Solubility of hyperbranched polymer,Boltorn W-3000, in alcohols,ethers and hydrocarbons

(Solid/liquid + liquid) phase diagrams at ambient pressure have been determined for the hyperbranched polymer, Boltorn W3000 with alcohols (methanol, ethanol, 1-propanol, 1-hexanol, 1-decanol), or with ethers (tert-butyl methyl ether, tert-butyl ethyl ether), or with hydrocarbons (n-hexane, n-heptane, benzene, toluene) by a dynamic method from T = 240 K to the boiling temperature of the solvent. (Solid + liquid) phase equilibria with immiscibility in the liquid phase were detected for B-W3000 with the alcohols and aliphatic hydrocarbons. The upper critical solution temperatures, UCSTs, were measured for (B-W3000 + 1-hexanol and 1-decanol) systems. The experimental results of (solid + liquid) phase equilibria have been correlated using NRTL equation.     

Ternary equilibrium data of mixtures consisting of 2-butanol,water, and heavy alcohols at T = 298.2 K

Experimental solubility curves and tie-line data for the (water + 2-butanol + organic solvents) systems were obtained at T = 298.2 K and atmospheric pressure. The organic solvents were four heavy alcohols, i.e. 1-hexanol, 1-heptanol, 1-octanol, and 1-decanol. The consistency of the experimental tie-line data was determined through the Othmer–Tobias and Bachman equations. Distribution coefficients and separation factors were calculated to evaluate the extracting capability of the solvents. The experimental data were correlated using the NRTL (α = 0.2) and UNIQUAC models, and binary interaction parameters were obtained. The average root mean square deviation values between the experimental and calculated data show the capability of these models, in particular NRTL model, in correlation of the phase behavior of the ternary systems.     

Thermophysical properties and phase equilibria study of the binary systems {N-hexylquinolinium bis(trifluoromethylsulfonyl)imide + aromatic hydrocarbons,or an alcohol}

The new quinolinium ionic liquid has been synthesised as a continuation of our work with quinolinium-based ionic liquids (ILs). The work includes specific basic characterisation of synthesized compounds: N-hexylquinolinium bromide, [HQuin][Br] and N-hexylquinolinium bis{(trifluoromethyl)sulfonyl}imide [HQuin][NTf₂] by NMR spectra, elementary analysis and water content. The basic thermal properties of the pure [HQuin][NTf₂] i.e. melting and glass-transition temperatures, the enthalpy of fusion as well as heat capacity have been measured using a differential scanning microcalorimetry technique (DSC) and thermal analysis instrument (TA). Densities and viscosities were determined as a function of temperature. Phase equilibria for the binary systems: {[HQuin][NTf₂]) + aromatic hydrocarbon (benzene, or toluene, or ethylbenzene, or n-propylbenzene), or an alcohol (1-butanol, or 1-hexanol, or 1-octanol, or 1-decanol)} have been determined at ambient pressure. A dynamic method was used over a broad range of mole fractions and temperatures from (270 to 320) K. For all the binary systems with benzene and alkylbenzenes, the eutectic diagrams were observed with immiscibility gap in the liquid phase beginning from (0.13 to 0.28) mole fraction of the IL with very high an upper critical solution temperature (UCST). For mixtures with alcohols, the complete miscibility was observed for 1-butanol and immiscibility with UCST in the liquid phase for the remaining alcohols. The typical dependence was observed, that with increasing chain length of an alcohol the solubility decreases. The well-known NRTL equation was used to correlate experimental (solid + liquid), SLE and (liquid + liquid), LLE phase equilibria data sets. For the systems containing immiscibility gaps, (IL + an alcohol) parameters of the LLE correlation were used to the prediction of SLE.     

