jose david esteban valderrama - Academia.edu (original) (raw)
Papers by jose david esteban valderrama
Revista de Estudios Sociales, 1999
Alimentacion Equipos Y Tecnologia, 1994
Se propone una metodología de identificación individual de potenciales beneficiarios de programas... more Se propone una metodología de identificación individual de potenciales beneficiarios de programas sociales. La metodología tiene dos etapas. En la primera etapa, se estima un índice de bienestar siguiendo una práctica extendida en la literatura especializada: análisis de componentes principales con escalamiento óptimo. En la segunda etapa, se determinan los puntos de corte del índice estimado que permiten distinguir a
Industrial & Engineering Chemistry Research, 2015
The group contribution method proposed by Valderrama and Robles in 2007 and updated by Valderrama... more The group contribution method proposed by Valderrama and Robles in 2007 and updated by Valderrama and coworkers in 2012 to estimate the critical properties of ionic liquids is extended to evaluate these properties for ionic liquids of higher molecular mass. The modifications are done to follow the behavior that these properties have for other type of substances, such as the asymptotic tendency of the normal boiling temperature as the molecular mass M increases. The magnitudes of the modifications are found so that the pressure test and the density test previously defined by the authors are fulfilled for most substances. The proposed extension does not change anything of the original method already in use which is valid for ILs with M < 500 g/mol. A total of 316 ionic liquids with M > 500 g/mol are considered in this work. Of these, 310 passed the pressure test. Also, 111 of these ILs have experimental density values and 103 pass the density test, with absolute average deviation of 4.1 %. A spreadsheet for calculating the critical properties and performing the tests is provided as Supporting Information. The spreadsheet file includes at present the properties for 1630 ionic liquids of molecular mass going from 77 to 1730.
Fluid Phase Equilibria, 2014
Solubility data of mixtures containing hydrogen sulfide in ionic liquids and sulfur dioxide in io... more Solubility data of mixtures containing hydrogen sulfide in ionic liquids and sulfur dioxide in ionic liquids at several temperatures and pressures have been tested for thermodynamic consistency. Accurate and consistent data of these mixtures are needed for the design of separation processes for removing sulfur compounds from industrial gases, processes in which ionic liquids present tremendous potential as solvents and extracting agents. The study considers data of twelve binary hydrogen sulfide + ionic liquids mixtures and three binary sulfur dioxide + ionic liquid mixtures. The modified Peng-Robinson equation of state proposed by Kwak and Mansoori is used for correlating the solubility data and a flexible thermodynamic consistency method is applied to analyze 80 isothermal P-x data sets including 630 data points available in the open literature. Modeling is found acceptable in all cases and the thermodynamic consistency method gives a clear conclusion about consistency or inconsistency of each set of data.
Comptes Rendus Chimie, 2014
ABSTRACT Artificial neural networks have been used for the correlation and prediction of solubili... more ABSTRACT Artificial neural networks have been used for the correlation and prediction of solubility data of ammonia in ionic liquids. This solubility of ammonia is highly variable for different types of ionic liquids at the same temperature and pressure, its correlation and prediction is of special importance in the removal of ammonia from flue gases for which effective and efficient solvents are required. Nine binary ammonia + ionic liquids mixtures were considered in the study. Solubility data (P–T–x) of these systems were taken from the literature (208 data points for training and 50 data points for testing). The training variables are the temperature and the pressure of the binary systems (T, P), being the target variable the solubility of ammonia in the ionic liquid (x). The study shows that the neural network model is a good alternative method for the estimation of solubility for this type of mixtures. Absolute average deviations were below 5.6%, for each isothermal data set and overall absolute average deviations were below 3.0%. Only in the range of low solubility (below 0.2 in mole fraction) did predicted solubility give deviations higher than 10%.
Industrial & Engineering Chemistry Research, 2014
The use of artificial neural networks (ANN) for the correlation and prediction of the melting tem... more The use of artificial neural networks (ANN) for the correlation and prediction of the melting temperature of ionic liquids is analyzed in this paper. Several network architectures and two sets of data were analyzed and results compared with others from the literature. The independent variables considered for training the ANN were: groups forming the molecules, mass of the cation, mass of the anion and mass connectivity index. As a measure of the accuracy of the method the average deviation and the average absolute deviation are evaluated. Results of this work and others from the literature indicate that appropriate selection of data, a good combination of architecture and variables can lead to acceptable correlation of data but accurate prediction is not yet possible.
