Application Notes

Supercritical fluids and in particular supercritical carbon dioxide have shown to be a viable technology for a variety of extractions. While process conditions require high pressures, technological advances have now made it feasible to acquire such equipment for the undergraduate laboratory. One novel application we are currently investigating involves supercritical fluid extraction of organic binders from metal parts produced by powder injection molding (PIM). The initial proof-of-concept studies have been undertaken in our laboratory with bench top equipment manufactured by Supercritical Fluid Technologies, Inc.

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Supercritical fluid extraction was successfully used to extract peanut oil from peanuts at temperatures between 40 and 80 °C and pressures of 5000-7000 psi. Static/dynamic cycling was used with a 10 minute static soak time, followed by a 10 minute dynamic interval. The overall extraction time was held constant at 3 hours. Peanut oil yield was determined gravimetrically. The crossover phenomenon was observed with the crossover pressure occurring at 6000 psi. Above the crossover pressure, an isobaric increase in temperature has a positive effect on the extraction yield, while below the crossover pressure an increase in temperature resulted in a decrease in oil yield. Yields between static/dynamic cycling and continuous runs were comparable, suggesting CO₂ usage could be reduced by half by static/dynamic cycling, creating a cost effective, greener process.

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Substituted phenols are an important class of compounds having widespread use (germicides, disinfectants, ingredients in fuel, etc.).  In this work, the solubilities of selected substituted phenols (2,5-dimethylphenol, 2,4,6-trimethylphenol,2,3,5-trimethylphenol, 4-phenylphenol, 4-tertbutylphenol) in binary (single solute + SCF CO₂) and ternary (two solutes + SCF CO₂) systems were investigated using a SFT Phase Monitor.

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Carbon dioxide is widely recognized today as a “Green Chemistry” solvent. The unique physical and chemical properties of carbon dioxide in its supercritical state, namely the absence of surface tension, low viscosity, high diffusivity, and easily tunable solvent strength provide for utility in a variety of industrial and scientific applications. In the microelectronics fabrication industry this non-toxic, environmentally friendly solvent is being heavily investigated as an alternative agent for device cleaning, microelectromechanical  systems (MEMS) drying, and lithographic processing. With the emerging advances in fabrication techniques and materials, microelectronic device features with dimensions below 100 nm are now possible to produce.

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Supercritical carbon dioxide extraction is currently used in several food and pharmaceutical manufacturing applications. Its “greener” nature makes it a desirable option when compared with traditional organic solvent extractions. The purpose of this work is to compare the cost of using supercritical CO₂ to commercially extract peanut oil with that of the traditional hexane extraction process. Solubility values of peanut oil in supercritical CO₂ were also obtained under different conditions of temperature and pressure.

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The purpose of this study was to test the utility of rapid expansion of supercritical solution (RESS) based cocrystallizations in inducing polymorph conversion and crystal disruption of chlorpropamide (CPD). CPD crystals were recrystallized by the RESS process utilizing supercritical carbon dioxide as the solvent. The supercritical region investigated for solute extraction ranged from 45 to 100°C and 2000 to 8000 psi. Solute extraction was made possible by utilizing a SFT-150.

Chandra Vemavarapu ^1,2, Matthew J. Mollan ¹and Thomas E. Needham²

¹Pharmaceutical Sciences, Pfizer Global R&D, Ann Arbor, MI 48105 ²Applied Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881

AAPS PharmSciTech 2002; 3 (4) article 29 (http://www.aapspharmsci.org)

Substituted phenols are an important class of compounds having widespread use (germicides, disinfectants, ingredients in fuel, etc.) There is little information in the literature regarding the solubilities of phenols in SCF CO₂. Accurate and precise solubility data for the compounds of interest is essential for the design of any SCF-based process. In this work, the solubilities of selected substituted phenols (2,5-dimethylphenol, 2,4,6-trimethylphenol,2,3,5-trimethylphenol, 4-phenylphenol, 4-tertbutylphenol) in binary (single solute + SCF CO₂) and ternary (two solutes + SCF CO₂) systems were investigated using a SFT Phase Monitor.

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The phase behavior of solutes in SCF is an important aspect, which is often overlooked in the solubility determinations. Solid solutes when in contact with supercritical CO₂ can exhibit complex phase behavior such as depression in melting point resulting in multiple phases, and therefore can considerably influence the determination of solid solubility.  The purpose of this study is to research solubilities of aromatic carboxylic acids and substituted phenols in SCF- CO₂ using the SFT phase monitor.

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Consistent production of solid drug materials of desired particle and crystallographic morphologies under cGMP conditions is a frequent challenge to pharmaceutical researchers.  The purpose of this article is therefore to provide the information and resources necessary for startup research involving particle formation using supercritical fluids. The importance of each stage of particle formation in tailoring the particle morphology is discussed in this article along with presenting various alternatives to perform these operations.

Chandra Vemavarapu ^a, ^b, ^∗, Matthew J. Mollan a, Mayur Lodaya a, Thomas E. Needham ^b

^a Pharmaceutical Sciences, Pfizer Global R&D, 2800 Plymouth Road, Ann Arbor, MI 48105, USA

^b Applied Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881

C. Vemavarapu et al. / International Journal of Pharmaceutics 292 (2005) 1–16

Of the variety of methods used to synthesize CNTs(carbon nanotubes), metalencapsulated dendrimers represent a particularly attractive catalyst for nanotube growth.  For such nanocomposite growth, our synthetic strategy has been to find a method to control the size and distribution of the catalyst seed particle, as well as to develop a low-temperature, nonreactive means of carbon production, to best preserve the structure of temperature-sensitive dendrimers. As an initial step toward this goal, we present the use of supercritical carbon dioxide as a medium for the decomposition of CCl4 using iron-encapsulated polypropyleneimine (PPI) dendrimers as a catalyst for MWNT growth.

Jason K. Vohs, Jonathan J. Brege, Jeffery E. Raymond, Allan E. Brown, Geoffrey L. Williams,† and Bradley D. Fahlman*

Departments of Chemistry and Biology, Central Michigan UniVersity, Mount Pleasant, Michigan 48859

B J. AM. CHEM. SOC. PAGE EST: 1.9

Within the last five years, there has been an explosion of research in supercritical fluids; more recent reports are now exploiting this medium for nanomaterials synthesis.  An important goal for undergraduate curricula should be the constant upgrading of content to include the most leading-edge techniques. To this end, this Journal has published a few articles related to SCF technology for undergraduates. This article describes a module to introduce undergraduate inorganic chemistry students to an exciting area of nanotechnology that also incorporates SCFs, an environmentally-friendly alternative to organic solvents.

Geoffrey L. Williams

Department of Biology, Central Michigan University, Mount Pleasant, MI 48859

Jason K. Vohs, Jonathan J. Brege, and Bradley D. Fahlman*

Department of Chemistry, Central Michigan University, Mount Pleasant, MI 48859; *fahlm1b@cmich.edu

Journal of Chemical Education  •  Vol. 82 No. 5 May 2005  •  www.JCE.DivCHED.org

Mitragyna speciosa is a narcotic plant but with specific medicinal importance. The main components of the leaves of M. speciosa are indole alkaloids. Previous scientific researches have shown that the alkaloidal extracts possess very potent anti-inflammatory, analgesic and opioid properties. The three most abundant indoles are mitragynine, paynanthine and speciogynine – the first two of which appear to be unique to this species. All these compounds were obtained from classical organic solvent (diethyl acetate, dichloromethane or methanol) extraction. In this research programme, supercritical fluid extraction (SFE) of M. speciosa was performed. An optimal condition of supercritical fluid extraction was developed using an analytical-scale SFE system. The conventional extraction methods were conducted in parallel for comparison. CO₂ extract of M.speciosa has never been studied yet and CO₂ was chosen as the media of extraction because it is non-toxic and environmentally safe to prepare and use.

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Cellulose and corn stover were subjected to a reaction with polar cosolvents (methanol and water)/CO₂ at subcritical and supercritical conditions. Resulting products from a cellulose reaction at 300oC analyzed by GCMS consisted of a mixture of organic acids, sugars, and several other components. Examples of organic acids included acetic, hexanoic, heptanoic and malonic acids, whereas sugars were levoglucosan, D-Allose, and D-Galactose. Furthermore product samples from a corn stover reaction at 300°C suggested presence of ketones, aromatic hydrocarbons, and methyl esters. As evidenced by these results, reactions at high pressure are plausible although they are accompanied by a complex product composition, and an unreacted residue of cellulose and lignin.

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Catharantrus roseus is a well-known medicinal plant belonging to the family Apocynaceae. It is regarded as a rich source of pharmaceutically important indole alkaloids that are used as antitumor, hypotensive and antiarrhythmic agents.  Among the indole alkaloids, vinblastine and vincristine are currently used to treat a wide variety of neoplasms and is recommended for treatment of Hodgkin’s disease, acute leukemia and choriocarcinoma, which is resistant to other types of therapy. The unique antitumor activities of these indole alkaloids have resulted in a great demand for vinblastine and vincristine as anticancer agents.

