Universal Quasichemical Research Articles

Deacidification of Amazonian Pracaxi (Pentaclethra macroloba) and Patawa (Oenocarpus bataua) oils: experimental and modeling of liquid–liquid extraction using alcoholic solvents

This paper presents a study about the deacidification of typical Amazonian oils, namely, patawa and pracaxi oils. The liquid–liquid extractions were carried out using three alcoholic solvents: anhydrous ethanol, azeotropic ethanol, and azeotropic isopropanol at 298.15 K and atmospheric pressure. Liquid–liquid equilibrium data for the oils + oleic acid + solvents systems were determined. The azeotropic ethanol was found to be the best extractant for removing free fatty acids (FFAs) since its use provided the highest selectivity values (from 62.98 to more 1.53 × 103), reasonable distribution coefficients (from 1.06 to 1.47), and reduced loss of neutral oil (oil concentrations lower than 1.49 wt% in the alcoholic phases). Moreover, the obtained experimental data were correlated using the nonrandom two-liquid (NRTL) and universal quasi chemical (UNIQUAC) activity coefficient models. The deviations between calculated and experimental values ranged from 0.39 to 1.22 and from 0.28 to 1.10 for the various studied systems using the UNIQUAC and the NRTL models, respectively. Such results indicate the positive perspective of using the liquid–liquid extraction technique for patawa and pracaxi oils refining and the feasibility of using ethanol as an FFA extractant.

Determination and correlation of solubility of 4,4′-difluorobenzophenone in pure and binary mixed solvents and thermodynamic properties of solution

The target of this study was to determine and correlate the solubility of 4,4′-difluorobenzophenone in various solvents from 293.15 K to 333.15 K by gravimetric method at 0.1 MPa, and at the same time got the thermodynamic parameters. In this work, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, ethyl acetate, methyl acetate, acetone, acetonitrile pure solvents and ethanol + n-propanol mixed solvents were selected as the experimental solvents. The results showed that the solubility of 4,4′-difluorobenzophenone in selected solvents increased with increasing temperature within the investigated temperature range. The effect of solvent properties on 4,4′-difluorobenzophenone solubility behaviors was discussed by solvent polarity, hydrogen bonding donor and acceptor propensity, and cohesive energy density. Furthermore, the dissolution behavior was explained using the Hansen solubility parameter (HSP). In pure solvents, the modified Apelblat equation, van't Hoff equation, λh equation, nonrandom two-liquid (NRTL) equation, Wilson equation and universal quasichemical (UNIQUAC) equation were used to correlate the experimental solubility of 4,4′-difluorobenzophenone. While the solubility in ethanol + n-propanol mixed solvents was correlated by the modified Apelblat equation, van't Hoff equation, λh equation, NRTL model, Wilson model, Jouyban-Acree and the modified Jouyban-Acree model. The results indicated that the calculated values of all selected equations were in good agreement with the experimental data. Furthermore, the thermodynamic properties (∆H°sol, ∆S°sol, ∆G°sol, %ξH and %ξTS) were measured by Van't Hoff analysis. In a word, the physicochemical data of 4,4′-difluorobenzophenone obtained in this work will be helpful for the purification, crystallization, recrystallization and designing a new synthetic route of 4,4′-difluorobenzophenone.

Novel ethyl lactate based ATPS for the purification of rutin and quercetin

The application of new aqueous two-phase systems (ATPS) composed by a hydrophilic green solvent, ethyl lactate, and two low environmental impact salts: sodium and potassium citrate have been studied for the recovery of two flavonoids from aqueous solutions. First, to understand the phase formation process of the ATPS, binodal curves and tie-lines and their respective slopes and tie-line lengths were determined at T = 298.15 K and atmospheric pressure. The degree of consistency of the tie-lines was evaluated using Othmer-Tobias and Bancroft equations. Moreover, the influence of the change of the salt cation on the phase behaviour has been assessed. Furthermore, the UNIversal QUAsiChemical (UNIQUAC) thermodynamic model was applied to describe the phase equilibria presented in this work. Furthermore, the partitioning of two flavonoids, rutin and quercetin, in these ATPS {ethyl lactate (1) + citrate salts (2) + water (3)} was measured at T = 298.15 K and atmospheric pressure. Finally, the obtained results were compared with those found in literature.

