On the volatility of aromatic hydrocarbons in ionic liquids: Vapor-liquid equilibrium measurements and theoretical analysis

The use of ionic liquids (ILs) as solvent in the liquid-liquid extraction of aromatic compounds is one of their most studied applications. Nevertheless, the recovery of the extracted hydrocarbons has been much less investigated, being a required task to complete the global separation process. Taking into account the negligible vapor pressure of the ILs, this step could be easily carried out by flash distillation, which requires the study of vapor-liquid equilibrium (VLE). In order to study this topic deeper, in this work a systematic analysis of the VLE and vapor-liquid-liquid equilibrium (VLLE) data for {aromatic hydrocarbon + IL} binary mixtures was carried out, from both an experimental and computational point of view. For that, new experimental VLE and VLLE data of 24 {toluene + IL} binary mixtures were measured at 323.15 K using a technique based on the static headspace gas chromatography (HS-GC), providing relevant information on the toluene retained in the liquid depending on the cation/anion structure of the IL in the mixture. Furthermore, the quantum chemical Conductor-like Screening Model for Real Solvents (COSMO-RS) method was applied to better understand the structure-property relationship determining the phase behavior of {aromatic hydrocarbon + IL} binary systems. First, the suitability of COSMO-RS to predict VLE and VLLE data of {toluene + IL} binary mixtures was evaluated by comparison to 225 experimental data at 323.15 K, including 24 different ILs over the whole composition range. Valuable conclusions were achieved respect to the molecular model of IL needed to adequately predict VLE and VLLE data of the {aromatic hydrocarbon + IL} binary mixtures. Once the computational approach was stated, COSMO-RS methodology was used to analyze the influence of the intermolecular interactions between the toluene and the IL component on the phase behavior of their mixtures. As a result, COSMO-RS was demonstrated as a useful tool for the rational design of ILs with optimized properties for the separation of aromatic + aliphatic hydrocarbon binary mixtures, considering both liquid-liquid extraction and solvent regeneration stepsThe authors are grateful to Ministerio de Economía y Competitividad (MINECO) of Spain for financial support of Projects CTQ2014-52288-R and CTQ2014–53655-R and to Comunidad Autónoma de Madrid for the Project S2013/MAE-2800. Pablo Navarro thanks Fundação para a Ciência e a Tecnologia for awarding him a postdoctoral grant (Reference SFRH/BPD/117084/2016). Marcos Larriba also thanks MINECO for awarding him a Juan de la Cierva-Formación Contract (Reference FJCI-2015-25343)

Thermal stability of choline chloride deep eutectic solvents by TGA/FTIR-ATR analysis

Deep eutectic solvents (DESs) based on the cation choline have been proposed to date for a variety of applications due to their remarkable physicochemical properties. The thermal stability is one of the first properties of DESs that needs to be known since it limits the maximum operating temperature for which these solvents are useful in many applications. In this work, the thermal stability of eight different choline chloride-based DESs formed using levulinic acid, malonic acid, glycerol, ethylene glycol, phenylacetic acid, phenylpropionic acid, urea, and glucose as hydrogen bond donors (HBDs) has been studied using isothermal and dynamic thermogravimetric analysis/Fourier transform infrared-attenuated total reflectance spectroscopy (TGA/FTIR-ATR) techniques. Isothermal and dynamic FTIR-ATR were carried out to confirm the formation and to show the structural changes with temperature of the DESs, respectively. The onset decomposition temperatures of the DESs were obtained from dynamic TGA. However, the maximum operating temperatures determined by isothermal TGA in long-term scenarios have demonstrated to be significantly lower than the onset decomposition temperatures for every DES studied. The thermal stability and the boiling point of HBDs have a crucial impact on the maximum operating temperature of DESs.publishe

Imidazolium and pyridinium-based ionic liquids for the cyclohexane/cyclohexene separation by liquid-liquid extraction