Solubility of ethyl-(2-hydroxyethyl)-dimethylammonium bromide in alcohols (C2–C12)

The solubilities of a novel third generation of the precursor of ionic liquids, named ethyl-(2-hydroxyethyl)-dimethylammonium bromide, C₂Br, in alcohols {ethanol, 1-butanol, 1-hexanol, 1-octanol, 1-decanol, 1-dodecanol, 2-butanol, 2-methyl-2-propanol (tert-butyl alcohol)} have been measured by a dynamic method from 240 to 440 K.The solubility of ethyl-(2-hydroxyethyl)-dimethylammonium bromide in primary alcohols decreases with an increase of the molecular weight of the alcohol from C₂ to C₁₂. The differences in solubilities between the primary and secondary alcohols are not significant. The solubility of C₂Br in tert-butyl alcohol is much lower than in 1-butanol and 2-butanol.The data were correlated by means of the UNIQUAC ASM, NRTL1 and NRTL2 equations, utilizing parameters derived from the (solid + liquid) equilibrium (SLE) data. The root-mean-square deviations of the solubility temperatures for all calculated data are from 2.36 to 7.17 K and depend on the particular equation used. In the calculations, the existence of a solid–solid first-order phase transition in pure C₂Br has also been taken into account.     

Thermodynamic properties of the N-butylisoquinolinium bis(trifluoromethylsulfonyl)imide

A new isoquinolinium ionic liquid (IL) has been synthesised as a continuation of our work with quinolinium-based ionic liquids (ILs). The work includes specific basic characterization of synthesized compounds: N-isobutylquinolinium bromide, [BiQuin][Br] and N-isobutylquinolinium bis{(trifluoromethyl)sulfonyl}imide [BiQuin][NTf₂] by NMR spectra, elementary analysis and water content. The basic thermal properties of the pure [BiQuin][NTf₂], i.e. melting and glass-transition temperatures, the enthalpy of fusion as well as heat capacity at glass transition have been measured using a differential scanning microcalorimetry technique (DSC). Densities and viscosities were determined as a function of temperature. The temperature-composition phase diagrams of 8 binary mixtures composed of organic solvent dissolved in the IL: {[BiQuin][NTf₂] + aromatic hydrocarbon (benzene, or toluene, or ethylbenzene, or n-propylbenzene), or an alcohol (1-butanol, or 1-hexanol, or 1-octanol, or 1-decanol)} were measured at ambient pressure. A dynamic method was used over a broad range of mole fraction and temperature from (270 to 320) K. For all the binary systems with benzene and alkylbenzenes, the eutectic diagrams were observed with an immiscibility gap in the liquid phase existing at low mole fraction of the IL with a very high upper critical solution temperature (UCST). For mixtures with alcohols, complete miscibility was observed for 1-butanol and also an immiscibility gap with UCST in the liquid phase for the remaining alcohols. The typical dependence was observed that with increasing chain length of an alcohol, the solubility decreases. The well-known NRTL equation was used to correlate experimental (solid + liquid), SLE and (liquid + liquid), LLE phase equilibrium data sets.     

The partition coefficients of ethylene between vapor and hydrate phase for methane + ethylene + THF + water systems

The vapor-hydrate equilibria were studied experimentally in detail for CH₄ + C₂H₄ + tetrahydrofuran (THF) + water systems in the temperature range of 273.15–282.15 K, pressure range of 2.0–4.5 MPa, the initial gas–liquid volume ratio range of 45–170 standard volumes of gas per volume of liquid and THF concentration range of 4–12 mol%. The results demonstrated that, because of the presence of THF, ethylene was remarkably enriched in vapor phase instead of being enriched in hydrate phase for CH₄ + C₂H₄ + water system. This conclusion is of industrial significance; it implies that it is feasible to enrich ethylene from gas mixture, e.g., various kinds of refinery gases or cracking gases in ethylene plant, by forming hydrate.     

Mineralization of aqueous phenolate solutions: A combination of irradiation treatment and wet oxidation

Wet oxidation (high-temperature, high-pressure oxidation of organic wastes in aqueous solution) and radiation technology were combined in γ-ray and electron beam induced oxidation of 4×10^?4–1×10^?2 mol dm^?3 Na-phenolate solutions in a wide O₂ concentration (1–20 bar pressure) and absorbed dose (0–50 kGy) range. Most experiments were made in stainless steel high pressure autoclave equipped with magnetic stirrer. The rate of oxidation was followed by chemical oxygen demand and total organic carbon content measurements. The rate was similar in γ-ray and pulsed electron beam irradiation and increased with O₂ concentration in the liquid.     

