Phase equilibrium of the CO2/glycerol system: Experimental data by in situ FT-IR spectroscopy and thermodynamic modeling

Phase equilibrium experimental data for the CO2/glycerol system are reported in this paper. The measurements were performed using an in situ FT-IR method for temperatures ranging from 40 ◦C to 200 ◦C and pressures up to 35.0 MPa, allowing determination of the mutual solubility of both compounds. Concerning the CO2 rich phase, it was observed that the glycerol solubility in CO2 was extremely low (in the range of 10−5 in mole fraction) in the pressure and temperature domains investigated here. Conversely, the glycerol rich phase dissolved CO2 at mole fractions up to 0.13. Negligible swelling of the glycerol rich phase has been observed. Modeling of the phase equilibrium has been performed using the Peng–Robinson equation of state (PR EoS) with classical van der Waals one fluid and EoS/GE based mixing rules (PSRK and MHV2). Satisfactory agreement was observed between modeling results and experimental measurements when PSRK mixing rules are used in combination with UNIQUAC model, although UNIFAC predictive approach gives unsatisfactory representation of experimental behavior

Cellulosic materials as biopolymers and supercritical CO2as a green process: chemistry and applications

In this review, we describe the use of supercritical CO2 (scCO2) in several cellulose applications. The focus is on different technologies that either exist or are expected to emerge in the near future. The applications are wide from the extraction of hazardous wastes to the cleaning and reuse of paper or production of glucose. To put this topic in context, cellulose chemistry and its interactions with scCO2 are described. The aim of this study was to discuss the new emerging technologies and trends concerning cellulosic materials processed in scCO2 such as cellulose drying to obtain aerogels, foams and other microporous materials, impregnation of cellulose, extraction of highly valuable compounds from plants and metallic residues from treated wood. Especially, in the bio-fuel production field, we address the pre-treatment of cellulose in scCO2 to improve fermentation to ethanol by cellulase enzymes. Other reactions of cellulosic materials such as organic inorganic composites fabrication and de-polymerisation have been considered. Cellulose treatment by scCO2 has been discussed as well. Finally, other applications like deacidification of paper and cellulosic membranes fabrication in scCO2 have been reviewed. Examples of the discussed technologies are included as well

Advanced Supercritical Fluids Technologies

Using SuperCritical Fluids (SCFs) in various processes is not new, because Mother Nature has been processing minerals in aqueous solutions at critical and supercritical pressures for billions of years. Somewhere in the 20th century, SCFs started to be used in various industries as working fluids, coolants, chemical agents, etc. Written by an international team of experts and complete with the latest research, development, and design, Advanced Supercritical Fluids Technologies is a unique technical book, completely dedicated to modern and advanced applications of supercritical fluids in various industries.Advanced Supercritical Fluids Technologies provides engineers and specialists in various industries dealing with SCFs as well as researchers, scientists, and students of the corresponding departments with a comprehensive overview of the current status, latest trends and developments of these technologies.Dr Igor Pioro is a professor at the University of Ontario Institute of Technology, Canada, and the Founding Editor of the ASME Journal of Nuclear Engineering and Radiation Science

Equilibrium, extraction and fractionation of oil and phenolic compounds from coffee with supercritical carbon dioxide and ethanol

