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Aspen HYSYS is a typical tool used in some Master in Chemical Engineering courses at the University of Castilla-La Mancha like “Analysis and Optimization of Chemical Processes” and “Dynamic of Process: Regulation of Chemical Plants.” Automation is the process of linking commercial software to third-parties applications built in EXCEL-Visual Basic for Applications. The capability of automation as a powerful tool for simulating unprecedented complex processes suggests that it could be a relevant background complement to the classical one offered by a university. In this sense, a seminar about automation based on the study of two cases: a refrigeration process and a production one taken from literature, has been proposed at the University of Castilla-La Mancha. The analysis of the survey performed for the subject evaluation resulted to be very positive. Students consider the methodology of the course and the potentiality of automation for developing their research and professional skills appropriately. However, more examples are required to better understand the automation concept and its potential application to other situations. Finally, they declare that the concept of automation requires a lot of expertise and deep knowledge of programming and the correct application of numerical methods for solving complex problems

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Industrial and Engineering Chemistry Research, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/abs/10.1021/acs.iecr.9b04603, There are a large number of liquid-liquid extraction processes where ionic liquids (ILs) are proposed as solvents. However, the development of purification and IL regeneration units still represents a challenge. Several effective separation trains were proposed to regenerate ILs, but extreme vacuum is needed to achieve commercial standards, which demands extra energy and extra solvent consumptions due to recycling streams. In this proposal, the use of stripping columns stands as a promising IL regeneration technology to avoid vacuum conditions and to enhance the separation of the compounds that form the extract stream, explored in the aromatic-aliphatic separation. COSMO-based/Aspen Plus methodology is applied to extensively evaluate the role of the IL nature and easily evaluate the influence of the main operating variables, namely, temperature feed, column pressure, reboiler heat, and number of stages, in the separation efficiency. A critical comparison between the current proposal and the benchmark IL regeneration process is reported, analyzing the aromatic recovery, energy duty, and operating cost. The use of two stripping columns for the IL regeneration stage evidences the potential of this new configuration, drawing a new paradigm in which mild conditions are enough to conceptually design new separation processes involving ILs, The authors are grateful to Comunidad de Madrid (project P2018/EMT4348) and Ministerio de Economía y Competitividad of Spain (project CTQ2017-89441-R) for financial support and Centro de Computación Científica de la Universidad Autónoma de Madrid (CCC) for its computational resources

Durante a pandemia da COVID-19, observou-se a rápida disseminação de desinformação no que tange a doença, especialmente envolvendo líderes estatais ao redor do mundo. Nesse sentido, este artigo analisa o alcance de tais mensagens desinformativas, a partir do uso da ferramenta do Google Trends, avaliando, assim, o nível de procura do público na plataforma em questão após os eventos analisados. Dessa forma, foram observados que, a partir do fenômeno de ressonância de Koopmans (2004), o interesse geral dos termos analisados obtiveram um aumento expressivo, sendo representado por altos picos nas buscas.

A COSMO-based/Aspen HYSYS methodology has been used to perform an extensive thermodynamic evaluation of potential application of ionic liquids (ILs) to absorption refrigeration cycles. By applying this a priori methodology, 7200 systems, formed by 900 ILs and 8 refrigerants, representative of available commercial/cation and refrigerant, were evaluated, which would be otherwise unviable due to the lack of experimental data. Firstly, COSMO-RS analysis was carried out for the preliminary selection of suitable ILs as absorbents for each refrigerant, by means of predicted values of Henry’s Law constants of refrigerants in ILs. Selected ILs were then introduced in Aspen HYSYS simulator database by using the molecular information by COSMO-RS method. The reliability of COSMO-based/Aspen HYSYS calculations was successfully validated by comparison to available experimental data (>2700 points) of pure and mixture properties of absorbent-refrigerant systems. Then, the performance of selected ILs (and other proposed in the bibliography) in absorption refrigeration cycles was evaluated by process simulations (>230 refrigerant/IL pairs studied at 60 different operating conditions) using COSMO-based/Aspen HYSYS methodology. Cycle efficiency was analyzed in terms of the coefficient of performance (COP), solution circulation ratio (f ratio) and the total mass flow pumped from the absorber to the generator, a new parameter proposed to compare the results obtained with different refrigerants. COSMO-based/Aspen HYSYS methodology allowed the selection of adequate refrigerant-absorbent pairs (refrigerant with high cooling capacities and IL with absorption capacity) competitive to conventional systems as H2O/LiBr or NH3/H2O. Furthermore, the analysis of operating condition effects by COSMO-based/Aspen HYSYS methodology allows selecting refrigerant/IL pairs with maximum efficiency in the cycle for a fixed cooling temperature, revealing additional advantage of the applications of IL in absorption refrigeration technologies., The authors are grateful to Comunidad Autónoma de Madrid for the Project S2013/MAE-2800 and to Ministerio de Economía y Competitividad (MINECO) of Spain for financial support of Project CTQ2017-89441-R. Marcos Larriba also thanks MINECO for awarding him a Juan de la Cierva-Formación Contract (Reference FJCI-2015-25343).

