Viscosities Of Pure Components Research Articles

قياس ونمذجة الخواص الزائدة للمخاليط الثنائية والثلاثية من سيكلوهكسان و بيوتانول العادي 1-أوكتانول عند درجات حرارة مختلفة

This study aims to correlate the excess thermodynamic properties for new desirable mixtures. The density, refractive index, and viscosity of pure components and mixtures were measured over the entire composition range at atmospheric pressure and different temperatures. The results of measuring the density, viscosity, and refractive index were used to calculate the excess molar volumes, viscosity deviation, excess refractive index, and excess activation energies of viscous flow were reported for binary and ternary mixtures of cyclohexane, n-butanol, and 1-octanol at temperatures 20, 30, 40, and 50oC and over the whole mole fraction range. For all of the binary and ternary mixtures the computed excess molar volumes were correlated by applying the Redlich–Kister equation. and Prigogine–Flory–Patterson (PFP) theory. The correlations of excess molar volume, viscosity deviation, excess refractive index and excess activation energy to understand the effect of polar and nonpolar and temperature increase in the systems. Many works carried out to predict the excess thermodynamic properties, but the mixtures of this work have not been studied so far at such conditions. It is hoped that the present work will help in the availability of experimental data for some unknown mixtures to understand their behavior in the chemical processes, petrochemical industries and design processes. Keywords: Correlations, Excess properties, Density, Viscosity, cyclohexane and Alcohols, Binary and Ternary mixtures

Physiochemical properties of the binary liquid mixtures of 2-methyl-2,4-pentanediol with selected di- and tri-chloro-substituted benzene and correlation with the Jouyban–Acree model at various temperatures

ABSTRACT Excess molar volume, excess isentropic compressibility, deviation in viscosity and excess Gibbs free energy for the activation of viscous flow for binary mixtures of 2-methyl-2,4-pentanediol (MPD) with 1,2-dichlorobenzene (1,2-DCB), 1,3-dichlorobenzene (1,3-DCB) and 1,2,4-trichlorobenzene (1,2,4-TCB) components selected compositions are determined from the measured values of densities (ρ), speeds of sound (u) and viscosities (η) of pure components and their mixtures from 303.15 K to 313.15 K. The results are analysed in terms of intermolecular interactions or hydrogen bonding or hetero-association interactions in the binary mixtures. The Prigogine–Flory–Patterson (PFP) theory is applied to identify the predominant molecular interaction. The results of Jouyban–Acree model are discussed in terms of mean relative deviation (MRD) and individual relative deviation (IRD) between the calculated and experimental densities, speeds of sound and viscosities as accuracy criteria.

Viscosity of molten Cu–M alloys (M = Ni, Al)

The viscosities of the molten Cu–Ni and Cu–Al alloys were measured using an oscillating crucible method over the entire composition range to obtain reliable data and examine composition dependence precisely. The measured viscosities of all alloys showed good consistency in heating and cooling processes, and the logarithmic viscosities showed good Arrhenius-type linearity, indicating that no considerable change in the liquid structure occurs in the temperature range studied. The composition dependence of the viscosity of Cu–Ni alloys was close to that defined by the additive law of logarithmic viscosities of pure components, whereas the composition dependence of the viscosity of Cu–Al alloys was far from that defined by the additive law, where the logarithmic viscosity increased with the addition of a small amount of Al and showed a peak. Over the peak concentration, the logarithmic viscosity monotonically decreased with further addition of Al. Deviations from the additive law of logarithmic viscosity of molten Cu–Al alloys at 1773 K were maximum at low Al concentrations; in contrast, the excess molar volumes of Cu–Al alloys showed minimum at low Al concentrations. The increase in viscosity in the low-Al-concentration region of the Cu–Al alloy is attributed to the decrease in the interatomic distance, which reduces the freedom of movement of atoms.