The separation of isopropyl alcohol from diisopropyl ether system using glycols: Phase equilibrium and rigorous correlation

The liquid-liquid equilibria data for the (diisopropyl ether + isopropyl alcohol + ethylene glycol or 1,3-propanediol ternary) system were measured at 303.2 K and 323.2 K under 101.3 kPa. The tie-line data for both systems are displayed in the phase diagram with typical type-I behaviour. The distribution coefficient and separation factor were calculated according to the measured tie-line data. The calculated results suggest that both the two solvents can separate the diisopropyl ether and isopropyl alcohol mixture. Ethylene glycol possesses much better separation efficiency for low concentration extraction. The non-random two liquids (NRTL) and universal quasi-chemical (UNIQUAC) models were applied to obtain the binary interaction parameters of pure components with all the root-mean-square deviation values less than 1.0%, indicating the deviation of regression process can be acceptable. Based on Gibbs stability criteria, the topological analysis with a graphical user interface confirmed the binary interaction parameters from data regression were well consistent with the experimental tie-line data.

Measurement and modelling of solid-liquid equilibria, density and viscosity of fatty acid methyl or ethyl esters

The solid-liquid equilibria (SLE), densities and viscosities of few selective methyl or ethyl esters, required for the reformulation of biodiesel fuel, have been studied at different temperatures and at atmospheric pressure 0.1 MPa. The SLE, density (ρ) and kinematic viscosity (ν) of ethyl decanoate (1) + methyl laurate (2) or methyl myristate (2) binary systems were measured at different temperatures from 298.15 K to 318.15 K and were further used to derive other thermodynamic properties like excess molar volume (VmE) and deviations in dynamic viscosity (Δη). The experimental SLE data showed single eutectic point and correlated well with common nonrandom two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) equations. The kinematic viscosity (ν) data were best correlated with McAllister equation and deviations in dynamic viscosity (Δη) were described by Singh approach whereas excess molar volume (VmE) data were predicted well with Prigogine–Flory–Patterson (PFP) theory for the composition x1 ≤ 0.5634. The derived thermodynamic properties were also correlated with Redlich-Kister polynomial.

Isobaric vapor–liquid equilibrium and isothermal surface tension for hexane + cyclopentyl methyl ether binary mixture: Experimental determinations and theoretical predictions

This work reports the measurements and the theoretical predictions of the vapor–liquid equilibrium (VLE) at the isobaric conditions of 50, 75, and 94 kPa and over the temperature range from 332 K to 372 K and the surface tensions (ST) at atmospheric pressure (101.3 kPa) and the isothermal condition of 298.15 K in the whole mole fraction range for the hexane + cyclopentyl methyl ether binary mixture. The experimental determinations of VLE are carried out in a dynamic all-glass Guillespie type cell, where both vapor and liquid phases are circulating. The ST measurements are obtained from a maximum differential bubble pressure tensiometer. The theoretical predictions of VLE and ST are carried out by applying the square gradient theory to the Peng–Robinson Stryjek-Vera equation of state, appropriately extended to mixtures with a modified Huron–Vidal mixing rule, where the excess Gibbs energy is obtained from classical models whose parameters are obtained from the VLE data reported here.Experimental results of VLE show that this mixture is zeotropic and exhibits a slight positive deviation from ideal behavior over the experimental range. ST, in turn, exhibits negative deviation from the linear behavior. The measured VLE data of this binary mixture satisfy the Fredenlund's consistency test and are well-correlated by classical activity coefficients models (e.g., the Wohl, nonrandom two-liquid (NRTL), Wilson, and universal quasichemical (UNIQUAC)) for all of the isobaric conditions. According to the results, the NRTL activity coefficients model is the most appropriate model to describe the VLE of this semi-ideal binary mixture. The dependence of surface tensions on mole fraction is satisfactorily smoothed using the Myers-Scott equation.The theoretical approach uses the pure fluids properties and the NRTL activity coefficients model to predict both VLE and ST. According to the results, this full predictive schema is able to reproduce VLE and ST with an absolute average deviation of 1.0% and 1.2%, respectively. Additionally, the square gradient theory describes a surface activity of hexane, which increases with the bulk mole fraction of hexane until it reaches a maximum value at 0.63 mol fraction of hexane. This interfacial behavior enhances the concentration of hexane at the interfacial region over the corresponding bulk phases concentration.