The separation of olefins/paraffins is a challenge for the petrochemical industry due to the close boiling points of these hydrocarbons. In this work we have studied the feasibility of different imidazolium and pyridinium-based ionic liquids (ILs) as alternative solvents in the cyclohexane/cyclohexene separation. Five ILs have been studied, namely 1-butyl-4-methylpyridinium tricyanomethanide ([4bmpy][TCM]), bis(1-ethyl-3-methylimidazolium) tetrathiocyanatocobaltate ([emim]2[Co(SCN)4]), bis(1-butyl-3-methylimidazolium) tetrathiocyanatocobaltate ([bmim]2[Co(SCN)4]), 1-ethyl-4-methylpyridinium bis(trifluoromethylsulfonyl)imide ([4empy][Tf2N]), and 1-butyl-4-methylpyridinium bis(trifluoromethylsulfonyl)imide ([4bmpy][Tf2N]). Experimental liquid-liquid equilibrium (LLE) data were obtained for the equimolar ternary mixtures {cyclohexane (1) + cyclohexene (2) + IL (3)} at T = (298.2, 313.2 and 328.2) K and atmospheric pressure in order to study the effect of the temperature on the extractive properties. Afterwards, LLE data for every ternary system was determined at the best temperature and for the whole cyclohexane/cyclohexene composition range. These ILs have shown promising results in terms of distribution ratio and selectivity, showing the [4bmpy][TCM] IL the best extractive properties at 298.2 K and atmospheric pressure. The Non-Random Two Liquids (NRTL) model was used to successfully correlate the experimental LLE data.publishe

Novel process to reduce benzene, thiophene, and pyrrole in gasoline based on [4bmpy][TCM] Ionic Liquid

This document is the accepted version of a published work that appeared in final form in Energy Fuels copyright © American Chemical Society after peer review and technical editing bu the publisher. to access final edited work see Novel Process to Reduce Benzene, Thiophene, and Pyrrole in Gasoline Based on [4bmpy][TCM] Ionic Liquid Marcos Larriba, Noemí Delgado-Mellado, Pablo Navarro, Roberto Alcover, Cristian Moya, José Palomar, Julián García, and Francisco Rodríguez Energy & Fuels 2018 32 (4), 5650-5658 DOI: 10.1021/acs.energyfuels.8b00529Regulations 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 tricyanomethanide ([4bmpy][TCM]) ionic liquid (IL). A distillation sequence is also proposed for the isolation of the three aromatic hydrocarbons. The conceptual design of the whole process has been based on experimental data from the liquid-liquid extraction and vapor-liquid separation of benzene, thiophene, and pyrrole from isooctane using the IL [4bmpy][TCM]. A COSMO-based/Aspen Plus methodology has been used to simulate the conceptual design. The a priori COSMO-based/Aspen Plus approach was validated by comparison with the experimental liquid-liquid extraction results and conventional simulations based on experimental distribution ratios and K values. Benzene, thiophene, and pyrrole contents in the gasoline would be reduced from 5.0% to 0.1% using the proposed process with a solvent-to-feed mass ratio of 5.0, and also three streams with high content in each aromatic would be obtained. Increasing the solvent-to-feed mass ratio above 5.0, benzene content in the treated gasoline could be reduced up to 200 ppm.The authors are grateful to Ministerio de Economía y Competitividad (MINECO) of Spain and Comunidad Autónoma de Madrid for financial support of Projects CTQ2014–53655-R and S2013/MAE-2800, respectively. N.D.M. thanks MINECO for her FPI grant (Reference BES–2015–072855) and M.L. also thanks MINECO for his Juan de la Cierva-Formación Contract (Reference FJCI-2015-25343). P.N. thanks Fundação para a Ciência e a Tecnologia for awarding him a postdoctoral grant (Reference SFRH/BPD/117084/2016

Application of Sludge-Based Activated Carbons for the Effective Adsorption of Neonicotinoid Pesticides

The amount of sludge produced in wastewater treatment plants (WWTPs) has increased over the years, and the methods used to reduce this waste, such as incineration, agricultural use, or disposal in landfills, cause problems of secondary pollution. For this reason, it is necessary to find sustainable and low-cost solutions to manage this waste. Additionally, emerging and priority pollutants are attracting attention from the scientific community as they can generate health problems due to inadequate removal in conventional WWTPs. In this work, a pharmaceutical industry sludge was used as a precursor in the synthesis of four activated carbons (ACs) using different activating agents (ZnCl2, FeCl3∙6H2O, Fe(NO3)3∙9H2O, and Fe(SO4)3∙H2O), to be used for the removal by adsorption of three neonicotinoid pesticides included in latest EU Watch List (Decision 2018/840): acetamiprid (ACT), thiamethoxam (THM), and imidacloprid (IMD). The prepared ACs showed micro–mesoporous properties, obtaining relatively slow adsorption kinetics to reach equilibrium, but despite this, high values of adsorption capacity (qe) were obtained. For example, for AC-ZnCl2 (SBET = 558 m2/g), high adsorption capacities of qe = 128.9, 126.8, and 166.1 mg/g for ACT, THM, and IMD, respectively, were found. In most cases, the adsorption isotherms showed a multilayer profile, indicating an important contribution of the mesoporosity of the activated carbons in the adsorption process.Depto. de Ingeniería Química y de MaterialesFac. de Ciencias QuímicasTRUEComunidad de Madridpu

