Salting‐out of acetone, 1‐butanol,and ethanol from dilute aqueous solutions

The salting‐out phase equilibria for acetone, 1‐butanol, and ethanol (ABE) from dilute aqueous solutions using potassium carbonate (K₂CO₃) and dipotassium hydrogen phosphate trihydrate (K₂HPO₄?3H₂O) as outstanding salting‐out agents were investigated. Increasing the salt concentration strengthened the salting‐out effects and improved the distribution coefficients of all three solvents (ABE) significantly. Temperature had a slight effect on the phase equilibria. The K₂HPO₄ solution (69 wt %) showed a stronger salting‐out effect than the K₂CO₃ solution (56 wt %) on recovering ABE from dilute aqueous solutions. Dilute aqueous solutions containing more solvents increased the recoveries of acetone and 1‐butanol, while the results showed a negligible effect on the solubility of ABE. The solubility of ABE was also correlated well with the molar number of salt per gram of water in the aqueous phase. A new equation demonstrated this satisfactorily. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3470–3478, 2015     

MBr(M=Na,K)在离子液体[Bmim]Br水溶液中的溶解度

为探索溴化1-丁基-3-甲基咪唑([Bmim]Br)离子液体对无机溴化物MBr(M=Na,K)在水中溶解度的影响,采用等温溶解平衡法在常压下测定了298.15~328.15 K范围内MBr在[Bmim]Br(1)+H₂O(2)溶液中的溶解度,考察了离子液体含量对溶解度的影响。实验结果表明,[Bmim]Br的加入会显著降低MBr(M=Na,K)在水中的溶解度,离子液体[Bmim]Br对KBr的盐析作用比对NaBr的盐析作用大。不同温度下的溶解度数据可用Pitzer混合电解质溶液模型进行关联,得到了混合离子相互作用参数以及MBr在混合溶剂中的平均活度因子和溶剂的渗透系数。模型计算的溶解度与实验结果吻合良好,平均活度因子和溶剂的渗透系数均随离子液体含量的增加而增加。     

Generalized LIQUAC model for the single‐ and mixed‐solvent strong electrolyte systems

A generalized strong electrolyte LIQUAC model is presented to describe the vapor–liquid equilibria, osmotic coefficients, mean ion activity coefficients, and solid–liquid equilibria for the single‐ and mixed‐solvent electrolyte systems over the entire concentration range from infinite dilution to saturated solutions. An appropriate reference state for the ions was first applied to test the capability of the model in simultaneously describing the mean ion activity coefficients and the solubility of a salt in a binary solvent mixture. The influence of salt on the vapor–liquid equilibrium behavior is predicted with the new correlated parameters. The generalized activity coefficient formulations are presented through the investigation of thermodynamic properties and phase phenomena in the single‐ and mixed‐solvent electrolyte systems. This work is a continuous study for the LIQUAC activity coefficient model. A reliable representation of the single‐ and mixed‐solvent salt solutions is obtained. © 2010 American Institute of Chemical Engineers AIChE J, 2011     

Measuring and modeling alcohol/salt systems

Liquid densities, osmotic coefficients, and mean ionic activity coefficients (MIAC) at 25 °C of single-salt alcohol (methanol and ethanol) solutions containing univalent ions were measured and modeled with the ePC-SAFT equation of state. In accordance with our previous work [Held, C., Cameretti, L.F., Sadowski, G., Fluid Phase Equlilib. 270 (2008) 87–96], only two solvent-specific ion parameters were adjusted to experimental solution densities and osmotic coefficients: the solvated ion diameter and the dispersion-energy parameter. ePC-SAFT was able to reproduce experimental data of the respective alcohol/salt systems with reasonable accuracy. Based on the solvent-specific ion-parameter sets, it is possible to predict densities and MIACs in ternary and quaternary water/alcohol(s)/salt solutions by introducing appropriate mixing rules that do not contain any additional fitting parameters.     