High pressure phase behavior and modeling of CO2–propyl acrylate and CO2–propyl methacrylate systems

High pressure phase behavior are obtained for CO₂–propyl acrylate system at 40, 60, 80, 100 and 120 °C and pressure up to 161 bar and for CO₂–propyl methacrylate systems at 40, 60, 80, 100 and 120 °C and pressure up to 166 bar. The solubility of propyl acrylate and propyl methacrylate for the CO₂–propyl acrylate and CO₂–propyl methacrylate systems increases as the temperature increases at constant pressure. The CO₂–propyl acrylate and CO₂–propyl methacrylate systems have continuous critical mixture curves that exhibit maximums in pressure at temperatures between the critical temperatures of CO₂ and propyl acrylate or propyl methacrylate. The CO₂–propyl acrylate and CO₂–propyl methacrylate systems exhibit type-I phase behavior with a continuous mixture critical curve.The experimental results for CO₂–propyl acrylate and CO₂–propyl methacrylate systems are modeled using both the statistical associating fluid theory (SAFT) and Peng–Robinson equations of state. A good fit of the data are obtained with SAFT using two adjustable parameters for CO₂–propyl acrylate and CO₂–propyl methacrylate systems and Peng–Robinson equation using one and two adjustable parameter for CO₂–propyl acrylate and CO₂–propyl methacrylate system.     

Thermodynamic properties of the N-octylquinolinium bis{(trifluoromethyl)sulfonyl}imide

This work is a continuation of our wide ranging investigation on quinolinium based ionic liquids (ILs). The study includes specific basic characterisation of the synthesized compounds N-octylquinolinium bromide, [OQuin][Br] and N-octylquinolinium bis{(trifluoromethyl)sulfonyl}imide [OQuin][NTf₂] by NMR spectra, elementary analysis and water content. Differential scanning calorimetry (DSC) measurements gave us properties of the pure [OQuin][NTf₂] i.e. melting and glass-transition temperatures, the enthalpy of fusion as well as heat capacity at the glass transition. Densities and viscosities were determined as a function of temperature. The temperature-composition phase diagrams of 10 binary mixtures composed of organic solvent dissolved in the IL: {[OQuin][NTf₂] + aromatic hydrocarbon (benzene, or thiophene, or toluene, or ethylbenzene, or n-propylbenzene), or an alcohol (1-butanol, or 1-hexanol, or 1-octanol, or 1-decanol, or 1-dodecanol)} were measured at ambient pressure. A dynamic method was used over a broad range of mole fractions and temperatures from (250 to 370) K. For mixtures with benzene and alkylbenzenes, the immiscibility gap in the liquid phase in a low mole fraction of the IL was observed with upper critical solution temperature (UCST) higher than the boiling point of the solvent. In the system with thiophene, the immiscibility gap is lower and UCST was measured. For binary mixtures with alcohols, complete miscibility in the liquid phase was observed for 1-butanol and 1-hexanol. In the systems with longer chain alcohols, the immiscibility gap with UCST was noted. Typical behaviour for ILs was observed with an increase of the chain length of an alcohol the solubility decreases. The well-known NRTL equation was used to correlate experimental (solid + liquid), SLE and (liquid + liquid), LLE phase equilibrium data sets.     

Effect of the temperature on the physical properties of pure 1-propyl 3-methylimidazolium bis(trifluoromethylsulfonyl)imide and characterization of its binary mixtures with alcohols

In this paper, physical properties of a high purity sample of the ionic liquid 1-propyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [PMim][NTf₂], and its binary mixtures with methanol, ethanol, 1-propanol, and 2-propanol were measured at atmospheric pressure. The temperature dependence of density, refractive index and speed of sound (293.15 to 343.15) K and dynamic viscosity (298.15 to 343.15) K were studied at atmospheric pressure by conventional techniques for the pure ionic liquid. For its mixtures with alcohols, density, speed of sound, and refractive index were measured at T = 298.15 K over the whole composition range. The thermal expansion coefficient of the [PMim][NTf₂] was calculated from the experimental results using an empirical equation, and values of the excess molar volume, excess refractive index, and excess molar isentropic compressibility for the binary systems at the above mentioned temperature, were calculated and fitted to the Redlich–Kister equation. The heat capacity of the pure ionic liquid at T = 298.15 K was determined using DSC.     