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Aluminum hydride (alane) has received a great deal of interest in recent years due its possible use as a hydrogen storage material. Alane contains 10.1 weight % hydrogen which meets the 2015 target set by the DOE of 9 weight % hydrogen. The decomposition of alane to its elements has no side reactions and has a decomposition enthalpy of 10 KJ/mol H2.  Thermal decomposition begins above 60 °C, but is slow. Decomposition studies have shown an ideal temperature range of 130 – 150 °C but with added dopant of TiCl3 or LiH decomposition can be achieved at an acceptable rate at <100 °C.  This, accompanied with recognition that rehydrogenation is realistic, makes alane a contender for use as an ideal hydrogen storage material.

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The purpose of this work was to develop an extraction technique to yield a betulinic acid-(BA) enriched extract of the traditional anti-anxiety plant Souroubea sympetala Gilg (Marcgraviaceae). Five extraction techniques were compared: supercritical carbon dioxide extraction (SCE), conventional solvent extraction with ethyl acetate (EtOAc), accelerated solvent extraction (ASE), ultrasonic assisted extraction (UAE) and soxhlet extraction (Sox). The EtOAc and SCE extraction methods resulted in BA-enriched extracts, with BA concentrations of 6.78 [1] 0.2 and 5.54 [1] 0.2 mg/g extract, respectively, as determined by HPLC-APCI-MS.The bioactivity of the BA-enriched extracts was compared in the elevated plus maze (EPM), a validated rodent anxiety behavior assay. Rats orally administered a 75 mg/kg dose of SCE extract exhibited anxiolysis as compared with vehicle controls, with a 50% increase in the percent time spent in the open arms, a 73% increase in unprotected head dips and a 42% decrease in percent time spent in the closed arms. No significant differences were observed between the SCE and EtOAc extracts for these measures, but the animals dosed with SCE extract had significantly more unprotected head dips than those dosed with the EtOAc extract. The SCE extract demonstrated a dose-response in the EPM, with a trend toward decreased anxiety at 25 mg/kg, and significant anxiolysis was only observed at 75 mg/kg dose. This study demonstrates that SCE can be used to generate a betulinic acid-enriched extract with significant anxiolysis in vivo. Further, the study provides a scientific basis for the ethnobotanical use of this traditional medicine and a promising lead for a natural health product to treat anxiety.

Martha Mullally,^1† Kari Kramp,¹,^4† Chris Cayer,¹,² Ammar Saleem,¹ Fida Ahmed,¹ Calum McRae,³ John Baker,³ Andrew Goulah,⁴ Marco Otorola,⁵ Pablo Sanchez,⁵ Mario Garcia,⁵ Luis Poveda,⁵ Zul Merali,² Tony Durst,¹,⁶ Vance L. Trudeau⁷ and John Thor Arnason^1*

¹Centre for Research in Biopharmaceuticals and Biotechnology, Department of Biology, University of Ottawa, Ottawa, ON, Canada, K1N 6N5

²Institute of Mental Health Research, University of Ottawa, Ottawa, Ontario, Canada K1N 6N5

³Bioniche Life Sciences Inc., 231 Dundas Street East, Belleville, ON, Canada, K8N 1E2

⁴Loyalist College,Wallbridge-Loyalist Road, P.O. Box 4200, Belleville ON, Canada, K8N 5B9

⁵Universidad Nacional, Heredia, Costa Rica

⁶Department of Chemistry, University of Ottawa, Ottawa, ON, Canada, K1N 6N5

⁷Centre for Advanced Research in Environmental Genomics, Department of Biology, University of Ottawa, Ottawa, ON, Canada, K1N 6N5

PHYTOTHERAPY RESEARCH    Phytother. Res. (2010)   Published online inWiley InterScience (www.interscience.wiley.com) DOI: 10.1002/ptr.3246

Supercritical carbon dioxide (scCO₂) was used to extract components of interest from Scenedesmus dimorphus, a microalgae species, under varied algal harvesting and extraction conditions. Liquid chromatography-mass spectrometry (LC-MS) was used to quantify the concentration of fatty acid methyl esters (FAME) and the FAME profile of transesterified lipids, phospholipids and pigments extracted under varied supercritical temperatures and pressures. The scCO₂ extraction results are compared with conventional solvent extraction to evaluate differences in the efficiency and nature of the extracted materials. Algae harvested by centrifugation (vs. lyophilization) demonstrated a similar extraction efficiency in scCO₂, indicating potential energy benefits by avoiding conventional algal mass dehydration prior to extraction. Centrifuged algae and optimized extraction conditions (6000 psi; 100°C) resulted in comparable FAME yields to conventional processes, as well as increased selectivity, reflected in the decreased pigment, nitrogen and phospholipid contamination of the FAME. Cell pre-treatments—sonication, microwave, bead beating and lyophilization—showed an enhancement in extraction yield in both conventional solvent and scCO₂ extraction, allowing for improved extraction efficiencies. This study suggests that scCO₂, a green solvent, shows great potential for algal lipid extraction for the sustainable production of biodiesel.

Lindsay Soha and Julie Zimmerman^*a,^b

^aYale University, Chemical and Environmental Engineering, 9 Hillhouse Ave., New Haven, CT, USA. E-mail: julie.zimmerman@yale.edu; Fax: +1 203.432.9703; Tel: +1 203.432.4837

^bYale University, School of Forestry and Environmental Studies, 195 Prospect St., New Haven, CT, USA

Green Chem., 2011, 13, 1422 www.rsc.org/greenchemDOI: 10.1039/c1gc15068e

Biodiesel was synthesized under catalyst-free supercritical methanol reactions using a variety of oils at 250 to 325°C in a 1-liter high-pressure batch reactor. Multiple experiments were performed at 6 to 80 molar ratios of methanol to oil; product samples were then analyzed by titration, and a Gas Chromatograph which monitored conversion of triglyceride by measuring total glycerine. At 300°C and 27 molar ratios, 97% conversion was attained. Following the experiment samples were placed in separatory funnel and the crude biodiesel layer was treated further to remove free glycerine by centrifugation and also with an Amberlite BD10dry which was more effective.

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Coprecipitation of active pharmaceutical ingredients (API) with additives can provide the ability to add functionality to API’s at early stages of drug discovery and synthesis. It is with this objective that a number of drugs were recrystallized in the presence of structurally related additives. The rapid expansion of supercritical solution (RESS) process was evaluated to recrystallize the drug–additive mixtures. Results of RESS aided coprecipitation studies involving twelve drug–additive mixtures are reported in this manuscript. Characterization of these mixtures revealed a number of interesting phenomena. These include habit modification, solubility enhancement, particle size reduction, eutectic formation, reduction in crystallinity, amorphous conversion, hydrate formation, polymorph conversion and selective extraction. In viewing each of these phenomena from an application standpoint, this manuscript serves as proof of concept for altering the physicochemical and mechanical properties of API’s using supercritical fluid (SCF) coprecipitation. It was concluded from these studies that the rapid crystallization conditions offered by the SCF media alone does not provide the ability to consistently dope crystals. Competing mechanisms based on the relative solubility of drugs and additives in SCF media, as well as the selectivity of SCF solvents are to be taken into consideration while undertaking coprecipitations.

Chandra Vemavarapu ^a,^b,^⁎, Matthew J. Mollan b, Thomas E. Needham ^a

^a Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881, USA

^b Pharmaceutical Sciences, Pfizer Global R&D, Ann Arbor, MI 48105, USA

C. Vemavarapu et al. / Powder Technology 189 (2009) 444–453

The utilization of carbon dioxide under supercritical conditions in the delignification of wood has already been reported in the literature for several species of tree. In these studies organic solvents (acetic acid, ethanol, methanol, dioxane, etc.) were used as co-solvent and very high pressures (15–25MPa) were employed. Organosolv treatments of various woods have also been reported and have shown good results with ethanol–water mixtures, normally at volume ratios close to unit.

This article describes a study of the pulping of Pinus taeda wood chips and sugar cane bagasse, combining the use of ethanol–water mixtures and carbon dioxide at high pressures. Ethanol–water mixture was varied from 50 to 100% ethanol for sugar cane bagasse and from 30 to 100% ethanol for P. taeda wood chips, and the reaction times from 30 to 120 min and from 30 to 150 min for sugar cane bagasse and P. taeda wood chips, respectively. The effect of pressure and temperature on the yield and extent of delignification was studied, using a factorial experimental design, over the ranges 14.7–23.2MPa and 142–198 ◦C, respectively.

The obtained results indicate important differences from the organosolv process, which may be due to the presence of carbon dioxide and/or the high pressure employed in this work. The pulp yields and extent of delignification showed, as expected, a much greater influence of temperature than of pressure. The best results were obtained at 16.0MPa and 190 ◦C. Under these conditions the pulping yield and the residual Klason lignin content from P. taeda wood chips were 43.7 and 4.9%, respectively, and from sugar cane bagasse 32.7 and 8.7%, respectively. These data correspond to a delignification extent in the order of 93.1% for P. taeda wood chips and 88.4% for sugar cane bagasse. Higher pressures lead to similar pulp yields but higher residual lignin contents.

