conversion rate and degree of conversion compared with TPP, TPP‐BQ as expected from the catalyst structure and basicity. This study indicates the curing kinetic reaction of EMC depends on the latency of catalysts, and the MFK method can be used to describe the kinetics of curing reaction more accurately. These results help engineers in relevant fields to improve the reliability of EMCs by understanding the curing kinetic reaction of EMC with various latent catalysts. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45252.     

Modeling of CO2 equilibrium solubility in a novel 1‐Diethylamino‐2‐Propanol Solvent

In this work, the equilibrium solubility of CO₂ in a 1‐diethylamino‐2‐propanol (1DEA2P) solution was determined as a function of 1DEA2P concentration (over the range of 1–2 M), temperature (in the range of 298–333 K), and CO₂ partial pressure (in the range of 8–101 kPa). These experimental results were used to fit the present correlation for K₂ (Kent‐Eisenberg model, Austgen model, and Li‐Shen model). It was found that all of the models could represent the CO₂ equilibrium solubility in 1DEA2P solution with ADDs for Kent‐Eisenberg model, Austgen model, and Li‐Shen model of 6.3, 7.3, and 12.2%, respectively. A new K₂ correlation model, the Liu‐Helei model, was also developed to predict the CO₂ equilibrium solubility in 1DEA2P solution with an excellent ADD of 3.4%. In addition, the heat of absorption of CO₂ in 1DEA2P solution estimated by using the Gibbs‐Helmholtz equation was found to be ?45.7 ± 3.7 kJ/mol. Information and guidelines about effectively using data for screened solvents is also provided based on the three absorption parameters: CO₂ equilibrium solubility, second order reaction constant (k₂), and CO₂ absorption heat. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4465–4475, 2017     

Efficient capture of carbon dioxide with novel mass‐transfer intensification device using ionic liquids

A novel mass‐transfer intensified approach for CO₂ capture with ionic liquids (ILs) using rotating packed bed (RPB) reactor was presented. This new approach combined the advantages of RPB as a high mass‐transfer intensification device for viscous system and IL as a novel, environmentally benign CO₂ capture media with high thermal stability and extremely low volatility. Amino‐functionalized IL (2‐hydroxyethyl)‐trimethyl‐ammonium (S)?2‐pyrrolidinecarboxylic acid salt ([Choline][Pro]) was synthesized to perform experimental examination of CO₂ capture by chemical absorption. In RPB, it took only 0.2 s to reach 0.2 mol CO₂/mol IL at 293 K, indicating that RPB was kinetically favorable to absorption of CO₂ in IL because of its efficient mass‐transfer intensification. The effects of operation parameters on CO₂ removal efficiency and IL absorbent capacity were studied. In addition, a model based on penetration theory was proposed to explore the mechanism of gas–liquid mass transfer of ILs system in RPB. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2957–2965, 2013     

Influence of ionic liquid composition on the stability of polyvinyl chloride‐based ionic liquid inclusion membranes in aqueous solution

Membrane technology has gained significant importance with the incorporation of ionic liquids into their structure. This work shows the influence of ionic liquid composition on the stability of PVC‐based polymer ionic liquid inclusion membranes (PILIMs) in aqueous solution. Among the ILs investigated, those membranes which contain between 20 and 30%_w/w of the least soluble, [OMIM⁺][PF₆^?] and [OMIM⁺][Ntf₂^?], exhibit losses of IL lower than 10%. For both ILs, the amount immobilized was maximum for the membranes with 30%_w/w of IL (0.0838 and 0.0832 g, respectively). On the contrary, the ionic liquid loss increases as its solubility in water increase, reaching 99.52% when PILIMs are prepared with 70%_w/w of [OMIM⁺][BF₄^?]. The results demonstrate that the stability of PILIMs depends on the solubility of the IL in the surrounding phase and the specific interaction between the IL and the polymeric support for PVC‐to‐IL ratios higher than 30%_w/w. © 2016 American Institute of Chemical Engineers AIChE J, 63: 770–780, 2017     

Influence of electrolytes of Li salts,EMIMBF4, and mixed phases on electrochemical and physical properties of Nafion membrane