Improving the separation of guaiacol from n-hexane by adding choline chloride to glycol extracting agents

Bio-oil is an important candidate to replace oil-derived products since it origins from renewable sources such as biomass. However, oxygenated bio-oil-based compounds require upgrading and further separation and purification for obtaining valuable compounds. Guaiacol is an important lignin derivative obtained from bio-oil, and it is a precursor for obtaining high-value-added molecules through heterogeneous catalysis. Alkanes are typical solvents for the guaiacol catalytical upgrading, so it is important to understand the extraction of guaiacol or guaiacol-like molecules from alkanes systems. This work reports the potential applicability of glycols and their corresponding eutectic mixtures with choline chloride as liquid–liquid extracting agents of guaiacol from n-hexane. The liquid–liquid equilibrium of six ternary systems composed of guaiacol + n-hexane + glycol or eutectic mixture is reported at 313.15 K and 101.3 kPa. Glycols selected as hydrogen bond donors were ethylene glycol, 1,2-propanediol, and 1,4-butanediol, while choline chloride was chosen as the hydrogen bond acceptor for preparing three eutectic mixtures using the glycols mentioned earlier. Density and viscosity of pure components and binary mixtures composed of guaiacol + glycols or guaiacol + eutectic mixture were measured at temperatures between 293.15 K and 333.15 K at 101.13 kPa. Density and liquid–liquid equilibrium data were modeled with PC-SAFT, and binary parameters were only used between the studied glycols and guaiacol. The results showed that the constituents of the eutectic mixtures did not distribute in the n-hexane phase, which was validated by NMR and GC. The viscosity of the pure components was correlated using PC-SAFT + Free Volume Theory, which allowed predicting the viscosity of mixtures by using binary parameters that were fitted to viscosity-independent data. The results obtained show that there is a high affinity between the guaiacol and the eutectic mixtures, based on observations about the negative excess volumes and the liquid–liquid equilibria. The eutectic mixtures are better for extracting guaiacol than their respective glycol-based constituents since they have higher selectivity and distribution coefficients and are larger miscibility gaps with the n-hexane phase compared to the studied glycols.

Modelling the Diffusion Coefficients of Dilute Gaseous Solutes in Hydrocarbon Liquids

In this work, we present a model, based on rough hard-sphere theory, for the tracer diffusion coefficients of gaseous solutes in non-polar liquids. This work extends an earlier model developed specifically for carbon dioxide in hydrocarbon liquids and establishes a general correlation for gaseous solutes in non-polar liquids. The solutes considered were light hydrocarbons, carbon dioxide, nitrogen and argon, while the solvents were all hydrocarbon liquids. Application of the model requires knowledge of the temperature-dependent molar core volumes of the solute and solvent, which can be determined from pure-component viscosity data, and a temperature-independent roughness factor which can be determined from a single diffusion coefficient measurement in the system of interest. The new model was found to correlate the experimental data with an average absolute relative deviation of 2.7 %. The model also successfully represents computer-simulation data for tracer diffusion coefficients of hard-sphere mixtures and reduces to the expected form for self-diffusion when the solute and solvent become identical.

COSMO-RS Analysis of CO2 Solubility in N-Methyldiethanolamine, Sulfolane, and 1-Butyl-3-methyl-imidazolium Acetate Activated by 2-Methylpiperazine for Postcombustion Carbon Capture.

Novel aqueous (aq) blends of N-methyldiethanolamine (MDEA), sulfolane (TMSO2), and 1-butyl-3-methyl-imidazolium acetate ([bmim][Ac]) with amine activator 2-methylpiperazine (2-MPZ) are analyzed through conductor-like screening model for real solvents (COSMO-RS) for possible application in the chemisorption of CO2. The molecules associated are analyzed for their ground-state energy, σ potential, and σ surface. Thermodynamic and physicochemical properties have been assessed and paralleled with the experimental data. Vapor pressure of the blended systems and pure component density and viscosity have been compared successfully with the experimental data. Important binary interaction parameters for the aqueous blends over a wide temperature, pressure, and concentration range have been estimated for NRTL, WILSON, and UNIQUAC 4 models. The COSMO-RS theory is further applied in calculating the expected CO2 solubility over a pressure range of 1.0–3.0 bar and temperature range of 303.15–323.15 K. Henry’s constant and free energy of solvation to realize the physical absorption through intermolecular interaction offered by the proposed solvents. Perceptive molecular learning from the behavior of chemical constituents involved indicated that the best suitable solvent is aq (MDEA + 2-MPZ).

