Electrolyte Nonrandom Two-liquid Research Articles

1-Ethyl-3-methylimidazolium Dicyanamide as a Very Efficient Entrainer for the Extractive Distillation of the Acetone + Methanol System

Isobaric vapor–liquid equilibria (VLE) for the ternary system acetone + methanol +1-ethyl-3-methylimidazolium dicyanamide ([emim][DCA]) as well as the two solvent + IL binary systems have been obtained at 100 kPa using a recirculating still. The addition of [emim][DCA] to the solvent mixture produced a salting-out effect greater than that produced by other ionic liquids, showing that this ionic liquid is, until now, the best IL tested as an entrainer for the extractive distillation of the acetone + methanol mixtures, causing the azeotrope to disappear for an ionic liquid mole fraction as low as 0.031, at 100 kPa. This behavior can be explained on the basis of the influence of the IL concentration on the activity coefficient of each solvent in the binary mixtures. The electrolyte nonrandom two-liquid (NRTL) model was used for fitting successfully the experimental data.

Experimental Measurement and Modeling of Aniline Hydrochloride Solubility in Water, Methanol, Ethanol, Propan-1-ol, and Their Mixed Systems

The solubilities of aniline hydrochloride ([HAE]Cl) in different aqueous solutions of methanol, ethanol, propan-1-ol, and their mixed solvent solutions were determined using the dynamic method in the temperature range between 288 K and 328 K. With the purpose of improving AspenPlus's prediction capability, in regards to [HAE]Cl solubilities in the CH(3)OH-C(2)H(5)OH-C(3)H(7)OH-H(2)O system at various temperatures, new interaction energy parameters tau([HAE]+-Cl-),(CH3OH)tau(CH3OH),([HAE]+-Cl-), tau([HAE]+-Cl-),(C2H5OH)tau(C2H5OH),([HAE]+-Cl-), and tau([HAE]+-Cl-),(C3H7OH)tau(C3H7OH,[HAE]+-Cl-) were obtained via regression of the experimental solubility of [HAE]Cl in binary mixed solvent systems with the maximum-likelihood principle. With the newly obtained electrolyte nonrandom two-liquid (NRTL) interaction parameters, a self-consistent model was established for the calculation of [HAE]Cl solubility in the system of CH(3)OH-C(2)H(5)OH-C(3)H(7)OH-H(2)O as a function of temperature and the composition of solvents. The maximum relative deviation between experimental and predicted solubility data is 2.3%, and the average relative deviation is 1.8 %.

Isobaric Vapor–Liquid Equilibria for the Extractive Distillation of Ethanol + Water Mixtures Using 1-Ethyl-3-methylimidazolium Dicyanamide

Isobaric vapor–liquid equilibria (VLE) for the binary systems ethanol + 1-ethyl-3-methylimidazolium dicyanamide ([emim][DCA]) and water + [emim][DCA] as well as the VLE for the ternary system ethanol + water + [emim][DCA] have been obtained at 100 kPa using a recirculating still. The effect of [emim][DCA] on the ethanol + water system has been compared with that produced by another ionic liquid reported in the literature on the basis of the variation of solvent activity coefficients in ionic liquid (IL) + molecular solvent binary systems. From the results, [emim][DCA] appears as one of the best entrainers for the extractive distillation of the ethanol + water mixtures, causing the azeotrope to disappear at 100 kPa for ionic liquid mole fractions as low as 0.019. The experimental data were fitted with the Mock's electrolyte nonrandom two-liquid (NRTL) model, with a good agreement.

Thermodynamic modeling for CO 2 absorption in aqueous MEA solution with electrolyte NRTL model

Accurate modeling of thermodynamic properties of CO 2 absorption in aqueous alkanolamine solutions is essential for simulation and design of such CO 2 capture processes. In this study, we use the Electrolyte Nonrandom Two-liquid activity coefficient model in Aspen Plus to develop a rigorous and thermodynamically consistent representation for the MEA–H 2O–CO 2 system. Vapor–liquid equilibrium (VLE), heat capacity and excess enthalpy data for the binary aqueous amine system (MEA–H 2O) are used to determine the NRTL interaction parameters for the MEA–H 2O binary. VLE, enthalpy of absorption, heat capacity and NMR spectroscopic data for the MEA–H 2O–CO 2 ternary system are used to identify the electrolyte NRTL interaction parameters for the molecule–electrolyte binaries and the previously unavailable standard state properties of the amine ions, MEA protonate and carbamate. The predicted VLE, enthalpy of absorption, heat capacity and speciation for the MEA–H 2O–CO 2 system are compared favorably to experimental data.