Modeling of aqueous electrolyte solutions based on perturbed-chain statistical associating fluid theory incorporated with primitive mean spherical approximation

In this work an equation of state applicable to the system containing electrolytes has been developed by coupling the perturbed chain statistical associating fluid theory (PC-SAFT) with the primitive mean spherical approximation. The resulting electrolyte equation of state is characterized by 4 ion parameters for each of the cation and anion contained in aqueous solutions, and 4 ion specific parameters for each of six cations (Li⁺, Na⁺, K⁺, Rb⁺, Mg²⁺ and Ca²⁺) and six anions (Cl⁻, Br⁻, I⁻, HCO₃⁻, NO₃⁻ and SO₄²⁻) were estimated, based upon the individual ion approach, from the fitting of experimental densities and mean ionic activity coefficients of 26 aqueous single-salt solutions at 298.15 K and 1 bar. The present equation of state with the estimated individual ion parameters has been found to satisfactorily describe not only the densities and mean ionic activity coefficients, but also osmotic coefficients and water activities of single-salt aqueous solutions. Furthermore, the present model was extended to two-salt aqueous solutions, and it has been found that thermodynamic properties such as mentioned above, of two-salt solutions, can be well predicted with the present model, without any additional adjustable parameters.     

Kinetics of release of particulate solutes incorporated in cellulosic polymer matrices as a function of solute solubility and polymer swellability. III. Moderately soluble solute

Our previous investigation of the kinetics of release of simple particulate solutes of very low (CaSO₄ or SrSO₄) or very high aqueous solubility (NaCl) from cellulose acetate (CA) matrices (in the form of thin films) in contact with an eluant aqueous phase is here extended to a solute of moderate solubility (CsNO₃). Simultaneous measurement of the concurrent variation of the water content of the matrix revealed the occurrence of osmotically induced excess water uptake by the loaded matrix for all loads studied, as previously observed in the case of NaCl at lower loads. The resulting enhancement of solute release rate was considerable but much less than that generated by NaCl. Sorption and diffusion of the solute in the corresponding particle‐depleted polymer matrices was also investigated. The results exhibited a pattern qualitatively very similar to that of NaCl but greatly attenuated in quantitative terms. These observations are in keeping with the relatively weak osmotic power of CsNO₃. A mechanism for osmotically induced enhancement of solute release rate previously formulated (in terms of the growth of zones of enhanced hydration of the polymer matrix surrounding the embedded solute particles) to account for NaCl release behavior observed at lower particle loads was found to be applicable here at all loads examined. The degree of hydration of the (neat) CA polymer matrix was also varied (by varying the conditions of film preparation or by wet thermal after‐treatment of the as‐prepared films) and its effect on CsNO₃ partition and diffusion coefficients was studied. The results provided the basic information needed for interpretation of the corresponding particle‐depleted film data, in comparison with the previous ones for NaCl. It was thus shown that imbibed water was more homogeneously distributed in NaCl‐depleted, than in CsNO₃‐depleted, films. It was also observed that variation of the degree of polymer hydration affected primarily the rate, and only secondarily the kinetics, of particulate CsNO₃ release. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2028–2039, 2002; DOI 10.1002/app.10499     

ESTIMATING ACTIVITY AND OSMOTIC COEFFICIENTS IN UO2 (NO3)2 - HNO3 - NaNO3 MIXTURES

The Pitzer treatment is employed to estimate activity and osmotic coefficients for these aqueous mixtures from literature data. A convenient formalism is presented for the inclusion of electrically neutral species such as undissociated HNO₃ in the treatment. The water vapor pressure and the solubility of uranyl nitrate hexahydrate in HNO₃ could be fitted reasonably well with parameters derived from solutions of the separate components. Isopiestic data for NaNO₃ - UO₂ (NO₃) ₂ mixtures required one mixture parameter. Stoichiometric activity coefficients and water activities are generated for UO₂ (NO₃)₂ - HNO₃ mixtures from the derived parameters.     

Synthesis and Properties of Alkoxyethyl β‐d‐Xylopyranoside

In order to improve the water solubility of sugar‐based surfactants, alkyl β‐d‐ xylopyranosides, novel sugar‐based surfactants, 1,2‐trans alkoxyethyl β‐d‐ xylopyranosides, with alkyl chain length n = 6–12 were stereoselectively prepared by the trichloroacetimidate method. Their properties including hydrophilic–lipophilic balance (HLB) number, water solubility, surface tension, emulsification, foamability, thermotropic liquid crystal, and hygroscopicity were investigated. The results indicated that their HLB number decreased with increase of alkyl chain, the water solubility improved since the hydrophilic oxyethene (─OCH₂CH₂─) fragment was introduced. The dissolution process was entropy driven at 25–45 °C for alkyl chain length n = 6–10. Octyloxyethyl β‐d‐ xylopyranoside had the best foaming ability. Nonyloxyethyl β‐d‐ xylopyranoside had the best foam stability and the emulsifying ability was better in toluene/water system than in rapeseed oil/water system. The surface tension of in aqueous solution dropped to 27.8 mN m^?1 at the critical micelle concentration, and it also showed the most distinct thermotropic liquid phases with cross pattern texture upon heating and the fan schlieren texture on cooling. Hexyloxyethyl β‐d‐ xylopyranoside possessed the strongest hygroscopicity. Based on the effective improvement of water solubility, the prepared alkoxyethyl β‐d‐ xylopyranosides showed excellent surface activity and are expected to develop their practical application as a class of novel sugar‐based surfactants.     

