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The primary objective of the present study is to consolidate and assess a method to determine the physical and transport properties of ionic liquids (LIs) by applying the geometric similitude concept and the equation of state model (EdE). The method assesses the geometric similitude that some characteristic lines adopt in a density-pressure-temperature graph (ρTP) against characteristic lines of other properties: viscosity (µTP), speed of sound (sTP), and thermal conductivity (kTP). Data for these properties, available in the literature, are gathered, analyzed, and selected to construct a database with consistent values to propose a general model. The results show that a cubic equation of state provides accurate and consistent results for each property. This is in spite of its simplicity as it only contains one adjustable parameter for each ionic liquid. It is concluded that a geometric similitude concept that uses the equation of state model is an attractive alternative for estimating ionic liquid properties. [ABSTRACT FROM AUTHOR]

In this work, an empirical model is generalized to predict the thermal conductivity of ionic liquids. Initially, experimental data are collected, which include different types of anions and cations. A total of 38 ionic liquids are evaluated (28 substances for correlation and 10 substances for prediction), which corresponds to 265 experimental data. The temperature ranges vary between 273 and 390 K at atmospheric pressure (1 atm). The model is generalized using 215 experimental data, and the average deviation is around 4.72%. Then, the predictive capabilities are evaluated in 50 experimental data with an average deviation of 3.48%. The generalized model is extended to binary mixtures using a simple mixing rule with an interaction parameter, and the absolute deviation is 0.77%. Finally, the generalized model is compared with others developed in the literature, and the statistical analysis shows that it provides acceptable results. [ABSTRACT FROM AUTHOR]

In recent decades, the application of ionic liquids (IL) as pretreatment of residual biomass (BM) before the hydrolysis reaction has proven to be an efficient system to improve yields towards obtaining monosaccharides. A greater recovery of monosaccharides translates into a higher yield in the production of biofuels, which can make this industry profitable. In this context, this bibliographic review analyzes the physicochemical characteristics, synthesis methods, dissolution conditions with application of variables, such as: IL: BM weigh ratio, temperature and time. In addition, a comparative assessment of the results of traditional acid hydrolysis processes with respect to those obtained with the application of IL is carried out, increasing in most cases their reaction yields. Finally, some recovery and recycling techniques are mentioned, which allow to reduce the costs of the process, so that it is economically profitable. [ABSTRACT FROM AUTHOR]

This study shows the catalytic evaluation for ruthenium nanoparticles stabilized in ionic liquids derived from imidazolium: LI1= butylmethylimidazolium tetrafluoroborate [BMIM][BF4] and LI2= butylmethylimidazolium hexafluorophosphate [BMIM][PF6] in the biphasic hydrogenation of myrcene and eugenol. The nanoparticles were synthesized using the method of reduction and displacement of ligand for tris(acetylacetonate) ruthenium (III) [Ru(acac)3], characterized through transmission electron microscopy (TEM), by which an average size of (2,0±0,2) nm, demonstrating that these catalysts are nanometric systems. Once these catalysts were used in the biphasic hydrogenation of eugenol, the production of 2- methoxy-4-propylphenol with 99% selectivity in a time of 4 hours could be observed, while in the biphasic hydrogenation of myrcene the formation of 6 hydrogenated species, the Ru/LI1 nanoparticles being more active and selective towards the formation of 7-methyl-3-methylene-6-octene in a time of 32 hours, in contrast to the Ru/LI2 nanoparticles were less active and selective generating a series of hydrogenated products. [ABSTRACT FROM AUTHOR]

This work analyzes and discusses the current situation of Chilean mining and its relation with environmental issues and with a proposal for capturing, transporting and sequestering carbon dioxide (CO2) in mine tailings. Some aspects related to climate change, greenhouse effect, and carbon footprint are discussed. Also, analysis is done on how the mining industry, not only in Chile but around the world, can make use of raw material being permanently formed such as the waste material forming mine tailings, to mitigate the problem of excess of CO2 in the atmosphere, mainly formed in power plants that provide energy to the mining and metallurgical processes. Also, sequestration of CO2 is analyzed as a viable alternative to reduce the amount of harmful gases in the atmosphere. Finally, a method for the capture of CO2 contained in flue gases and its transport to the place of sequestration using ionic liquids is proposed. It is concluded that despite the costs of sequestration are still high, work must be done to optimize processes for making the technology economically viable for the capture and transport of CO2 using ionic liquids and its sequestration in mineral tailings, in the shortest possible time. [ABSTRACT FROM AUTHOR]