Using COSMO-RS to design choline chloride pharmaceutical eutectic solvents

Deep eutectic solvents (DES) present interesting properties, mostly connected to their solvation ability, and have been subject to much research in the recent past. Currently, the discovery of new eutectic solvents is accomplished by experimentally measuring the eutectic point of random systems, often using choline chloride as a hydrogen bond acceptor. In this work, the eutectic temperatures of new choline chloride-based eutectic systems were experimentally assessed. These data, along with other previously reported in the literature, were used to evaluate a method based on COSMO-RS to predict the eutectic temperature of choline-chloride based mixtures. The predictive methodology herein developed allows for the quick scanning of a large matrix of systems in order to identify those more promising to be in the liquid state at a given temperature. To validate this method, the eutectic temperature of pharmaceutical drug mixtures was predicted and, then, assessed experimentally, showing that COSMO-RS is useful in the design of liquid drug-based formulations.This work was developed in the scope of the project CICECO e Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (Ref. FCT UID/CTM/50011/2013) and Associate Laboratory LSRE-LCM, POCI- 01-0145-FEDER-006984 (Ref. FCT UID/EQU/50020/2013), and project MultiBiorefinery (POCI-01-0145-FEDER-016403), financed by national funds through the FCT/MEC and when appropriate cofinanced by FEDDER under the PT2020 Partnership Agreement. FCT is also acknowledged for funding the project DeepBiorefinery (PTDC/AGRTEC/1191/2014). Marcos Larriba also thanks Ministerio de Eduación, Cultura y Deporte of Spain for awarding him a José Castillejo postdoctoral mobility grant (CAS17/00018).info:eu-repo/semantics/publishedVersio

An overview process analysis of the aromatic-aliphatic separation by liquid–liquid extraction with ionic liquids

There is a lack of knowledge on comprehensive studies when dealing with ionic liquids and extraction processes. In this work, the computational COSMO-based/Aspen multiscale methodology is applied to perform a comprehensive process analysis over a wide set of 100 common ILs after properly validating against all reliable data published, in the representative field of the aromatic/aliphatic separation. The analysis describes: i) the evolution from extractive properties to extractor behavior; ii) the influence of the rigor of the model -binary (n-heptane + toluene) or multicomponent (pyrolysis gasoline) and the process description, namely extractor or complete process with recycling streams; iii) the role of the IL at commercial specifications; iv) the role of the separation train. Main results highlight: i) leading role of mass-based distribution ratio to reduce energy consumption to assess a commercial recovery; ii) selecting an IL with a minimum selectivity required within the more efficient separation train to achieve specifications at the lower energy consumption. Therefore, this work presented a clear guide to properly select the IL extractive properties at process scale and commercial specifications, together with the development of an efficient separation train, as the best approac

COSMO-based/Aspen Plus process simulation of the aromatic extraction from pyrolysis gasoline using the {[4empy][NTf2] + [emim][DCA]} ionic liquid mixture