“This document is the Accepted Manuscript version of a Published Work that appeared in final form in Industrial & Engineering Chemistry Research copyright © American Chemical Society after peer review and technical editing by the publisher . To access the final and published work see Enterprise Ionic Liquids Database (ILUAM) for Use in Aspen ONE Programs Suite with COSMO-Based Property Methods V. R. Ferro, C. Moya, D. Moreno, R. Santiago, J. de Riva, G. Pedrosa, M. Larriba, I. Diaz, and J. Palomar Industrial & Engineering Chemistry Research 2018 57 (3), 980-989 DOI: 10.1021/acs.iecr.7b04031, An enterprise database of pure ionic liquids (ILs) for its use in the Aspen ONE programs is presented. The database is identified as ILUAM, and the first version (ILUAM01) contains 100 ILs composed of 30 cations and 23 anions. The IL components were introduced in Aspen Properties as pseudocomponents using information from the computational COSMO-RS method and from experimental viscosity data. ILUAM database was created to be used along with the COSMOSAC property model implemented in Aspen Plus, allowing evaluating IL process performance without needing further experimental data. Some validation tests were carried out to demonstrate the successful incorporation of ILs in the Aspen Plus property system. Then, the performance of ILUAM01 database in thermodynamic property predictions of mixtures involving ILs and conventional chemical compounds was revised in terms of activity coefficients at infinite dilution and phase equilibrium data. The property description of pure ILs and IL mixtures with conventional chemical compounds using COSMO-based/Aspen Plus approach was found with the accuracy level required in the conceptual design of new processes. ILUAM database offers the opportunity of performing systematic evaluation of potential industrial applications of ILs and their competitiveness as alternative to conventional solvents., The authors are grateful to the Comunidad de Madrid (project S2013- MAE-2800) and to the Ministerio de Economía y Competitividad of Spain (Project CTQ2014-52288-R) for financial support. M. Larriba also thanks Ministerio de Economía y Competitividad of Spain for awarding him a Juan de la Cierva-Formación Contract (Reference FJCI-2015-25343)

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 ILs, The 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).

The post-combustion CO 2 physical absorption with ionic liquids (ILs) is studied in this work using a COSMO-based methodology that allows including ILs into Aspen Plus. Firstly, the performance of 8 ILs with different nature in the absorption and regeneration individual operations is evaluated in commercial packed columns at different temperature and pressure conditions adding thermodynamic, mass transfer kinetic and technical criteria to the IL selection. Secondly, both the absorption and regeneration are integrated in a complete CO 2 capture process simulation. The interdependency of variables and their influence in the total operating cost (OPEX) is estimated. The total energy needed for this capture process is compared to homologue results presented in literature for other CO 2 capture technologies. Finally, we provide a preliminary estimation of the capital cost (CAPEX) of the process for a pilot near to industrial scaled plant.

A techno-economic assessment of Ionic Liquids (ILs)-based post-combustion, biogas and pre-combustion CO2 chemical capture processes was carried out using Aspen Plus and Aspen Process Economic Analyzer (APEA). This cost estimation procedure is newly integrated to our COSMO-based/Aspen Plus methodology used to design the chemical absorption processes with 90% of CO2 capture. The equipment investment and variable operating cost were analyzed relating to the process operating conditions and the IL performance. The total annualized cost was used as the index to economically evaluate the processes at three CO2 treatment capacities and employing three different ILs: [P2228][CNPyr], [P66614][CNPyr] and [Bmim][acetate]. It benefits from economy of scale as well as it is directly related to both IL enthalpy of reaction and process gap capacity, being [P2228][CNPyr] -which has the most exothermic reaction and highest gap capacity- the solvent achieving the lowest costs. Current results indicate that operating at vacuum pressure to better regenerate the IL entails a remarkable cost penalty. Hence, both capital (CAPEX) and operational expenses (OPEX) could be reduced to achieve a total cost of 81.32 $/tCO2 for [P2228][CNPyr] in post-combustion CO2 capture when regenerating the IL at atmospheric pressure and 121.5 °C. Three IL pricing basis were considered when calculating the solvent cost. A conservative IL scaled up price of 50 $/kg only increments around 5% the total annualized cost of the process.

Three activated carbons (ACs) obtained from wood and activated either by steam (AC1) or phosphoric acid (AC2, AC3) were characterized via nitrogen adsorption–desorption isotherms, zeta potentials, infrared and Raman spectroscopy, as well as their chemical analysis was determined. Adsorption experiments with Pemetrexed (PEME), a pharmaceutical used for the treatment of tumors, were carried out in which adsorbent doses, contact times, temperatures, and solution pH were investigated. Correlation between the physicochemical properties of ACs and the adsorption capacity was proposed. According to the results, it was found that AC1 and AC3 were better described by the Freundlich and Langmuir models, respectively, whereas both models could be used to fit the adsorptive isotherm of AC2. The higher the initial PEME concentration or the temperature, the higher the adsorption capacity was. The adsorption capacities of the adsorbents were in the following order, AC3 > AC2 > AC1, in agreement with their specific surface areas. A coexistence process of physical and chemical adsorption existed in all ACs as predicted by the best fitting obtained with the Dubinin–Radushkevich, pseudo–second–order kinetic and Elovich models. The adsorption mechanisms were researched using the Conductor–like Screening Model methodology to determine the proton donor and acceptor centres in PEME. As main conclusion, supported by DRIFTS analysis and O/C ratios, AC3 and AC2 containing more oxygenated groups, must adsorb PEME onto their surface according to a monolayer adsorption mechanism. Fitting procedure demonstrated that the equilibrium data obtained with these two materials can be fitted to the Langmuir isotherm.

The conceptual engineering of a new process proposed for the aromatic–aliphatic separation from naphtha has been developed based on extractive distillation using the 1-ethyl-3-methyl imidazolium dycianamide [EMIM][DCA] ionic liquid as entrainer. Process designs and simulations have been carried out with a computer-aided methodology recently developed in our group that integrates molecular modeling and process simulation via COSMO-based thermodynamic models in Aspen Plus. The computational analysis has been performed for two different multicomponent real-like naphtha models: a low aromatic content naphtha (10 wt%) and a naphtha with a high aromatic content (90 wt%). A sensitivity analysis with 8200 different extractive distillation column designs has been carried out varying the ionic liquid solvent to feed ratio, reflux ratio, number of stages and feed stage, in order to optimize the column design minimizing the reboiler duty and maximizing the throughput. In the low aromatic content naphtha, the results show that similar separation efficiencies to liquid–liquid extraction may be achieved by extractive distillation, requiring lower solvent to feed ratios but higher energy consumptions. For the high aromatic content naphtha, good separation performance is obtained with a significant reduction of the energy required per ton of naphtha fed to the system in comparison with the separation by liquid–liquid extraction. To evaluate the behavior of the process simulator using COSMOSAC, the classical NRTL thermodynamic model, fitted using experimental vapor–liquid and liquid–liquid data, was used to simulate the extractive distillation process for a simpler binary n-heptane–toluene mixture. Similar results are obtained using COSMOSAC and NRTL models for this binary aromatic–aliphatic mixture indicating the reliability of the COSMOSAC-based simulations of more complex multicomponent naphtha separation.