Daniel Pasquini ^a, Maria Teresa Borges Pimenta ^a, Luiz Henrique Ferreira ^b, Antonio Aprigio da Silva Curvelo ^a,^∗

^a Instituto de Quımica de Sao Carlos, Universidade de Sao Paulo, C.P. 780, 13560-970 Sao Carlos, S.P., Brazil

^b Departamento de Quımica, Universidade Federal de Sao Carlos, C.P. 676, 13565-905 Sao Carlos, S.P., Brazil

D. Pasquini et al. / J. of Supercritical Fluids 36 (2005) 31–39

A series of tetradentate pyridyl-imine terminated Schiff-base ligands has been investigated for their ability in the catalytic oxidation of alcohols when combined with copper bromide (CuBr2) and 2,2,6,6-tetramethylpiperidyl-1-oxy (TEMPO). Analogous bidentate ligands showed poorer catalytic activity and the ratio of Cu:ligand was of crucial importance in maintaining high yields. The polydimethylsiloxane (PDMS) derived pyridyl-imine terminated ligand combined with copper(II) ions affords an effective and selective catalyst for aerobic oxidations of primary and secondary alcohols under aqueous conditions. Preliminary mechanistic studies suggest that bimetallic complexes may be playing a role in the catalytic transformation.

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Production of cleaner fuels from increasingly low-grade feedstocks and non-edible biomass sources.

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From the point of view of Green Chemistry, polymer-based catalysts are very environmentally friendly. These catalysts can be used and recycled in green solvents such as liquid polymers and supercritical carbon dioxide. They can also be very selective. 

In our recent studies, a series of α-w pyridyl-imine terminated polydimethylsiloxane ligands have been synthesized and characterized. It is interesting that these carbon dioxide miscible ligands form metallocyclic complexes when coordinated with copper(I) salt. Meanwhile, they provide perfect binding sites for copper (II) ions which then work as catalysts for more efficient aerobic oxidations of primary and secondary alcohols.

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A group of 14 different bio-sourced, renewable feedstocks (homoserine, 1; glutamic acid, 2; aspartic acid, 3; 2,5-furandicarboxylic acid, 4; fumaric acid, 5; oxalacetic acid, 6; tartaric acid, 7; malic acid, 8; succinic acid, 9; levulinic acid, 10; g-hydroxybutyrolactone, 11; xylitol, 12; mannitol, 13; sorbitol, 14) have been examined for their solubility/miscibility in a variety of ‘green’ solvents, including water, supercritical carbon dioxide (scCO2), and ionic liquids. Two other bio-based compounds 5-hydroxymethylfurfural, 15, and D-xylose, 16, were studied in selected solvents. Trends in solubility have been assessed so that these data may be extrapolated to help predict solubilities of other related compounds. For example, 10, 11 and 15 all demonstrated appreciable solubility in scCO2, as they possess weak intermolecular interactions. The dicarboxylic acids studied (4–9) all proved soluble in modified scCO2 (by use of MeOH as a cosolvent). While the polyols (12–14) and 1 were insoluble in scCO2 but water of various pHs and ionic liquids proved adept at their dissolution. Some of the amino acids studied (2 and 3) were only soluble in water with an adjustment of pH.

Samantha M. Payne and Francesca M. Kerton*

Centre for Green Chemistry and Catalysis, Department of Chemistry, Memorial University of Newfoundland, St. John’s, Newfoundland and Labrador, Canada A1B 3X7. E-mail: fkerton@mun.ca; Fax: +1 709 7373702; Tel: +1 709 7378089

Green Chem., 2010, 12, 1648–1653 DOI: 10.1039/c0gc00205d

This study investigated the potential of Northern shrimp (Pandelus borealis Kreyer) by-products as a source of omega-3 polyunsaturated fatty acids (x-3 PUFAs). The by-products (heads, shell and tail) of processing accounted for approximately 50–60% of the catch. Supercritical CO2 extraction (SFE) of the by-products at 35 MPa and 40 [1]C generated a deep red oil, rich in x-3 PUFAs, specifically 7.8 ± 0.06% eicosapentaenoic acid (EPA) and 8.0 ± 0.07 % docosahexaenoic acid (DHA).

Virginie Treyvaud Amiguet ^a,¹, Kari L. Kramp ^a,^b,¹, JinQin Maoa, Calum McRae ^b, Andrew Goulah ^b, Linda E. Kimpe ^a, Jules M. Blais ^a, John T. Arnason ^a,^⇑

^a University of Ottawa, Department of Biology, Centre for Advanced Research in Environmental Genomics, 30 Marie-Curie, Ottawa, ON, Canada K1N 6N5

^b Loyalist College, BioSciences, 376 Wallbridge-Loyalist Road, P.O. Box 4200, Belleville, ON, Canada K8N 5B9

V. Treyvaud Amiguet et al. / Food Chemistry 130 (2012) 853–858

Mitragyna speciosa is a narcotic plant but with specific medicinal importance. The main components of the leaves of M. speciosa are indole alkaloids. Previous scientific researches have shown that the alkaloidal extracts possess very potent anti-inflammatory, analgesic and opioid properties. The three most abundant indoles are mitragynine, paynanthine and speciogynine, the first two of which appear to be unique to this species. All these compounds were obtained from classical organic solvent (ethyl acetate, dichloromethane or methanol) extraction. CO₂ extract of M. speciosa has never been studied yet. Hence, in this present investigation, supercritical fluid extraction (SFE) of M. speciosa was performed. Comparison of the TLC of SFE extracts with that of the ethyl acetate extract from this preliminary study shows no alkaloid was extracted out with 100% CO₂. Alkaloids were only extracted with eluent system using ethanol as co-solvent and the optimal conditions was CO2-ethanol (80% EtOH), 40 °C and 5000psi. CO₂ was chosen as the media of extraction because it is non-toxic and environmentally safe to prepare and use.

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Accurate knowledge of the phase equilibria of CO₂-expanded hydroformylation reaction mixtures is essential to rational process design and development. Vapor-liquid equilibria of the following systems were measured in a variable-volume view cell at temperatures ranging from (313.15 to 353.15) K and pressures up to 9 MPa: CO + 1-octene, CO2 + 1-octene, CO + 1-octene + CO₂, CO + nonanal, CO₂ + nonanal, CO + nonanal + CO₂, H2 + 1-octene, H2 + 1-octene + CO₂, H2 + nonanal, and H2 + nonanal + CO₂. The measured solubilities of CO and H2 in the liquid phases were consistent with literature values. The presence of CO2 was found to enhance the solubilities of both CO and H2 in the liquid phase. The enhancement factor is up to 1.54 for carbon monoxide and 1.82 for hydrogen. The Peng-Robinson equation of state (PR EoS) with van der Waals mixing rules and binary interaction parameters modeled the VLE data adequately, with much better fits for the 1-octene systems compared to the more polar nonanal systems.

Zhuanzhuan Xie, William K. Snavely, Aaron M. Scurto, and Bala Subramaniam*

Center for Environmentally Beneficial Catalysis, Department of Chemical & Petroleum Engineering, University of Kansas, Lawrence, Kansas 66045-7609

Journal of Chemical & Engineering Data, Vol. 54, No. 5, 2009

A group of 14 different bio-sourced, renewable feedstocks have been examined for their solubility/miscibility in a variety of ‘green’ solvents, and trends in solubility have been assessed so that the data may be extrapolated to help predict solubilities of other related compounds. This information could provide valuable insight into the workability of a host of new, green reactions using these compounds, opening the door to a realm of more environmentally friendly syntheses.

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The ability to sensitively detect and analyze large molecules and their reaction products is important for the analysis of biological materials, including medical samples, plants and foods. Such analyses present special challenges in terms of the need to selectively extract the compound or class of compounds in order to separate them from the complex mixture found in biological samples. In addition, conventional techniques for separating and identifying relatively small molecules are not applicable to high molecular weight materials where the volatility is low and they are often viscous liquids or solids at room temperature.

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The use of methyl acetate instead of methanol for supercritical synthesis of glycerol-free biodiesel from vegetable oils is a new process and its study is very limited in the literature. In this work, it has been tested for the first time on three edible and non-edible oils with different fatty acid composition. The process was also applied to waste oil with higher free fatty acid (FFA) content. The results demonstrate that the oil composition does not significantly influence the biodiesel yield.

The influence of temperature, pressure and molar ratio of reactants was studied. All the oils achieved complete conversion after 50 min at 345 [1]C, 20 MPa with methyl acetate:oil molar ratio equal to 42:1. The obtained data also allowed calculating the apparent rate coefficients and activation energies.

Eventually, some new information on the process was obtained. Thermal degradation of triacetin, which substitutes glycerol as the by-product of the transesterification reaction, was observed. Some indicative experiments were performed to understand the role of the acetic acid produced by FFA esterification.

