Abstract The combined use of a hydrophobic ionic liquid catalyst and a fatty alcohol is presented... more Abstract The combined use of a hydrophobic ionic liquid catalyst and a fatty alcohol is presented to synergistically improve cycloaddition reaction of CO2 to epoxides producing cyclic carbonates and envision catalyst recovery by cyclic carbonate removal using water as extracting solvent. This approach is described for the production of propylene carbonate using trihexyl(tetradecyl)phosphonium 2-cyanopyrrolide catalyst -which chemically captures CO2 reactant- and 1-decanol/water mixture as extracting solvent. The novel use of fatty alcohols on CO2 cycloaddition reaction not only permits the effective separation of the catalyst and the product purification, but also improves the CO2 conversion in the reactor, and opens the challenge of process intensification by integrated CO2 capture and conversion.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Abstract CO2 Capture and Utilization (CCU) strategy is being investigated trying to mitigate CO2 ... more Abstract CO2 Capture and Utilization (CCU) strategy is being investigated trying to mitigate CO2 emissions and producing value-added compounds. Specifically, CO2 conversion to cyclic carbonates using ionic liquids (ILs) is being studied as alternative due to the high yields obtained. The challenge to design a CO2 conversion process based on ILs is to efficiently and sustainably solve the product/catalyst separation, especially dealing with a homogeneous catalytic step. In this work, we report the use of ILs based on amino acids as catalysts in combination with water to achieve the reaction mixture separation, enhance the catalytic activity and increase the sustainability of the process. The total catalyst recovery and the product purification were achieved by means of liquid-liquid extraction using water as extracting agent, reaching remarkable distribution coefficients and selectivities. Moreover, the presence of water in the reaction stage increases in more than 40 % the conversion values. In the light of these individual impacts, it is proposed a sustainable process to efficiently produce cyclic carbonates in mild conditions, successfully modelled by COSMO/Aspen methodology. This work presents as first time a feasible CO2 conversion to cyclic carbonates process by addressing the separation of the catalyst from the reaction products with compatibleness with the reaction step, even enhancing catalytic activity, and avoiding high energy-demanding technologies.
Abstract Biogas stands out as an alternative to traditional sources of energy since it presents a... more Abstract Biogas stands out as an alternative to traditional sources of energy since it presents a high methane content, and it is mainly produced by anaerobic digestions of organic wastes. Typical biogas streams do not only consist of biomethane but also carbon dioxide, water, ammonia, hydrogen sulfide or siloxanes, depending on the source of the organic waste. Therefore, it is important to remove all these contaminants to obtain a high-quality stream in a process known as biogas upgrading. Currently, there is not a predominant technology, all of them presenting advantages and drawbacks to be solved. In this work, we test a biogas upgrading process based on CO2 chemical absorption by ionic liquids (ILs). The complete process was evaluated involving absorber and stripping column in a wide range of operating temperatures and pressures to reach biomethane of 97% purity from an industrial biogas stream. Best specific energy consumptions are found at 50 °C in the absorber and 95 °C in the stripper at atmospheric pressure. Increasing the operating pressure of the absorber to 6 bars reduces the energy consumption from 0.8 kWh/Nm3 to 0.2 kWh/Nm3. This is mainly because of the reduction in IL flow (almost a half) and that the thermal energy needed is provided by the exothermic reaction and no external requirements are needed. IL-based proposal for biogas upgrading was found able to efficiently retain CO2 but also other main impurities (H2S, H2O, siloxanes) producing biomethane with quality standards. Results from IL-based process reveal savings in operating cost and nearly the same equipment investment costs than available technologies (PSA, water and amine scrubbing, and membranes) for biogas upgrading process.