Three different processes to separate aromatic hydrocarbons from a very low-aromatic-content (10 wt.%) naphtha with the 4-methyl-N-butylpyridinium tetrafluoroborate ionic liquid are analyzed. A computer-aid methodology recently developed in our group that integrates the molecular modeling and the process simulation via COSMO-based thermodynamic models in Aspen Plus is used. The most commonly drawn process scheme is proposed as Base Case Configuration and two alternative configurations, one adding water as a co-solvent (Configuration 1) and the other including a stripper between the extraction and the solvent regeneration (Configuration 2), are studied. The processes performance is evaluated through the aliphatic and aromatic product purities and recoveries, and the solvent and energy consumptions. The results show that the separation of aromatic hydrocarbons from this type of naphtha using ionic liquids is possible. The Base Case Configuration is not able to achieve the separation successfully. The addition of water as co-solvent guaranties this demand but increases the solvent and energy consumption. The intermediate stripper seems to be a promising alternative as it allows achieving high purity aliphatic and aromatic products without increasing the solvent or energy needs. The results demonstrate that the computational strategy used is capable to discriminate among complex and relatively similar process alternatives.

This work aims to present an industrial perspective on Catalytic Wet Peroxide Oxidation (CWPO) technology. Herein, process simulation and experimental design have been coupled to study the optimal process conditions to ensure high-performance oxidation, minimum H2O2 consumption and maximum energetic efficiency in an industrial scale CWPO unit. The CWPO of phenol in the presence of carbon black catalysts was studied as a model process in the Aspen Plus&reg, v11 simulator. The kinetic model implemented, based on 30 kinetic equations with 11 organic compounds and H2O2 involvement, was valid to describe the complex reaction network and to reproduce the experimental results. The computer experiments were designed on a six-factor Doehlert Matrix in order to describe the influence of the operating conditions (i.e., the different process temperatures, inlet chemical oxygen demands, doses of H2O2 and space time) on each selected output response (conversion, efficiency of H2O2 consumption and energetic efficiency) by a quadratic model. The optimization of the WPO performance by a multi-criteria function highlighted the inlet chemical oxygen demand as the most influential operating condition. It needed to have values between 9.5 and 24 g L&minus, 1 for autothermal operation to be sustained under mild operating conditions (reaction temperature: 93&ndash, 130 &deg, C and pressure: 1&ndash, 4 atm) and with a stoichiometric dose of H2O2.

WILEY: "This is the peer reviewed version of the following article: ChemPhysChem 19.7 (2018): 801-815, which has been published in final form at http://doi.org/10.1002/cphc.201701093. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions." Este artículo apareció anteriormente con el siguiente título "Exploring molecular and thermodynamic properties of zwitterions vs ionic liquids: A comprehensive computational analysis to develop advanced separation processes", Zwitterion ionic liquids (ZIs) are compounds in which both counterions are covalently tethered, conferring them with unique characteristics; however, most of their properties are still unknown, representing a bottleneck to exploit their practical applications. Herein, the molecular and fluid properties of ZIs and their mixtures were explored by means of quantum chemical analysis based on the density functional theory (DFT) and COSMO-RS method, and compared against homologous ionic liquids (ILs) to provide a comprehensive overview of the effect of the distinct structures on their physicochemical and thermodynamic behavior. Overall, ZIs were revealed as compounds with higher polarity and stronger hydrogen-bonding capacity, implying higher density, viscosity, melting point, and even lower volatility than structurally similar ILs. The phase equilibrium of binary and ternary systems supports stronger attractive interactions between ZIs and polar compounds, whereas higher liquid–liquid immiscibility with nonpolar compounds may be expected. Ultimately, the performance of ZIs in the wider context of separation processes is illustrated, while providing molecular insights to allow their selection and design for relevant applications, The authors would like to acknowledge to Comunidad Autónoma de Madrid for the Project S2013/MAE-2800 and to Ministerio de Economía y Competitividad (MINECO) of Spain for financial support of Projects CTQ2014-52288-R. We are very grateful to Centro de Computación Científica de la Universidad Autónoma de Madrid for computational facilities. We all would like to acknowledge kind support in the framework of the COST Action EXIL-Exchange on Ionic Liquids (CM1206).

COSMO-based process simulations using Aspen Plus and Aspen HYSYS were systematically applied to the conceptual design of the two main unit operations commonly proposed to separate aromatic and aliphatic hydrocarbons with ionic liquids (ILs) as extracting solvents; the extraction itself and the vacuum distillation for regenerating the ionic liquid. By the first time, multi-component (up to 28 components) “real” mixture feeds were taken into account to model the naphtha in the process design. Binary model (n-hexane + benzene, n-heptane + toluene, n-octane + ethylbenzene, n-octane + m-xylene) mixture feeds were also considered to validate the computational procedure. Nine different ionic liquids and mixtures of them, (IL–IL) mixtures, were selected as extracting solvents. Ionic liquids were introduced in the process simulations as (pseudo)components and the COSMOSAC property model was used for estimating the activity coefficients of the individual components in the mixtures. The information needed to both create the non-data bank ionic liquid (pseudo)components and to specify the COSMOSAC property model was gathered from COSMO-RS calculations. COSMO-based models exhibited a reasonably good predictability of both the thermo-physical properties of the pure (hydrocarbons and ionic liquids) components and the LL and VL equilibria of their mixtures. The performances of extraction and regeneration individual operations were analyzed at different operating conditions, including the nature of the IL-based extracting agent, the solvent-to-feed ratio, and the hydrocarbon mixture composition. The present results suggest that COSMO-supported process simulations are capable of confidently dealing with complex multicomponent mixtures of hydrocarbons and ionic liquids. This opens new perspectives to improved developments of this process based on ionic liquids and their mixtures.