Pasquale Campanelli, Mauro Banchero *, Luigi Manna

Dipartimento di Scienza dei Materiali e Ingegneria Chimica, Politecnico di Torino, Corso Duca degli Abruzzi, 24, 10129 Torino, Italy

P. Campanelli et al. / Fuel 89 (2010) 3675–3682

Aqueous extraction using subcritical water is an environmentally friendly alternative to extracting oil and protein from oilseeds with flammable organic solvents. The effects of solids-to-liquid ratio (1:3.3–1:11.7), temperature (66–234 _C), and extraction time (13–47 min) were evaluated on the extraction of oil and protein from soybean flakes and from extruded soybeans flakes with subcritical water. A central composite design (23) with three center points and six axial points was used. Subcritical water extractions were carried out in a 1-L high-pressure batch reactor with constant stirring (300 rpm) at 0.03–3.86 MPa. In general, oil extraction was greater for extruded soybean flakes than with soybean flakes. More complete oil extraction for extruded soybean flakes was achieved at around 150 _C and extraction was not affected by solids-to-liquid ratios over the range tested, while oil extraction from soybean flakes was more complete at 66 _C and low solids-toliquid ratio (1:11.7). Protein extraction yields from flakes were generally greater than from extruded flakes. Protein extraction yields from extruded flakes increased as temperature increased and solids-to-liquid ratio decreased, while greater protein extraction yields from soybean flakes were achieved when using low temperatures and low solidsto- liquid ratio.

S. C. Ndlela  •  J. M. L. N. de Moura  •

N. K. Olson  •  L. A. Johnson

S. C. Ndlela • N. K. Olson, Iowa Energy Center-BECON, Nevada, IA 50201, USA

J. M. L. N. de Moura • L. A. Johnson (&), Center for Crops Utilization Research, Iowa State University, 1041 Food Sciences Building, Ames, IA 50011-1061, USA   e-mail: ljohnson@iastate.edu

J. M. L. N. de Moura • L. A. Johnson, Department of Food Science and Human Nutrition, Iowa State University, Ames, IA 50011-1061, USA

J Am Oil Chem Soc   DOI 10.1007/s11746-011-1993-7

To increase cotton’s consumption by inventing products and processes that demonstrate preferred use of cotton over competing fibers in needed and emerging applications involving plastics, textiles, and composites.

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 To advance the realization of algae as a feedstock for biodiesel, process technologies and closed-loop biomass use must be optimized. Life-cycle analysis (LCA) of the biodiesel production process highlights the potential significant impact of improvements in the extraction of algal lipids and conversion into biodiesel. Further, a single-step lipid extraction and transesterification process was shown to have the highest energy rewards. This work investigates the potential for using scCO2 for the extraction and conversion process. scCO2 is shown to be an effective and selective solvent for extracting triglycerides from algal biomass. This work also explores the fundamental science necessary to achieve a one-pot approach that both extracts and transesterifies lipid from algae using supercritical carbon dioxide/methanol (scCO2/MeOH) and heterogeneous catalysts. A variety of basic and acidic heterogeneous catalysts have been surveyed for their effectiveness at transesterification of triglyceride (TG) to fatty acid methyl esters (FAME). Further the enhanced solubility of FAME over reaction intermediates, TG, and glycerol, is likely to provide a driving force for reaction. This research offers the foundations for a simple one-pot system wherein biodiesel can be directly, selectively, and sustainably produced from algae for further application in an algae biorefinery.

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The first phase of this project evaluated the reaction pathways for biomass feedstock in the presence of various cosolvents including acetone, methanol, CO2, and water using a 1 liter (di: 7.6cm, l: 23.1cm) high pressure batch reactor. Additionally, the effect of temperature on the extent of the reaction was assessed at 200 to 350 oC. In both instances biomass conversion rates compared to the starting material ranged from 70 to 90 %, with the remaining portion being the unreacted fraction and lignin. The resulting products consisted of complex chemical fractions: organic acids, organic ester derivatives, sugars, sugar-alcohols, thermal degradation products and more. Although the impact of using various cosolvents was noticeable at lower temperatures, at higher temperatures the extent thermal degradation products increased due to longer heating times to reach the target temperature (2 to 8 hrs.). Despite the challenges with longer residence time when using the batch reactor, results from this study gave an important understanding of the reaction behavior and interaction of the solvent and biomass.

To have better control of the reaction extent at pilot scale, a flow reactor was assembled. The system consisted of a 250 ml/min slurry pump with reactor chamber that is 212 cm longer by 3 cm diameter, a maximum system working pressure up to 69 Mpa, electrical heating jackets and a condenser. Biomass slurry of 5 to 10% was fed into the reactor at varying temperatures from 200 to 350 oC and at residence times of 5 to 30 minutes. Analysis results from the flow reactor study will be main focus for this discussion.

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Chia (Salvia Hispanic, L.) is a crop that was used as food, medicine and paints by the Aztec Indians in Mexico before 1492, andnowhas a promissory future in several countries. Chia seeds oil is rich in polyunsaturated fatty acids, particularly omega-3 linolenic acid (54–67%) and omega-6 linoleic acid (12–21%) which pose great benefits for human and animal health.   The oil extraction from Chia seeds using supercritical CO2 seems to be a good alternative because it operates at low temperature with good mass-transfer rates and with no solvent residual in the final product.   The objective of this work is to evaluate the extraction yield of oil from chia seeds and the concentration of omega-3 and omega-6 acids using supercritical extraction with CO2 at three pressures: 136, 272, and 408 bar, and three temperatures: 40, 60, and 80◦C.

Jose Antonio Rocha Uribe^a,^∗ , Jorge Ivan Novelo Perez^a , Henry Castillo Kauil^a , Gabriel Rosado Rubio^a , Carlos Guillermo Alcocer^b

^a FIQ, Universidad Autónoma de Yucatán, Periferico Norte km 33.5, C. P. 97203, Mérida, Yucatán, Mexico

^b Oleox Industries S. A. de C.V. Anillo Periferico T.C. 13917 Int. 7 Col. Cholul, C. P. 97300, Merida, Yucatan, Mexico

J.A.R. Uribe et al. / J. of Supercritical Fluids 56 (2011) 174–178

Thevetia peruviana is an always green tree that grows well at adverse conditions and it is well adapted to Yucatan weather. Its kernal contains more than 60% of oil. Because the toxicity of the plat the oil is non edible and then a good candidate for biofuel production. In this study it is reported the results of supercritical extraction of oil from Thevetia peruviana kernals. The yield obtained 70% is higher than that obtained using solvent extraction 62% with petroleum ether, 60% with n-hexane, and to 40% using mechanical extraction.

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Looking for a good raw material for biodiesel at the Mexican-Yucatan peninsula, the study present data on the extraction of oil from Moringa oleifera kernals. Solvent extraction with n-hexane and ethanol, and supercritical extraction with CO2 are presented and compared with reported data. For supercritical extraction pressures of 200 to 400 bar and temperatures of 40 and 60⁰C were tested. Analysis with Gas Chromatography reveals that the main fatty acids are Oleic acid (69%), Palmitic acid (10%), and stearic acid (8%).

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Carbon Dioxide (CO2) extraction of cannabis is becoming more prevalent as the extract market grows with the spread of medical and recreational legalization. However, due to the historically underground nature of working with the substance, little true scientific experimentation and process development has occurred; even less has been published. Those new to the field have limited guidance.

The following is a compilation of the process learnings regarding feedstock selection and preparation that Supercritical Fluid Technologies (SFT) customers’ companies currently working in the CO2 cannabis extraction field, have shared with us. Due to the proprietary nature of each company’s specific process, the material here will be presented in a generic way that is applicable to the majority of processors.

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Abstract: Direct extraction of metals from solids with complexing agents in supercritical CO2 (SC-CO2) has recently attracted interests in separation, purification, recovery, and analysis of metals. In the present study, the static/dynamic extraction of rare earth elements (Nd, Ce) from their oxides (Nd2O3, CeO2) with organophosphorus complexes with HNO3 and H2O in SC-CO2 was investigated. The static extraction efficiency of Nd from Nd2O3 with the tri-n-butylphosphate (TBP)-HNO3 complex could reach 95%under optimized experimental conditions. However, the static extraction efficiency of Nd from Nd2O3 with the trilkyl phosphine oxide (TRPO)-HNO3 complex was less than 10%, and
the static extraction efficiency of Ce from CeO2 with the TBP-HNO3 complex was less than 1%. The dynamic extraction efficiency of Nd from Nd2O3 with the TBP-HNO3 complex could reach more than 97%. Effects of parameters were evaluated on the extraction efficiency to ascertain the optimum conditions. This study illustrated the extraction process using the TBP-HNO3 complex in SC-CO2 would be feasible for
separation, purification, recovery, and analysis of some rare earth elements from various oxide mixtures.

DUANWuhua (段五华), CAO Pijia (曹丕佳), ZHU Yongjun (朱永贝睿)
(Institute of Nuclear andNew Energy Technology, Tsinghua University,Beijing 102201, China)
Received 31May 2009; revised 7 September 2009

Carbon Dioxide (CO₂) extraction of cannabis is becoming more prevalent as the extract market grows with the spread of medical and recreational legalization.  However, due to the historically underground nature of working with the substance, little true scientific experimentation and process development has occurred; even less has been published. Those new to the field have limited guidance.

