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Surfactants are widely used in industrial applications associated with several solvents. Therefore, it is worthy to know the nature of the molecular interactions present in surfactants and cosurfac...

Liquid–liquid equilibrium data are widely used in many industrial sectors. For this reason, it is important to know thermodynamics binary mixture data to better understand molecular interactions be...

Surfactants are widely used for academic and industrial purposes. For this reason, thermodynamic and physical properties of surfactant and cosurfactant mixtures can provide important information about the nature of the molecular interactions present. In this work, volumetric and transport data of surfactant binary mixtures of the ethanol + Igepal series (Igepal CO-520, Igepal CO-630, Igepal CO-720, and Igepal CA-720) were determined experimentally within a range of temperature of T = 293.15–323.15 K, at atmospheric pressure. From these data, the following derivative properties have been calculated: the excess molar volume, viscosity deviation, and coefficient of thermal expansion. All of these mixtures showed that attractive intermolecular forces are dominant.

Over the last decade, ionic liquids (IL) have attracted considerable attention for their potential to replace traditional volatile organic solvents due to their well-known physico-chemistry properties. This is an important topic for industrial applications today, and have been the subject of extensive literature studies. Nevertheless, there is still a lack of experimental thermodynamics data on aqueous mixtures, i.e., ionic liquids + water, especially volumetric and transport properties. These data could provide essential information about interactions and molecular phenomena in such mixtures. To investigate volumetric and transport properties for ionic liquids + water, density and viscosity data of the protic ionic liquids 2-hydroxydiethanolamine formate (2-HDEAF), 2-hydroxydiethanolamine acetate (2-HDEAA), water and their binary mixtures were measured at T = (293.15 to 343.15) K and atmospheric pressure. Excess molar volumes and deviation of viscosity were computed from experimental density and viscosity values and were fit to the Redlich-Kister equation. We observed a negative behavior for both ionic liquids + water mixtures that can be attributed to a shrinkage of the mixtures.

In the petrochemical industry, the separation of aromatics from alkanes is a complex process due to the overlapping boiling points and azeotrope formation in specific operational conditions. In this work, 2-hydroxy ethylammonium formate (2-HEAF) and glycerol were evaluated as an extractor solvent of toluene from decane + toluene mixtures, by comparing with widespread solvent used in industrial applications, sulfolane. New liquid–liquid equilibrium (LLE) data for three ternary systems: {decane (1) + toluene (2) + glycerol (3); decane (1) + toluene (2) + [2-HEAF] (4); and decane (1) + toluene (2) + sulfolane (5)} at T = (303.15 and 333.15) K and atmospheric pressure has been studied. Heterogeneous region in LLE diagram presents a wide area and are not influenced by temperature, in the studied domain. From experimental data, distribution coefficients and selectivity parameters have been used determined and used to evaluate the efficiency of the studied solvents (sulfolane, glycerol and 2-HEAF) to extract toluene from decane. Two thermodynamics models (NRTL and UNIQUAC) were used to obtain binary interaction parameters. These models have been also used to correlate LLE experimental data for the studied ternary systems. A comparison between experimental and calculated data indicate that better agreement has been performed by using NRTL model.

Aromatic hydrocarbons are usually extracted from reformed naphtha, which are multicomponent mixtures with aliphatic hydrocarbons. These components have very close boiling point, which makes distillation process not so efficient and economically infeasible. For this reason, aromatics compounds are usually separated from aliphatic compounds by intermediate of solvent extraction unit operation. In this work, liquid–liquid equilibrium (LLE) data for systems containing decane + toluene + diethylene glycol (DEG) and decane + toluene + triethylene glycol (TEG) at T = (303.15 and 333.15) K and atmospheric pressure were studied. It was observed that temperature hardly influence the size of the two-phase region. Distribution coefficient and selectivity have been calculated from those experimental data. For all systems studied, selectivity parameter showed values greater than 1 indicating that the extraction is possible by using DEG and TEG as extractor solvents. Additionally, selectivity values ​​increase with increasing glycol carbon chain. LLE have been correlated by intermediate of NRTL and UNIQUAC activity coefficients.

During the biodiesel production process, generally, two purification steps are performed. The first is a settling process in order to remove the main byproduct (glycerol). Nevertheless, this simple stage is insufficient to achieve purity levels required for commercial specifications. Second, a water washing is used to remove an excess of alcohol and other contaminants. Given the importance of equilibrium data for operation and optimization for liquid–liquid extraction unit operation, the study of liquid–liquid equilibrium (LLE) for methylic cottonseed biodiesel + methanol + water and ethylic cottonseed biodiesel + ethanol + water systems are studied at (293.15 and 313.15) K at atmospheric pressure. LLE data have been quantified by intermediate of two different techniques (titration and densimetric). From these experimental data, distribution coefficients and selectivity have been calculated. As expected, a good extraction capacity of water to remove alcohol has been observed. The reliability of the experi...

Biodiesel is usually produced by transesterification reactions, by intermediate of a catalytic reaction in which a source of triglycerides (from vegetable, animal or residual oils) reacts with excess of alcohol producing as main product biodiesel and as side-product glycerol. After those reactions, it is usually necessary to purify the biodiesel produced by settling process. This step is followed by liquid–liquid extraction (wash up) unit operation. Systematic studies on biodiesel washing process, especially as function of composition data, are still scarce in the literature. Liquid–liquid equilibrium data provide important means to the development and design of equipment and also in the optimization of the extraction processes. This paper, as part of continuing study in our research group, reports equilibrium data for different ternary systems of methanol + water + (soybean, corn or brown shell of coconut, here named coconut) biodiesel at 293.15 and 313.15 K at atmospheric pressure. Experimental data were carried out in equilibrium cells, by using a bath, in order to control the temperature of the system. From experimental data, distribution coefficients of methanol have been determined. The quality and reliability of the tie-line were tested by Othmer-Tobias and Hand correlations. Liquid–liquid equilibrium (LLE) data were correlated with the following activity coefficient models: NRTL, UNIQUAC and UNIFAC, with a global deviation error of 1.34%, 1.34% and 4.13%, respectively.