Solubility of sodium 4-nitrotoluene-2-sulfonate in (propanol + water) and (ethylene glycol + water) systems

The solubility data of sodium 4-nitrotoluene-2-sulfonate (NTSNa) in aqueous organic solutions (propanol + water) and (ethylene glycol + water) were measured at temperatures ranging from (290 to 351) K using a dynamic method. The mole fraction of water in solvent mixtures ranged from 0 to 0.8. The solubility values are correlated with the electrolyte non-random two-liquid (E-NRTL) model. From the results obtained, the E-NRTL model provides a satisfactory mathematical representation of the experimental results for the (NTSNa + propanol + water) system and an unsatisfactory result for the (NTSNa + ethylene glycol + water) system. Thus, the modified Apelblat model is applied to describe the (NTSNa + ethylene glycol + water) system also. The calculated (solid + liquid) equilibrium temperatures with the modified Apelblat model are in good agreement with the experimental results. The root-mean-square deviations of solubility temperature varied from (0.08 to 0.94) K for two models. The effect of different aqueous organic solutions on the reaction of oxidation 4-nitrotoluene-2-sulfonic acid (NTS) to 4,4′-dinitrostilbene-2,2′-disulfonic acid (DNS) was discussed.

Isobaric Vapor–Liquid Equilibria of 1-Propanol + Water + Trifluoromethanesulfonate-Based Ionic Liquid Ternary Systems at 100 kPa

Isobaric vapor–liquid equilibria (VLE) for the 1-propanol + 1-butyl-3-ethylimidazolium trifluoromethanesulfonate ([beim][triflate]), water + [beim][triflate], 1-propanol + 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate ([bmpyr][triflate]), and water + [bmpyr][triflate] binary systems, as well as the VLE for the 1-propanol + water + [beim][triflate] and 1-propanol + water + [bmpyr][triflate] ternary systems have been obtained at 100 kPa using a recirculating still. The salting-out effect on the 1-propanol produced by the [bmpyr][triflate] was stronger than that produced by the [beim][triflate], although for the IL concentrations used in this study the effect was not enough to break the azeotrope, unlike of that produced by the 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([emim][triflate]). The electrolyte nonrandom two-liquid (NRTL) model was used for fitting successfully the experimental data.

Modeling of Solid–Liquid Equilibrium for the [HAE]Cl–MgCl2–H2O System

The study of the solid-liquid phase equilibrium for the [HAE]Cl-MgCl2-H2O system is of significance for the preparation of anhydrous magnesium chloride using the thermal decomposition of the complex ([HAE]Cl center dot MgCl2 center dot 6H(2)O), which is synthesized by the reaction of aniline hydrochloride ([HAE]Cl) and bischofite (MgCl2 center dot 6H(2)O). In this study, a rigorous and thermodynamically consistent representation for the [HAE]Cl-MgCl2-H2O system was developed on the basis of the electrolyte nonrandom two-liquid (ENRTL) activity coefficient model embedded in Aspen Plus. The solubility of [HAE]Cl in water and magnesium chloride solutions over the temperature range from 277 to 370 K was measured by use of the dynamic method. With the equilibrium constant of [HAE]Cl obtained using experimental solubility of [HAE]Cl in water and the phase equilibrium equation, the new ENRTL parameters were obtained by regressing the solubility data for the two binary systems [HAE]Cl-H2O and MgCl2-H2O and the one ternary system [HAE]Cl-MgCl2-H2O at MgCl2 concentrations of 0.51 and 2.17 mol.kg(-1). These obtained parameters could accurately predict the solubility for the ternary [HAE]Cl-MgCl2-H2O system at MgCl2 concentrations of 1.05, 1.56, 2.72, 3.21, 3.87, 4.32, and 5.05 mol.kg(-1). The values at multiple saturated points at 298.15 and 323.15 K were accurately predicted with help of the newly developed model. The behavior of the ternary [HAE]Cl-MgCl2-H2O system at the two temperatures are successfully visualized with lucidity on an equilateral triangle. All of these will provide a thermodynamic basis for the preparation of the [HAE]Cl center dot MgCl2 center dot 6H(2)O complex.