Abstract A novel modelling and simulation framework on CO2 desorption process from post-combustio... more Abstract A novel modelling and simulation framework on CO2 desorption process from post-combustion CO2 capture was developed by a coupled membrane vacuum regeneration technology (MVR) and four imidazolium ionic liquids (ILs) with remarkably different viscosity values. The ILs 1-ethyl-3-methylimidazolium acetate ([emim][Ac]), 1-butyl-3-methylimidazolium acetate ([bmim][Ac]), 1-butyl-3- methylimidazolium isobutyrate ([bmim][i-but]), 1-butyl-3-methylimidazolium glycinate ([bmim][GLY]) were selected. COSMO based/Aspen Plus methodology was effectively implemented to estimate the physical and chemical CO2 absorption parameters by kinetic and thermodynamic models fitted to experimental data to design the regeneration process in Aspen Plus software. The membrane contactor unit for solvent regeneration was custom-built and successfully imported into the simulation tool, as no model library for the MVR existed yet in the commercial package for the steady state process flowsheet simulation. The effect on CO2 desorbed flux and process performance was evaluated for the comparison purpose between ILs at different operational conditions. High temperature, vacuum level and module length are beneficial to the solvent regeneration process, while low liquid flow-rate increases the CO2 desorption flux but also decrease the process performance. The viscosity, CO2 solubility and reaction enthalpy were identified as key thermodynamic properties of IL selection. The IL ([emim][Ac]) presented the highest regeneration performance (around 92% at 313 K and vacuum pressure of 0.04 bar) with a total energy consumption of 0.62 MJ·kgCO2-1, which is lower than conventional amino-based high temperature regeneration process (1.55 MJ·kgCO2-1). These results pointed out the interest of the membrane vacuum regeneration technology based on ILs compared to the conventional solvent-based thermal regeneration, but further techno-economic evaluation is further needed to ensure the competitiveness of this novel CO2 desorption approach to the large-scale application.
Current chemical technologies present a negative impact on society and environment since they are... more Current chemical technologies present a negative impact on society and environment since they are based on processes that demand large energy and the use organic solvents, entailing relevant carbon footprint. Emerging solvents impose additional criteria in the design of new separation technologies. Aiming at addressing favorable solvent properties but also reducing emissions of carbon dioxide, cyclic carbonates are CO 2-based synthesizable designer solvents unexplored in the literature. Cyclic carbonates are a new class of tunable compounds with ability to enhance current standards and improve the sustainability of processes. Here a comprehensive and systematic study, covering fundamental and process scale insights, is developed on the use of cyclic carbonates in the most relevant hydrocarbon separations in the literature, namely {n-heptane + toluene}, {cyclohexane + benzene} and {cyclohexane + cyclohexene} by liquid-liquid extraction and extractive distillation. A priori COSMO-RS method described the driving interactions between cyclic carbonates and hydrocarbons, whereas COSMO-based/Aspen was used to further inspect phase equilibria and design liquid-liquid extraction and extractive distillation separation processes, using benchmark industrial solvents (sulfolane and N-formylmorpholine). The favorable process performance starts a new research line to fine-tune cyclic carbonates' structure, but currently drafting feasible approaches, competitive or even better when compared with conventional solvents.
Ionic liquids with an aprotic heterocyclic anion (AHA-ILs) is a promising family of compounds to ... more Ionic liquids with an aprotic heterocyclic anion (AHA-ILs) is a promising family of compounds to overcome the challenge of CO 2 capture. In this work, a computational methodology has been developed to predict CO 2 chemical absorption isotherms in AHA-ILs without the need of experimental data. This methodology combines DFT and COSMO-RS calculations allowing the design of new chemical absorbents for CO 2 capture. The CO 2 physical absorption equilibrium constants (Henry's law constants), chemical equilibrium constants and reaction enthalpies were reliably predicted by proposed computational approach, by means of comparison to available experimental data of 9 different AHA-ILs. Finally, 15 newly designed AHA-ILs were evaluated to demonstrate the flexibility of the DFT/COSMO-RS tool by predicting their CO 2 absorption isotherms. The evaluated absorbents compromise very different behaviors: from physical absorption to reactions completely displaced toward products at very low CO 2 partial pressure, emphasizing the extremely tunable character of AHA-ILs. Current results will definitively contribute to link molecular and processes scales in the research of new CO 2 capture technology based on ILs.