Electrolyte‐soaked Nafion is commonly used as an ionic polymer in soft actuators. Here, a multitechnique investigation was applied to correlate the electrochemical behavior of Nafion membranes with their microstructures and nanostructures as a function of electrolyte type. The influence of electrolytes of Li salts with different counteranions on the Nafion membranes was investigated in terms of hydration level, structure (using X‐ray diffraction and small angle X‐ray scattering), stress–strain characteristics, and electrochemical behavior (by cyclic voltammetery and electrochemical impedance spectroscopy). The effects of using ionic liquid (IL), as the electrolyte, addition of different supporting solvent and the addition of Li⁺ ions to water‐free IL‐soaked membranes on the structural and electrochemical properties of Nafion were examined. The nano‐ and microstructure of the Nafion changed considerably as a function of the identity of the electrolyte solution. The electrochemical behavior of the IL‐soaked samples was compared with that of the water‐soaked Li⁺‐exchanged Nafion. It was seen that the ionic conductivity of the Nafion membranes was reduced significantly when water was replaced by pure IL. Using the supporting solvents increased the conductivity of IL‐soaked Nafion membranes dramatically. The presence of a small amount of Li⁺ ions together with the IL ions caused a significant decrease in charge transfer resistance and increases in double layer capacitance and in ionic conductivity over that of the water‐free sample and also over water‐soaked Li⁺‐exchanged Nafion. These findings can be useful to improve the knowledge on Nafion's microstructure and also to improve the electromechanical behavior of Nafion‐based ionic polymer–metal composites actuators. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45239.     

Evidence for anchoring and partial occlusion of metallic clusters on the pore walls of MCM-41 and effect on the stability of the metallic clusters

In order to explain the high stability of the Co- and Ni-MCM-41 catalysts, the hypotheses of anchoring of small metallic clusters to cations in and partial occlusion of the metallic clusters by amorphous silica are proposed. Carbon monoxide chemisorption on model catalysts and Co-MCM-41 has given direct proof of the metal anchoring effect on the stability of metal cluster dispersion. The partial occlusion of metallic clusters, which may lead to physical confinement (inhibited migration) or chemical confinement (inhibited reaction), was monitored by CO in situ FTIR and CO methanation along with a kinetic study, which confirmed that the metallic clusters on the pore surface result in the stabilization of the catalysts against deactivation. A fine tuning of these physicochemical phenomena in the transition metal incorporated MCM-41 will make possible the design of stable catalytic systems for reactions requiring metallic active sites under severe reaction conditions.     

Preparation,optimization, and characterization of simvastatin nanoparticles by electrospraying: An artificial neural networks study

The purpose of this study was to determine major factors impacting the size of simvastatin (SIM)‐loaded poly(d , l ‐lactic‐co‐glycolide) (PLGA) nanoparticles (NPs) that was prepared using electrospraying. Three variables including concentration of polymer and salt as well as solvent flow rate were used as input variables. Size of NPs was considered as output variable. For the first time, our findings using a systematic and experimental approach, showed the importance of salt concentration as the dominant factor determining the size with a sharp and reverse effect. Optimum formulation (i.e., flow rate 0.08 mL h^?1, polymer concentration 0.7 w/v %, and salt concentration 0.8 mM) was then evaluated for aqueous solubility, encapsulation efficiency, particle size, in vitro drug release pattern and cytotoxicity. A very appreciable encapsulation efficiency (90.3%) as well as sustained release profile, considerable enhancement in aqueous solubility (～5.8 fold) and high IC₅₀ (>600 µM of SIM‐loaded PLGA NPs) indicated PLGA as a promising nanocarrier for SIM. The optimum formulation had particle size, zeta potential value, polydispersity index (PDI) and drug loading of 166 nm, +3 mV, 0.62 and 9%, respectively. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43602.     

A novel polymer composite with a small optical band gap: New approaches for photonics and optoelectronics

In this article, a novel approach is presented for the preparation of small band‐gap polymer composites. The intensity of the surface plasmon resonance (SPR) peak increased from 0.64 to 3.2 for the chitosan–silver nitrate sample containing 1 wt % titanium dioxide (TiO₂). In the cases of 3 and 5 wt % added TiO₂ particles, the SPR peak disappeared. A wide shift of the absorption coefficient from 4.36 to 0.93 eV was observed. The smallest optical band gap of about 0.98 eV was achieved for the sample containing 3 wt % TiO₂ filler. The wide shift in the optical band gap was interpreted on the bases of the formation of metal‐induced gap states between the metallic silver particles and the TiO₂ structure. A novel approach was achieved that was an alternative method to Tauc's semi‐empirical model for band‐gap estimation. The optical dielectric loss parameter for the band‐gap study was easily calculated and analyzed, whereas it unfolded a deep knowledge from the physics point of view. The established quantum mechanical expression revealed a strong relationship between the energy band gap and the optical dielectric loss parameter. The scanning electron microscopy results show the leakage of white aggregated silver particles and distinguishable intense peaks of metallic silver particles between 3 and 3.3 keV appearing in the energy‐dispersive X‐ray spectrum. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44847.