Separation of Acetic Acid from Water Using Organic Solvents: Liquid-Liquid Equilibrium Thermodynamic Investigation

Acetic acid is one of the most important carboxylic acids which is used in many reactions, including the synthesis of acetic esters. Because of industrial and environmental advantages, the separation of acetic acid from dilute aqueous solutions has recently received much attention. In this study we investigated liquid-liquid equilibrium of a ternary system consisted of water+ acetic acid+ organic solvent at various temperatures. In this study, various thermodynamic models (Non-Random Two-Liquid (NRTL) and Universal Quasi-Chemical (UNIQUAC) models) were used to predict the composition of component in aqueous and organic phases. In these models, intermolecular interaction were considered as a binomial function of reverse temperature. The parameters of two models were determined through the optimization of an objective function. Root mean square deviations of the NRTL and UNIQUAC models to predict the composition of the components in the ternary mixture of water+ acetic acid+ organic solvent were 0.0273 and 0.0422, respectively.

Assessment of the SM12, SM8, and SMD Solvation Models for Predicting Limiting Activity Coefficients at 298.15 K

The SMx (x = 12, 8, or D) universal solvent models are implicit solvent models which using electronic structure calculations can compute solvation free energies at 298.15 K. While solvation free energy is an important thermophysical property, within the thermodynamic modeling of phase equilibrium, limiting (or infinite dilution) activity coefficients are preferred since they may be used to parameterize excess Gibbs free energy models to model phase equilibrium. Conveniently, the two quantities are related. Therefore the present study was performed to assess the ability to use the SMx universal solvent models to predict limiting activity coefficients. Two methods of calculating the limiting activity coefficient where compared: (1) the solvation free energy and self-solvation free energy were both predicted and (2) the self-solvation free energy was computed using readily available vapor pressure data. Overall the first method is preferred as it results in a cancellation of errors, specifically for the case in which water is a solute. The SM12 model was compared to both the Universal Quasichemical Functional-group Activity Coefficients (UNIFAC) and modified separation of cohesive energy density (MOSCED) models. MOSCED was the highest performer, yet had the smallest available compound inventory. UNIFAC and SM12 exhibited comparable performance. Therefore further exploration and research should be conducted into the viability of using the SMx models for phase equilibrium calculations.

Isothermal Vapor-Liquid Equilibrium Measurement of Isobutanol + Isooctane/N-Heptane Binary Mixtures at Temperatures Range of 303.15-323.15 K

The addition of alcohol as an oxygenated compound in gasoline blends may increase the vapor pressure of gasoline mixture. As a result, the study of vapor-liquid equilibrium for gasoline component and alcohol is necessary. In this study, the vapor-liquid equilibrium of isobutanol – isooctane/n-heptane blends were obtained experimentally at temperatures in the range 303.15 to 323.15 K using modified simple quasi-static ebulliometer. The apparatus was validated by comparing the vapor pressure of pure isobutanol, isooctane, and n-heptane with the published data and giving average absolute deviation (AAD) between experimental and calculated ones with magnitude less than 1.0%. The addition of isobutanol with the mole fraction range from 0.2 to 0.6 would increase the vapor pressure of the isooctane and n-heptane up to 12% and 14% respectively. The vapor pressure of binary mixtures was correlated with the Wilson, Non-random two-liquid (NRTL), and Universal quasi-chemical (UNIQUAC) equations with AAD 1.6%, 1.5%, and 1.7%, respectively for isobutanol + isooctane system and 1.8%, 1.7%, and 2.0%, respectively for isobutanol + n-heptane system. The systems studied show positive deviation from Raoult’s Law.

Isobaric vapor-liquid equilibrium of methanol + glycerol binary mixture at 31.3 kPa

In this study the binary vapor-liquid equilibrium (VLE) data of methanol + glycerol system were determined experimentally of using modified Glass Otmher - Still. The equilibrium compositions of liquid and vapor phases were analysis using refractometer index type Bausch and Lomb ABBE. The experimental data obtained in this work were thermodynamically consistent based on the area test. The experimental data were correlated well with the Wilson and Non Random Two Liquid (NRTL) and Universal Quasi-Chemical (UNIQUAC) models. The performance of Universal Chemical Functional Group Activity Coefficients (UNIFAC) in predicting VLE of the system studied were evaluated as well.