The viscosity-to-temperature experimental data available in the open literature sources for 134 ionic liquids (ILs) was refined using a statistical procedure based on the confidence bands formalism. 1860 data points of 143 different references, among more than 2600 raw data points found in literature, were processed. As a result, 21% of the data set was rejected. The refined viscosity-to-temperature experimental data were successfully fitted to the η = f(T) Arrhenius-type equation with an R² correlation coefficient higher than 0.99 in all cases. Parameters A and B of the Arrhenius function for 134 ILs were given for the accurate estimation of viscosity in potential uses and compared to A and B parameters for 134 organic solvents. It was found that the obtained A and B values correlate linearly for the wide sample of 134 ionic liquids. As a consequence, it is concluded that ionic liquids having high viscosities at relatively low temperatures also exhibit an abrupt decay of the viscosity with the temperature. This A–B Arrhenius’ parameter relationship was also found in organic solvents, obtaining a regression line with a nearly identical slope but different intercept than that in the case of ILs. It indicated similar temperature dependence in the viscosity of ILs and organic compounds, but a differential higher viscosity of ionic fluids. In addition, it is observed that, for temperatures over 330–373 K, the viscosities of most ILs studied here are moderate, providing a potential range to manage this kind of solvent in practical applications with less transport property limitations.

COSMO-based process simulations with Aspen Plus/Aspen HYSYS are used, for the first time, to a priori estimate the thermodynamic performance of ammonia absorption refrigeration cycles using ionic liquids as absorbents. This allows not only broadening the criteria set used to select/design ionic liquids with optimized properties to be used in that role, but also evaluating innovative strategies to improve the cycle’s performances. COSMO-RS method provides the information required for both creating the ionic liquid non-database components and specifying the COSMOSAC property model to perform Aspen Plus calculations. The computational procedure used here gives at the same time reasonable good property predictions of the vapor (refrigerant) and the condensed (ammonia + ionic liquid) phases as well as physically consistent estimations of the cycle’s performance under different conditions. Current results agree with those previously reported in the literature for several ionic liquid-based systems taken for comparison. In addition, task-specific ionic liquids, with improved properties for ammonia absorption, and also binary ionic liquid mixtures are considered in the analysis. It is obtained that ionic liquids showing higher ammonia absorption capacity among the considered absorbents simultaneously provide the best cycle’s performances. The cycle performances vary in relatively wide intervals depending on the ammonia concentration in the (refrigerant + absorbent) solutions. This behavior is strongly modulated by the ammonia absorption capacity of the selected absorbent. IL mixtures allow not only the tailoring of the working concentration interval of the cycle but also improving its performance.

Solubilities are reported for methane, ethane, ethylene, and propane in trimethyloctylphosphonium bis(2,4,4-trimethylpentyl) phosphinate [P8111][TMPP] from 299 to 323 K up to 4 MPa. Consistent with prediction of COSMO-RS, [P8111][TMPP] shows large solubilities for all four hydrocarbons. Contrary to solubility data in conventional ionic liquids, in [P8111][TMPP] the solubility for ethane is higher than that for ethylene. When compared with solubilities in other similar phosphonium-based ionic liquids, the cation has only a small influence on the solubilities of small hydrocarbons. Ionic liquid [P8111][TMPP] may be useful for storage or separation of small hydrocarbons.

Conductor-like-screening model for real solvents (COSMO-RS) method was used to analyze the solute-solvent interactions and to screen Henry's law constant of toluene over 272 ionic liquids (ILs), to select high-capacity absorbents. Thermogravimetric experiments were carried out to evaluate the toluene absorption by selected ILs at different temperatures and atmospheric pressure. Experimental equilibrium data were found in good agreement with COSMO-RS predictions. Complete desorption of toluene by N2 stripping was achieved, indicating an easy regeneration. The kinetic curves were described by a phenomenological diffusion model, obtaining effective diffusivities in reasonable concordance with those calculated by Wilke–Chang correlation. The separation process with selected ILs was modeled by Aspen Plus and a comparison with organic absorbents was carried out. Equilibrium- and rate-based simulations were used to analyze the importance of thermodynamics and kinetics in toluene absorption by ILs. Current computational-experimental research allowed selecting a set of suitable ILs for toluene absorption. © 2012 American Institute of Chemical Engineers AIChE J, 59: 1648–1656, 2013

The integration of COSMO-RS methodology to Aspen Tech’s process simulators is used in this work to elaborate new criteria for the design/selection of ionic liquids to specific applications. These criteria are related to the operating conditions and energetic consumptions being the procedure capabilities demonstrated through the example of the IL regeneration in separation processes. Previously, the predictive capacity of the COSMO-RS method respect to VLE of mixtures (organic solvent + IL) is assessed and the correct transferability of the COSMO-RS results to Aspen Plus/Aspen HYSYS process simulators demonstrated.