Solubility of carbon dioxide in aqueous solution of 2-amino-2-methyl-1-propanol and piperazine

In this work, new experimental results of the vapour–liquid equilibrium (VLE) of CO 2 in aqueous 2-amino-2-methyl-1-propanol (AMP) and piperazine (PZ) have been presented in the temperature range of 298–328 K and PZ concentration range of 2–8 mass%, keeping the total amine concentration in the solution at 30 mass%. The partial pressures of CO 2 were in the range of 0.1–1450 kPa. A thermodynamic model was developed to correlate and predict the VLE of CO 2 in aqueous AMP + PZ. The electrolyte nonrandom two liquid (ENRTL) theory has been used to develop the VLE model for the quaternary system (CO 2 + AMP + PZ + H 2O) to describe the equilibrium behaviour of the solution. The experimental data from this work and data available in the literature were used to regress the ENRTL interaction parameters. The model predictions are in good agreement with the experimental data of CO 2 solubility in aqueous blends of this work as well as those reported in the literature. The current model can also predict speciation, heat of absorption, pH of the CO 2 loaded solution, and amine volatility.

Influence of Some Ionic Liquids Containing the Trifluoromethanesulfonate Anion on the Vapor–Liquid Equilibria of the Acetone + Methanol System

Isobaric vapor–liquid equilibria (VLE) for the binary systems acetone + 1-butyl-3-ethylimidazolium trifluoromethanesulfonate ([beim][triflate]), methanol + [beim][triflate], acetone + 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate ([bmpyr][triflate]), and methanol + [bmpyr][triflate] as well as the VLE for the acetone + methanol + [beim][triflate] and acetone + methanol + [bmpyr][triflate] ternary systems have been obtained at 100 kPa using a recirculating still. The addition of both ionic liquids to the solvent mixtures produced an important salting-out effect, and the azeotrope tended to disappear for small amounts of ionic liquid. The experimental binary data sets were independently fitted with the electrolyte nonrandom two-liquid (NRTL) model, and the parameters of the Mock's model were estimated for each binary system. These parameters were used to predict the ternary VLE, which agreed very well with the experimental ones.

Investigation of sodium 4-nitrotoluene-2-sulfonate solubility in aqueous organic solutions

The solubility of sodium 4-nitrotoluene-2-sulfonate (NTSNa) in binary solvent mixtures (methanol + water), (ethanol + water), and (2-methoxyethanol + water) was investigated over the temperature range from (288 to 344) K. The mole fraction of water in solvent mixtures ranged from 0 to 0.8. The solubility data are described by the electrolyte non-random two-liquid (E-NRTL) model. The E-NRTL binary interaction parameters are expressed as a function of temperature, and were obtained from the experimental data. The root-mean-square deviations of solubility temperature varied from (0.20 to 1.35) K.

(Vapour + liquid) equilibria (VLE) of CO 2 in aqueous solutions of 2-amino-2-methyl-1-propanol: New data and modelling using eNRTL-equation

This work presents new experimental results for carbon dioxide (CO 2) solubility in aqueous 2-amino-2-methyl-1-propanol (AMP) over the temperature range of (298 to 328) K and CO 2 partial pressure of about (0.4 to 1500) kPa. The concentrations of the aqueous AMP lie within the range of (2.2 to 4.9) mol · dm −3. A thermodynamic model based on electrolyte non-random two-liquid (eNRTL) theory has been developed to correlate and predict the (vapour + liquid) equilibrium (VLE) of CO 2 in aqueous AMP. The model predictions have been in good agreement with the experimental data of CO 2 solubility in aqueous blends of this work as well as those reported in the literature. The current model can also predict speciation, heat of absorption, enthalpy of CO 2 loaded aqueous AMP, pH of the loaded solution, and AMP volatility.

Absorption of carbon dioxide in piperazine activated concentrated aqueous 2-amino-2-methyl-1-propanol solvent