Alcell® lignin solubility in ethanol–water mixtures

The lignin solubility in aqueous solutions of different ethanol concentrations was studied. The concept of the solubility parameter was applied to account for the effect of ethanol concentration on the lignin solubility. Experimental results showed that the lignin solubility increased strongly as the ethanol concentration increased from 9.5 to 47.5% then, it increased much more slowly until a maximum was reached at an ethanol concentration of about 70%. Further increase in the ethanol concentration resulted in a slight decrease in the lignin solubility. Based on the lignin molecular formula, the solubility parameter (δ-value) of the ALCELL® lignin was 13.7 (cal/cm³)^1/2. The δ-value of aqueous ethanol solutions of increased ethanol concentration was calculated and was found to decrease continuously from 22.31 (cal/cm³)^1/2 for pure water to 12.08 (cal/cm³)^1/2 for pure ethanol. The effect of ethanol concentration on the solubility of the ALCELL lignin was then explained based on the theory that lignin exhibited the maximum solubility when the δ-value of the solvent was close to that of the ALCELL lignin and the H-bonding capacity of the solutions with different ethanol concentrations was similar. © 1995 John Wiley & Sons, Inc.     

Gas–liquid interfacial area and mass transfer coefficient in a co‐current down flow contacting column

The gas–liquid interfacial area and mass transfer coefficient for absorption of oxygen from air into water, aqueous glycerol solutions up to 1.5% (w/w) and fermentation medium containing glucose up to a 3% concentration were determined in a co‐current down flow contacting column (CDCC; 0.05 m i.d. and 0.8 m length). Experimental studies were conducted using various nozzle diameters at different gas and re‐circulation liquid rates. Specific interfacial area (a) is determined from the fractional gas hold‐up (ε_G) and the average bubble diameter (d_b). Once the interfacial area is determined, the volumetric mass transfer coefficient (k_La) is then used to evaluate the film mass transfer coefficient in the CDCC. The effects of operating conditions and liquid properties on the specific interfacial area were investigated. The values of interfacial area in air–aqueous glycerol solutions and fermentation media were found to be lower than those in the air–water system. As far as experimental conditions were concerned, the values of interfacial area obtained from this study were found to be considerably higher than those of the literature values of conventional bubble columns. The penetration theory is used to interpret the film mass transfer coefficient and results match the experimental k_L data reasonably well. Copyright © 2006 Society of Chemical Industry     

单乙醇胺和二乙醇胺甲酸盐离子液体对水、甲醇和乙醇挥发度的影响(英文)

Vapor pressures were measured for six binary systems containing water, ethanol, or methanol with one of the two ionic liquids （ILs） at different component concentrations and temperatures using a quasi-static ebulliometer, with the ILs mono-ethanolammonium formate （[HMEA][HCOO]） and di-ethanolammonium formate （[HDEA][HCOO]）. The vapor pressures of the IL-containing binary systems are well correlated using the NRTL model with an overall average absolute relative deviation （AARD） of 0.0062. The effect of ILs on the vapor pressure depression of sol-vents at 0.050 mole fraction of IL is that [HDEA][HCOO]〉[HMEA][HCOO], and the vapor pressure lowering de-gree follows the order of water〉methanol〉ethanol. Further, the activity coefficients of three solvents （viz. water, ethanol, and methanol） for the binary systems{solvent （1）＋IL （2）}predicted based on the fitted NRTL parameters at T=333.15 K indicate that the two ILs generate a negative deviation from Raoult’s law for water and methanol and a positive deviation for ethanol to a varying degree, change the relative volatility of a solvent. [HMEA][HCOO] may be a promising entrainer to efficiently separate ethanol aqueous solutions by special rectification.     