V. R. Ferro, E. Ruiz, M. Tobajas, and J. F. PalomarSeccio´n de Ingenieri´a Qui´mica, Universidad Auto´noma de Madrid, 28049 Madrid, SpainDOI 10.1002/aic.13746Published online February 1, 2012 in Wiley Online Library (wileyonlinelibrary.com).The conceptual design of a new process is developed via computer-aided simulation for separating and purifying reuterin,an antimicrobial substance obtained by bacterial fermentation of glycerol, from its mixture with the nonfermented substrate,the main subproduct of the process (1,3-propanediol) and water. The nondatabank components included in the simulationsare created by using the structures derived from quantum mechanical calculations and the properties (molecular weight,normal boiling point, and mass density) estimated by COSMO-RS method. The unknown remainder properties are estimatedby the methods and models used by default in Aspen Plus (v7.3). The COSMOSAC property model, also implemented inAspen Plus, is specified with the molecular volumes and sigma profiles obtained by COSMO-RS. The properties (boilingtemperatures, densities, VL equilibria, etc.) predicted for glycerol, 1,3-propanediol, water, and their mixtures by COSMO-based methods agree reasonably well with experimental reported values, whereas those obtained for reuterin derivativesare consistent with the behavior of amphoteric compounds having strong capabilities to interact attractively with hydrogendonor and acceptor groups all together. The process consists of a two-stage distillation operation, the first of whichremoves the water and the second one separates reuterin as a 99.5 wt %-pure bottom product. The second column operatesat low pressure (ca. 40 kPa) to avoid thermal decomposition of reuterin (over 280 C) and guaranties 99.9% recovery of thedesired product. Water removing offers different heat integration and energy-saving opportunities considering thatcondenser pressure of the first column can be increased to 15 bar preserving the thermal integrity of the reuterin.Dimensions of the equipments as well as capital and operating costs are evaluated.

A theoretical study was carried out on both porphyrin-based conjugates (with interest in the so-called artificial photosynthesis) and subphthalocyanine aggregates (with potential applications as new materials for optoelectronics, solar energy and other uses). A simple molecular orbital model for studying the role of the spacer groups in the electron transfer in porphyrin-quinone conjugates was developed. The influence of the π-π interaction, hydrogen association and covalent linkage on the stability and structural features in porphyrin-porphyrin complexes as well as the charge separation in donor-acceptor porphyrin dimers, were reproduced. Theoretical models suggest the potential feasibility of SubPc's aggregative processes leading to nanometer-sized fully aromatic fullerene-like molecular architectures.

In this work, the a priori computational tool for screening ILs, developed in previous part 1, is extended to the simultaneous prediction of a set of IL properties for 45 imidazolium-based ILs. In addition, current part 2 reports the development of a more useful design strategy, which introduces the target IL properties as input, resulting in the selections of counterions as output, that is directly designing ILs on the computer. For this purpose, inverse neural networks are used to estimate the Sσ-profile molecular descriptor of a potential IL solvent by the specification of its required properties, following a reverse quantitative structure−property relationship scheme. Subsequently, a statistical tool based on Euclidean distances is developed to select an adequate set of anion+cation combinations that fulfill the estimated Sσ-profile values, to obtain, in this case, the tailor-made ILs. Finally, the proposed computational tool for designing ILs is applied in liquid−liquid extraction of a system model (...

An innovative computational approach is proposed to design ionic liquids (ILs) based on a new a priori molecular descriptor of ILs, derived from quantum-chemical COSMO-RS methodology. In this work, the charge distribution on the polarity scale given by COSMO-RS is used to characterize the chemical nature of both the cations and anions of the IL structures, using simple molecular models in the calculations. As a result, a novel a priori quantum-chemical parameter, Sσ-profile, is defined for 45 imidazolium-based ILs, as a quantitative numerical indicator of their electronic structures and molecular sizes. Subsequently, neural networks (NNs) are successfully applied to establish a relationship between the electronic information given by the Sσ-profile molecular descriptor and the density properties of IL solvents. As a consequence, we develop here an a priori computational tool for screening ILs with required properties, using COSMO-RS predictions to NN design and optimization. Current methodology is validat...

The specific density and molar liquid volume of 40 imidazolium-based ionic liquids were predicted using the COSMO-RS method, a thermodynamic model based on quantum chemistry calculations. A molecular model of ion pairs was proposed to simulate the pure ionic liquid compounds. These ion-paired structures were generated at the B3LYP/6-31++G** computational level by combining the cations 1-methyl- (Mmim+), 1-ethyl- (Emim+), 1-butyl- (Bmim+), 1-hexyl- (Hxmim+), and 1-octyl-3-methylimidazolium (Omim+) with the anions chloride (Cl-), tetrafluoroborate (BF4-), tetrachloroferrate (FeCl4-), hexafluorophosphate (PF6-), bis(trifluoromethanesulfonyl)imide (Tf2N-), methylsulfate (MeSO4-), ethylsulfate (EtSO4-), and trifluoromethanesulfonate (CF3SO3-). Satisfactory agreement with the available experimental measurements was obtained, showing the capability of the current computational approach to describe the effect of the anion nature and cation substituent on the volumetric properties of this family of ionic liquids. ...

A broad set of structural models and theoretical methods has been successfully used for studying both the molecular electron structure of the silacalix[3]phosphinine and the changes of the macrocycle core under the conditions that frequently correspond to its complexes with metals. The macrocycle core of the silacalix[3]phosphinine and its neutral derivatives are strongly deviated from the main molecular plane. The phosphorous electron lone pairs and the pi-cloud of the phosphinine units give the main contribution to the electron valence structure in the silacalix[3]phosphinine and also in its both oxidized and reduced derivatives. Although the electron lone pairs of the P atoms tend to be strongly repulsive, they are either totally or partially extended above all the fragment of the phosphorous atoms depending on geometrical factors or even strongly coupled with the pi-cloud of the phosphinine units. Electronic processes that take away part of the electron density from the macrocyle favor both its planar configuration and the asymmetric distribution of the valence electrons in the silacalix[3]phosphinine and its derivatives. The limit condition to this effect is the appearance of a new in-plane sigma molecular orbital between the P atoms of two neighboring phosphinine units.

Subphthalocyanine (SubPc)-fused dimers and trimers bearing fluorine, iodine, and thioether peripheral substituents were synthesized and characterized. Absorption spectroscopy and electrochemical studies revealed (i) that the substituents have a strong effect on the electronic properties of the macrocycles and (ii) that there is good communication between the subphthalocyaninic moieties within the oligomeric structures. Theoretical calculations at DFT/6-31G(d,p) computational level and electron density studies support the experimental findings. The frontier orbitals in the dimers and trimers were also shown to be significantly altered with respect to those of SubPcs as a consequence of the extension of the conjugation associated with symmetry breaking. Time-dependent density functional theory calculations reproduced the differences observed in the UV-vis spectra of the fused dimers and the monomeric SubPcs.