Se propone una metodología de identificación individual de potenciales beneficiarios de programas... more Se propone una metodología de identificación individual de potenciales beneficiarios de programas sociales. Esta herramienta comprende dos etapas: en la primera se determina un índice de bienestar y en la segunda los puntos de corte que permiten distinguir a los hogares que califican como potenciales beneficiarios. La estimación del índice se basa en una práctica extendida en la literatura especializada:
Thermochimica Acta, 2011
A simple and accurate model to predict the heat capacity of ionic liquids is presented. The propo... more A simple and accurate model to predict the heat capacity of ionic liquids is presented. The proposed model considers variables readily available for ionic liquids and that have important effect on heat capacity, according to the literature information. Additionally a recently defined structural parameter known as mass connectivity index is incorporated into the model. A set of 602 heat capacity data for 146 ionic liquids have been used in the study. The results were compared with experimental data and with values reported by other available estimation methods. Results show that the new simple correlation gives low deviations and can be used with confidence in thermodynamic and engineering calculations.
Thermochimica Acta, 2007
Solvent effects in the calculation of the sublimation pressure of pure solids using high pressure... more Solvent effects in the calculation of the sublimation pressure of pure solids using high pressure solubility data are discussed. Three binary gas-solid systems containing anthracene, napthalene and phenanthrene as solutes and carbon dioxide, ethane, ethylene, fluoroform, chlorotrifluoromethane as solvents are considered in the study. The Peng-Robinson EoS with the mixing rules proposed by Wong and Sandler are used to evaluate the fugacity coefficient ϕ S included in the classical solubility equation which relates the mole fraction of a dissolved solid in a compressed gas phase. The sublimation pressure P S of the solid is considered as a parameter to be determined by regression analysis of experimental solubility data (TPy), and theoretically it should be independent of the solvent. The results show that the determination of sublimation pressure using high pressure solubility data is reliable and produce unique values of sublimation pressure independent of the solvents in the mixtures.
The Journal of Chemical Thermodynamics, 2011
A simple and accurate group contribution method to estimate the heat capacity of ionic liquids is... more A simple and accurate group contribution method to estimate the heat capacity of ionic liquids is presented. The method considers groups previously defined for a successful method used to estimate critical properties of ionic liquids. Additionally a structural parameter known as mass connectivity index recently defined by the authors has been incorporated to define the model equation. To better define
The Journal of Supercritical Fluids, 2012
Gas-liquid equilibrium in mixtures containing supercritical carbon dioxide and an ionic liquid ha... more Gas-liquid equilibrium in mixtures containing supercritical carbon dioxide and an ionic liquid has been modeled using the Peng-Robinson equation of state and the interesting modification proposed by Kwak and Mansoori. The proposal is based on statistical-mechanical arguments and on the fact that mixing rules are for constants of an equation of state and not for functions such as the alpha expression that makes the attractive term temperature dependent. Experimental data for mixtures containing carbon dioxide and ionic liquids were obtained from literature sources and the adjustable parameters of the mixing rules were found by minimizing the errors between predicted and experimental bubble pressure. Results were compared with experimental data and with results of other classical mixing rules, such as the proposal of Wong and Sandler. The deviations in correlating gas-liquid equilibrium found with the model Peng-Robinson/Kwak-Mansoori are lower in general than the results obtained with other models.
The Journal of Supercritical Fluids, 2013
The effect on the melting temperature depression (MTD) of organic substances and ionic liquids ca... more The effect on the melting temperature depression (MTD) of organic substances and ionic liquids caused by different types of pressurizing gases is analyzed. A high pressure gas produces a combined effect between solubility and pressure that causes the melting temperature to decrease. The authors have previously used phase equilibrium relations to correlate MTD of organic substances and ionic liquids under high pressure carbon dioxide, but other gases were not considered. The Peng-Robinson equation of state with the Wong-Sandler mixing rules showed to be appropriate for correlating the phase equilibrium in these high pressurized systems and is the model used is in this work. Three organic substances (naphthalene, biphenyl and octacosane) under high pressure produced by three gases (ethane, ethylene and carbon dioxide) for which experimental data on MTD are available were considered in this study. Then extension to an ionic liquid under high pressure carbon dioxide and high pressure ethylene was done. The proposed thermodynamic method and the model used show to have the necessary flexibility to acceptably correlate the MTD produced in these systems.