Orientadores: Antonio José de Almeida Meirelles, Fernando Antonio CabralTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: Esse projeto objetivou obter dados de solubilidade de compostos fenólicos e óleo de café em dióxido de carbono supercrítico (scCO2) na presença de cossolventes, ajustar parâmetros de modelos termodinâmicos para descrever estes dados e, posteriormente, avaliar a extração e fracionamento dessas substâncias, que se destacam por seu alto valor agregado e por sua diversidade de aplicações em diferentes ramos industriais, a partir do resíduo da produção de café solúvel. As determinações experimentais de solubilidade dos ácidos cafeico e ferúlico e do óleo de café verde foram realizadas em diferentes condições de temperatura (313 a 333 K) e pressão (20 a 40 MPa), e as quantidades de cossolvente (etanol e/ou água) adicionadas ao scCO2 variaram de 0 a 10 mol%. No geral, os maiores valores de solubilidade foram obtidos nas maiores condições de pressão. Ao se adicionar aproximadamente 10 mol% de etanol ao scCO2, verificou-se aumento de 120 e 30000 vezes na solubilidade dos ácidos ferúlico e cafeico, respectivamente. Os dados experimentais dos sistemas binários foram bem representados pelas equações de Peng-Robinson, Soave-Redlich-Kwong e Cubic Plus Association (CPA). Porém, apenas a equação CPA foi capaz de predizer satisfatoriamente os dados de equilíbrio dos sistemas ternários e/ou quaternários a partir dos parâmetros de interação binária, pois, diferentemente das equações de estado cúbicas, este modelo considera as fortes interações, como ligações de hidrogênio, que ocorrem entre as moléculas do soluto e do cossolvente. A solubilidade do óleo de café verde em scCO2 mostrou-se similar à de diversos outros óleos vegetais. Ela aumentou cerca de 60% com a adição de 2,3 % (em massa) de etanol, e as amostras obtidas mostraram-se mais concentradas em ácidos graxos livres e diterpenos em relação ao óleo obtido por prensagem. Extrações com fluido supercrítico (Supercritical Fluid Extraction - SFE) e líquido pressurizado (Pressurized Liquid Extraction - PLE) em uma ou duas etapas e usando apenas dióxido de carbono e etanol como solventes foram avaliadas para obtenção de compostos fenólicos e lipídicos da borra de café. Os maiores rendimento global de extração, concentração de compostos fenólicos e taxa de extração foram verificados quando o etanol foi utilizado como solvente (extrato E). O fracionamento de E, tanto por um processo integrado de SFE + PLE ou usando o scCO2 como antissolvente por meio de quatro separadores em série, forneceu frações aproximadamente quatro vezes mais concentradas que o extrato etanólico obtido em etapa única. Contudo, o uso de cossolventes, principalmente etanol, mostrou-se fundamental para extração de compostos fenólicos por consequência do aumento da sua solubilidade em scCO2. O conhecimento da solubilidade de solutos em scCO2 + cossolventes e de como alguns parâmetros, como temperatura, pressão e tipo e concentração de cossolvente a influenciam pode ser útil para otimizar processos de separação que utilizam o scCO2 como solvente ou antissolventeAbstract: This work proposed to obtain solubility data of phenolic compounds and green coffee oil in supercritical carbon dioxide (scCO2) with cosolvents, to describe these data through thermodynamic models, and posteriorly to evaluate the extraction and fractionation of compounds from the residue of soluble coffee production. These substances are highlighted by their high value added and its diversity of applications in different industrial sectors. Experimental measurements of solubility of caffeic and ferulic acids and green coffee oil were performed at different temperatures (313 to 333 K) and pressures (20 to 40 MPa), and the amounts of cosolvent (ethanol and/or water) added to scCO2 ranged from 0 to 10 mol%. In general, the highest solubility values were obtained under the highest pressure conditions. By adding approximately 10 mol% of ethanol to scCO2, it was verified an increase up to 120 and 30,000 times on the solubility of ferulic and caffeic acids, respectively. Experimental data of the binary systems were well described by the equations of Peng-Robinson, Soave-Redlich-Kwong and Cubic Plus Association (CPA). However, CPA equation was the only one suitable to predict the equilibrium data of the ternary and/or quaternary systems from the binary interaction parameters, because unlike the cubic state equations this model describes the strong interactions, such as hydrogen bonds, that occur between the solute and cosolvent molecules. Solubility data of green coffee oil in scCO2 was similar to several other vegetable oils. It increased by up to 60% with the addition of 2.3% ethanol (w/w), and the samples obtained were more concentrated in free fatty acids and diterpenes in comparison with oil obtained by pressing. Supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE) in one or two steps and using CO2 and ethanol as solvents were evaluated to extract phenolic and lipid compounds from spent coffee grounds. The highest overall extraction yield, total phenolic content and extraction rate were verified when ethanol was used as a solvent (extract E). The fractionation of E, either by an integrated process with SFE + PLE or by using scCO2 as antisolvent through four separators in series, favors obtaining fractions approximately four times more concentrated than the single-stage ethanolic extract. Therefore, the use of cosolvents, mainly ethanol, confirms to be crucial for the extraction of phenolic compounds, due to the increase of its solubility in scCO2. In addition, knowledge on the effect of the parameters, such as temperature, pressure and type and cosolvents concentration, on the solubility of solutes in scCO2 + cosolvents can be useful to optimize separation processes using scCO2 as solvent or antisolventDoutoradoEngenharia de AlimentosDoutora em Engenharia de Alimentos140345/2014-0CNP

Synthesis and Characterization of Acetate Based Ionic Liquid for C02 Removal

This report basically discusses the preliminary research done and basic understanding of "Synthesis and Characterization of Acetate Based Ionic Liquid for C02 Removal". This project aims at simulation modeling for studying the C02 solubility and its behavior towards ionic liquids at room temperature with variable pressure condition. The simulation process part is currently running byusing special software for simulation ofionic liquid called COSMO-RS software. The simulation process is selecting two types of ionic liquid which are l-butyI-3- methyHmidazolium bis(trifluoromethylsulfonyl)imide and l-butyl-3methylimidazoliiim acetate as a sample solution for C02 removal. This report basically remains consist of four sections. The first section is on the introduction partof the project including background study ofthe project, problem statement, objectives and scope ofstudy and relevancy ofproject. The next section is on the literature review. In this section, there will be a brief theory on the ionic liquids regarding the characteristics, conditions and experimental data from journal for C02 solubility in ionic liquids. Then this report followed by third chapter which is methodology that covers on the steps and process flow of simulation using COSMO-RS software for examining two selected types ofionic liquids. Lastly in final section which is result and discussion part for complete simulation process regarding the selected ionic liquids. Final results are presented by validating some parameters such as interaction energy and sigma profile for completion of simulation data regarding the particular types ofionic liquids that has been selected earlier