A cubic equation of the state model to correlate the solubility of ionic liquids in partially miscible mixtures with alcohols is presented. The model is obtained using the geometric similitude concept between the diagram pressure-volume-temperature (P-v-T) at saturation conditions and the solubility diagram pressureconcentration- temperature (P-x-T). The model that provides the geometric similitude is the Patel-Teja-Valderrama equation of state including the simple mixing rules proposed by van der Waals with one interaction parameter. The adjustable parameter is estimated by fitting 455 experimental data for 28 binary mixtures (322 data for correlation and 133 data for prediction). The temperature range varies from 277 K to 403 K, with all data at 1 bar. Similar deviations below 10% are obtained for the correlation and prediction steps. The model is compared with different approaches found in the literature and the results show that the proposed model is simpler and provides acceptable results. [ABSTRACT FROM AUTHOR]

The capacity of artificial neural network models (ANN) to correlate and predict the solubility of gases in ionic liquids (ILs) is analyzed. Solubility data of sulfur dioxide (SO2) in eight ionic liquids are considered. A total of 155 data points of solubility (pressure, temperature, and mole fraction; T,P,x) for these systems were taken from the literature. Of these total, 131 data were used for training the network, 16 for testing and 8 for prediction. The dependent variable (target variable) is the solubility and the independent variables are the temperature and pressure. Also some ionic liquid properties were employed as independent variables to distinguish between different ionic liquids: the critical temperature (Tc), the critical pressure (Pc), the mass connectivity index (λ), the acentric factor (ω), the cation mass (M+) and the anion mass (M-). Three cases were considered for analysis, modifying in each case the ionic liquid properties. The study shows that the proposed neural model (2,6,1) with five variables in the inner layer (T, P, Tc, Pc, and ω), is the recommended architecture for this study. [ABSTRACT FROM AUTHOR]

Densities of aqueous mixtures of DL-alanine + 1-butyl-3-methylimidazolium chloride [Bmim+][Cl-] were measured over the concentration range 0 to 1.0007 mol.kg-1 at temperatures from 283.15 to 313.15 K at intervals of 5 K, using an Anton Paar DMA 5000 vibrating tube densitometer, within the allowable range of solubility. The infinite dilution apparent molar volume, the second derivative of the infinite dilution partial molar volume with respect to temperature, and the transfer partial molar volume at infinite dilution were calculated. The values of the transfer partial molar volume at infinite dilution are negative. This indicates the predominant interactions between ions of the amino acid and the non-polar groups of the ionic liquid or vice versa. It also was found that the DL-alanine acts as an hydrophilic solute in the pseudo binary mixtures containing the ionic liquid [Bmim+][Cl-]. [ABSTRACT FROM AUTHOR]

The behavior and the electrochemical function of the carbon paste electrode, chemically modified by ionic liquid, have been investigated mathematically from the point of view of steady-state stability. The corresponding mathematical model is analyzed by linear stability theory and bifurcation analysis. The modeling results are being compared with experimental results (for this system and for the similar ones), and with theoretical results for other cases. [ABSTRACT FROM AUTHOR]

In this paper the advances done by the research groups of the University of La Serena and University of Concepción on thermodynamic consistency tests of low to high pressure phase equilibrium data of binary mixtures are presented. The main advances of the group consist of the extension of a thermodynamic consistency test previously proposed by the Group of La Serena to mixtures containing an ionic liquid. The method has been especially designed to analyze data sets that do not cover the whole concentration range and is based on the Gibbs-Duhem equation and an appropriate application of equations of state, mixing rules and combining rules. The proposed method allows analyzing single data from an experimental data set and determining thermodynamic consistency or inconsistency of the equilibrium data in all cases. [ABSTRACT FROM AUTHOR]

Copyright of Revista ION is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Fuentes, El Reventón Energético is the property of Universidad Industrial de Santander and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The advances done by the research group in La Serena-Chile on the estimation of several physical, physicochemical, and transport properties of ionic liquids (ILs) are presented and analyzed. Although it has been mentioned in the literature that the methods usually applicable to organic fluids cannot be used to estimate the properties of ILs and a new formalism to explain the especial behavior of ILs should be formulated, the group in La Serena has demonstrated that this is not correct. This work presents the results of applying several traditional methods for estimating some properties of ILs; in particular, group contribution techniques, generalized correlation, empirical correlations, and neural networks have been employed. Until now, the critical properties, the vapor pressure, the density and the viscosity of ILs have been correlated and predicted. [ABSTRACT FROM AUTHOR]