Excess Properties for the Binary System Diethylene Glycol Dibutyl Ether � Ethanol

This paper reports propertiesdata at 20, 25 and 30 0C and 1 atmosphere pressure for diethylene glycol dibutyl ether - ethanol system depending on concentration. The experimental values of density and viscosities of pure components and mixtures were correlated with temperature. The excess properties were determined from experimental data of densities and viscosities. These excess values were correlated to Hwang and Redlich-Kister equations. The value of excess molar volume for equimolar solution was compared with the values calculated from the Flory and Prigogine-Flory-Patterson theories.

Physico-chemical properties of binary systems involving modifier (methanol or propionic acid) and an acidic extractant di (2-ethylhexyl) phosphoric acid (DEHPA): volumetric, acoustic and viscometric routes

In solvent extraction, a suitable modifier, basically polar liquid is used with extractant like DEHPA, TBP, TOPO and MIBK to enhance the efficiency in extraction processes. This paper is related to the study of physico-chemical properties of polar – polar binary mixtures at 303.15K and 0.1 MPa. Molar volume, free volume, isentropic compressibility, intermolecular free length, specific acoustic impedance, relaxation time, Rao’s constant, Wada’s constant, absorption coefficient have been calculated from the experimentally measured data of density, ultrasonic velocity and viscosity of pure components and binary mixtures of methanol/ propionic acid + DEHPA. In addition, excess molar volume, excess Gibb’s energy of activation of viscous flow, deviations in viscosity, isentropic compressibility, free volume, intermolecular free length and acoustic impedance were also computed from the experimental data. The observed variations of excess/deviation functions with the composition of DEHPA have been discussed in terms of molecular interaction between unlike molecules in two binary mixtures due to chemical, physical and structural effects. It is found that the molecular interaction of methanol with extractant DEHPA is better than that of propionic acid and so methanol may be used as a suitable modifier with DEHPA in the solvent extraction process.

A predictive group-contribution model for the viscosity of aqueous organic aerosol

Abstract. The viscosity of primary and secondary organic aerosol (SOA) has important implications for the processing of aqueous organic aerosol phases in the atmosphere, their involvement in climate forcing, and transboundary pollution. Here we introduce a new thermodynamics-based group-contribution model, which is capable of accurately predicting the dynamic viscosity of a mixture over several orders of magnitude (∼10-3 to >1012 Pa s) as a function of temperature and mixture composition, accounting for the effect of relative humidity on aerosol water content. The mixture viscosity modelling framework builds on the thermodynamic activity coefficient model AIOMFAC (Aerosol Inorganic–Organic Mixtures Functional groups Activity Coefficients) for predictions of liquid mixture non-ideality, including liquid–liquid phase separation, and the calorimetric glass transition temperature model by DeRieux et al. (2018) for pure-component viscosity values of organic components. Comparing this new model with simplified modelling approaches reveals that the group-contribution method is the most accurate in predicting mixture viscosity, although accurate pure-component viscosity predictions (and associated experimental data) are key and one of the main sources of uncertainties in current models, including the model presented here. Nonetheless, we find excellent agreement between the viscosity predictions and measurements for systems in which mixture constituents have a molar mass below 350 g mol−1. As such, we demonstrate the validity of the model in quantifying mixture viscosity for aqueous binary mixtures (glycerol, citric acid, sucrose, and trehalose), aqueous multicomponent mixtures (citric acid plus sucrose and a mixture of nine dicarboxylic acids), and aqueous SOA surrogate mixtures derived from the oxidation of α-pinene, toluene, or isoprene. We also use the model to assess the expected change in SOA particle viscosity during idealized adiabatic air parcel transport from the surface to higher altitudes within the troposphere. This work demonstrates the capability and flexibility of our model in predicting the viscosity for organic mixtures of varying degrees of complexity and its applicability for modelling SOA viscosity over a wide range of temperatures and relative humidities.