The following is a compilation of the process learnings regarding selection of extraction parameters that Supercritical Fluid Technologies (SFT) customers’ companies who are currently working in the CO₂ cannabis extraction field have shared with us. Due to the proprietary nature of each company’s specific process, the material here will be presented in a generic way that is applicable to the majority of processors.

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All Cannabis feedstock contains water, even that which is properly dried and cured. Removing this water from the extract after processing raises the cannabinoid concentration of the extract, prevents it from spattering when consumed directly though vaping or in a rig, presents a cleaner taste to the consumer, and enables a more attractive appearance.

CO₂ processing creates extract that will be laden with dry ice.  Depending on the equipment and processing conditions the extract will need to be de-gassed and/or heated prior to dewatering.

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Extraction of anthocyanins from haskap berry pulp using supercritical carbon dioxide: Influence of co-solvent composition and pretreatment

Guangling Jiao, Azadeh Kermanshahi pour∗

Biorefining and Remediation Laboratory, Department of Process Engineering and Applied Science, Dalhousie University, PO, 15000, Halifax, Nova Scotia, B3H 4R2,
Canada

Extracts rich in anthocyanin compounds were obtained from haskap berry pulp paste using supercritical carbon dioxide (scCO2) and water as co-solvent. The extraction conditions including pressure, temperature, and amount of water were further optimized by Box-Behnken design. The highest total anthocyanins (TA) yield of 52.7% was
achieved at 45 MPa, 65 °C, 5.4 g water to 3.2 g berry pulp paste, 15 min static and 20 min dynamic time. Different combinations of water and ethanol as co-solvent did not significantly affect the TA yield. Furthermore, similar anthocyanin extraction yields were obtained in the case of the pulp paste and rehydrated freeze-dried berry pulp powder, which indicates that freeze drying pretreatment is not required prior to scCO2 extraction.
Compared with conventional extraction, the use of scCO2 and water as co-solvent offered higher anthocyanin extraction efficiency (52.7% versus 38.3%) with improved antioxidant activity (89.8% versus 72.2%).

Ahmed M. Galal1,*, Desmond Slade1, Waseem Gul1,5, Abir T. El-Alfy2, Daneel Ferreira1,3 and Mahmoud A. Elsohly1,4,5

Abstract: Naturally occurring cannabinoids (phytocannabinoids) are biosynthetically related terpenophenolic compounds uniquely produced by the highly variable plant, Cannabis sativa L. Natural and synthetic cannabinoids have been extensively studied since the discovery that the psychotropic effects of cannabis are mainly due to ! 9-THC. However,
cannabinoids exert pharmacological actions on other biological systemssuch as the cardiovascular, immune and endocrine systems. Most of these effects have been attributed to the ability of these compounds to interact with the cannabinoid CB1 and CB2 receptors. The FDA approval of Marinol®, a product containing synthetic ” 9-THC (dronabinol), in 1985 for the control of nausea and vomiting in cancer patients receiving chemotherapy, and in 1992 as an appetite stimulant for AIDS patients, has further intensified the research interest in these compounds. This article reviews patents (2003-2007) that describe methods for isolation of cannabinoids from cannabis, chemical and chromatographic methods for their purification, synthesis, and potential therapeutic applications of these compounds.

AP-144 – Cannabidiol from inflorescences of Cannabis sativa L.: Green extraction and purification processes..

Cannabidiol from inflorescences of Cannabis sativa L.: Green extraction and purification processes

Stefania Marzoratia,*, Danilo Friscioneb, Enrico Picchib, Luisella Verottaa

a Università degli Studi di Milano, Department of Environmental Science and Policy, Via Celoria 2, 20133 Milano, Italy
b Alfatech S.p.A., Via Angelo Scarsellini 97, 16149 Genova, Italy

This work investigates an extraction and purification downstream process able to provide cannabidiol (CBD) enriched products starting from inflorescences of Cannabis sativa L. Even though the legislation concerning nonpsychoactive Cannabis derivatives is still an open issue, the interest in this compound is justified worldwide by the scientifically demonstrated health beneficial effects of CBD for the treatment of many disorders. For these reasons, the interest in CBD-based formulations, for the sake of readiness for the future market demands, is quite high. Despite the fact that the recent literature is highly addressed to the topic of cannabinoids and their related biological activities, there is still a general lack in strategic proposals aiming at recovering and purifying specifically CBD through scalable processes.
In this work, preliminary studies were addressed to convert the main product of the plant metabolism, cannabidiolic acid, to CBD by heat-treatment-induced decarboxylation of the dried biomass. Then, a “green strategy”, supercritical CO2 extraction, enabled to yield a 50 % w/w CBD-enriched oil, avoiding any use of toxic organic solvents. Yields and compositions of methanolic extraction and supercritical CO2 were compared. Results confirmed the enhanced selectivity of supercritical CO2. A winterization process, followed by flash chromatography, successfully removed waxes and the psychotropic fraction, providing an almost 80 % w/w CBD-enriched final product.

Stefania Marzorati,  *^aAndrea Schievano, ^aAntonio Idà^b  and  Luisella Verotta^a Author affiliations

^aDepartment of Environmental Science and Policy, Università degli Studi di Milano, via Celoria 2, 20133 Milano, Italy
E-mail: stefania.marzorati@unimi.it
Tel: +390250314114

^bAlgaria srl, via Tucidide 61, 20133 Milano, Italy

Abstract

In the last decade, the cyanobacterium Spirulina has gained a high commercial interest as a food supplement, mainly due to its high protein content as well as high amounts of pigments, such as carotenoids, chlorophylls and phycocyanins. In particular, phycocyanin has been widely considered as a precious food-dye because of its protein-based structure and the rare intense-blue color. Different strategies were developed for the isolation and purification of phycocyanin. The main drawback of such processes is that carotenoids and chlorophylls are generally wasted together with the residual biomass. In this study, a different approach is proposed, suggesting an integrated pigment extraction chain. The body of the strategy involves two consecutive steps of the supercritical-CO₂ extraction of carotenoids and chlorophylls, before phycocianin extraction. The total carotenoid, chlorophyll a and chlorophyll b contents in the extracts were equal to 3.5 ± 0.2 mg g⁻¹, 5.7 ± 0.2 mg g⁻¹ and 3.4 ± 0.3 mg g⁻¹, respectively (by dry Spirulina weight). The biomass residue, exhausted in terms of carotenoids and chlorophylls, was then extracted in water to yield phycocyanin. Consecutive steps were developed in order to ehance the phycocyanin purity, including electrocoagulation, dialysis and protein salting-out. These processes yielded 250 mg g⁻¹ of phycocyanin (by dry Spirulina weight). A potentially scalable strategy to obtain the blue pigment with high purity (A₆₂₀/A₂₈₀ = 2.2) was developed. The practical application of the extracted blue phycocyanin pigment as a cotton-based tissue colorant was also experimented.

Victoria Bernardo⁎, Judith Martín-de León, Ester Laguna-Gutiérrez, Miguel Ángel Rodríguez-Pérez

Cellular Materials Laboratory (CellMat), Condensed Matter Physics Department, University of Valladolid, Campus Miguel Delibes, Paseo de Belén n7, 47011 Valladolid, Spain

In this work, a new system based on poly(methyl methacrylate) (PMMA) sepiolite nanocomposites that allow producing nanocellular polymers by using the gas dissolution foaming technique is described. Nanocomposites with different nanoparticle types and contents have been produced by extrusion. From these blends, cellular materials have been fabricated using the so-called gas dissolution foaming method. An extensive study of the effect of the processing parameters (saturation pressure and foaming temperature) on the cellular materials produced has been performed. Results showed that among the three sepiolites used, only those modified with a quaternary ammonium salt are suitable for being used as nucleating agents in PMMA. With these nanoparticles bimodal cellular polymers, with micro and nanometric cells, have been produced. Cell sizes in the range of 300–500 nm and cell densities of the order of 1013–1014 nuclei/cm3 have been obtained in the nanocellular region. A foaming temperature of 80 °C and a wide range of saturation pressures (between 10 and 30 MPa) and low particle contents (between 0.5 and 1.5 wt%) allow obtaining these materials. Furthermore, it has been found that cell size in the nanometric population can be controlled by means of the particles content; a reduction in the cell size is obtained when the particles content increases. Finally, results indicate that an increase in the foaming temperature leads to cellular nanocomposites with lower relative densities (below 0.21) and larger cell sizes (above 450 nm).

J. Martín-de Le´on a,*, M. Jim´enez a, J.L. Pura d, V. Bernardo b, M.A. Rodriguez-P´erez a,c
a Cellular Materials Laboratory (CellMat), Condensed Matter Physics Department, University of Valladolid, Valladolid, 47011, Spain
b CellMat Technologies S.L. Paseo de Belen 9A, 47011, Valladolid, Spain
c BioEcoUVA Research Institute on Bioeconomy, University of Valladolid, Spain
d Gds Optronlab, Condensed Matter Physics Department, Universidad de Valladolid, 47011, Spain

Abstract:

The key parameters and production route for the easy production of highly transparent nanocellular films based on polymethylmethacrylate (PMMA) with thickness below 1 mm are herein described. The use of the gas dissolution foaming process (CO2 as physical blowing agent) with saturation pressures of 40
and 50 MPa, a saturation temperature of 0 ◦C and a saturation time of 2.5 h together with an adequate approach to foam the samples leads to the production of directly transparent nanocellular PMMA with relative densities in the range of 0.47–0.80 and cell sizes in the internal part of the film ranging 23–29 nm.
The produced materials present maximum transparency of 61% for a thickness of 0.5 mm without any postprocessing, a value comparable to the one previously obtained in the literature for nanocellular PMMA produced using a long-lasting process that included additional time-consuming post-processing of the samples. The produced cellular materials have been in-deep characterized, and the influence of several key parameters such as the solid skin thickness, transition region, and cellular structure on the final optical transmittance has been studied.