International Journal of Thermophysics, 2011
Artificial neural networks and the concept of mass connectivity index are used to correlate and p... more Artificial neural networks and the concept of mass connectivity index are used to correlate and predict the heat capacity at constant pressure of ionic liquids (ILs). Different topologies of a multilayer feed-forward artificial neural network were studied, and the optimum architecture was determined. Heat-capacity data at several temperatures taken from the literature for 31 ILs with 477 data points were used for training the network. To discriminate among the different substances, the molecular mass of the anion and of the cation and the mass connectivity index were considered as the independent variables. The capabilities of the designed network were tested by predicting heat capacities for situations not considered during the training process (65 heat-capacity data for nine ILs). The results demonstrate that the chosen network and the variables considered allow estimating the heat capacity of ILs with acceptable accuracy for engineering calculations. The program codes and the necessary input Electronic supplementary material The online version of this article
Industrial & Engineering Chemistry Research, 2012
ABSTRACT The group contribution method proposed by Valderrama and Robles in 2007 and extended by ... more ABSTRACT The group contribution method proposed by Valderrama and Robles in 2007 and extended by Valderrama and Rojas in 2009 to estimate the critical properties of ionic liquids is revised and an additional test for determining the consistency of the estimated properties is proposed. The new testing method includes the calculation of the saturation pressure at the normal boiling temperature using an equation of state and an accurate model to represent the temperature function of the attractive term in the equation of state. In determining the vapor pressure, the critical temperature, the critical pressure, the critical volume, and the acentric factor determined by group contribution are included. The proposed method complements the previous density test of the authors that tested the critical temperature, the critical volume, and the normal boiling temperature only. A total of 1130 ionic liquids are considered in this work, and double checking, using the density and the normal vapor pressure, is applied. Also, a spreadsheet file that allows any reader to calculate and check the critical properties of other ionic liquids containing any of the 44 groups defined by the method is provided. ■ INTRODUCTION In a series of previous papers the authors proposed and applied a group contribution method to determine several basic properties of ionic liquids. 1−3 The critical properties (T c , P c , V c), the normal boiling temperature (T b), and the acentric factor (ω) of ionic liquids were calculated and checked for accuracy and consistency. The proposed group contribution method has been used by several researchers for correlating and estimating several properties of ionic liquids and even determining gas−liquid equilibrium in mixtures. 4−14
Food and Bioproducts Processing, 2012
Several studies done in the literature on the simulation of distillation processes of interest in... more Several studies done in the literature on the simulation of distillation processes of interest in the alcoholic food industry are reviewed, with emphasis on the advances done by the authors group on the thermodynamic modeling of water + ethanol + congener mixtures. In wine and must distillation the presence of polar substances found in the mixture to be distilled and the very low concentration of many components (different from ethanol and water), called congeners, make it difficult to model these mixtures, for simulation and design purposes. This is probably the main cause for the little progress done in obtaining accurate simulation of alcohol distillation processes. This review discusses the availability of appropriate data for modeling these processes, analyzes the different models available and their capabilities. Conclusions on the accuracy of the most appropriate models and recommendations for current and future studies are provided.
Fluid Phase Equilibria, 2013
Fluid Phase Equilibria, 2013
ABSTRACT Phase equilibrium data of temperature, pressure and solubility (T–P–x) of ammonia in dif... more ABSTRACT Phase equilibrium data of temperature, pressure and solubility (T–P–x) of ammonia in different types of ionic liquids over wide ranges of temperatures and pressures are modeled and tested for thermodynamic consistency. The modified Peng–Robinson equation of state proposed by Kwak and Mansoori is used for correlating the isothermal PX data and a flexible thermodynamic consistency method applied to analyze forty seven isothermal P–x data available in the open literature. Modeling is found acceptable in all cases, meaning that deviations in correlating the data are low, proving at the same time the claimed flexibility of a well-founded model that uses simple van der Waals mixing rules. For all cases, the thermodynamic consistency method gives a clear conclusion about consistency or inconsistency of a set of experimental T–P–x data based on the established criteria.