Kinetic study of CO2 absorption in aqueous solutions of 2‐((2‐aminoethyl)amino)‐ethanol using a stirred cell reaction calorimeter

AbstractIn the literature, aqueous 2‐((2‐aminoethyl)amino) ethanol (AEEA) is identified as a promising solvent for postcombustion CO2 capture. In this work, the kinetics of CO2 absorption in the aqueous AEEA, containing a primary and a secondary amino group, is studied over a wide temperature range of 303.15‐343.15 K and the amine concentration in the range of 0.47‐2.89 M using the fall‐in‐pressure technique in a stirred cell reaction calorimeter setup with a horizontal gas‐liquid interface. The overall rate constants for (AEEA + H2O + CO2) reaction system are estimated in the pseudo–first‐order reaction regime. The kinetic models based on zwitterion and the termolecular reaction mechanisms are used to predict kinetic rate constants. The experimental kinetic data are better correlated using the zwitterion mechanism (AAD 9.18%) than that of the termolecular mechanism (AAD 10.4%). The density, viscosity, and physical solubility of pure components and aqueous binary mixtures of AEEA are also measured at the similar temperature and concentration ranges of rate kinetics. Empirical models are proposed to predict pure component density and viscosity data with AAD of 0.02% and 7.17%, respectively. The Redlich‐Kister model, the Grunberg‐Nissan model, and the O'Connell's model are used to correlate experimental density, viscosity, and physical solubility data of the binary mixtures with AAD of 0.034%, 4.92%, and 6.5%, respectively. The reaction activation energy (Ea ∼ 32 kJ/mol) of the (AEEA + H2O + CO2) system is calculated from the Arrhenius power‐law model using the zwitterion mechanism, which indicates lower energy barrier than that of the reported value for monoethanolamine (∼44 kJ/mol) in the literature.

Volume-based mixing rules for viscosities of methane + n-butane liquid mixtures

We present a study of viscosities of methane, n-butane and their mixtures by the non-equilibrium molecular dynamics simulations and derivation of semiempirical volume-based mixing rules. The Batchinski equation η=C/(V−b) is used to describe the viscosities of pure components, with parameters fitted to reproduce molecular dynamics results. Cubic root, Arrhenius and Batchinski mixing rules are tested for mixtures. The viscosities of pure components used in mixing equations are expressed as functions of volume of component rather than pressure. This allows to apply the mixing rules to metastable and stable liquids, dense supercritical fluids and solutions of gas in liquid. To obtain volumes of components in mixture, molecular dynamics method is used. The mixing rules predictions are compared against direct non-equilibrium molecular dynamics calculations of mixture viscosities. The best agreement with the molecular dynamics data is found when Batchinski mixing is used. The proposed viscosity model predictions are in agreement with the experimental data on viscosities of methane-butane mixtures. The model can be used for the interpretation and interpolation of the experimental data on viscosities of liquids, which is demonstrated on the example of methane + propane system.