The ionic liquids (ILs) have been widely studied as potential replacements of conventional solvents in the extraction of aromatic hydrocarbons from alkanes. However, most of the literature is focused in obtaining liquid-liquid equilibria experimental data without studying the complete extraction and IL regeneration process. In this paper, a computer-aided methodology combining COSMO-based molecular simulations and Aspen Plus process simulations has been used to study the extraction process of aromatic hydrocarbons from pyrolysis gasoline employing a binary mixture of 1-ethyl-4-methylpyridinium bis(trifluoromethylsulfonyl)imide ([4empy][NTf2]) and the 1-ethyl-3-methylimidazolium dicyanamide ([emim][DCA]) ILs as solvent. An extensive comparison (more than 600 points) between experimental data and the predictions obtained by the COSMO-based thermodynamic model of liquid–liquid and vapor–liquid equilibria and ILs physical properties was made for validation purposes. Process simulations were performed in three system configurations: with one, two, or three flash distillations in the IL recovery section. The potential advantage of using binary IL-IL mixture as extracting solvent was studied in the whole range of composition. The configuration with three flash distillations and the binary IL-IL mixture with a 75% of [4empy][NTf2] were selected as the optimal conditions to increase aromatic recovery and purity, improving the separation performance respect to the neat ILsThe authors are grateful to Ministerio de Economía y Competitividad (MINECO) of Spain for financial support of Projects CTQ2014-52288-R and CTQ2014–53655-R and to Comunidad Autónoma de Madrid for the Project S2013/MAE-2800. Noemí Delgado-Mellado also thanks MINECO for awarding them an FPI grant (Reference BES–2015–072855) and Marcos Larriba also thanks MINECO for awarding him a Juan de la Cierva-Formación Contract (Reference FJCI-2015-25343). Pablo Navarro thanks Fundação para a Ciência e a Tecnologia for awarding him a postdoctoral grant (Reference SFRH/BPD/117084/2016)

Machine learning screening tools for the prediction of extraction yields of pharmaceutical compounds from wastewaters

Pharmaceutical compounds have become an increasingly important source of pollutants in wastewaters being conventional treatments ineffective in removing them, so they are commonly discharged into the environment. Pharmaceuticals can be successfully removed using liquid-liquid extraction, and COSMO-RS can be used to predict interactions and identify the most promising solvents. However, COSMOtherm models cannot account for key process parameters, which reduces the accuracy of these computational models. Therefore, there is a need for alternative computational approaches to accurately predict the extraction yields of pharmaceuticals which can incorporate both processing and interaction variables. This work used machine learning to predict the extraction yield of eleven pharmaceuticals using eight solvents. Six regression models and two classification models were explored. The best performance was obtained with ANN regressor (test MAE: 4.510, test R2: 0.884) and RF classifier (test accuracy: 0.938, test recall: 0.974). The RF regression analysis and classification also showed key extraction yield features: solvent-to-feed ratio, n–octanol–water partition coefficient, hydrogen bond and Van der Waals contributions to excess enthalpy, and pH distance to nearest pKa. Machine learning showed as an excellent tool for screening and selecting the most promising solvents and process conditions to remove pharmaceuticals from wastewater.This work was supported by Comunidad Autónoma de Madrid [project numbers P2018/EMT-4341 and PR65/19-22441]. Diego Rodríguez-Llorente thanks Ministerio de Ciencia, Innovación y Universidades for awarding an FPU grant (FPU18/01536)

Extraction of pharmaceuticals from hospital wastewater with eutectic solvents and terpenoids: Computational, experimental, and simulation studies

The presence of pharmaceuticals in wastewater, mainly in hospital wastewater, is a serious environmental concern, as they are not removed by conventional processes in wastewater treatment plants and are discharged into the natural environment. This work proposes extracting drugs from hospital wastewater using natural, renewable, and non-toxic solvents such as terpenes and eutectic solvents. First, molecular simulation has been used with the COSMO-RS method performing a massive screening of 43 terpenes, 11 eutectic solvents, and 5 conventional solvents with 31 common pharmaceuticals. The most promising solvents in the screening have been chosen to extract 11 pharmaceuticals simultaneously. Experimental tests with ultrapure water and real hospital wastewater matrices showed a strong influence of pH and matrix on extraction. Under the optimal conditions, global pharmaceutical extraction yields with carvacrol of 94.16 % and the eutectic solvent thymol + dodecanoic acid of 96.86 % were obtained. The regeneration and reuse of both solvents were studied in 5 consecutive stages, showing the carvacrol's high stability and regenerability. Using carvacrol, countercurrent extraction tests showed a fast mass transfer of pharmaceuticals and high extraction yields using low solvent-to-feed (S/F) ratios. The predictions obtained with COSMO-RS were similar to the experimental results, confirming the reliability of this method for selecting alternative solvents for the extraction of pharmaceuticals. Finally, the drug removal process was simulated in a countercurrent extraction. The complete removal of pharmaceuticals from hospital wastewater could be achieved using carvacrol with an S/F of 2.00 at pH 4.00 in an extractor with six equilibrium stagesP2018/EMT-4341, PR65/19-22441, CTM2017-84033-