In this work new experimental data on the rate of absorption of CO 2 into piperazine (PZ) activated concentrated aqueous solutions of 2-amino-2-methyl-1-propanol (AMP) over the temperature range 303–323 K are presented. The absorption experiments have been carried out in a wetted wall contactor over CO 2 partial pressure range of 5–15 kPa. PZ is used as a rate activator with a concentration ranging from 2 to 8 wt% keeping the total amine concentration in the solution at 40 wt%. The physical properties such as density and viscosity of concentrated aqueous AMP+PZ, as well as physical solubility of CO 2 in concentrated aqueous AMP+PZ, are also measured. New experimental data on vapor liquid equilibrium (VLE) of CO 2 in these concentrated aqueous solutions of AMP+PZ in the temperature range of 303–323 K have also been presented. The VLE measurements are carried out in an equilibrium cell in CO 2 pressure range of 0.1–140 kPa. A thermodynamic model based on electrolyte non-random two-liquid (eNRTL) theory is used to represent the VLE of CO 2 in aqueous AMP+PZ. Liquid phase speciations are estimated considering the nonideality of concentrated solutions of the amines and the calculated activity coefficients by eNRTL model. The CO 2 absorption in the aqueous amine solutions is described by a combined mass transfer-reaction kinetics model developed according to Higbie's penetration theory. The model predictions have been found to be in good agreement with the experimental results of the rates of absorptions of CO 2 into aqueous AMP+PZ.

Vapour liquid equilibria of carbon dioxide in dilute and concentrated aqueous solutions of piperazine at low to high pressure

This work presents new experimental results for carbon dioxide (CO 2) solubility in aqueous piperazine (PZ) in the temperature range of (298–328) K and CO 2 partial pressure of about (0.1–1500) kPa. The concentrations of the aqueous PZ were in the range of about (0.2–4.5) M. A thermodynamic model based on electrolyte nonrandom two-liquid (ENRTL) theory has been developed to correlate and predict the vapour–liquid equilibrium (VLE) of CO 2 in aqueous PZ. The model predictions have been in good agreement with the experimental data of CO 2 solubility in aqueous blends of this work as well as those reported in the literature. It is observed that, at low temperature (up to 333 K) and low PZ concentration, using regressed ENRTL interaction parameters and Henry's constant of CO 2 in water is sufficient to predict VLE of CO 2 in aqueous PZ. However, at high temperature and high PZ concentration, it is required to adjust Henry's law constant in aqueous solution of PZ for better prediction of CO 2 partial pressure over aqueous PZ solution. The current model can also predict speciation, heat of absorption, pH of the loaded solution, and PZ volatility.

Using 1-Ethyl-3-methylimidazolium Trifluoromethanesulfonate as an Entrainer for the Extractive Distillation of Ethanol + Water Mixtures

Isobaric vapor−liquid equilibria (VLE) for the ethanol + water + [emim][triflate] ternary system have been obtained at 100 kPa using a recirculating still. The ethanol + water binary system was also obtained. Furthermore, data were simulated with the Mock’s electrolyte nonrandom two-liquid (NRTL) model, using the solvent−solvent interaction parameters obtained from VLE data of the ethanol + water system and taking the solvent−ionic liquid (IL) interaction parameters for the other binary systems from previous works. The agreement between experimental and calculated data is very good, showing the predictive capacity of the model. The addition of [emim][triflate] produces the disappearance of the ethanol + water azeotrope when the mole fraction of ionic liquid in the liquid phase is greater than 0.023 at 100 kPa. The effect of [emim][triflate] on the ethanol + water system has been compared with that produced by other ionic liquids reported in the literature.

Bioenergy II: Furfural Destruction Kinetics during Sulphuric Acid-Catalyzed Production from Biomass

The interest for furfural has increased in the last years due to its potential for competing with oil derivatives as platform chemical. In addition, furfural, derived from C5 sugars, can play a key role in the valorization of the hemicellulose contained in biomass when considering the development of a modern biorefinery concept. The development of such new and competitive biorefinery processes must be based on accurate kinetic data for the reactions involving furfural in the conditions used for its production.This work addresses the determination of furfural destruction kinetics in aqueous acidic environment, using sulphuric acid as catalyst, in the temperature range 150 - 200°C, acid concentration range 36.4 - 145.5 mM and furfural initial concentration between 60.4 and 72.5 mM. These studies were carried out using a recently built lab-scale titanium reactor that enables liquid phase reactions in a relatively broad range of conditions.The obtained results show that destruction of furfural follows first-order reaction kinetics within the range of temperature and acid concentration evaluated. Moreover, the proposed kinetic model takes into account the effects of temperature and acid dilution on the ions activity, and thus H3O+, by using the electrolyte Non-Random Two-Liquid (eNRTL) model. By using this approach, the rate constant dependence on temperature could be described by the Arrhenius law and thus the activation energy could be estimated as being 125.1 [kJ/mol] and the pre-exponential factor 3.71•1011[s-1]. Separation of different reaction products was achieved by means of HPLC, these products were not yet completely identified. Contrarily to what is reported in previous works, formic acid formation from furfural under the tested conditions can be regarded as playing a far less pronounced role than suggested before.