Revista de Estudios Sociales, 1999
Alimentacion Equipos Y Tecnologia, 1994
Se propone una metodología de identificación individual de potenciales beneficiarios de programas... more Se propone una metodología de identificación individual de potenciales beneficiarios de programas sociales. La metodología tiene dos etapas. En la primera etapa, se estima un índice de bienestar siguiendo una práctica extendida en la literatura especializada: análisis de componentes principales con escalamiento óptimo. En la segunda etapa, se determinan los puntos de corte del índice estimado que permiten distinguir a
Industrial & Engineering Chemistry Research, 2015
The group contribution method proposed by Valderrama and Robles in 2007 and updated by Valderrama... more The group contribution method proposed by Valderrama and Robles in 2007 and updated by Valderrama and coworkers in 2012 to estimate the critical properties of ionic liquids is extended to evaluate these properties for ionic liquids of higher molecular mass. The modifications are done to follow the behavior that these properties have for other type of substances, such as the asymptotic tendency of the normal boiling temperature as the molecular mass M increases. The magnitudes of the modifications are found so that the pressure test and the density test previously defined by the authors are fulfilled for most substances. The proposed extension does not change anything of the original method already in use which is valid for ILs with M < 500 g/mol. A total of 316 ionic liquids with M > 500 g/mol are considered in this work. Of these, 310 passed the pressure test. Also, 111 of these ILs have experimental density values and 103 pass the density test, with absolute average deviation of 4.1 %. A spreadsheet for calculating the critical properties and performing the tests is provided as Supporting Information. The spreadsheet file includes at present the properties for 1630 ionic liquids of molecular mass going from 77 to 1730.
Fluid Phase Equilibria, 2014
Solubility data of mixtures containing hydrogen sulfide in ionic liquids and sulfur dioxide in io... more Solubility data of mixtures containing hydrogen sulfide in ionic liquids and sulfur dioxide in ionic liquids at several temperatures and pressures have been tested for thermodynamic consistency. Accurate and consistent data of these mixtures are needed for the design of separation processes for removing sulfur compounds from industrial gases, processes in which ionic liquids present tremendous potential as solvents and extracting agents. The study considers data of twelve binary hydrogen sulfide + ionic liquids mixtures and three binary sulfur dioxide + ionic liquid mixtures. The modified Peng-Robinson equation of state proposed by Kwak and Mansoori is used for correlating the solubility data and a flexible thermodynamic consistency method is applied to analyze 80 isothermal P-x data sets including 630 data points available in the open literature. Modeling is found acceptable in all cases and the thermodynamic consistency method gives a clear conclusion about consistency or inconsistency of each set of data.
Comptes Rendus Chimie, 2014
ABSTRACT Artificial neural networks have been used for the correlation and prediction of solubili... more ABSTRACT Artificial neural networks have been used for the correlation and prediction of solubility data of ammonia in ionic liquids. This solubility of ammonia is highly variable for different types of ionic liquids at the same temperature and pressure, its correlation and prediction is of special importance in the removal of ammonia from flue gases for which effective and efficient solvents are required. Nine binary ammonia + ionic liquids mixtures were considered in the study. Solubility data (P–T–x) of these systems were taken from the literature (208 data points for training and 50 data points for testing). The training variables are the temperature and the pressure of the binary systems (T, P), being the target variable the solubility of ammonia in the ionic liquid (x). The study shows that the neural network model is a good alternative method for the estimation of solubility for this type of mixtures. Absolute average deviations were below 5.6%, for each isothermal data set and overall absolute average deviations were below 3.0%. Only in the range of low solubility (below 0.2 in mole fraction) did predicted solubility give deviations higher than 10%.
Industrial & Engineering Chemistry Research, 2014
The use of artificial neural networks (ANN) for the correlation and prediction of the melting tem... more The use of artificial neural networks (ANN) for the correlation and prediction of the melting temperature of ionic liquids is analyzed in this paper. Several network architectures and two sets of data were analyzed and results compared with others from the literature. The independent variables considered for training the ANN were: groups forming the molecules, mass of the cation, mass of the anion and mass connectivity index. As a measure of the accuracy of the method the average deviation and the average absolute deviation are evaluated. Results of this work and others from the literature indicate that appropriate selection of data, a good combination of architecture and variables can lead to acceptable correlation of data but accurate prediction is not yet possible.