Ionic liquids have gathered special attention due to their potential for carbon dioxide capture, ... more Ionic liquids have gathered special attention due to their potential for carbon dioxide capture, and their potential as solvents for mitigation of climate change. Following the scope of previous works, amino‐acid‐based ionic liquids encapsulated (ENILs) into carbonaceous submicrocapsules are here proposed as a novel material for CO2 capture. The ENILs prepared using tetrabutylphosphonium acetate ([P4,4,4,4][Ac]), used as reference, (2‐hydroxyethyl)trimethylammonium l‐phenylalaninate ([N1,1,1,2(OH)][L‐Phe]), (2‐hydroxyethyl)trimethylammonium l‐prolinate ([N1,1,1,2(OH)][L‐Pro]), and tetrabutylammonium l‐prolinate ([N4,4,4,4][L‐Pro]) were characterized by SEM, TEM, elemental analysis, TGA, and BET to assess their morphology, chemical composition, porous structure, and thermal stability. The absorption of CO2 on these materials was studied up to 0.5 MPa and 343 K. The desorption of CO2 from the saturated ENILs was evaluated, under mild conditions, evidencing these materials as promising...
Ionic liquids are proposed as siloxanes absorbents for biogas upgrading. • The most promising ILs... more Ionic liquids are proposed as siloxanes absorbents for biogas upgrading. • The most promising ILs are selected based on molecular simulation. • ILs satisfy silicon outlet legislation on packed absorption columns. • Solvent regeneration is possible using air stripping column in mild conditions of temperature and pressure.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Regulations on benzene, nitro-and sulfur-containing aromatic hydrocarbon content in commercial ga... more Regulations on benzene, nitro-and sulfur-containing aromatic hydrocarbon content in commercial gasolines are becoming more restrictive due to environmental and health issues. The benzene content in reformulated commercial gasoline is currently around 1 %. The reduction of benzene levels to comply with future regulations will imply significant changes in refinery configurations. This paper reports a novel extraction process to simultaneously separate benzene, thiophene, and pyrrole from a gasoline using the 1-butyl-4-metylpyridinium
CO2 capture by fixed-bed sorption has been evaluated using Supported Ionic Liquid Phase (SILP) ba... more CO2 capture by fixed-bed sorption has been evaluated using Supported Ionic Liquid Phase (SILP) based on the ionic liquid 1-butyl-3-methylimidazolium acetate ([bmim][acetate]). The SILP sorbent was prepared with three remarkably different mean particle sizes and characterized by porous texture, morphology, thermal stability, and elemental composition. The thermodynamics and kinetics of the CO2 capture process has been studied, testing the effects of SILP particle size, sorption temperature, gas flow rate, and CO2 partial pressure. The CO2 sorption isotherms at different temperatures were obtained by gravimetric measurements, revealing that the equilibrium sorption capacity is only due to the IL incorporated on the silica support of SILP. The experimental isotherms were successfully fitted to the Langmuir–Freundlich model. Fixed-bed experiments of CO2 capture were carried out to evaluate the performance of the SILP sorbents at different operating conditions. All the breakthrough curves were well described b...
Journal of Environmental Chemical Engineering, 2017
The separation of ILs from water by fixed-bed adsorption with AC was evaluated. Particle size... more The separation of ILs from water by fixed-bed adsorption with AC was evaluated. Particle size and superficial liquid velocity are key factor regarding the efficiency. The nature of IL plays a key role in the thermodynamics and kinetics of adsorption. Fixed-bed adsorption with AC was found a feasible for hydrophobic ILs removal.