Thermodynamic Behavior of the Phase Equilibrium of Ethyl Acetate + Ethanol + Water Systems at Atmospheric Pressure: Experiment and Modeling

The fluid phase behavior of liquid–liquid equilibrium (LLE) is an important piece of the separation processes in chemical engineering, mainly for solvent extraction or liquid–liquid extraction. In this work, experimental studies were carried out in the LLE of a ternary system composed of water, ethanol, and ethyl acetate at four different temperatures at atmospheric pressure. A two-step procedure was done for each temperature in the experimental stage. First, the construction of the binodal curve of the ternary system, and second, the determination of the tie-lines (LLE). For the tie-lines, because the configuration of the binodal curve and the refractive index of the liquid phases at equilibrium were known, their compositions were determined. The LLE experimental data were evaluated through the method developed by Marcilla and collaborators. The gamma–gamma approach was used for the modeling, by using the analytical solutions of groups (ASOG), the nonrandom two-liquids (NRTL), and the universal quasichemical (UNIQUAC) models. Results of the thermodynamic modeling were compared with the experimental values, and the deviations of the compositions of the lighter phase were very low for the thermodynamic models used.

Liquid–Liquid Equilibrium Study for the Ternary System of Water + Acetic Acid + 2-Octanol

Excellent extraction ability and easy regeneration of the extractant are highly important for the recovery of acetic acid from water by solvent extraction. In this paper, the extraction capability of octanol isomers and some conventional extractants was investigated. It was found that the extraction capability of 2-octanol was significantly better than that of the traditional extractant isopropyl acetate. The liquid–liquid equilibrium data for the ternary system of water + acetic acid + 2-octanol were measured at different temperatures (293.2, 303.2, and 313.2 K) under 101 kPa. The results showed that the distribution coefficient and selectivity decreased with an increase in acetic acid concentration and the temperature had little impact on the distribution coefficient, suggesting that the extraction could be conducted over a large temperature range. The reliability of the equilibrium data was also verified using the Othmer–Tobias and Hand equations, and the correlation coefficients were all close to 1.0, suggesting that the experimental data was reliable. Furthermore, the NRTL (nonrandom two-liquid) and UNIQUAC (universal quasichemical) models were employed to correlate the experimental data, and the binary interaction parameters of the ternary system were obtained. The results indicated that, for the UNIQUAC model, the root-mean-square deviations between the experimental and simulated data at different temperatures were from 0.63% to 0.94% and those for the NRTL model were all within 0.6%, which indicate that the NRTL model is more suitable for the ternary system of water + acetic acid + 2-octanol.

Experimental and thermodynamic modeling of cefixime trihydrate solubility in an aqueous deep eutectic system

The solubility of drugs and raw materials in solvents and their mixtures has presented an important role in the pharmaceutical industry. To enhance the solubility of poorly soluble drugs in water, we can use Deep Eutectic Solvents (DESs), which consist of a Hydrogen Bond Acceptor (HBA) and Hydrogen Bond Donor (HBD). In this work, for the formation of the present DES, choline chloride (ChCl) and glycolic acid (GA) with a molar ratio of 1:2 were used. Then, we measured the solubility of cefixime trihydrate in pure water, pure DES and their mixtures at the different weight percent of DES in the temperature range of 298.15 to 323.15 K at atmospheric pressure. The results of experimental solubility data showed that the solubility of cefixime trihydrate was enhanced by increasing the weight percent of DES and temperature. The solubility data of cefixime trihydrate was correlated by local composition models of NRTL (nonrandom two-liquid theory) and UNIQUAC (universal quasichemical), and empirical relations of modified Apelblat and λh Buchowski. Moreover, the thermodynamic properties such as enthalpy, entropy and Gibbs energy of dissolution were calculated for the present systems. The results indicated that the solubility of cefixime trihydrate in both mono solvents, i.e. water and DES, and aqueous DES solution was endothermic. Thus, the main contribution of the dissolution process of cefixime trihydrate in the mono solvents and their mixtures was enthalpy.