The acid–base properties of some peripheral substituted triazoleporphyrazines in proton-donating media with poor-donating character were experimentally studied. The substitution of one pyrrole moiety in the porphyrazine-like compounds by one triazole ring in the triazoleporphyrazines leads to an increase in the basicity. The protonation of the triazoleporphyrazines results in a hypsochromic shift of the Q-bands in the UV–visible spectra. A DFT study of some selected structural models of the unsubstituted triazoleporphyrazine shows that the protonation strongly influences on the molecular electron structure of this compound and that it occurs preferentially through the nitrogen atom located at position 4 of triazole ring. The protonation through the other basic centers (the triazoleporphyrazine is a multicenter conjugated base) leads to different protonated forms which differ notably in their aromatic character. Therefore, this compound could be considered an intramolecular switch of aromaticity. Copyright © 2004 John Wiley & Sons, Ltd.

Second order nonlinear optical properties of a series of trinitrosubphthalocyanine (SubPc) isomers were studied experimentally by electric field induced second harmonic (EFISH) generation and hyper Rayleigh scattering (HRS). These experimental values were compared to the ones obtained theoretically employing both sum over states (SOS) and finite field (FF) methods. From these studies, it was shown that the dipolar contributions to the beta tensor are very much dependent on the substitution pattern at the periphery of the subphthalocyanine macrocycle, whereas the octupolar contributions remain mostly unchanged. Consequently, it was deduced that SubPc is extremely well suited for the decoupling of octupolar and dipolar contribution to the NLO response.

The second harmonic generation (SHG) hyperpolarizabilities of a family of peripherally substituted push−pull phthalocyanines 1, 2, and 3, having an ethynediyl subunit in the linking bridge between the acceptor and donor moieties, have been measured. Electric field induced second harmonic (EFISH) generation experiments at 1.064 and 1.900 μm and hyper-Rayleigh scattering (HRS) experiments at 1.064 μm have been carried out. The quadratic hyperpolarizabilities values derived from these experiments are quite significant and superior to those found for similar push−pull compounds lacking of a triple C-bond in the donor−acceptor path. The main electronic parameters of the three compounds (electric dipole moments, orbital electronic distributions, and optical transition moments) have been calculated using the ZINDO/S method for molecular geometries that have been optimized through the PM3 method. Excellent agreement with spectroscopic data has been achieved. The SHG results have been analyzed through a 3-level mo...

A theoretical investigation of both the ortho-Si(CH3)3 phosphinine and some silacalix[n]phosphinines was performed. The optimized geometries agree well with those reported from X-ray analysis and other structural studies. The silacalix[n]phosphinine macrocyle is very flexible because of the CSiC bridges. This, in turn, makes possible the formation of strained configurations in solid packed structures. In the silacalix[3]phosphinine, a PP bonding interaction that is presumably responsible for its structural and electronic features seems to exist. The molecular orbital calculations corroborate that both the π-accepting properties and the σ-donating capacities of the phosphinine unit may be enhanced by ortho-Si(CH3)3 substitution. These features satisfy the proposal of the synthesizers as regards the production of macrocyclic phosphorus compounds, with good π-accepting properties and strong σ-donating capacities, which are sufficiently flexible as to encapsulate metals with coordination spheres of different geometries. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:160–169, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10118

A theoretical investigation on the redox processes in the subphthalocyanines (SubPcs) was performed. Singly and doubly oxidative and reductive transformations were considered. The full geometry optimization of the participating molecules showed that the cone shape arrangement of the SubPc is preserved in their ionic derivatives even when two electrons are either donated or subtracted from the molecule. The biggest geometric changes under electron exchange processes were calculated for the BCl bond distance. The electronic density distribution over all the products remains almost invariable with respect to the neutral molecule. Our calculations on the neutral and charged SubPcs demonstrated that they behave as conjugated systems, their electronic parameters being correlatively altered by the redox electron exchange. Further, the electronic state of the macrocycle atoms also depends on an intense electronic flow among the macrocyclic skeleton and the surrounding (axial chlorine and peripheral hydrogen) atoms that is associated with the redox process. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003

The effect of tautomerism on the aromaticity was studied for the free base triazoleporphyrazine at the Density Functional Theory level, using double-zeta double polarized basis sets. The porphyrazine (1), the three tautomers (2a, 2b and 2c) as well as the Ni complex (3) of triazoleporphyrazine were examined. Two independent aromaticity criteria, the geometry-based index HOMA and the magnetic properties-based index NICS, were used to estimate the aromaticity of the complete and selected fragments of the above compounds. Results show that structure 2a, which has the H atom in position 1 of the triazole ring, has low aromaticity, although it contains structural fragments with large conjugation. The aromatic character of both tautomers 2b and 2c is similar to that of both the porphyrin and the porphyrazine. The central ring contour was found to be the most aromatic part of the triazoleporphyrazine tautomers. Occupancy of the central position of the macrocycle cavity of the triazoleporphyrazine by a metal atom increases the aromaticity of the macrocycle as a whole, but reduces the conjugation of the central cross sub-unit. In conclusion, both criteria can be used confidently for evaluating the aromaticity for the studied systems.

The use of ionic liquid mixtures (IL-IL mixtures) is being investigated for fine solvent properties tuning of the IL-based systems. The scarce available studies, however, evidence a wide variety of mixing behaviors (from almost ideal to strongly nonideal), depending on both the structure of the IL components and the property considered. In fact, the adequate selection of the cations and anions involved in IL-IL mixtures may ensure the absence or presence of two immiscible liquid phases. In this work, a systematic computational study of the mixing behavior of IL-IL systems is developed by means of COSMO-RS methodology. Liquid-liquid equilibrium (LLE) and excess enthalpy (H(E)) data of more than 200 binary IL-IL mixtures (including imidazolium-, pyridinium-, pyrrolidinium-, ammonium-, and phosphonium-based ILs) are calculated at different temperatures, comparing to literature data when available. The role of the interactions between unlike cations and anions on the mutual miscibility/immiscibility of IL-IL mixtures was analyzed. On the basis of proposed guidelines, a new class of immiscible IL-IL mixtures was reported, which only is formed by imidazolium-based compounds.