Victoria Bernardoa,∗, Judith Martin-de Leona, Ester Laguna-Gutierreza, Tiziano Catelanib, Javier Pintob, Athanassia Athanassioub, Miguel Angel Rodriguez-Pereza

a Cellular Materials Laboratory (CellMat), Condensed Matter Physics Department, University of Valladolid, Valladolid, Spain
b Nanophysics, Istituto Italiano di Tecnologia (IIT), Genova, Italy

Nanostructured polymer blends with CO2-philic domains can be used to produce nanocellular materials with controlled nucleation. It is well known that this nanostructuration can be induced by the addition of a block copolymer poly(methyl methacrylate)-poly(butyl acrylate)-poly(methyl methacrylate) (MAM) to a poly(methyl methacrylate) (PMMA) matrix. However, the effect of the block copolymer molecular weight on the production of nanocellular materials is still unknown. In this work, this effect is analysed by using three types of MAM triblock copolymers with different molecular weights, and a fixed blend ratio of 90 wt% PMMA and 10 wt% of MAM. Blends were produced by extrusion. As a result of the extrusion process, a non-equilibrium nanostructuration takes place in the blends, and the micelle density increases as MAM molecular weight increases. Micelle formation is proposed to occur as result of two mechanisms: dispersion, controlled by the extrusion parameters and the relative viscosities of the polymers, and self-assembly of MAM molecules in the dispersed domains. On the other hand, in the nanocellular materials produced with these blends, cell size decreases from 200 to 120 nm as MAM molecular weight increases. Cell growth is suggested to be controlled by the intermicelle distance and limited by the cell wall thickness. Furthermore, a theoretical explanation of the mechanisms underlying the limited expansion of PMMA/MAM systems is proposed and discussed.

Victoria Bernardoa,∗, Judith Martin-de Leona, Javier Pintob, Tiziano Catelanic, Athanassia Athanassioub, Miguel Angel Rodriguez-Pereza

a Cellular Materials Laboratory (CellMat), Condensed Matter Physics Department, University of Valladolid, Campus Miguel Delibes, Paseo de Belén nº7, 47011, Valladolid, Spain
b Smart Materials, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genova, Italy
c Electron Microscopy Facility, Istituto Italiano di Tecnologia, Via Morego 30, 16163, Genova, Italy

Low-density nanocellular polymers are required to take advantage of the full potential of these materials as high efficient thermal insulators. However, their production is still a challenging task. One promising approach is the use of nanostructured polymer blends of poly(methyl methacrylate) (PMMA) and a block copolymer poly(methyl methacrylate)-poly(butyl acrylate)-poly(methyl methacrylate) (MAM), which are useful for promoting nucleation but seem to present a severe drawback, as apparently avoid low relative densities. In this work, new strategies to overcome this limitation and produce low-density nanocellular materials based on these blends are investigated. First, the effect of very low amounts of the MAM copolymer is analysed. It is detected that nanostructuration can be prevented using low copolymer contents, but nucleation is still enhanced as a result of the copolymer molecules with high CO2 affinity dispersed in the matrix, so nanocellular polymers are obtained using very low percentages of the copolymer. Second, the influence of the foaming temperature is studied. Results show that for systems in which there is not a clear nanostructuration, cells can grow more freely and smaller relative densities can be achieved. For these studies, blends of PMMA with MAM with copolymer contents from 10 wt% and as low as 0.1 wt% are used. For the first time, the production strategies proposed in this work have allowed obtaining low density (relative density 0.23) nanocellular polymers based on PMMA/MAM blends.

V. Bernardo n, J.Martín-deLeón,M.A.Rodríguez-Pérez Cellular MaterialsLaboratory(CellMat),CondensedMatterPhysicsDepartment,UniversityofValladolid,CampusMigue Delibes,PaseodeBelénno. 7,47011 Valladolid, Spain

Nanocellular foams have been produced by means of a gas dissolution process using polyphenylsulfone
(PPSU) as matrix polymer. Cell sizes in the range 20–30 nm and cell nucleation densities higher than
1015 cm3 have been achieved for materials with relative densities in the range 0.65–0.75. The influence
of both saturation pressure and foaming temperature has been studied. On the one hand, it has been
proved that there is a large influence of the amount of gas (CO2) absorbed in the final cellular structure,
in fact it has been found a critical CO2 uptake between 9% and 9.5% at which the cell sizes evolve from the micro to the nanoscale. On the other hand, it has been found that there is a wide range of foaming
parameters(foaming time and foaming temperature) in which nanocellular foams can be produced.

Victoria Bernardo,* Judith Martin-de Leon and Miguel Angel Rodriguez-Perez

This work presents a new strategy for obtaining nanocellular materials with high anisotropy ratios by means of the addition of needle-like nanoparticles. Nanocellular polymers are of great interest due to their outstanding properties,whereas anisotropic structures allowthe realization of improved thermal and mechanical properties in certain directions.Nanocomposites based on poly(methyl methacrylate) (PMMA)with nanometric sepiolites are generated by extrusion. Fromthe extruded filaments, cellular materials are produced using a two-step gas dissolution foaming method. The effect of adding various types and contents of sepiolites is investigated. As a result of the extrusion process, the needle-like sepiolites are aligned in the machine direction in the solid nanocomposites. Regarding the cellular materials, the addition of sepiolites allows one to obtain anisotropic nanocellular polymers with cell sizes of 150 to 420nm and cell nucleation densities of 1013–1014 nuclei cm−3 and presenting anisotropy ratios ranging from 1.38 to 2.15, the extrusion direction being the direction of the anisotropy. To explain the appearance of anisotropy, a mechanism based on cell coalescence is proposed and discussed. In addition, it is shown that it is possible to control the anisotropy ratio of the PMMA/sepiolite nanocellular polymers by changing the amount of well-dispersed sepiolites in the solid nanocomposites

Yuxiang Yao,† Nina F. Farac,† and Gisele Azimi*,†,‡
†Laboratory for Strategic Materials, Department of Chemical Engineering and Applied Chemistry, 200 College Street, Toronto,
Ontario M5S 3E5, Canada
‡Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario M5S 3E4, Canada

ABSTRACT: Today’s world relies upon critical green technologies that are made of elements with unique properties irreplaceable by other materials. Such elements are classified under strategic materials; examples include rare earth elements that are in increasingly high demand but facing supply uncertainty and near zero recycling. For tackling the sustainability challenges associated with rare earth elements supply, new strategies have been initiated to mine these elements from secondary sources. Waste electrical and electronic equipment contain considerable amounts of rare earth elements; however, the current level of their recycling is less than 1%. Current recycling practices use either pyrometallurgy, which is energy intensive, or hydrometallurgy that rely on large volumes of acids and organic solvents, generating large volumes of environmentally unsafe residues. This study put emphasis on developing an innovative and sustainable process for the urban mining of rare earth elements from waste electrical and electronic equipment, in particular, a nickel metal hydride battery. The developed process relies on supercritical fluid extraction utilizing CO2 as the solvent, which is inert, safe, and abundant. This process is very efficient in the sense that it is safe, runs at low temperature, and does not produce hazardous waste while recovering ∼90% of rare earth elements. Furthermore, we propose a mechanism for the supercritical fluid extraction of rare earth elements, where we considered a trivalent rare earth element state bonded with three tri-n-butyl phosphate molecules and three nitrates model for the extracted rare earth tri-n butyl phosphate complex. The supercritical fluid extraction process has the double advantage of waste valorization without utilizing hazardous reagents, thus minimizing the negative impacts of process tailings.
KEYWORDS: Rare earth elements, Supercritical fluid extraction, Recycling, Urban mining, Waste electrical and electronic equipment, Nickel metal hydride battery

Victoria Bernardo a,⇑, Judith Martin-de Leon a, Miguel Angel Rodriguez-Perez a,b

a Cellular Materials Laboratory (CellMat), Condensed Matter Physics Department, University of Valladolid, Valladolid, Spain
b Instituto BIOECOUVA, Universidad de Valladolid, Valladolid, Spain

ABSTRACT:

One strategy to produce nanocellular polymers is the use of nucleating species to promote nucleation. Whereas two-phase systems are widely studied, tri-phasic blends with two nucleating agents are uncommonly investigated. In this work, nanocellular polymers are obtained using tri-phasic blends of polymethylmethacrylate (PMMA) with two nucleating agents: needle-like sepiolites and a polymethylmethacrylate-polybutylacrylate-polymethylmethacrylate (MAM) block copolymer. Blends of PMMA with different concentrations of MAM and a fixed amount of sepiolites are produced by extrusion. Results show that at low MAM contents (1 wt%), the nucleation is a combination of the action of the two additives, but the addition of sepiolites induces the appearance of anisotropic structures. Meanwhile, at high MAM concentrations (10 wt%), MAM nanostructuration controls the nucleation and sepiolites increase the anisotropy. The alignment of the MAM micelles and the sepiolites in the extrusion direction promotes coalescence in this direction, leading to highly anisotropic nanocellular structures. Mean cell sizes of 100–300 nm and an average anisotropy ratio of 2.77 are obtained thanks to the combined effect of MAM and sepiolites.

