Solid-liquid Equilibrium Data Research Articles

Diastereomeric salt crystallization synthesis for chiral resolution of ibuprofen

AbstractConceptual design and experimental investigations are integrated for synthesizing diastereomeric salt crystallization processes for chiral resolution. An anti‐inflammatory drug ibuprofen and a common resolving agent N‐methyl‐D‐glucamine were chosen to illustrate this integrative approach. Bench data were generated in a systematic manner. Solvent screening was conducted first to identify the right solvent to precipitate the diastereomeric salts. Solid–liquid equilibrium data of the diastereomeric salt system were then measured. Seeding was used to facilitate the precipitation of the desired component. All of this information was used to generate flow sheet alternatives to recover the desired diastereomeric salts. © 2007 American Institute of Chemical Engineers AIChE J 2007

Measurement and Correlation for Solubility of ( S)-(+)-2,2-Dimethyl-cyclopropane Carbox Amide in Different Solvents

( S)-(+)-2,2-dimethylcyclopropane carbox amide is a key intermediate of Cilastatin, an inhibitor of dehydropeptidase-I. Its corresponding solid-liquid equilibrium data will provide essential support for industrial design and further theoretical studies. The solubilities of ( S)-(+)-2,2-dimethylcyclopropane carbox amide in toluene, dichloromethane, trichloromethane, ethyl acetate, ethanol and pure water at different temperature were measured using the synthetic method by a laser monitoring observation technique. The solubility data were correlated with the modified Apelblat equation. The calculated values were good in agreement with the experimental values.

Coupling activity coefficient models, Henry constant equations, and equations of state to calculate vapor–liquid and solid–liquid equilibrium data

The sour gas sequestration problems require the knowledge of the gas solubility in brines. Phase equilibrium involving very diluted species as dissolved gas molecules in water or in electrolytic solutions are commonly modeled by a heterogeneous approach needing an activity model coupled to a Henry's constant for the aqueous phase and an equation of state (EOS) for the vapor phase. Because models contain assumptions and parameters fitted in specific conditions, it is necessary to ensure that the coupling of these different elements is consistent. In this work, after having separately tested three activity models (the Pitzer model, a Bromley model parameterized by Jager and the extended Uniquac model) on a freezing-point water depression calculation in the presence of thermodynamic inhibitors, different couplings with Henry's constant (Dhima, Duan, and Shock and Helgeson equations) and with two EOS (Soave–Redlich–Kong and Peng–Robinson) are carried out. The comparison of these different associations highlights the role of interaction parameters, Henry's constant and EOS on the CH 4 and CO 2 solubility calculation in electrolytic solutions. It is shown that if it is naturally preferable to use the same conditions as those used for the fitting of the activity model parameters to get the best reliability in predictions, a good accuracy can also be obtained by coupling rigorously different approaches.

Adsorption of egg yolk plasma cholesterol using a hydrophobic adsorbent

Data on hydrophobic adsorption equilibrium of egg yolk plasma cholesterol were obtained using Streamline Phenyl® resin in batch suspension at room temperature (25 °C). Influence of two types of salt (NaCl and Na2SO4) at four concentrations (0.0; 0.05; 0.1, and 0.2 M) on equilibrium was analyzed. Increased salt concentration reduced the amount of cholesterol adsorbed in the resin. Two isotherm models (Langmuir and a modified model based on type S-isotherm) were used to represent solid-liquid equilibrium data. The latter led to a better fit of the equilibrium data, with a 99.8% value of RSSE. A 70% reduction of the cholesterol content in the plasma was obtained with a 1:4 plasma:water dilution ratio.

Paraffin crystallization in synthetic mixtures: Predictive local composition models revisited

Aiming at identify the shortcomings of the available models for the description of the solid phase non-ideality, new solid liquid equilibrium data for multicomponent hydrocarbon systems was measured. The Predictive UNIQUAC and Wilson models for the description of the solid phase non-ideality, previously proposed, are here compared against this new data. The weaknesses displayed by these models on the predictive description of the measured phase behavior helps to identify their limitations and this is expected to lead to a new improved model for the solid phase non-ideality. Following this approach a new UNIQUAC based model is proposed that seems to overcome the limitations of the models identified on this work.