Determination of the Dynamic Viscosity of Liquid Alloys from the Phase Diagram

That viscosity and fluidity are equilibrium processes may be established on the basis of the Boltzmann distribution in terms of randomized particles. Specifically, the virtual presence of three classes of particles— with crystal mobility, liquid mobility, and vapor mobility—is assumed. Accordingly, the viscosity and fluidity of solutions—in particular, molten metallic alloys—may be considered in terms of the equilibrium contributions of each component to the total viscosity and fluidity, despite the kinetic interpretation of the usual expressions for these liquid properties. A linear additive equation for the viscosity is only possible for perfect solutions; for present purposes, that corresponds to alloys with unlimited mutual solubility of the components. Alloys with eutectics, chemical compounds, and other singularities in the phase diagram are characterized by viscosity equations that reproduce the shape of the liquidus curve over the whole range of alloy composition at different temperatures. Greater smoothness and closeness of the curves is observed at higher temperatures. These aspects of the temperature dependence of the viscosity may be explained on the basis of randomized particles and the visual cluster model of viscosity, with calculation of the proportions of the clusters that determine the alloy viscosity. Such viscosity is determined from a formula in which the thermal barrier to randomization is the thermal energy RTcr at the liquidus temperature, which is characterized by the temperature of melt crystallization Tcr, analogously to the melting point of the pure materials. On that basis, we propose a method of calculating the alloy viscosity from the phase diagram. From the temperature dependences of the viscosity of the pure components, the alloy viscosity may be determined from the proportion of clusters at any temperature above the liquidus curve and the viscosities of the pure components, taking account of the mole fraction of each component. The result is a trifactorial model of the viscosity of a liquid alloy. In this model, the variable is the thermal barrier RTcr to randomization, which determines the proportion of clusters both for pure materials (at RTcr = RTm) and for alloys. Overall, this model corresponds to the virtual cluster theory of viscosity and is consistent with the concept of randomized particles.

Synergistic effects and specific molecular interactions in the binary mixtures of [bmim][BF4] and poly (ethylene glycol)s

Solvent systems composed of ionic liquid (IL)+poly(ethylene glycol) (PEG) provide “hybrid green” systems where “green meets green.” In this work, the density and viscosity of binary mixtures of 1-butyl-3-methylimidazolium tetrafluoroburate ([bmim][BF4]) and PEG with different number average molecular weights (i.e. 200, 400, 600, and 1000) were measured and analyzed as a function of temperature and composition. Excess molar properties of these mixtures were calculated and interpreted. A synergistic effect or super-viscosity was observed in the mixtures of [bmim][BF4] with PEG400, PEG600, and PEG1000 in which the mixture viscosity is higher than the viscosity of both pure components. By adding PEG to [bmim][BF4] in these mixtures, the decrease in the columbic attractive and van der Waals interactions is overcompensated by the formation of extensive H-bonding interactions which is responsible for observing the synergistic effect in the viscosity behavior of these mixtures. This effect can also influence on the excess properties. The FTIR spectroscopy was used for better analysis of molecular interactions. The variation in the positions and intensities of the peaks of FTIR spectra may be attributed to the possibility of H-bonding between C2 hydrogen of [bmim]+ and terminus OH as well as ethoxy O of PEG.

Measurements and Predictions of Binary Component Aerosol Particle Viscosity.

Organic aerosol particles are known to often absorb/desorb water continuously with change in gas phase relative humidity (RH) without crystallization. Indeed, the prevalence of metastable ultraviscous liquid or amorphous phases in aerosol is well-established with solutes often far exceeding bulk phase solubility limits. Particles are expected to become increasingly viscous with drying, a consequence of the plasticizing effect of water. We report here measurements of the variation in aerosol particle viscosity with RH (equal to condensed phase water activity) for a range of organic solutes including alcohols (diols to hexols), saccharides (mono-, di-, and tri-), and carboxylic acids (di-, tri-, and mixtures). Particle viscosities are measured over a wide range (10-3 to 1010 Pa s) using aerosol optical tweezers, inferring the viscosity from the time scale for a composite particle to relax to a perfect sphere following the coalescence of two particles. Aerosol measurements compare well with bulk phase studies (well-within an order of magnitude deviation at worst) over ranges of water activity accessible to both. Predictions of pure component viscosity from group contribution approaches combined with either nonideal or ideal mixing reproduce the RH-dependent trends particularly well for the alcohol, di-, and tricarboxylic acid systems extending up to viscosities of 104 Pa s. By contrast, predictions overestimate the viscosity by many orders of magnitude for the mono-, di-, and trisaccharide systems, components for which the pure component subcooled melt viscosities are ≫1012 Pa s. When combined with a typical scheme for simulating the oxidation of α-pinene, a typical atmospheric pathway to secondary organic aerosol (SOA), these predictive tools suggest that the pure component viscosities are less than 106 Pa s for ∼97% of the 50,000 chemical products included in the scheme. These component viscosities are consistent with the conclusion that the viscosity of α-pinene SOA is most likely in the range 105 to 108 Pa s. Potential improvements to the group contribution predictive tools for pure component viscosities are considered.