Quantum chemical calculations and in situ infrared spectroscopy were applied to analyze the role ... more Quantum chemical calculations and in situ infrared spectroscopy were applied to analyze the role of CO 2 activation by aprotic heterocyclic anion ionic liquids (AHA-ILs) in its reaction with propylene oxide to form propylene carbonate. Two AHA-ILs with remarkably different behavior as CO 2 chemical absorbent were considered: triethyl(octyl)-phosphonium indazole, [P 2228 ][Inda], and triethyl(octyl)-phosphonium 2-cyanopyrrol-1-ide [P 2228 ][2-CNPyr]. The structure and energy of reaction intermediates were predicted by Density Functional Theory (DFT) method, observing that CO 2 and AHA-IL reaction form an anionic carbamate that promotes a nucleophilic attack on the propylene oxide, causing the ring opening with negligible energy barrier. Later intramolecular cyclization occurs, followed by the AHA-IL regeneration and propylene carbonate production, both requiring appreciable activation energy. The proposed reaction mechanism were experimentally validated by ATR-FTIR measurements, identifying the characteristic signals of reactants, products and intermediate species. Finally, the reaction using the AHA-ILs [P 2228 ][Inda] and [P 2228 ][2-CNPyr] was followed over time using operando ATR-FTIR technique at different operating conditions (temperature and catalyst concentration). A close relationship between the performance of AHA-IL as CO 2 chemical absorbent and CO 2 conversion catalyst is revealed, opening opportunities for the efficient application of AHA-ILs in intensified process of CO 2 capture and utilization.
The performance of an ionic liquid with an aprotic heterocyclic anion (AHA-IL), trihexyl(tetradec... more The performance of an ionic liquid with an aprotic heterocyclic anion (AHA-IL), trihexyl(tetradecyl)phosphonium 2-cyanopyrrolide ([P][2-CNPyr]), for CO capture has been evaluated considering both the thermodynamics and the kinetics of the phenomena. Absorption gravimetric measurements of the gas-liquid equilibrium isotherms of CO-AHA-IL systems were carried out from 298 to 333 K and at pressures up to 15 bar, analyzing the role of both chemical and physical absorption phenomena in the overall CO solubility in the AHA-IL, as has been done previously. In addition, the kinetics of the CO chemical absorption process was evaluated by in situ Fourier transform infrared spectroscopy-attenuated total reflection, following the characteristic vibrational signals of the reactants and products over the reaction time. A chemical absorption model was used to describe the time-dependent concentration of species involved in the reactive absorption, obtaining kinetic parameters (such as chemical rea...
Abstract The combined use of a hydrophobic ionic liquid catalyst and a fatty alcohol is presented... more Abstract The combined use of a hydrophobic ionic liquid catalyst and a fatty alcohol is presented to synergistically improve cycloaddition reaction of CO2 to epoxides producing cyclic carbonates and envision catalyst recovery by cyclic carbonate removal using water as extracting solvent. This approach is described for the production of propylene carbonate using trihexyl(tetradecyl)phosphonium 2-cyanopyrrolide catalyst -which chemically captures CO2 reactant- and 1-decanol/water mixture as extracting solvent. The novel use of fatty alcohols on CO2 cycloaddition reaction not only permits the effective separation of the catalyst and the product purification, but also improves the CO2 conversion in the reactor, and opens the challenge of process intensification by integrated CO2 capture and conversion.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Abstract CO2 Capture and Utilization (CCU) strategy is being investigated trying to mitigate CO2 ... more Abstract CO2 Capture and Utilization (CCU) strategy is being investigated trying to mitigate CO2 emissions and producing value-added compounds. Specifically, CO2 conversion to cyclic carbonates using ionic liquids (ILs) is being studied as alternative due to the high yields obtained. The challenge to design a CO2 conversion process based on ILs is to efficiently and sustainably solve the product/catalyst separation, especially dealing with a homogeneous catalytic step. In this work, we report the use of ILs based on amino acids as catalysts in combination with water to achieve the reaction mixture separation, enhance the catalytic activity and increase the sustainability of the process. The total catalyst recovery and the product purification were achieved by means of liquid-liquid extraction using water as extracting agent, reaching remarkable distribution coefficients and selectivities. Moreover, the presence of water in the reaction stage increases in more than 40 % the conversion values. In the light of these individual impacts, it is proposed a sustainable process to efficiently produce cyclic carbonates in mild conditions, successfully modelled by COSMO/Aspen methodology. This work presents as first time a feasible CO2 conversion to cyclic carbonates process by addressing the separation of the catalyst from the reaction products with compatibleness with the reaction step, even enhancing catalytic activity, and avoiding high energy-demanding technologies.