En los últimos años la preparación de muestras mediante técnicas miniaturizadas ha ganado una gran atención en la comunidad científica, ya que estas metodologías cumplen con los preceptos de la química verde, lo que ha conducido a una creciente aplicación en una variedad cada vez mayor de compuestos orgánicos. En las técnicas que involucran microextracción, la fase sorbente es un componente esencial, por lo que la búsqueda de nuevas fases que sean más afines a los compuestos de interés es un desafío. La arcilla Montmorillonita (MMT) es un material ecológico abundante en el planeta y es una buena opción para extraer compuestos orgánicos. En este estudio, se desarrolló una nueva aplicación para la extracción de Triclosán (TCS) en muestras de aguas mediante extracción con disco rotatorio (RDSE) utilizando como fase sorbente Montmorillonita modificada con el líquido iónico 1-hexadecil-3-metilimidazolio bromuro (MMT-Br). La determinación final del TCS se realizó mediante cromatografía de líquidos de alta eficiencia (HPLC) con detección de matriz de diodos fotométricos (PDA). Se obtuvieron características analíticas satisfactorias utilizando la técnica RDSE con fase sorbente MMT-Br, para un volumen de muestra de 5,0 mL a pH de 5 y a 800 rpm de agitación; el tiempo óptimo de extracción se fijó en 60 minutos. Las recuperaciones relativas de una muestra de aguas fueron superiores al 80%, el límite de detección fue 0,203±0,006 mg L-1 y la precisión expresada como la desviación estándar relativa de 3%. Bajo las condiciones de extracción optimizadas, esta nueva metodología se aplicó en el análisis de las aguas residuales de una planta de tratamiento Hospitalaria y en la bocatoma de una planta de tratamiento de agua potable. Se encontraron concentraciones no cuantificables de TCS por debajo del límite de cuantificación para la muestra de agua residual Hospitalaria. Se comparó la eficiencia de método propuesto por RDSE con la fase absorbente MMT-Br con el método EPA 1694, basado en la extracción en fase sólida (SPE); los resultados indicaron que no hubo diferencias significativas entre las concentraciones de las medidas de TCS de ambos métodos a un nivel de confianza del 95%, lo que confirmó la eficiencia de la RDSE/MMT-Br para monitorear las concentraciones de este compuesto en aguas. [ABSTRACT FROM AUTHOR]

La investigación de sistemas supramoleculares autoensamblados de escala nanométrica (sistemas organizados) ha ganado cada vez más atención debido a su gran potencial en aplicaciones relacionadas con la nanotecnología. Cuando se disuelven moléculas anfifílicas (surfactantes) en distintos medios, éstas forman diferentes sistemas supramoleculares, dentro de los que se destacan las vesículas y micelas inversas. El tipo de sistema formado dependerá, entre otras variables, de la estructura del surfactante y del tipo de solvente utilizado. Así, las micelas inversas se esquematizan como una monocapa de surfactantes que rodea un solvente polar, formando gotas uniformemente distribuidas en una fase orgánica no polar. Las vesículas son estructuras supramoleculares esféricas formadas por bicapas autoensambladas de surfactantes en solución acuosa. Los líquidos iónicos (LIs) son una familia de compuestos que ha revolucionado la Química en las últimas décadas y por ello se han utilizado en diferentes transformaciones inorgánicas, orgánicas, y organometálicas. Estos compuestos, son sales líquidas con relativamente bajos puntos de fusión (< 100 °C). Dentro de los más utilizados, se destacan los LIs formados por cationes de 1-alquil-3-metilimidazolio y aniones típicamente inorgánicos en naturaleza. Dadas las propiedades tan versátiles que presentan los LIs como solventes, es de interés investigar su encapsulamiento en micelas inversas, ya que es sabido que los solventes cambian dramáticamente su estructura "bulk" cuando son incorporados en el interior polar micelar. Por otro lado, un área todavía poco explorada es la de utilizar LIs con propiedades anfifílicas para generar diferentes sistemas organizados. Teniendo en cuenta todos estos antecedentes, en esta presentación se discutirá como el encapsulamiento de diferentes LIs a escala nanométrica cambia drásticamente las propiedades de los mismos, afectando además la interfaz de los sistemas organizados formados. Además, se expondrán algunos resultados utilizando LIs tanto como surfactantes como en reemplazo de solventes orgánicos no polares, mostrando como cada sistema ofrece una potencial aplicación diferente. Finalmente, se mostrarán resultados del uso de solventes no polares amigables al ambiente en la formación de micelas inversas con posibles aplicaciones en el transporte de fármacos y al desarrollo de formulaciones tópicas. En este sentido y aprovechando la biocompatibilidad de sus componentes se comentará sobre las distintas líneas de investigación que se han generado en torno a estos fascinantes sistemas supramoleculares. [ABSTRACT FROM AUTHOR]