Using Aniline as an Adductive Agent for Separation of an m-Chlorophenol + p-Chlorophenol Mixture

The experimental solid-liquid equilibrium data of ternary mixtures consisting of m-chlorophenol, p-chlorophenol, and aniline, and those of the constituent binary pairs were determined using the solid-disappearance method. The isomer mixture consisting of m-chlorophenol + p-chlorophenol exhibits one eutectic point at 276.0 K with 0.52 mole percentage of m-chlorophenol. The binary mixture of aniline + m-chlorophenol exhibits two eutectic points, 278.7 K and 257.2 K, at aniline compositions of 0.22 and 0.85, respectively , and one congruent point at aniline mole fraction of 0.5. And another pair of aniline + p-chlorophenol also exhibits two eutectic points, 286.2 K and 259.2 K, at aniline compositions of 0.28 and 0.87, respectively , and one congruent point at aniline mole fraction of 0.5. Ternary mixtures with designated mole ratios of m-chlorophenol to p-chlorophenol exhibit two eutectic points and one congruent point also at aniline mole fraction of 0.5. All the experimental SLE data were fitted by the empirical equation of Ott and Goates with an optimization technique. The results showed the equation of Ott and Goates represents the experimental data fairly well with the average absolute deviation of temperature less than 1.0 K. All the parameters were given and can be used for interpolation purpose. Based on the experimental data and the ternary phase diagram showing all the eutectic and congruent points, three conceptual feasible processes using aniline as an adductive agent for separating m-chlorophenol from p-chlorophenol are proposed.

Solid–liquid phase equilibria of binary indole mixtures with some aromatic compounds using a solid–liquid–vapor equation-of-state

The separation of useful chemicals, such as indole from coal tar, is an important subject of research in the field of fossil energy, renewable energy, and utilization of byproducts and waste materials. High-pressure crystallization is one of the proposed separation methods. To understand the process requires detailed knowledge of solid–liquid phase behaviors. Solid–liquid phase equilibrium data of various binary mixtures of indole have been reported in the literature. In the present report, we analyze some of the experimental data with our unified solid–liquid–vapor equation-of-state to see whether our model can be useful for the calculation of solid–liquid equilibria in these organic systems. Good correlations of the data and predictions of phase behavior, at very high pressures, are demonstrated.

SOLID-LIQUID EQUILIBRIA FOR THE BINARY MIXTURES 1,4-XYLENE+ETHYLBENZENE AND 1,4-XYLENE+TOLUENE

Solid-liquid equilibrium (SLE) data for the binary mixtures 1,4–xylene + ethylbenzene and 1,4-xylene + toluene were measured using differential scanning calorimetry (DSC) in the temperature range from 133.15 to 293.15 K.

Study of the solid–liquid equilibria in the Ga–In–As–Sb system at 973 and 1073 K

The present research interprets various binary, ternary and quaternary interactions using a generalised liquid solution model for the Ga–In–As–Sb alloys at 973 and 1073K. The excess free energy equations for the liquid and solid solutions are used in conjunction with the solid–liquid equilibrium data in order to express equilibrium properties including the evaluation of the quaternary interactions in the alloys. The use of the derived values of the equation enables one to interpret the phase equilibria and thermodynamic properties of the system.

Solid–liquid equilibria of closely boiling compounds of 4-methoxyphenol and catechol with p-cresol

Solid–liquid equilibrium data were measured for binary and ternary mixtures composed of p-cresol with closely boiling compounds: 4-methoxyphenol and catechol. Experimental results revealed that all the binaries behave as simple eutectic systems. The eutectic loci were also observed for the mixtures of 4-methoxyphenol+catechol+p-cresol, from which a ternary solid–liquid equilibrium phase diagram was obtained. The Wilson and the NRTL models were employed to correlate the equilibrium data of binary systems. The NRTL model with the determined binary parameters predicted the solid-disappearance temperatures of the ternary system to an overall average absolute deviation of 0.55%.

Solid–liquid equilibria for systems containing 1-butyl-3-methylimidazolium chloride

The solubility of 1-butyl-3-methylimidazolium chloride [C 4mim][Cl] in alcohols {ethanol, 1-butanol, 1-hexanol, 1-octanol, 1-decanol, 1-dodecanol, 2-butanol, 2-methyl-2-propanol ( tert-butanol)} has been measured by a dynamic method from 270 K to the melting point of the ionic liquid or to the boiling point of the solvent. The melting point, enthalpy of fusion, and the temperature of the glass phase transition were determined by differential scanning calorimetry. The solubility data were correlated by means of the Wilson, UNIQUAC ASM and modified NRTL1 equations utilizing parameters derived from the solid–liquid equilibrium data. The root-mean-square deviations of the solubility temperatures for all calculated data were higher than 0.9 K and depended on the particular equation used.