Abstract Biogas stands out as an alternative to traditional sources of energy since it presents a... more Abstract Biogas stands out as an alternative to traditional sources of energy since it presents a high methane content, and it is mainly produced by anaerobic digestions of organic wastes. Typical biogas streams do not only consist of biomethane but also carbon dioxide, water, ammonia, hydrogen sulfide or siloxanes, depending on the source of the organic waste. Therefore, it is important to remove all these contaminants to obtain a high-quality stream in a process known as biogas upgrading. Currently, there is not a predominant technology, all of them presenting advantages and drawbacks to be solved. In this work, we test a biogas upgrading process based on CO2 chemical absorption by ionic liquids (ILs). The complete process was evaluated involving absorber and stripping column in a wide range of operating temperatures and pressures to reach biomethane of 97% purity from an industrial biogas stream. Best specific energy consumptions are found at 50 °C in the absorber and 95 °C in the stripper at atmospheric pressure. Increasing the operating pressure of the absorber to 6 bars reduces the energy consumption from 0.8 kWh/Nm3 to 0.2 kWh/Nm3. This is mainly because of the reduction in IL flow (almost a half) and that the thermal energy needed is provided by the exothermic reaction and no external requirements are needed. IL-based proposal for biogas upgrading was found able to efficiently retain CO2 but also other main impurities (H2S, H2O, siloxanes) producing biomethane with quality standards. Results from IL-based process reveal savings in operating cost and nearly the same equipment investment costs than available technologies (PSA, water and amine scrubbing, and membranes) for biogas upgrading process.
Abstract A novel modelling and simulation framework on CO2 desorption process from post-combustio... more Abstract A novel modelling and simulation framework on CO2 desorption process from post-combustion CO2 capture was developed by a coupled membrane vacuum regeneration technology (MVR) and four imidazolium ionic liquids (ILs) with remarkably different viscosity values. The ILs 1-ethyl-3-methylimidazolium acetate ([emim][Ac]), 1-butyl-3-methylimidazolium acetate ([bmim][Ac]), 1-butyl-3- methylimidazolium isobutyrate ([bmim][i-but]), 1-butyl-3-methylimidazolium glycinate ([bmim][GLY]) were selected. COSMO based/Aspen Plus methodology was effectively implemented to estimate the physical and chemical CO2 absorption parameters by kinetic and thermodynamic models fitted to experimental data to design the regeneration process in Aspen Plus software. The membrane contactor unit for solvent regeneration was custom-built and successfully imported into the simulation tool, as no model library for the MVR existed yet in the commercial package for the steady state process flowsheet simulation. The effect on CO2 desorbed flux and process performance was evaluated for the comparison purpose between ILs at different operational conditions. High temperature, vacuum level and module length are beneficial to the solvent regeneration process, while low liquid flow-rate increases the CO2 desorption flux but also decrease the process performance. The viscosity, CO2 solubility and reaction enthalpy were identified as key thermodynamic properties of IL selection. The IL ([emim][Ac]) presented the highest regeneration performance (around 92% at 313 K and vacuum pressure of 0.04 bar) with a total energy consumption of 0.62 MJ·kgCO2-1, which is lower than conventional amino-based high temperature regeneration process (1.55 MJ·kgCO2-1). These results pointed out the interest of the membrane vacuum regeneration technology based on ILs compared to the conventional solvent-based thermal regeneration, but further techno-economic evaluation is further needed to ensure the competitiveness of this novel CO2 desorption approach to the large-scale application.