Evidence of an odd–even effect on the thermodynamic parameters of odd fluorotelomer alcohols

A phase transition study, including vapour pressure determinations of odd fluorotelomer alcohols {oFTOH; CF₃(CF₂)_nCH₂OH, with n = 5 to 9}, is reported in order to explore the effect of the successive introduction of –CF₂– groups into the molecule on the thermodynamic properties related to (solid + liquid, solid + gas, and liquid + gas) equilibria. An odd–even effect on the thermodynamic parameters of fusion and sublimation was observed in the homologous series of odd fluorotelomer alcohols indicating an increase of the stability in the crystal packing for the members with an odd number of carbon atoms. The vaporization parameters of o-FTOH were compared with the literature data for their alkane analogues and the results showed a higher volatility of liquid fluorotelomer alcohols than their congeners. The higher molecular conformation restriction of perfluorinated alcohols and/or the higher molar mass seems to contribute to their higher entropy of vaporization which drives the volatility of the 1H,1H-perfluorinated alcohols.     

Impact of configuration and fluorination on the solubility of octyl ester benzoate dimers in CO2

Data are reported on the phase behavior of hydrocarbon and semifluoroinated octyl ester benzoate dimers in CO₂ to temperatures of 100 °C and pressures of 1 600 bar. The experimental data at 75 °C demonstrate that the non-fluorinated head-to-head (H–H) dimer dissolves in CO₂ at ∼400 bar lower pressures than the non-fluorinated tail-to-tail (T–T) dimer. Even though partially fluorinating the octyl tails of the H–H and T–T dimers renders them soluble in CO₂ at pressures near 200 bar, it still takes ∼40 bar more pressure to dissolve the fluorinated T–T dimer as compared to the H–H dimer. The difference in pressures needed to dissolve these dimers is attributed to steric constraints on the coplanarity of the benzene rings imposed by the H–H regiochemistry that do not exist with T–T dimers. Semi-empirical quantum mechanics calculations suggest that the H–H dimer has a twisted, non-coplanar conformation due to the steric effect of the octyl ester groups while the T–T dimer has a less twisted conformation. Steric hindrance in the H–H dimer reduces considerably resonance or conjugation between the π electrons of the aromatic groups which also reduces the dipole moments of the H–H dimers compared to those of the T–T dimers.     

Phase equilibrium study of the binary systems (N-hexyl-3-methylpyridinium tosylate ionic liquid + water,or organic solvent)

The (solid + liquid) phase equilibrium (SLE) and (liquid + liquid) phase equilibrium (LLE) for the binary systems ionic liquid (IL) N-hexyl-3-methylpyridinium tosylate (p-toluenesulfonate), {([HM³Py][TOS] + water, or an alcohol (1-butanol, or 1-hexanol, or 1-octanol, or 1-decanol), or an aromatic hydrocarbon (benzene, toluene, or ethylbenzene, or propylbenzene), or an alkane (n-hexane, n-heptane, n-octane)} have been determined at ambient pressure using a dynamic method. Simple eutectic systems with complete miscibility in the liquid phase were observed for the systems involving water and alcohols. The phase equilibrium diagrams of IL and aromatic or aliphatic hydrocarbons exhibit eutectic systems with immiscibility in the liquid phase with an upper critical solution temperature as for most of the ILs. The correlation of the experimental data has been carried out using the UNIQUAC, Wilson and the non-random two liquid (NRTL) correlation equations. The results reported here have been compared with analogous phase diagrams reported by our group previously for systems containing the tosylate-based ILs.     