Cycloalkane solubility determination through differential scanning calorimetry

Solid–liquid equilibrium data for hydrocarbons are necessary in modeling of paraffin deposition in crude oil production. A multi-cell differential scanning calorimeter (DSC) has been used to measure solubility of pentadecylcyclohexane and nonadecyclohexane in pentane, octane and toluene. The equilibrium solubility temperature of solutions of known composition was determined by a simple linear extrapolation of the characteristic solubility temperature to an infinitely slow heating rate. The thermodynamic properties necessary for solubility prediction (enthalpy of fusion and melting point temperature) were obtained for the pure solutes.

Removal and Recovery of Phenol From Phenolic Wastewater Via Ion Exchange and Polymeric Resins

ABSTRACT Different polymeric adsorbents, Amberlites XAD-4, XAD-7, IRA-94, and Ionac AFP-329, as well as activated carbon, were chosen for study based on their reported effectiveness in the removal of phenol from wastewater. These adsorbents were tested for efficiency, equilibrium time, and overall capacity. Apart from activated carbon, AFP-329 proved to have the highest removal efficiency, the shortest equilibrium time, and the highest capacity for phenol. Based on this solid-liquid equilibrium data, isotherms were constructed for each adsorbent. The data for all adsorbents used can be fitted by a Freundlich-type equation. The desorptive properties of the adsorbents were investigated using temperature as a driving force. At elevated temperatures of 50, 60, and 70°C, XAD-4 showed an excellent and almost complete desorption capability. It also required the smallest amount of energy. Activated carbon showed the least desorption capability at these moderate temperatures. It appears that macroreticular polymer...

Fundamental Study of the Phase Behavior of Wash Oil with Diphenyl Ether

Diphenyl ether is a potential modifier to decrease the melting temperatures of wash oils and thus to prevent solid formation from the recycled stream in an aromatics removal process. Fundamental study of the solid-liquid equilibria for the related mixtures was undertaken in the present work. Solid-liquid equilibrium data were measured for binary and multicomponent mixtures containing model compounds of wash oils (acenaphthene, dibenzofuran, fluorene, and phenanthrene) and diphenyl ether. The results showed that adding diphenyl ether substantially lowered the melting points of wash oils. A series of batch distillations with various initial feeds were also made to investigate further the property changes of the wash oils before and after recovery. It was found that diphenyl ether could still remain in the residues (the recovered wash oils) and changes in the melting temperature of oils were minor. These low-melting wash oils can be recycled directly to benzol scrubber for reuse. The binary solid-liquid equilibrium data were correlated with the NRTL model. The solution model with the determined parameters is capable of predicting the solid-liquid equilibrium temperatures of the pseudo-binary (multicomponent) system to an AAD of 0.3%.

Evaluation of Heterodimerization Constant from Solid-Liquid and Vapor-Liquid Equilibrium Data

Activity coefficients obtained from the solid-liquid equilibrium data were used to fit the isobaric vapor-liquid equilibrium data to evaluate the vapor-phase equilibrium constant of heterodimerization of the system propanoic acid-trifluoroethanoic acid. The found hetero-dimerization constant is several times higher than that estimated on the basis of the "double-geometric-mean" rule and its temperature dependence has the form ln KAB = 7 196.7/T - 26.80.

Aqueous solubility of m-phthalic acid, o-phthalic acid and p-phthalic acid from 298 to 483 K

In an equilibrium cell, the aqueous solubility of m-phthalic acid (m-PTA), o-phthalic acid (o-PTA), p-phthalic acid (p-PTA) was determined from 298 to 483 K using a method in which an excess amount of solubilizate was equilibrated with the aqueous solution and the saturated liquid compositions were analyzed by titration. The logarithm of the solubility plotted against the inverse temperature shows good linearity. The Soave–Redlich–Kwong equation of state (SRK EOS) was applied to correlate the solid–liquid equilibrium data. The interaction parameter of the SRK EOS has been correlated to a function of reduced temperature. The relative deviations of the calculated solubility to the experimental data are 0.24%, 1.18% and 0.38% for m-PTA, o-PTA and p-PTA respectively.