Current chemical technologies present a negative impact on society and environment since they are... more Current chemical technologies present a negative impact on society and environment since they are based on processes that demand large energy and the use organic solvents, entailing relevant carbon footprint. Emerging solvents impose additional criteria in the design of new separation technologies. Aiming at addressing favorable solvent properties but also reducing emissions of carbon dioxide, cyclic carbonates are CO 2-based synthesizable designer solvents unexplored in the literature. Cyclic carbonates are a new class of tunable compounds with ability to enhance current standards and improve the sustainability of processes. Here a comprehensive and systematic study, covering fundamental and process scale insights, is developed on the use of cyclic carbonates in the most relevant hydrocarbon separations in the literature, namely {n-heptane + toluene}, {cyclohexane + benzene} and {cyclohexane + cyclohexene} by liquid-liquid extraction and extractive distillation. A priori COSMO-RS method described the driving interactions between cyclic carbonates and hydrocarbons, whereas COSMO-based/Aspen was used to further inspect phase equilibria and design liquid-liquid extraction and extractive distillation separation processes, using benchmark industrial solvents (sulfolane and N-formylmorpholine). The favorable process performance starts a new research line to fine-tune cyclic carbonates' structure, but currently drafting feasible approaches, competitive or even better when compared with conventional solvents.
Ionic liquids with an aprotic heterocyclic anion (AHA-ILs) is a promising family of compounds to ... more Ionic liquids with an aprotic heterocyclic anion (AHA-ILs) is a promising family of compounds to overcome the challenge of CO 2 capture. In this work, a computational methodology has been developed to predict CO 2 chemical absorption isotherms in AHA-ILs without the need of experimental data. This methodology combines DFT and COSMO-RS calculations allowing the design of new chemical absorbents for CO 2 capture. The CO 2 physical absorption equilibrium constants (Henry's law constants), chemical equilibrium constants and reaction enthalpies were reliably predicted by proposed computational approach, by means of comparison to available experimental data of 9 different AHA-ILs. Finally, 15 newly designed AHA-ILs were evaluated to demonstrate the flexibility of the DFT/COSMO-RS tool by predicting their CO 2 absorption isotherms. The evaluated absorbents compromise very different behaviors: from physical absorption to reactions completely displaced toward products at very low CO 2 partial pressure, emphasizing the extremely tunable character of AHA-ILs. Current results will definitively contribute to link molecular and processes scales in the research of new CO 2 capture technology based on ILs.
Ionic liquids have gathered special attention due to their potential for carbon dioxide capture, ... more Ionic liquids have gathered special attention due to their potential for carbon dioxide capture, and their potential as solvents for mitigation of climate change. Following the scope of previous works, amino‐acid‐based ionic liquids encapsulated (ENILs) into carbonaceous submicrocapsules are here proposed as a novel material for CO2 capture. The ENILs prepared using tetrabutylphosphonium acetate ([P4,4,4,4][Ac]), used as reference, (2‐hydroxyethyl)trimethylammonium l‐phenylalaninate ([N1,1,1,2(OH)][L‐Phe]), (2‐hydroxyethyl)trimethylammonium l‐prolinate ([N1,1,1,2(OH)][L‐Pro]), and tetrabutylammonium l‐prolinate ([N4,4,4,4][L‐Pro]) were characterized by SEM, TEM, elemental analysis, TGA, and BET to assess their morphology, chemical composition, porous structure, and thermal stability. The absorption of CO2 on these materials was studied up to 0.5 MPa and 343 K. The desorption of CO2 from the saturated ENILs was evaluated, under mild conditions, evidencing these materials as promising...
Ionic liquids are proposed as siloxanes absorbents for biogas upgrading. • The most promising ILs... more Ionic liquids are proposed as siloxanes absorbents for biogas upgrading. • The most promising ILs are selected based on molecular simulation. • ILs satisfy silicon outlet legislation on packed absorption columns. • Solvent regeneration is possible using air stripping column in mild conditions of temperature and pressure.