Excess molar volumes, speeds of sound and viscosities for binary mixtures of 3-chloroaniline with selected di- and tri-chloro substituted benzene at various temperatures: Comparison with Prigogine–Flory–Patterson theory

Excess volume (VE), excess isentropic compressibility (κsE), viscosity deviation (8η) and excess Gibbs energy of activation of viscous flow (G*E) for binary mixtures of 3-chloroaniline (CA) with 1,2-dichlorobenzene (1,2-DCB), 1,3-dichlorobenzene (1,3-DCB) and 1,2,4-trichlorobenzene (1,2,4-TCB) at selected compositions are determined from the measured values of densities, speeds of sound, and viscosities of pure components and their mixtures at (T) of 303.15–318.15K, at atmospheric pressure of 0.1MPa. The excess volume (VE), excess isentropic compressibility (κsE), viscosity deviation (8η) and excess Gibbs energy of activation of viscous flow (G*E) have been analyzed in terms of interactions arising due to structural effect, charge–transfer complexes and dipole–dipole interaction between unlike molecules from the experimental data. Excess properties are correlated by the Redlich–Kister equation. The partial molar volumes (V̅m,1, V̅m,2), partial molar isentropic compressibilities (K̅s,m,1, K̅s,m,2), excess partial molar volumes (V̅m,1E and V̅m,2E) and excess partial molar isentropic compressibilities (K̅s,m,1E and K̅s,m,2E) over whole composition range; partial molar volumes (V̅m,1° and V̅m,2°), partial molar isentropic compressibilities (K̅s,m,1° and K̅s,m,2°), excess partial molar volumes (V̅m,1°E and V̅m,2°E) and excess partial molar isentropic compressibilities (K̅s,m,1°E and K̅s,m,2°E) of the components at infinite dilution have also been calculated. The VE results have been analyzed in the light Prigogine–Flory–Patterson theory. An analysis of each of the three contributions viz. interactional, free volume and P* to VE shows that interactional contribution is positive for all binary systems. The free volume effect and P* contribution are negative for all mixtures. The variations of these parameters with composition and temperature have been discussed in terms of intermolecular interactions prevailing in these mixtures.

An excess Gibbs free energy based model to calculate viscosity of multicomponent liquid mixtures

Solution densities and viscosities are important parameters for the design and simulation of absorption processes. Accurate models are needed and in this work, a new model for calculating the liquid viscosity of mixtures is presented. The model uses an analogy to excess Gibbs energy models to account for the deviation from a simple mixing rule based on the pure component viscosities. In this work, we chose the functional form of the NRTL model to represent the excess Gibbs energy and the resulting model is referred to as NRTL-DVIS. Eleven systems (eight binaries and three ternary) were chosen for testing the accuracy of the model. The ternary systems were built from the optimized binaries and pure component systems. With few adjustable parameters, the NRTL-DVIS model represented the tested systems with good accuracy. With few exceptions the calculated total deviation (AARD) was within 3.5%. The NRTL-DVIS model shows better accuracy than other models proposed in the literature.