Synergistic Extraction of Hydroquinone from an Aqueous Solution with a Solvent Mixture of Diisopropyl Ether and n-Pentanol at T = 298.15 K and P = 101.3 kPa: Liquid–Liquid Equilibria and Data Correlation

The synergistic effect for a solvent mixture of diisopropyl ether and n-Pentanol to extract hydroquinone from aqueous solution was investigated. Liquid–liquid equilibrium data of the quaternary (n-Pentanol + diisopropyl ether + water + hydroquinone) system were measured at T = 298.15 K and P = 101.3 kPa, using various compositions of solvent mixture. It can be seen from the slope of the tie lines that with the increase of distribution coefficients of hydroquinone, the size of the immiscible solution region decreased slightly. The extraction efficiency was evaluated by calculating the separation factor and distribution coefficient. Using the universal quasichemical (UNIQUAC) and nonrandom two-liquid (NRTL) models to correlate with experimental data, the corresponding binary interaction parameters were obtained. The RMSD values of UNIQUAC and NRTL models showed that the calculated results were in good agreement with the liquid–liquid equilibrium data.

Liquid–liquid equilibria of the ternary system (cyclopentanol + water + cyclopentyl formate) at (298.2–338.2) K: Measurements and correlation

Cyclopentanol is an important intermediate in a production of many chemical specialties. This paper relates to a development of a new technology of indirect cyclopentene hydration in the presence of formic acid and presents the data of liquid-liquid equilibrium (LLE) for the ternary system of (cyclopentanol + water + cyclopentyl formate) under atmospheric pressure and within a temperature range from 298.2 K to 338.2 K. The experiments were conducted in a temperature-controlled glass cell and the received data were correlated with nonrandom two-liquid (NRTL) and universal quasichemical (UNIQUAC) equations in order to obtain binary coefficients describing LLE of the given system. A consistency of the experimental tie-lines data was validated by the Bachman and Othmer-Tobias equations and the data fitting accuracy was evaluated by the use of the calculated average absolute deviation and the root-mean-square-error values. According to our best knowledge, the LLE of this system have not yet been published elsewhere and the values of binary interaction parameters should be used for the design of the reactor and separation units in the process of indirect cyclopentene hydration.

Experimental Determination and Correlation of Liquid–Liquid Equilibria Data for the Ternary Systems of Water + 1-Butanol + Solvents (Isophorone and Mesityl Oxide) at Different Temperatures

Liquid–liquid equilibria (LLE) data for {water + 1-butanol + isophorone} and {water + 1-butanol + mesityl oxide} ternary systems were investigated systematically at different temperatures under atmospheric pressure. The Othmer–Tobias and Bachman equations were applied to analyze the dependability of the experimental LLE data. Selectivities and distribution coefficients were used to evaluate the extractive efficiency of the extractants. The Non-Random Two Liquid (NRTL) and Universal Quasi-Chemical (UNIQUAC) models were applied to correlate the studied systems and were well represented with all root mean square deviations (RMSD) less than 0.2%. Meanwhile, binary interaction parameters among these compounds were acquired during the correlation process.

Thermodynamic modelling and Hansen solubility parameter of N-hydroxy-5-norbornene-2,3-dicarboximide in twelve pure solvents at various temperatures