Judith Martín-de Leon,* Victoria Bernardo, Paula Cimavilla-Román, Saul Perez-
Tamarit, and Miguel Angel Rodríguez-Perez

Although nanocellular polymers are interesting materials with improved properties in comparison with conventional or microcellular polymers, the production of large and flat parts of those materials is still challenging. Herein, gas dissolution foaming process is used to produce large and flat nanocellular polymethylmethacrylate samples. In order to do that, the foaming step is performed in a hot press. The methodology is optimized to produce flat samples with dimensions of 100
100
6mm3, relative densities in the range 0.25–0.55 and cell sizes around 250 nm. Additionally, foaming parameters are modified to study their influence on the final cellular structure, and the materials produced in this paper are compared with samples produced by using a most conventional approach in which foaming step is conducted in a thermal bath. Results obtained show that an increment in the foaming temperature leads to a reduction in relative density and an increase of cell nucleation density. Moreover, differences in the final cellular structure for materials produced by both foaming routes are studied, proving that although there exist some differences, the mechanisms governing the nucleation and growing are the same in both processes, leading to the production of homogeneous materials with very similar cellular structures.

Judith Martín-de Leóna,∗, Frederik Van Loockb, Victoria Bernardoa, Norman A. Fleckb,
Miguel Ángel Rodríguez-Péreza

a Cellular Materials Laboratory (CellMat), Condensed Matter Physics Department, University of Valladolid, Valladolid, Spain
b Engineering Department, University of Cambridge, Trumpington Street, CB2 1PZ, Cambridge, United Kingdom

A B S T R A C T
Solid-state foaming experiments are conducted on three grades of polymethyl methacrylate (PMMA). Nanocellular PMMA foams are manufactured with an average cell size ranging from 20 nm to 84 nm and a relative density between 0.37 and 0.5. For benchmarking purposes, additional microcellular PMMA foams with an average cell size close to 1 μm and relative density close to that of the nanocellular foams are manufactured. Uniaxial compression tests and single edge notch bend tests are conducted on the PMMA foams. The measured Young’s modulus and yield strength of the PMMA foams are independent of cell size whereas the fracture toughness of the PMMA foam increases with decreasing average cell size from the micron range to the nanometer range.

Judith Martín-de Leóna,∗, Jose Luis Purab, Victoria Bernardoa, Miguel Ángel Rodríguez-Péreza

a Cellular Materials Laboratory (CellMat), Condensed Matter Physics Department, Universidad de Valladolid, 47011, Spain
b Gds Optronlab, Condensed Matter Physics Department, Universidad de Valladolid, 47011, Spain

ABSTRACT: In this work, the optical properties of transparent nanocellular polymethylmethacrylate (PMMA) have been studied, experimental and theoretically. Transmittance measurements of samples presenting different cell sizes (14, 24, 39 and 225 nm) and a constant relative density of around 0.45 have been carried out obtaining values as high as 0.94 for the sample with the smaller cell size and a thickness of 0.05 mm. In addition, the light absorption coefficient has been measured as a function of cell size and wavelength. It has been found that the transmittance has a strong dependence with the wavelength, presenting these transparent materials Rayleigh scattering. On the other hand, the transmission of visible light through these nanocellular materials has been modelled for the first time. The developed model reproduces with good accuracy the trends observed in the experimental results and provides remarkable insights into the physics mechanisms controlling the optical behavior of these materials.

Judith Martín-de León *, Victoria Bernardo and Miguel Ángel Rodríguez-Pérez
Cellular Laboratory (CellMat), Universidad de Valladolid, Valladolid 47011, Spain; vbernardo@fmc.uva.es (V.B.); marrod@fmc.uva.es (M.Á.R.-P.) Correspondence: jmadeleon@fmc.uva.es; Tel.: +34-983-184-035

Academic Editor: Michael D. Guiver
Received: 13 May 2016; Accepted: 11 July 2016; Published: 18 July 2016

Abstract: This paper describes the processing conditions needed to produce low density nanocellular
polymers based on polymethylmethacrylate (PMMA) with relative densities between 0.45 and 0.25,
cell sizes between 200 and 250 nm and cell densities higher than 1014 cells/cm3. To produce these
nanocellular polymers, the foaming parameters of the gas dissolution foaming technique using CO2
as blowing agent have been optimized. Taking into account previous works, the amount of CO2
uptake was maintained constant (31% by weight) for all the materials. Foaming parameters were
modified between 40 C and 110 C for the foaming temperature and from 1 to 5 min for the foaming
time. Foaming temperatures in the range of 80 to 100 C and foaming times of 2 min allow for
production of nanocellular polymers with relative densities as low as 0.25. Cellular structure has
been studied in-depth to obtain the processing-cellular structure relationship. In addition, it has
been proved that the glass transition temperature depends on the cellular structure. This effect is
associated with a confinement of the polymer in the cell walls, and is one of the key reasons for the
improved properties of nanocellular polymers.

Keywords: nanocellular polymer; nanocellular foam; gas dissolution foaming; confinement; PMMA

Judith Martín-de León,* Victoria Bernardo, and Miguel Ángel Rodríguez-Pérez

Transparent nanocellular polymethylmethacrylate (PMMA) with relative density around 0.4 is produced for the first time by using the gas dissolution foaming technique. The processing conditions and the typical characteristics of the cellular structure needed to manufacture this novel material are discovered. It is proved that low saturation temperatures (−32 °C) combined with high saturation pressures (6, 10, 20 MPa) allow increasing the solubility of PMMA up to values not reached before. In particular, the highest CO2 uptake ever reported for PMMA, (i.e., 48 wt%) is found for a saturation pressure of 20 MPa and a saturation temperature of −32 °C. Due to these processing conditions, cell nucleation densities of 1016 nuclei cm−3 and cell sizes clearly below 50 nm are achieved. The nanocellular polymers obtained, with cell sizes ten times smaller than the wavelength of visible light and very homogeneous cellular structures, show a significant transparency.

Judith Martín-de León,* Victoria Bernardo, and Miguel Ángel Rodríguez-Pérez

ABSTRACT: Nanocellular polymethylmethacrylate (PMMA) is produced through a newly proposed method, a two-stage depressurization in the gas dissolution foaming process. This method modifies the depressurization step and allows controlling the pressure during cell growth, avoiding this way, the appearance of micrometric defects in the produced cellular materials. Three grades of PMMA, as well as different production parameters, are tested in order to study their influence on the final materials. Moreover, cellular structures are compared with those obtained with a one-stage depressurization process. Additionally, this work analyzes the foaming mechanisms taking place during the production of nanocellular materials.

Lauren MacEachern a,b, Azadeh Kermanshahi-pour a,*, Mahmoud Mirmehrabi b,*
a Biorefining and Remediation Laboratory, Department of Process Engineering and Applied Science, Dalhousie University, 1360 Barrington Street, Halifax, Nova Scotia B3J 1Z1, Canada
b Solid State Pharma Inc., 1489 Hollis Street, Suite 300, Halifax, Nova Scotia B3J 3M5, Canada

A B S T R A C T
Supercritical carbon dioxide (CO2) has been used as a processing technique to control polymorphism of pharmaceuticals. However, there are fewer reports of novel polymorphs being discovered by supercritical CO2 processing. As supercritical crystallization methods gain attention for potential in pharmaceutical processing, they may become a critical screening tool for discovery of new polymorphs. In this work, a case study is presented for a novel crystalline form of the anthelmintic drug, Praziquantel, found through supercritical CO2 processing. The novel form of Praziquantel was characterized by chromatography, nuclear magnetic resonance and infrared spectroscopy, X-ray powder diffraction, thermal analysis, and scanning electron microscopy. Furthermore, the novel form exhibited 13–20% improved solubility compared to commercial Form A between pH 1.6 and 7.5 and was physically stable under stressed conditions (40 ◦C and 75% relative humidity) for 7.5 weeks. Overall, this work showed that supercritical CO2 processing is a valuable tool to screen for novel, and possibly viable polymorphs of pharmaceutical compounds with improved properties.