Density and Viscosity of Binary Liquid Mixtures of Ethanol + 1-Hexanol and Ethanol + 1-Heptanol from (293.15 to 328.15) K at 0.1 MPa

This paper presents experimental viscosity and density measurements for two binary mixtures of ethanol with 1-hexanol and 1-heptanol that cover the complete composition range from (293.15 to 328.15) K at 0.1 MPa. A vibrating tube densimeter provides density measurements, whereas viscosities come from a pellet microviscometer. The excess molar volumes calculated from the experimental data have positive deviations from ideality over the temperature range. Calculated viscosity deviations from the experimental data show negative deviations from a mole fraction weighted average of the pure component viscosities over the temperature range. A Redlich–Kister type equation correlates the data satisfactorily. We have correlated the three-body McAllister to the experimental kinematic viscosity. Comparison of the experimental viscosity data to predictions from a generalized, three-body McAllister and a generalized corresponding states principle (GCSP) equation shows that the generalized McAllister equation is superio...

Predicting Fluid Viscosity of Nonassociating Molecules

Previous work by the author demonstrated that a new predictive corresponding-states viscosity model, based on entity Chapman–Enskog scaling, correlated pure n-alkane component viscosity data with entity scaled residual entropy. With five fitting constants, a 5.2% average absolute relative deviation (AARD) was obtained over the entire fluid region for a group of 17 n-alkanes, ranging from methane to 1280 Mw linear polyethylene. The work reported here demonstrates that this same model and fitting constants predicts fluid viscosity of other molecular classifications over a wide range of temperature and pressure. Molecular structure was incorporated to improve the predictability of the earlier corresponding-states viscosity model. With the inclusion of molecular structure, an AARD of 6.6% was obtained over the entire fluid region for ten classifications of nonassociating molecules and a wide range of temperature (60–800 K) and pressure (1–46 800 atm). Thus, a predictive corresponding-states fluid viscosity mo...

Measurement, correlation and prediction of biodiesel blends viscosity

The viscosity is one of the most important transport properties of a fuel, influencing especially the injection system, mainly at low temperatures when viscosity increases. Biodiesel is considered an alternative fuel for diesel engines, but some of its properties such as density and viscosity, have higher values than those of diesel fuel. In this paper, the viscosity of binary blends biodiesel+diesel fuel, biodiesel+benzene and biodiesel+toluene in the temperature range 293.15–323.15K is presented. Experimental data were used to evaluate the accuracy of viscosity calculations with different models, both for blends of biodiesel with pure components (benzene or toluene) and for biodiesel with diesel fuel. The biodiesel+benzene and biodiesel+toluene blends were used as base of comparison, to better understand the behavior of biodiesel+diesel fuel blends. The Grunberg–Nissan, Wilke and McAllister equations were used to predict the blends viscosity from the viscosities of pure components and to correlate the experimental data. Also, the viscosity of the biodiesel blends was calculated from the refractive index of the blends or by the means of viscosity–temperature and viscosity–temperature–composition empirical correlative equations.

Removal of crystal violet dye from aqueous solution using triton X-114 surfactant via cloud point extraction

In this work, the cloud point extraction (CPE) was carried out for the removal of crystal violet dye from aqueous solution using triton X-114 surfactant. Density, refractive index and viscosity of pure components and two different phases of the mixture were measured, and the corresponding excess molar volume was calculated. Most of the dye molecules get solubilized in the coacervate phase, leaving a dye free dilute phase. This experiment was conducted for different sets of surfactant and solute concentration in order to find out the cloud point temperature and their influencing factors such as extraction efficiency, phase volume ratio, distribution coefficient and pre-concentration factor. Furthermore, the thermodynamic parameters like change in Gibbs-free energy (ΔG0), the change in enthalpy (ΔH0) and the change in entropy (ΔS0) were analyzed and found that cloud point extraction with surfactant was a more feasible process in the removal of dyes from aqueous solution.