Solubility of N-hydroxy-5-norbornene-2,3-dicarboximide (HONB) in methanol, ethanol, n-propanol, isopropanol, 2-methoxyethanol, 2-propoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, acetonitrile, ethyl acetate, acetone at (278.15–323.15) K and 1,4-dioxane at (288.15–323.15) K was determined with a laser monitoring method at pressure of 0.1 MPa. The experimental results indicated that solubility of HONB increased positively with the increase of temperature in selected neat solvents. At 298.15 K, solubility data in studied solvents followed the sequence of 2-methoxyethanol (0.1412) > methanol (0.1108) > 2-ethoxyethanol (0.1007) > 1,4-dioxane (0.0963) > 2-propoxyethanol (0.0718) > 2-butoxyethanol (0.0601) > ethanol (0.0592) > acetone (0.0520) > isopropanol (0.0402) > n-propanol (0.0401) > acetonitrile (0.0298) > ethyl acetate (0.0156). The solubility behaviors of HONB in investigated solvents were analyzed by Hansen solubility parameter (Δδd, Δδp, Δδh, Δδt and Δδ), the consequences showed that solubility order of HONB resulted from the comprehensive function of several solubility parameters. Experimental solubility values were correlated with five thermodynamic models including Nonrandom Two-Liquids (NRTL), Two-Suffix Margules, Universal Quasi-chemical (UNIQUAC), Nonrandom Two-Liquid Segment Activity Coefficient (NRTL-SAC) and Wilson model. Results showed that the smallest average values of average relative deviation (ARD) and root-mean square deviation (104RMSD) were obtained by Wilson model with values of 1.06% and 8.73. Moreover, mixing properties (mixing enthalpy ΔmixH, entropy ΔmixS, Gibbs energy ΔmixG) were evaluated based on measured solubility and equation parameters of Wilson model. The positive values of ΔmixS and negative values of ΔmixG revealed that mixing process of HONB in considered solvents was entropy-driven and spontaneous.

Liquid–Liquid Equilibrium Measurements for the Ternary System of Water/2,3-Butanediol/4-Methyl-2-pentanol at Various Temperatures

Liquid–liquid equilibrium (LLE) of a ternary mixture of water, 2,3-butanediol, and 4-methyl-2-pentanol has been measured at three different temperatures (298.2, 308.2, and 318.2 K) under atmospheric pressure. The experimentally measured solubility and tie-line data for the two-phase system were used to construct a ternary phase diagram at each temperature. With the experimental data, the distribution coefficients and separation factors were also calculated and Othmer–Tobias and Hand plots were used to verify the consistency of the measured data. The universal quasichemical (UNIQUAC) and nonrandom-two liquid (NRTL) models were used for the LLE, and the root-mean-square deviation values between the calculated and experimental data were less than 1.21% by the UNIQUAC model and less than 1.96% by the NRTL model, indicating that both model calculations provide excellent agreement with the experimentally measured LLE data in the present study.

Liquid–Liquid Equilibria for Benzene/Thiophene + Cyclohexane/Hexadecane + Deep Eutectic Solvents: Data and Correlation

The experimental liquid–liquid equilibria (LLE) for several systems containing benzene or thiophene + cyclohexane or hexadecane + choline chloride-based deep eutectic solvents (DESs) including mono-, di-, and triethanolamines and mono-, di-, and triethylene glycols were measured at T = 298.15 to 308.15 K and atmospheric pressure. The distribution coefficients (β) and selectivities (S) were calculated to evaluate the efficiency of the studied solvents for aromatics (benzene or thiophene) extraction from nonaromatic phases. Generally, the selectivity values decrease with increasing of the temperature for our studied DESs. The Othmer–Tobias equation was used to ensure the consistency of the obtained LLE data. The nonrandom two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) models were used to correlate the experimental LLE data. The Hansen solubility parameters confirm the performance of the studied DESs for benzene and thiophene extraction. The measured LLE data in this study shows better performance ...

Flexible heuristic algorithm for automatic molecule fragmentation: application to the UNIFAC group contribution model

A priori calculation of thermophysical properties and predictive thermodynamic models can be very helpful for developing new industrial processes. Group contribution methods link the target property to contributions based on chemical groups or other molecular subunits of a given molecule. However, the fragmentation of the molecule into its subunits is usually done manually impeding the fast testing and development of new group contribution methods based on large databases of molecules. The aim of this work is to develop strategies to overcome the challenges that arise when attempting to fragment molecules automatically while keeping the definition of the groups as simple as possible. Furthermore, these strategies are implemented in two fragmentation algorithms. The first algorithm finds only one solution while the second algorithm finds all possible fragmentations. Both algorithms are tested to fragment a database of 20,000+ molecules for use with the group contribution model Universal Quasichemical Functional Group Activity Coefficients (UNIFAC). Comparison of the results with a reference database shows that both algorithms are capable of successfully fragmenting all the molecules automatically. Furthermore, when applying them on a larger database it is shown, that the newly developed algorithms are capable of fragmenting structures previously thought not possible to fragment.