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Regulations on benzene, nitro-and sulfur-containing aromatic hydrocarbon content in commercial ga... more Regulations on benzene, nitro-and sulfur-containing aromatic hydrocarbon content in commercial gasolines are becoming more restrictive due to environmental and health issues. The benzene content in reformulated commercial gasoline is currently around 1 %. The reduction of benzene levels to comply with future regulations will imply significant changes in refinery configurations. This paper reports a novel extraction process to simultaneously separate benzene, thiophene, and pyrrole from a gasoline using the 1-butyl-4-metylpyridinium
CO2 capture by fixed-bed sorption has been evaluated using Supported Ionic Liquid Phase (SILP) ba... more CO2 capture by fixed-bed sorption has been evaluated using Supported Ionic Liquid Phase (SILP) based on the ionic liquid 1-butyl-3-methylimidazolium acetate ([bmim][acetate]). The SILP sorbent was prepared with three remarkably different mean particle sizes and characterized by porous texture, morphology, thermal stability, and elemental composition. The thermodynamics and kinetics of the CO2 capture process has been studied, testing the effects of SILP particle size, sorption temperature, gas flow rate, and CO2 partial pressure. The CO2 sorption isotherms at different temperatures were obtained by gravimetric measurements, revealing that the equilibrium sorption capacity is only due to the IL incorporated on the silica support of SILP. The experimental isotherms were successfully fitted to the Langmuir–Freundlich model. Fixed-bed experiments of CO2 capture were carried out to evaluate the performance of the SILP sorbents at different operating conditions. All the breakthrough curves were well described b...
Journal of Environmental Chemical Engineering, 2017
The separation of ILs from water by fixed-bed adsorption with AC was evaluated. Particle size... more The separation of ILs from water by fixed-bed adsorption with AC was evaluated. Particle size and superficial liquid velocity are key factor regarding the efficiency. The nature of IL plays a key role in the thermodynamics and kinetics of adsorption. Fixed-bed adsorption with AC was found a feasible for hydrophobic ILs removal.
Quantum chemical calculations and in situ infrared spectroscopy were applied to analyze the role ... more Quantum chemical calculations and in situ infrared spectroscopy were applied to analyze the role of CO 2 activation by aprotic heterocyclic anion ionic liquids (AHA-ILs) in its reaction with propylene oxide to form propylene carbonate. Two AHA-ILs with remarkably different behavior as CO 2 chemical absorbent were considered: triethyl(octyl)-phosphonium indazole, [P 2228 ][Inda], and triethyl(octyl)-phosphonium 2-cyanopyrrol-1-ide [P 2228 ][2-CNPyr]. The structure and energy of reaction intermediates were predicted by Density Functional Theory (DFT) method, observing that CO 2 and AHA-IL reaction form an anionic carbamate that promotes a nucleophilic attack on the propylene oxide, causing the ring opening with negligible energy barrier. Later intramolecular cyclization occurs, followed by the AHA-IL regeneration and propylene carbonate production, both requiring appreciable activation energy. The proposed reaction mechanism were experimentally validated by ATR-FTIR measurements, identifying the characteristic signals of reactants, products and intermediate species. Finally, the reaction using the AHA-ILs [P 2228 ][Inda] and [P 2228 ][2-CNPyr] was followed over time using operando ATR-FTIR technique at different operating conditions (temperature and catalyst concentration). A close relationship between the performance of AHA-IL as CO 2 chemical absorbent and CO 2 conversion catalyst is revealed, opening opportunities for the efficient application of AHA-ILs in intensified process of CO 2 capture and utilization.
The performance of an ionic liquid with an aprotic heterocyclic anion (AHA-IL), trihexyl(tetradec... more The performance of an ionic liquid with an aprotic heterocyclic anion (AHA-IL), trihexyl(tetradecyl)phosphonium 2-cyanopyrrolide ([P][2-CNPyr]), for CO capture has been evaluated considering both the thermodynamics and the kinetics of the phenomena. Absorption gravimetric measurements of the gas-liquid equilibrium isotherms of CO-AHA-IL systems were carried out from 298 to 333 K and at pressures up to 15 bar, analyzing the role of both chemical and physical absorption phenomena in the overall CO solubility in the AHA-IL, as has been done previously. In addition, the kinetics of the CO chemical absorption process was evaluated by in situ Fourier transform infrared spectroscopy-attenuated total reflection, following the characteristic vibrational signals of the reactants and products over the reaction time. A chemical absorption model was used to describe the time-dependent concentration of species involved in the reactive absorption, obtaining kinetic parameters (such as chemical rea...
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