IDENTIFICATION, DESIGN AND SYNTHESIS OF OXYGENATED HYDROCARBON-BASED CO2-SOLUBLE POLYMERS FOR CHEMICAL AND PETROLEUM ENGINEERING APPLICATIONS

Over the past two decades the use of near-/super-critical carbon dioxide has received much attention as a green alternative to organic solvents for chemical reactions, separations, and extractions because of its pressure-tunable physicochemical properties and economic advantages. However the advantages are diminished because of a relative narrow range of CO2-soluble materials. The goal of this work is to identify, design and synthesize oxygenated hydrocarbon-based CO2-soluble polymers that are able to serve as construction blocks for copolymers, dispersants, surfactants, thickeners, and chelating agents. Without concerning on the cost and the environmental persistence like fluorinated materials, the inexpensive, environmentally benign materials would significantly enhance the viability of near-/super-critical carbon dioxide-based technology. Based on both experimental heuristics and ab initio simulation results of molecular modeling (performed by Dr. Johnson's group), we proposed specific new polymer structures: poly(3-acetoxy oxetane) (PAO), poly(vinyl methoxymethyl ether) (PVMME), poly(vinyl 1-methoxyethyl ether) (PVMEE), and cellulose triacetate (CTA) oligomers. Phase behavior studies were also performed with novel CO2-philic compounds containing vinyl acetate, propylene glycol, or multiple tert-butyl groups. PAO, PVMME and PVMME were soluble in CO2, but not as soluble as poly(vinyl acetate). Oligomers of cellulose triacetate with as many as four repeat units solubilized into dense CO2 less than 14 MPa in the concentration range of 1-5 wt%. Phase behaviors of more than thirty compounds in dense CO2 were studied in this project. A new type of phase behavior for solid (at ambient temperature) CO2-philes that melt and dissolve in CO2 was detailed using a model binary mixture of β-D-maltose octaacetate and CO2. Copolymers of tetrafluoroethylene (TFE) and vinyl acetate (VAc) exhibited lower miscibility pressures than either of the homopolymers, probably due to quadradentate binding configurations with CO2. Phase behavior investigation of poly(propylene glycol) (PPG) monobutyl ether in CO2 demonstrated ether-CO2 interactions should receive as much attention as carbonyl-CO2 interactions when designing CO2-philic functional groups. 1,3,5-tri-tert-butylbenzene and tri-tert-butyl-phenol were both extraordinarily soluble in CO2, and are excellent candidates for CO2-soluble sand binders. In summary, although a new CO2 thickener was not identified, new non-fluorous CO2-soluble materials were identified that were, in general, acetate-rich with flexible chains, weak self-interactions, and multidentate interaction between CO2 and solute functional groups

Hydrophobization of Cellulose-Based Fibers for Packaging Applications with Alkyl Ketene Dimers (AKD) and Food-Grade Waxes via Supercritical Impregnation with Carbon Dioxide – Experimental and Thermodynamic Modeling Approaches

This modified material has applications in food packaging, where frequently water-repellant surfaces are required. This method is preferable to traditional coating methods because it sizes across the entire thickness of the substrate rather than just the surface and can be used for non-planar surfaces; uses significantly less material than traditional methods and will be an excellent technique for multilayered and intelligent coating

Solubility Measurement Method and Mathematical Modeling in Supercritical Fluids

Supercritical fluids technology (SFT) is gaining significance application in the field of food and drug processing. Since supercritical fluid possess dual characteristic of gas and liquid, it exhibits outstanding extraction features such as high penetration ability and able to dissolve materials. To aid the design of processes including extraction, separation, purification, and synthesis, solubility data of compound of interest is required. In addition, with the solubility data, a more environmental friendly and productive operating condition can be resulted. However, there is lack of review that summarizes the method and correlation to gain this data. Thus, the review is accomplished to give concise discussion on the fundamental knowledge of solubility. This review will discuss the solubility measurement method, quantification method and mathematical correlation models for explaining the thermodynamic relationship of solubility

Solubility of caffeic acid in CO2 + ethanol: experimental and predicted data using Cubic Plus Association Equation of State

This work evaluated the solubility of caffeic acid (CA) in mixtures of supercritical carbon dioxide (scCO2) and ethanol at different temperatures (313, 323 and 333 K), pressures (20, 30 and 40 MPa) and concentrations of ethanol (2.2, 5.4 and 10.2 mol%). The Soave-Redlich-Kwong and Cubic Plus Association (CPA) equations of state were used to correlate the binary mixture data and to predict the ternary system data. CA solubility in ethanol is approximately 106 times higher than its solubility in pure scCO2. By using 10.2 mol% ethanol in scCO2, CA solubility increased 30,000 times at 313 K and 20 MPa. Both models provided reasonable descriptions of the experimental data for the binary systems. However, CPA-EoS can better describe the strong interactions between acid molecules and ethanol, and can predict that the addition of small amounts of ethanol to scCO2 provides a large increase in CA solubility.publishe