Theoretical calculations were performed for studying the electronic molecular structure of axial subphthalocyanine (SubPc) derivatives. The intermolecular SubPc interactions were also investigated at theoretical level using adequate models. These models represent the interaction of one Cl (OR)-SubPc with the surrounding molecules through the Cl atom as well as the interaction of the Cl -SubPc with an incoming diiminoisoindole group in the first steps of the open ring reaction. The SubPc complexes with more electronegative atoms than Cl heteroatoms in apical positions are more pyramidal than Cl -SubPc. The B–X and B–Np are the most sensitive macrocycle positions with respect to the axial substitutions in SubPcs. The B–X bond has an elevated polarity and seems to correlate with the chemical reactivity of these compounds. The theoretical calculations of the near-frontier orbitals reveal an outstanding energetic and structural homogeneity along the studied series which is in correspondence with the fact that the axial ligand has only a small influence on the position of the maximum bands in UV-vis spectra as well as in the first half-wave potentials for oxidative processes. The study of the intermolecular interactions give information about their influence on the molecular structure of the axial complexes of the SubPcs. The characterization of the interaction of one Cl -SubPc with a pyrrol containing group may be useful in the understanding of the mechanism of the ring expansion reactions. In general, the present results indicate that the apical position may be a critical reactive center both for redox and axial substitution processes.

The unsubstitute subphthalocyanine (SubPc) and their tertbutyl- (tertbutyl-SubPc) and nitro-(nitro-SubPc) derivatives have been theoretically studied at Hartree–Fock (HF) and Density Functional Theory (DFT) levels using STO-3G and 6-31G basis sets. The geometric optimization of the molecules was carried out. The calculated geometry for SubPc agrees with experimental X-ray data. No significant geometrical changes with respect to SubPc were observed in the tertbutyl-SubPc and nitro-SubPc macrocycles. B–Cl distance systematically changes with the electron donor/acceptor properties of the peripheral substituents. The calculated dipole moments reproduce very well the experimental values, whereas the atomic charges reveal the polar character of the SubPc macrocycle. An extensive study of some frontier orbitals was performed. The present calculations reproduce the breakdown of Gouterman's four-orbital model in SubPcs, this effect being less dramatic in the DFT description. The nodal patterns for the two highest occupied molecular orbitals and the two lowest unoccupied molecular orbitals obtained from different computational methods exhibit important differences, but in general an explanation for some of the most important aspects of the chemical reactivity of the SubPcs can be put forward.

Nonplanar saddled (sad) ruffled (ruf) and domed (dom) conformations of the Mg-porphyrin (MgP) macrocycle in several degrees of deformation have been computed. These symmetrical distortion modes were induced in unsubstituted macrocycle using molecular definitions for calculations which permits us to achieve a systematical variation of the nonplanarity varying only a convenient geometrical parameter of the molecule. Series of nonplanar macrocycles like those synthesized in previous works employing peripheral substitutions are obtained. The procedure here used to induce deformations gives the possibility of investigating the modulator role of the out-of-plane distortions on the geometry and electronic properties of the porphyrin avoiding additional influences due to the substituents or the surrounding protein scaffolding.

The MNDO/PM3 semiempirical method was used for predicting nonplanar distortion modes in highly substituted porphyrins. Octaethyl-tetraphenylporphyrin (MOETPP) and dodecaphenylporphyrin (MDPP) (M = H2, Mg and Zn) were obtained as minimum energy structures and exist in saddle-shape conformations. Optimized meso-substituted tetra-tert-butylporphyrin (MTtBuP) (M = Mg, Zn) adopts a nonplanar ruffled structure. Atomic deviations from planarity and geometrical variations induced by ruffling are in good agreement with reported data in previous crystallographic studies and molecular mechanic calculations of highly substituted Ni, Zn, Cu and Co porphyrins. The present semiempirical calculations confirm that the macrocycle deformations respond to steric repulsions of peripheral substituents. The degree of deformation does not only depend on the sterical crowding of the substituents, but it is also very sensitive to the size of the metal located into the macrocycle cavity. Large Zn metal gives rise to a flattening of the macrocycle, whereas small Mg metal favors a marked ruffling. In the last case the small size of Mg metal is enough by itself for disturbing the unsubstituted Mg-porphyrin into a saddle conformer. The PM3 method used here predicts very accurately the typical nodal patterns: a1u and a2u, for the HOMOs in porphyrins. The reversal of a2u/a1u ordering has been investigated in previous papers as a function of either electron-withdrawing or -donating character of the substituents placed in different peripheral positions. The present results reveal that nonplanar macrocycle distortion affects the ordering of the two highest occupied molecular orbitals. The saddle form exists in an a1u/a2u (HOMO/HOMO-1) orbital structure, while the ruffled deformation raises the energy of the a2u orbital due to the large meso-carbon deviations. These results suggest that possible transitions between conformers induced under excitations may give rise to important electronic differences between ground and excited states of the nonplanar porphyrins.

The interactions between ionic liquids (ILs) and acetone have been studied to obtain a further understanding of the behavior of their mixtures, which generally give place to an exothermic process, mutual miscibility, and negative deviation of Raoult's law. COSMO-RS was used as a suitable computational method to systematically analyze the excess enthalpy of IL-acetone systems (300), in terms of the intermolecular interactions contributing to the mixture behavior. Spectroscopic and COSMO-RS results indicated that acetone, as a polar compound with strong hydrogen bond acceptor character, in most cases, establishes favorable hydrogen bonding with ILs. This interaction is strengthened by the presence of an acidic cation and an anion with dispersed charge and non-HB acceptor character in the IL. COSMO-RS predictions indicated that gas-liquid and vapor-liquid equilibrium data for IL-acetone systems can be finely tuned by the IL selection, that is, acting on the intermolecular interactions between the molecular and ionic species in the liquid phase. NMR measurements for IL-acetone mixtures at different concentrations were also carried out. Quantum-chemical calculations by using molecular clusters of acetone and IL species were finally performed. These results provided additional evidence of the main role played by hydrogen bonding in the behavior of systems containing ILs and HB acceptor compounds, such as acetone.