Excess enthalpy data for the ternary system methane—ethylene—carbon dioxide by flow calorimetry

Excess enthalpy data for the ternary system methane – ethylene – carbon dioxide was obtained utilizing an isothermal flow calorimeter. The measurements were made at three temperatures: 293.15, 305.15 and 313.15 K and pressures of 1.114, 1.520 and 3.445 MPa (11, 15 and 34 atm). The determination of excess enthalpies for the binary systems methane—ethylene, ethylene—carbon dioxide and methane—carbon dioxide has been reported in three preceeding articles, respectively: Gagné et al., 1985; Ba et al., 1979 and Barry et al., 1982a. The binary interaction coefficients k_ij obtained for these systems have been utilized as initial values for the optimization procedure leading to the k_ij for the ternary system. For the case of the ternary system studied in this investigation, two types of binary interaction coefficients k_ij have been determined from experimental data: k_ij independent of temperature and pressure and k_ij adjusted as function of temperature and pressure. Experimental data were compared with the predictions from Benedict—Webb—Rubin and Redlich—Kwong equations of state. In both cases, the coefficients k_ij dependent on temperature and pressure led to better prediction of excess enthalpies.     

Impact of osmotic agent on the transport of components using forward osmosis to separate ethanol from aqueous solutions

The separation of low molecular weight organic compounds such as the ethanol from aqueous solutions represents an important area to be investigated and increment the range of applications of forward osmosis. This investigation assesses the effects of using different draw solutes for ethanol separation from dilute aqueous solutions. The influence of glucose, sucrose, sodium chloride, and magnesium chloride was evaluated in terms of total permeate, reverse solute and ethanol fluxes. Inorganic solutes promoted higher total permeate and ethanol fluxes than the organic solutes (2.5 and 1.5 times higher in average, respectively) for the same molar concentration, while presenting only 1.1 times higher reverse solute fluxes. Despite the lower ethanol flux promoted by the organic draw solutes, these osmotic agents promoted higher concentration of ethanol in the total permeate flux, suggesting that they can also be alternatives for specific processes. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4499–4507, 2017     

Predicting NRTL parameters for binary hydrocarbon mixtures for calculating liquid—vapor equilibriums of multicomponent systems

The parameters of the NRTL method are fitted, for binary hydrocarbon systems, on the activity coefficients calculated by the Flory—Hildebrand method with binary coefficients l_ij of deviation from the geometric mean assumption for cohesive energy densities (NRTL-FH parameters). For aromatic saturated hydrocarbon mixtures, the l_ij coefficients are correlated to the products δ_iδ_j of solubility parameters. The predicted NRTL-FH parameters are used in calculations of bubble pressures and vapor phase compositions of binary hydrocarbon mixtures and of ternary mixtures with at least two hydrocarbon components. The NRTH-FH method is compared to the Chao—Seader and the zero l_ij-Flory-Hildebrand methods for many hydrocarbon systems, and gives the best results among these three predictive methods. The introduction of the non zero l_ij coefficients is an improvement in regards to the case with zero l_ij coefficients, particularly for the cycloparaffin-aromatic hydrocarbon mixtures. The NRTL-FH method is also compared to the NRTL-EXP method (parameters fitted on experimental data), and results obtained with the two methods are satisfactory for binary and ternary mixtures.     

含盐聚电解质溶液的分子热力学模型

A molecular thermodynamic model of polyelectrolyte developed previously was extended to polyelectrolyte solutions with added salts.Thermodynamic properties,such as activity coefficients of polyelectrolytes or added salts and osmotic coefficients of solvent, of a number of aqueous mixtures of polyelectrolytes and salts are analyzed with the proposed model.Successful correlation is obtained in the range of moderate or higher polyion concentration.For the same sample,thermodynamic properties of polyelectrolytes with and without simple electrolytes can be predicted mutually using parameters from regression data.     

Zur physikalisch‐chemischen Charakterisierung von 5‐Amino‐1‐aryl‐1H‐tetrazolen: Kinetik der Verteilung im Zweiphasensystem Octan‐1‐ol/Wasser

The kinetics of distribution of 27 5‐amino‐1‐aryl‐1H‐tetrazoles in the two‐phase system octan‐1‐ol/water were investigated UV/Vis‐spectrophotometrically at various temperatures. Studies on relationships between the obtained firstorder rate constants (logk₁, logk₂) and the hydrophobicity of the tetrazoles described by their partition coefficients (logP) show a nearly constant rate of transport from the aqueous to the organic phase (k₁) above logP = 1,5 while the reverse rate (k₂) strongly depends on hydrophobicity. In the whole logP range investigated the kinetic behaviour can be described by bilinear relationships between logk and logP corresponding to known kinetic models for distribution processes in two‐layer systems.     