A thermodynamic model for calculating nitrogen solubility,gas phase composition and density of the N2–H2O–NaCl system

A thermodynamic model is presented to calculate N₂ solubility in pure water (273–590 K and 1–600 bar) and aqueous NaCl solutions (273–400 K, 1–600 bar and 0–6 mol kg⁻¹) with or close to experimental accuracy. This model is based on a semi-empirical equation used to calculate gas phase composition of the H₂O–N₂ system and a specific particle interaction theory for liquid phase. With the parameters evaluated from N₂–H₂O–NaCl system and using a simple approach, the model is extended to predict the N₂ solubility in seawater accurately. Liquid phase density of N₂–H₂O–NaCl system at phase equilibrium and the homogenization pressure of fluid inclusions containing N₂–H₂O–NaCl can be calculated from this model. A computer code is developed for this model and can be downloaded from the website: www.geochem-model.org/programs.htm.     

The buffering-out effect and phase separation in aqueous solutions of EPPS buffer with 1-propanol, 2-propanol,or 2-methyl-2-propanol at T = 298.15 K

Buffering-out is a new liquid–liquid phase separation phenomenon observed in mixtures containing a buffer as a mass separating agent. The (liquid + liquid) equilibrium (LLE) and (solid + liquid + liquid) equilibrium (SLLE) data were measured for the ternary systems {3-[4-(2-hydroxyethyl)piperazin-1-yl]propanesulfonic acid (EPPS) buffer + 1-propanol, 2-propanol, or 2-methyl-2-propanol + water} at T = 298.15 K under atmospheric pressure. The phase boundary data were fitted to an empirical equation relating to the concentrations of organic solvent and buffer. The effective excluded volume (EEV) values of EPPS were obtained from the phase boundary data. The phase-separation abilities of the investigated aliphatic alcohols were discussed. The reliability of the experimental tie-lines was satisfactorily confirmed by the Othmer–Tobias correlation. The experimental tie-lines data for the ternary systems have been correlated using the NRTL activity coefficient model. The separation of these aliphatic alcohols from their azeotropic aqueous mixtures is of particular interest to industrial process. The addition of the EPPS as an auxiliary agent breaks the (1-propanol + water) and (2-methyl-2-propanol + water) azeotropes. The possibility of using the new phase separation systems in the extraction process is demonstrated by using different dyestuffs.     

Excess molar volumes and viscosities of (1,1,2,2-tetrabromoethane + 1-alkanols) at T = (293.15 and 303.15) K

Density and viscosity measurements for binary mixtures of (1,1,2,2-tetrabromoethane + 1-pentanol, or + 1-hexanol, or + 1-heptanol, or + 1-octanol, or + 1-decanol) at T = (293.15 and 303.15) K, have been conducted at atmospheric pressure. The excess molar volumes V^E, have been calculated from the experimental measurements, and the results were fitted to Redlich–Kister equation. The viscosity data were correlated with the model of Grunberg and Nissan, and McAllister four-body model. The excess molar volumes of (1,1,2,2-tetrabromoethane + 1-pentanol, or + 1-haxanol, or + 1-heptanol, or + 1-octanol) had a sigmoidal shape and the values varied from negative to positive with the increase in the molar fraction of 1,1,2,2-tetrabromoethane. The remaining binary mixture of (1,1,2,2-tetrabromoethane + 1-decanol) was positive over the entire composition range. The effects of the 1-alkanol chain length as well as the temperature on the excess molar volume have been studied. The results have been qualitatively used to explain the molecular interaction between the components of these mixtures.     

(Solid + liquid) equilibria predictions of ionic liquid containing systems using COSMO-RS