A COSMO-RS descriptor (S(sigma-profile)) has been used in quantitative structure-property relationship (QSPR) studies by a neural network (NN) for the prediction of empirical solvent polarity E(T)(N) scale of neat ionic liquids (ILs) and their mixtures with organic solvents. S(sigma-profile) is a two-dimensional quantum chemical parameter which quantifies the polar electronic charge of chemical structures on the polarity (sigma) scale. Firstly, a radial basis neural network exact fit (RBNN) is successfully optimized for the prediction of E(T)(N), the solvatochromic parameter of a wide variety of neat organic solvents and ILs, including imidazolium, pyridinium, ammonium, phosphonium and pyrrolidinium families, solely using the S(sigma-profile) of individual molecules and ions. Subsequently, a quantitative structure-activity map (QSAM), a new concept recently developed, is proposed as a valuable tool for the molecular understanding of IL polarity, by relating the E(T)(N) polarity parameter to the electronic structure of cations and anions given by quantum-chemical COSMO-RS calculations. Finally, based on the additive character of the S(sigma-profile) descriptor, we propose to simulate the mixture of IL-organic solvents by the estimation of the S(sigma-profile)(Mixture) descriptor, defined as the weighted mean of the S(sigma-profile) values of the components. Then, the E(T)(N) parameters for binary solvent mixtures, including ILs, are accurately predicted using the S(sigma-profile)(Mixture) values from the RBNN model previously developed for pure solvents. As result, we obtain a unique neural network tool to simulate, with similar reliability, the E(T)(N) polarity of a wide variety of pure ILs as well as their mixtures with organic solvents, which exhibit significant positive and negative deviations from ideality.

A new COSMO-RS descriptor (S(sigma-profile)) has been used in quantitative structure-property relationship (QSPR) studies based on neural networks (NN) for the prediction of polarity/polarizability scales of pure solvents and mixtures. S(sigma-profile) is a two-dimensional quantum chemical parameter which quantifies the polar electronic charge on the polarity (sigma) scale. Firstly, radial base neural networks (RBNN) are successfully optimized for the prediction of polarizability (SP) and polarity/polarizability (SPP) scales of pure solvents using the S(sigma-profile) of individual molecules. Subsequently, based on the additive character of the S(sigma-profile) parameter, we propose to simulate the solvents mixture by the estimation of S descriptor, defined as the weighted mean of S(sigma-profile) values of the components. Then, the SPP parameters for binary and ternary mixtures are accurately predicted using the S values into the RBNN model previously developed for pure solvents. As result, we obtain a unique neural network tool to simulate, with similar reliability, the polarity/polarizability of a wide variety of pure organic solvents as well as binary and ternary mixtures which exhibit significant deviations from ideality.

The molecular structure of the chloro-dodecafluorosubphthalocyaninato boron(III) (F-SubPc) was determined with use of Gas Electron Diffraction (GED) and high-level quantum chemical calculations. The present results show that the F-SubPc molecule has a cone-shaped configuration, isoindole units are not planar, and the pyrrole ring has an envelope conformation. The structure parameters in the gas phase are determined. Some structural details can be observed such as the dihedral angle about the bond connecting the pyrrole ring and the benzene ring being ca. 174 degrees . High-level theoretical calculations with several extended basis sets for this molecule have been carried out. The calculations are in very good agreement with experimental methods: X-ray and GED. Nevertheless, some disagreements particularly related to the B-Cl bond distance found in GED are discussed. Vibrational frequencies were computed obtaining eight values below 100 cm-1 and three bending potentials were examined. They suggest that this molecule is very flexible.

A quantum-chemical computational approach to accurately predict the nuclear magnetic resonance (NMR) properties of 1-alkyl-3-methylimidazolium ionic liquids has been performed by the gauge-including atomic orbitals method at the B3LYP/6-31++G** level using different simulated ionic liquid environments. The first molecular model chosen to describe the ionic liquid system includes the gas-phase optimized structures of ion pairs and separated ions of a series of imidazolium salts containing methyl, butyl, and octyl substituents and PF6-, BF4-, and Br- anions. In addition, a continuum polarizable model of solvation has been applied to predict the effects of the medium polarity on the molecular properties of 1,3-dimethylimidazolium hexafluorophosphate (MmimPF6). Furthermore, the specific acidic and basic solute-solvent interactions have been simulated by a discrete solvation model based on molecular clusters formed by MmimPF6 species and a discrete number of water molecules. The computational prediction of the NMR spectra allows a consistent interpretation of the dispersed experimental evidence in the literature. The following are main contributions of this work: (a) Theoretical results state the presence of a chemical equilibrium between ion-pair aggregates and solvent-separated counterions of 1-alkyl-3-methylimidazolium salts which is tuned by the solvent environment; thus, strong specific (acidic and basic) and nonspecific (polarity and polarizability) solvent interactions are predicted favoring the dissociated ionic species. (b) The calculated 1H and 13C NMR properties of these ionic liquids are revealed as highly dependent on the nature of solute-solvent interactions. Thus, the chemical shift of the hydrogen atom in position two of the imidazolium ring is deviated to high values by the specific interactions with water molecules, whereas nonspecific interaction with water (as a solvent) affects, in the opposite direction, this 1H NMR parameter. (c) Last, current calculations support the presence of hydrogen bonding between counterions, suggesting the importance of this interaction in the properties of the solvent in the 1-alkyl-3-methylimidazolium ionic liquids.