Chemistry and characterization of binary organic eutectics and molecular complexes. The urea-m-nitrobenzoic acid system

Abstract Solid-liquid equilibrium data on a binary organic system involving urea and m -nitrobenzoic acid show the formation of a 1:1 molecular complex surrounded by two eutectics. Growth data studied by measuring the growth velocity ( v ) at different undercoolings ( ΔT ) by following the rate of movement of the interface suggest that they obey the Hillig-Turnbull equation, v = u ( ΔT ) n , where u and n are constants depending on the nature of the materials involved. From the heat of the fusion values, determined by the D.S.C. method, the heat of mixing, entropy of fusion, roughness parameter, interracial energy, radius of the critical nucleus and the excess thermodynamic functions were calculated. While the X-ray diffraction data show that the eutectics are not a mechanical mixture of the components under investigation, the microstructural investigations give their characteristic features. The spectral studies suggest intermolecular hydrogen bonding between the components forming the molecular complex.

A modified UNIFAC model for the calculation of thermodynamic properties of aqueous and non-aqueous solutions containing sugars

A UNIFAC based model is proposed to describe experimental thermodynamic properties of aqueous and non-aqueous solutions containing common sugars, e.g., d -glucose, d -fructose and sucrose. A new group ‘OHring’ is introduced due to proximity effects. New temperature-independent UNIFAC interaction parameters are estimated based on the binary data available for both d -glucose and d -fructose and only on the solubility data for sucrose. The UNIFAC model used in this work is able to accurately predict the water activity, boiling temperature and freezing point of aqueous sucrose solutions. However, the predictions of the osmotic coefficients for the sucrose/water system present relative deviations up to 9%. Satisfactory predictions of vapor-liquid and solid-liquid equilibrium data for ternary and quaternary mixtures of d-fructose, sucrose and water components are also obtained. This approach uses the symmetric convention for all the components, i.e. the pure fused sugar at solution pressure and temperature is its reference state. Therefore, it allows to carry out in a straightforward way, calculations of solid-liquid equilibria of sugars in mixed solvents. It is shown that the new UNIFAC model is able to qualitatively predict the ternary solubility data of d -glucose d -xylose, d -mannose and sucrose in mixed solvent mixtures of ethanol/water, methanol/water and ethanol/methanol. A comparison with a modified UNIQUAC—essentially correlative model—and a UNIFAC—correlative and predictive model—approaches available in the literature is also given: the performance of the model proposed in this work is in general inferior to that of the UNIQUAC model, however it gives always a better agreement with the experimental data when compared with another UNIFAC based model available in the literature.

Thermodynamic properties of sugars in aqueous solutions: correlation and prediction using a modified UNIQUAC model

A modified UNIQUAC model with linear temperature-dependent parameters is proposed to describe the thermodynamics properties (water activity, osmotic coefficient, vapor pressure, boiling temperature, freezing point and solubility data) of three binary systems: D-glucose/water, D-fructose/water and sucrose/water. New UNIQUAC interaction parameters are presented, estimated using the above mentioned binary data, collected from the literature. Good predictions of vapor-liquid and solid-liquid equilibrium data for ternary and quaternary mixtures of D-glucose, D-fructose, sucrose and water components are obtained. This approach uses the symmetric convention for all the components, pure fused sugar at solution pressure and temperature being its reference state. Therefore, it allows straightforward calculations of solid-liquid equilibria of sugars in mixed solvents. This constitutes an important advance over the approach based on the knowledge of the dilution enthalpy data available in the literature.

Solidification behaviour of binary organic monotectic alloys

The solid-liquid equilibrium data on a faceted-nonfaceted system involving diphenyl and succinonitrile show the formation of a eutectic (0.9679 mole fraction of succinonitrile) and a monotectic (0.0742 mole fraction of succinonitrile) with a liquid miscibility gap in the system. From the linear velocity of crystallization data on the pure components, the eutectic and the monotectic, determined by the capillary method at different undercoolings, it can be inferred that they obey the Hillig-Turnbull equation. The microstructural investigations show peculiar characteristic features in the eutectic and the monotectic.