Se propone una metodología de identificación individual de potenciales beneficiarios de programas... more Se propone una metodología de identificación individual de potenciales beneficiarios de programas sociales. Esta herramienta comprende dos etapas: en la primera se determina un índice de bienestar y en la segunda los puntos de corte que permiten distinguir a los hogares que califican como potenciales beneficiarios. La estimación del índice se basa en una práctica extendida en la literatura especializada:
Thermochimica Acta, 2011
A simple and accurate model to predict the heat capacity of ionic liquids is presented. The propo... more A simple and accurate model to predict the heat capacity of ionic liquids is presented. The proposed model considers variables readily available for ionic liquids and that have important effect on heat capacity, according to the literature information. Additionally a recently defined structural parameter known as mass connectivity index is incorporated into the model. A set of 602 heat capacity data for 146 ionic liquids have been used in the study. The results were compared with experimental data and with values reported by other available estimation methods. Results show that the new simple correlation gives low deviations and can be used with confidence in thermodynamic and engineering calculations.
Thermochimica Acta, 2007
Solvent effects in the calculation of the sublimation pressure of pure solids using high pressure... more Solvent effects in the calculation of the sublimation pressure of pure solids using high pressure solubility data are discussed. Three binary gas-solid systems containing anthracene, napthalene and phenanthrene as solutes and carbon dioxide, ethane, ethylene, fluoroform, chlorotrifluoromethane as solvents are considered in the study. The Peng-Robinson EoS with the mixing rules proposed by Wong and Sandler are used to evaluate the fugacity coefficient ϕ S included in the classical solubility equation which relates the mole fraction of a dissolved solid in a compressed gas phase. The sublimation pressure P S of the solid is considered as a parameter to be determined by regression analysis of experimental solubility data (TPy), and theoretically it should be independent of the solvent. The results show that the determination of sublimation pressure using high pressure solubility data is reliable and produce unique values of sublimation pressure independent of the solvents in the mixtures.
The Journal of Chemical Thermodynamics, 2011
A simple and accurate group contribution method to estimate the heat capacity of ionic liquids is... more A simple and accurate group contribution method to estimate the heat capacity of ionic liquids is presented. The method considers groups previously defined for a successful method used to estimate critical properties of ionic liquids. Additionally a structural parameter known as mass connectivity index recently defined by the authors has been incorporated to define the model equation. To better define
The Journal of Supercritical Fluids, 2012
Gas-liquid equilibrium in mixtures containing supercritical carbon dioxide and an ionic liquid ha... more Gas-liquid equilibrium in mixtures containing supercritical carbon dioxide and an ionic liquid has been modeled using the Peng-Robinson equation of state and the interesting modification proposed by Kwak and Mansoori. The proposal is based on statistical-mechanical arguments and on the fact that mixing rules are for constants of an equation of state and not for functions such as the alpha expression that makes the attractive term temperature dependent. Experimental data for mixtures containing carbon dioxide and ionic liquids were obtained from literature sources and the adjustable parameters of the mixing rules were found by minimizing the errors between predicted and experimental bubble pressure. Results were compared with experimental data and with results of other classical mixing rules, such as the proposal of Wong and Sandler. The deviations in correlating gas-liquid equilibrium found with the model Peng-Robinson/Kwak-Mansoori are lower in general than the results obtained with other models.
The Journal of Supercritical Fluids, 2013
The effect on the melting temperature depression (MTD) of organic substances and ionic liquids ca... more The effect on the melting temperature depression (MTD) of organic substances and ionic liquids caused by different types of pressurizing gases is analyzed. A high pressure gas produces a combined effect between solubility and pressure that causes the melting temperature to decrease. The authors have previously used phase equilibrium relations to correlate MTD of organic substances and ionic liquids under high pressure carbon dioxide, but other gases were not considered. The Peng-Robinson equation of state with the Wong-Sandler mixing rules showed to be appropriate for correlating the phase equilibrium in these high pressurized systems and is the model used is in this work. Three organic substances (naphthalene, biphenyl and octacosane) under high pressure produced by three gases (ethane, ethylene and carbon dioxide) for which experimental data on MTD are available were considered in this study. Then extension to an ionic liquid under high pressure carbon dioxide and high pressure ethylene was done. The proposed thermodynamic method and the model used show to have the necessary flexibility to acceptably correlate the MTD produced in these systems.