Characterization of 2‐(2‐methoxyethoxy)ethanol‐substituted phosphazene polymers using pervaporation,solubility parameters,and sorption studies

Two linear phosphazene polymers were synthesized with differing amounts of hydrophilic 2‐(2‐methoxyethoxy)ethanol (MEE) and hydrophobic 4‐methoxyphenol (MEOP) substituted on the backbone. These high polymers were cast into membranes and their permeability to water, methanol, ethanol, and 2‐propanol was evaluated as a function of temperature. An additional polymer with a low content of MEE was studied for water permeation and was characterized by trace flux. At higher levels of MEE on the backbone, fluxes of all solvents increased. Solubility also was found to increase with increasing MEE content for all solvents except water. Unexpectedly, water was found to be less soluble in the higher MEE polymer, although higher membrane fluxes were observed. Diffusion coefficients showed the following trend: methanol ? 2‐propanol > ethanol ? water. Finally, the affinity of solvents and polymers was discussed in terms of Hansen solubility parameters. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 939–945, 2005     

Vapour–liquid equilibrium of CO2 in aqueous solutions of N‐methyl‐2‐ethanolamine

The equilibrium solubility of CO₂ into aqueous solution of sterically hindered N‐methyl‐2‐ethanolamine or methyl amino ethanol (MAE) was investigated in the temperature range of 303.1–323.1 K and total CO₂ pressure in the range of 1–350 kPa. The N‐methyl‐2‐ethanolamine aqueous solutions studied were 0.968, 1.574, 2.240 and 3.125 mol kg^?1 of solvent. © 2011 Canadian Society for Chemical Engineering     

Prediction of Equilibrium Partitioning of Nonpolar Organic Solutes in Water‐ Surfactant Systems by UNIFAC and COSMO‐RS Models

In the present study the potential of two thermodynamic‐based models (the group‐contribution UNIFAC model and the a priori predictive COSMO‐RS model) to predict solute partitioning in aqueous surfactant solutions is evaluated. In order to take into account the small size of micelles, the UNIFAC model was extended by the interfacial contribution based on the Gibbs‐Thompson equation. The applicability of the approach was successfully proved for the partitioning of nonpolar solutes (toluene, p‐xylene) in aqueous solutions of nonionic surfactants. The original COSMO‐RS model underestimates the concentration of the solute in the aqueous phase in the case of micellar systems since it does not account for the small size of micelles. At the same time, this model gives quantitative results for the octanol/water partition coefficients of both solutes under study leading to the conclusion that the affinity of both solutes to a certain solvent is well described. Thus, extending the COSMO‐RS by the interfacial term seems to be promising.     

Water Activities and Osmotic Coefficients of Aqueous Solutions of Five Alkylaminium Sulfates and Their Mixtures with H2SO4 at 25oC

Alkylaminium sulfates are frequently detected in ambient aerosols, and are believed to be important in the nucleation of new particles in the atmosphere, despite the comparatively low gas phase concentrations of amines. In this study, water activities and osmotic coefficients have been measured, using a chilled mirror dew point technique, of aqueous mixtures of sulfuric acid and the following alkylaminium sulfates: methylaminium, ethylaminium, dimethylaminium, diethylaminium, and trimethylaminium sulf-ate. The samples were prepared by mixing solutions of the five corresponding amines and aqueous sulfuric acid and determining the exact aminium to sulfate molar ratios by ion chromatography. The results were correlated using an extended Zdanovskii–Stokes–Robinson equation to enable concentration/water activity rela-tionships to be calculated over the entire composition range from pure aqueous sulfuric acid to pure aqueous aminium sulfate. Water activities and osmotic coefficients for aminium:sulfate ratios of 1:1 (the bisulfate salts) and lower showed great similarity with ammonium bisulfate, but osmotic coefficients for the 2:1 ratio (the aminium sulfates) were significantly larger (and water activities lower) than for ammonium sulfate. These results differ from those obtained in Clegg et al.'s (2013) study. The relative values of the osmotic coefficients, in concentrated solutions, suggest that the numbers of methyl or ethyl groups in the aminium ion may have a stronger lowering effect on water activity than the alkyl chain length.

Copyright 2015 American Association for Aerosol Research