Isobaric Vapor−Liquid and Liquid−Liquid Equilibria for Chloroform + Methanol + 1-Ethyl-3-methylimidazolium Trifluoromethanesulfonate at 100 kPa

Isobaric vapor−liquid equilibria for the binary system chloroform + methanol as well as the vapor−liquid equilibria for the chloroform + methanol + [emim][triflate] ternary system have been obtained at 100 kPa using a recirculating still. The ternary ionic liquid (IL) system presents an immiscibility zone at high chloroform composition, which increases with the temperature. Liquid−liquid equilibria for this system have also been determined. The measured ternary vapor−liquid equilibrium data were correlated using the Mock’s electrolyte nonrandom two-liquid (NRTL) model which reproduces reasonably well the experimental values and predicts the total disappearance of the azeotrope when the mole fraction of ionic liquid in the liquid phase is 0.25. The immiscibility does not affect the use of [emim][triflate] as the entrainer for the complete chloroform + methanol separation.

Symmetric Electrolyte Nonrandom Two-Liquid Activity Coefficient Model

The electrolyte nonrandom two-liquid (eNRTL) model is reformulated as a symmetric activity coefficient model with the reference states chosen to be pure liquids for solvents and pure fused salts for electrolytes. These reference states are consistently used in the local interaction term, represented by a reformulated NRTL expression, and the long-range interaction term, represented by an extended symmetric Pitzer−Debye−Huckel expression. Retaining the local electroneutrality and like-ion repulsion hypotheses, the new symmetric electrolyte NRTL model yields simpler activity coefficient expressions for both molecular and ionic species. The utility of the model is demonstrated with vapor−liquid equilibrium, liquid−liquid equilibrium, and solid−liquid equilibria of several mixed solvent electrolyte systems.

Measurement and correlation of the solubility of MnSO 4·H 2O in 2-propanol + water + MgSO 4·7H 2O solutions

Data on the solubility of manganese sulphate monohydrate in water, and in aqueous alcohols is essential for salting-out crystallization studies. The solubilities of the quaternary system MnSO 4·H 2O + MgSO 4·7H 2O + H 2O + (CH 3) 2CHOH were determined in the temperature range 293.2–313.2 K over the 2-propanol mole fraction range of 0.00–0.07. The solubility data were used for modelling with the modified extended electrolyte non-random two-liquid (NRTL) equation. The present extension uses ion-specific parameters instead of the electrolyte-specific NRTL binary interaction parameters. This approach has feasibility for many electrolytes and mixed aqueous solution systems in principle. The model was found to correlate the solubility data satisfactorily.

Vapor−Liquid Equilibrium of Ammonia + Lithium Nitrate + Water and Ammonia + Lithium Nitrate Solutions from (293.15 to 353.15) K

The vapor pressure of ammonia + lithium nitrate + water and ammonia + lithium nitrate mixtures was measured by a static method from (293.15 to 353.15) K in ammonia mass fractions ranging from 0.2 to 0.6. The experimental vapor pressure data were correlated with the temperature and the liquid-phase composition using an analytical polynomial equation. The capability of the electrolyte nonrandom two liquid (E-NRTL) model to predict the vapor−liquid equilibrium (VLE) of the ternary mixture was evaluated by comparing predicted and experimental data of the ammonia + lithium nitrate + water solutions. The binary interaction parameters of ammonia + lithium nitrate needed for the prediction of ternary VLE were determined from binary experimental data.

Measurement and correlation of the solubility of MnSO 4·H 2O in ethanol + water + MgSO 4·7H 2O solutions

Data on the solubility of manganese sulphate monohydrate in water, and in aqueous alcohols is essential for salting-out crystallisation studies. The solubilities of the quaternary system MnSO 4·H 2O + MgSO 4·7H 2O + H 2O + EtOH were determined in the temperature range 293.2–323.2 K over the ethanol mole fraction range of 0.00–0.12. The solubility data were used for modelling with the modified extended electrolyte non-random two-liquid (NRTL) equation. The present extension uses ion-specific parameters instead of the electrolyte-specific NRTL binary interaction parameters. This approach has feasibility for many electrolytes and mixed aqueous solution systems in principle. The model was found to correlate the solubility data satisfactorily.