International Journal of Thermophysics, 2011
Artificial neural networks and the concept of mass connectivity index are used to correlate and p... more Artificial neural networks and the concept of mass connectivity index are used to correlate and predict the heat capacity at constant pressure of ionic liquids (ILs). Different topologies of a multilayer feed-forward artificial neural network were studied, and the optimum architecture was determined. Heat-capacity data at several temperatures taken from the literature for 31 ILs with 477 data points were used for training the network. To discriminate among the different substances, the molecular mass of the anion and of the cation and the mass connectivity index were considered as the independent variables. The capabilities of the designed network were tested by predicting heat capacities for situations not considered during the training process (65 heat-capacity data for nine ILs). The results demonstrate that the chosen network and the variables considered allow estimating the heat capacity of ILs with acceptable accuracy for engineering calculations. The program codes and the necessary input Electronic supplementary material The online version of this article
Industrial & Engineering Chemistry Research, 2012
ABSTRACT The group contribution method proposed by Valderrama and Robles in 2007 and extended by ... more ABSTRACT The group contribution method proposed by Valderrama and Robles in 2007 and extended by Valderrama and Rojas in 2009 to estimate the critical properties of ionic liquids is revised and an additional test for determining the consistency of the estimated properties is proposed. The new testing method includes the calculation of the saturation pressure at the normal boiling temperature using an equation of state and an accurate model to represent the temperature function of the attractive term in the equation of state. In determining the vapor pressure, the critical temperature, the critical pressure, the critical volume, and the acentric factor determined by group contribution are included. The proposed method complements the previous density test of the authors that tested the critical temperature, the critical volume, and the normal boiling temperature only. A total of 1130 ionic liquids are considered in this work, and double checking, using the density and the normal vapor pressure, is applied. Also, a spreadsheet file that allows any reader to calculate and check the critical properties of other ionic liquids containing any of the 44 groups defined by the method is provided. ■ INTRODUCTION In a series of previous papers the authors proposed and applied a group contribution method to determine several basic properties of ionic liquids. 1−3 The critical properties (T c , P c , V c), the normal boiling temperature (T b), and the acentric factor (ω) of ionic liquids were calculated and checked for accuracy and consistency. The proposed group contribution method has been used by several researchers for correlating and estimating several properties of ionic liquids and even determining gas−liquid equilibrium in mixtures. 4−14
Food and Bioproducts Processing, 2012
Several studies done in the literature on the simulation of distillation processes of interest in... more Several studies done in the literature on the simulation of distillation processes of interest in the alcoholic food industry are reviewed, with emphasis on the advances done by the authors group on the thermodynamic modeling of water + ethanol + congener mixtures. In wine and must distillation the presence of polar substances found in the mixture to be distilled and the very low concentration of many components (different from ethanol and water), called congeners, make it difficult to model these mixtures, for simulation and design purposes. This is probably the main cause for the little progress done in obtaining accurate simulation of alcohol distillation processes. This review discusses the availability of appropriate data for modeling these processes, analyzes the different models available and their capabilities. Conclusions on the accuracy of the most appropriate models and recommendations for current and future studies are provided.
Fluid Phase Equilibria, 2013
Fluid Phase Equilibria, 2013
ABSTRACT Phase equilibrium data of temperature, pressure and solubility (T–P–x) of ammonia in dif... more ABSTRACT Phase equilibrium data of temperature, pressure and solubility (T–P–x) of ammonia in different types of ionic liquids over wide ranges of temperatures and pressures are modeled and tested for thermodynamic consistency. The modified Peng–Robinson equation of state proposed by Kwak and Mansoori is used for correlating the isothermal PX data and a flexible thermodynamic consistency method applied to analyze forty seven isothermal P–x data available in the open literature. Modeling is found acceptable in all cases, meaning that deviations in correlating the data are low, proving at the same time the claimed flexibility of a well-founded model that uses simple van der Waals mixing rules. For all cases, the thermodynamic consistency method gives a clear conclusion about consistency or inconsistency of a set of experimental T–P–x data based on the established criteria.