(Solid + liquid) equilibria (SLE) prediction are an important phase equilibria property for ionic liquid (IL) mixtures especially when the IL exists as a solid. In this work, the SLE for the binary systems of (IL + thiophene) consisting of the ILs: n-butyl-4-methylpyridinium tosylate [BM₄Py][TOS], n-butyl-3-methylpyridinium tosylate [BM₃Py][TOS], n-hexyl-3-methylpyridinium tosylate [HM₃Py][TOS], and 1,4-dimethylpyridinium tosylate [M_1,4Py][TOS] are predicted using the quantum chemical based COSMO-RS (COnductor like Screening MOdel for Real Solvents) model. Initially, benchmarking studies are performed on binary mixtures which are known beforehand. The values of the predicted solubility are then compared with the experimental results by calculating the root mean square error (RMSE). The SLE predictions of the solubility of pyrene and dibenzothiophene in five different solvents were carried out giving an average RMSE of 4%. Further the applicability of COSMO-RS to binary systems consisting of (ionic liquid + alcohol) mixtures and (ionic liquid + hydrocarbons) are predicted. The ionic liquids concerned are n-butyl-3-methylpyridinium tosylate [BM₃Py][TOS] while the alcohols and hydrocarbons are 1-butanol, 1-hexanol, 1-octanol, 1-decanol, and benzene, toluene, ethylbenzene, n-propylbenzene respectively. The experimental data for the ionic liquid [BM₄Py][TOS] with thiophene gave the smallest deviation of 10.2%. The overall RMSE for IL–thiophene, IL–alcohol, and IL–hydrocarbons were 15%, 17.2% and 12.9% respectively. Thus the predicted solubility values were found to be in reasonable agreement with the experimental values.     

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

The solubility of 1-butyl-3-methylimidazolium chloride [C₄mim][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.     

Assembly of succinic acid and isoxazolidine motifs in a single entity to mitigate CO2 corrosion of mild steel in saline media

Inhibition of CO₂ corrosion of mild steel in 0.5 M NaCl under atmospheric pressure at 40 °C as well as high pressure (10 bar) at 120 °C by 2-[2-methyl-4(or 5)-alkylisoxazolidin-5(or 4)-yl)methyl]succinic acids, a new class of molecules having inhibitive motifs of succinic acid, isoxazolidine and hydrophobic alkyl chain assembled in a single entity, has been examined by gravimetric and electrochemical methods. Inhibitor molecule containing CH₃(CH₂)₈ outperformed its counterpart with a shorter hydrophobe CH₃(CH₂)₄ and two other commercial imidazoline-based inhibitors. The effectiveness of these new inhibitors was also evaluated by electrochemical impedance spectroscopy. The inhibition efficiency by EIS was found to be 75%, 91% and 98% in the presence of 1, 5 and 20 ppm, respectively, at 40 °C. The potentiodynamic polarization studies indicated that the new inhibitors act as anodic inhibitors. The adsorption of the synthesized inhibitors follows Temkin adsorption isotherm model with favorable high values of –ΔG°_ads and −ΔH°_ads pointing the inhibitors adsorbed on the metal surface by chemisorption process. The XPS study confirmed the adsorption of the inhibitors on the metal surface.     

Phase equilibria in ternary (carbon dioxide + tetrahydrofuran + water) system in hydrate-forming region: Effects of carbon dioxide concentration and the occurrence of pseudo-retrograde hydrate phenomenon

In the present work, the three- and four-phase hydrate equilibria of (carbon dioxide (CO₂) + tetrahydrofuran (THF) + water) system are measured by using Cailletet equipment in the temperature and pressure range of (272 to 292) K and (1.0 to 7.5) MPa, respectively, at different CO₂ concentration. Throughout the study, the concentration of THF is kept constant at 5 mol% in the aqueous solution. In addition, the fluid phase transitions of L_W–L_V–V → L_W–L_V (bubble point) and L_W–L_V–V → L_W–V (dew point) are determined when they are present in the ternary system. For comparison, the three-phase hydrate equilibria of binary (CO₂ + H₂O) are also measured. Experimental measurements show that the addition of THF as a hydrate promoter extends hydrate stability region by elevating the hydrate equilibrium temperature at a specified pressure. The three-phase equilibrium line H–L_W–V is found to be independent of the overall concentration of CO₂. Contradictory, at higher pressure, the phase equilibria of the systems are significantly influenced by the overall concentration of CO₂ in the systems. A liquid–liquid phase split is observed at overall concentration of CO₂ as low as 3 mol% at elevated pressure. The region is bounded by the bubble-points line (L_W–L_V–V → L_W–L_V), dew points line (L_W–L_V–V → L_W + V) and the four-phase equilibrium line (H + L_W + L_V + V). At higher overall concentration of CO₂ in the ternary system, experimental measurements show that pseudo-retrograde behaviour exists at pressure between (2.5 and 5) MPa at temperature of 290.8 K.