Dr. James Louey, Nathan Petersen, Dennis Salotti, Heather Shaeffer
Chemistry Department, Sacred Heart University 5151 Park Avenue, Fairfield, CT 06432-1000

Dr. Kenneth James, Supercritical Fluid Technologies, Inc. One Innovation Way, Suite 303, Newark, Delaware 19711; Tel: 302-738-3420 x201; Fax: 302-738-4320; E-mail: ken.james@supercriticalfluids.com 

Abstract

Supercritical fluids and in particular supercritical fluid carbon dioxide have shown to be a viable technology for a variety of extractions. While process conditions require high pressures, technological advances have now made it feasible to acquire such equipment for the laboratory. Traditionally, the oil of catnip has been isolated by steam distillation. Working with dried plant material, we have introduced supercritical fluid carbon dioxide as an alternative extraction medium. Results of our work including characterization of the major constituent components will be presented.

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Jonathan A. Peters, The Pennsylvania State University, Applied Research Laboratory, P.O. Box 30, State College, PA 16804; Tel: 814-865-6373; Fax: 814-863-7842; E-mail: PNU@PSU.EDU

Dr. Kenneth James, Supercritical Fluid Technologies, Inc. One Innovation Way, Suite 303, Newark, Delaware 19711; Tel: 302-738-3420 x201; Fax: 302-738-4320; E-mail: ken.james@supercriticalfluids.com

Abstract

Carbon dioxide can be used in its liquid (near critical) or supercritical fluid state as a replacement for conventional cleaning solvents, reducing the pollution associated with the operations that would otherwise require significant amounts of volatile organic compounds, ozone depleting substances, or hazardous air pollutants.

The results of several near critical/supercritical parts cleaning and treatment studies performed at the Applied Research Laboratory are discussed. Near critical/supercritical processing is a commercially viable process for many industrial, electronic and medical device cleaning applications. This applications note will focus on industrial applications such as oxygen-service pressure gauges, fuel and transmission oil filters, and bearings.

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Kenneth J. James, Ph.D.,* Supercritical Fluid Technologies, Inc., David Chesney, Ph.D., Michigan Technology University, Jennifer L. Lefler, GlaxoSmithKline

Abstract

Direct, visual observation of materials under supercritical conditions is an important first step in the development and refinement of supercritical fluid extraction, reaction, and chromatographic processes. A specially designed phase equilibrium view cell or “Phase Monitor” is used to observe the dissolution, melting, precipitation, swelling and crystallization of compounds at a wide range of pressures and temperatures. Observations of materials are performed in the supercritical region, under precisely controlled conditions. The Phase Monitor simplifies the determination of critical point for binary, tertiary or complex mixtures. Through a better understanding of phase behavior as a function of temperature, pressure, and sample concentration, a significant time and cost savings for supercritical process development is realized. Examples of the Phase Monitor’s utility are presented.

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Kenneth J. James, Ph.D.,* Supercritical Fluid Technologies, Inc.,

Abstract

The primary goal of a laboratory SFE and Phase Monitor unit testing is to assess technical feasibility of a potential supercritical fluid extraction application. Experimental work begins using a supercritical fluid extraction bench top laboratory unit. The bench scale laboratory extraction unit typically has 10ml to 4 liter sample vessel capacity. Product samples and data from the feasibility testing are used to assess product quality, and to research the following process variables: 1) Preparation of feedstock 2) Extractor conditions 3) Separator conditions. The extract product is analyzed to determine how changes in these parameters change extract yield, concentration, and quality. Phase equilibrium experiments should be carried out to determine the preliminary processing conditions in which the compound of interest solubilizes and precipitates from the supercritical fluid. This information can then be utilized to give a “starting point” to the extraction and separator processing conditions and insight to a commercial scale supercritical fluid extraction system. If the results from preliminary testing are encouraging, process development protocol is followed by proceeding to the next step. Examples demonstrating the use of both laboratory SFE and supercritical fluid phase equilibrium instrument will be shown in this poster.

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Dr. James Louey, Chemistry Department, Sacred Heart University 5151 Park Avenue, Fairfield, CT 06432-1000

Dr. Kenneth James, Supercritical Fluid Technologies, Inc. One Innovation Way, Suite 303, Newark, Delaware 19711; Tel: 302-738-3420 x201; Fax: 302-738-4320; E-mail: ken.james@supercriticalfluids.com

Abstract

Currently, the U. S. produces millions of tons of pollution each year, and spends billions of dollars controlling this pollution.1 This data clearly indicates that sustainable economic growth will require more than end-product environmental monitoring of existing industrial processes. Rather, the worldwide focus on technology development must include new industrial processing methodology that supports pollution prevention at the source. Such a change in production methodology will effect numerous immediate and long-term benefits, including financial, as fewer capital investments will be necessary for future environmental remediation.

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Kenneth J. James, Ph.D.,* Supercritical Fluid Technologies, Inc.

Kenneth R. Krewson, Supercritical Fluid Technologies, Inc

Abstract

The primary goal of laboratory supercritical fluid reaction unit testing is to assess technical feasibility of a potential supercritical fluid reaction application. Initial screening with a Phase Equilibrium analyzer should be carried out to determine the processing conditions in which the reagents and products of interest solubilize and/or precipitate from the supercritical fluid. Experimentation then moves to the use of a supercritical fluid reaction laboratory unit. The laboratory unit typically has a 50ml to 4 liter reaction vessel fitted with the appropriate reagent addition modules, mixing, flow meters, and sensors. Product samples and data from the feasibility testing are used to assess product quality, and to research process variables such as: 1) Preparation and solubility of reagents 2) Reaction conditions (temperatures, pressures, use of Co-Solvents to enhance reagent or product

solubility. 3) Collection conditions. The reaction product is analyzed to determine how changes in these parameters change yield, purity, and economics of the proposed process. This information can then be utilized to fine tune the reaction to maximize key parameters for a commercial scale supercritical fluid reaction process. Examples demonstrating the use of both and laboratory SFR unit and supercritical fluid phase equilibrium instrument will be presented.

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Kenneth J. James, Ph.D.,* Supercritical Fluid Technologies, Inc.

Kenneth R. Krewson, Supercritical Fluid Technologies, Inc.,

Abstract

Supercritical fluid extraction has been gaining acceptance in quality control/quality assurance laboratories as a replacement technology for the traditional “organic solvent intensive” fat analysis methods. Conventional methods of fat analysis for baking dough, milk, and chocolate products are time and labor intensive, and require large amounts of hazardous organic solvents. Supercritical fluid extraction using CO2 as a solvent is an alternative method for extraction and isolation of fat content from these products. SFE for baking dough, liquid milk, and chocolate will be explored in this poster using the SFT-100

Extraction Unit and results compared to the traditional solvent intensive methods.

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Kenneth J. James, Ph.D.,* Supercritical Fluid Technologies, Inc.

Kenneth R. Krewson, Supercritical Fluid Technologies, Inc

Abstract

The goal of a high pressure laboratory reaction unit is to assess technical feasibility of pressurized reaction applications such as Catalytic Chemistry, Hydrolysis, Polymerization, Synthesis, and investigate Process Development. The High Pressure Laboratory Reaction Unit typically consists of a 50 ml to 4 liter reaction vessel fitted with the appropriate solvent (CO2, Liquid, or Gas) and reagent addition modules, mixing, heating/cooling, temperature controls, safety features, flow meters, sensors, and controls. Typical Operation conditions for these units are up to 10,000 psi (68.9 MPa) and 350 degrees Celsius.

Product samples and data from the laboratory unit feasibility testing can be used to assess product quality, and to research process variables such as:

1) Preparation and solubility of reagents
2) Reaction conditions (temperatures, pressures, use of Co-Solvents to enhance reactant or product solubility.
3) Collection conditions.

The reaction product is analyzed to determine how changes in these parameters change yield, purity, and economics of the proposed process. This information can then be utilized to fine tune the reaction to maximize key parameters for a commercial scale reaction process or simply be used for repetitive laboratory scale applications. Examples demonstrating the utility of a High Pressure Reaction Unit for traditional organic synthesis and supercritical fluid synthesis are presented.

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Rudy Baskette, Supercritical Fluid Technologies, Inc

The practice of beer brewing is seven thousand years old and has out survived most of the cultures that drank it. While the ancient Babylonians, Romans, Assyrians, and Incan cultures can no longer partake in the nectar of the gods, striving to brew the best beer is still a prevalent goal.  One of the methods to improve the flavor of a beer is to enhance the intensity of the hops.  Supercritical carbon dioxide hop extraction is a method to obtain hop oil extracts with high concentrations (both yield and purity) and quality (less artifacts).

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Rudy Baskette, Supercritical Fluid Technologies, Inc

Traditionally, the food industry utilizes steam distillation to extract peppermint oil. Steam distillation processes yield an extract that is a combination of pure and thermally decomposed peppermint oil. The extract from traditional steam distillation results in the familiar peppermint taste you find in peppermint candy.

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Rudy Baskette, Supercritical Fluid Technologies, Inc

Perchloroethylene (as seen in the figure below) has been the standard dry cleaning solvent for over seven decades. Dry cleaning with perchloroethylene not only leaves a distinctive chemical odor on clothes, but can damage colored clothing, buttons, and beads.  Perchloroethylene is also highly carcinogenic substance.  Perchloroethylene remains in clothes; ergo consistent clothing exposure to perchloroethylene substantially raises levels of the carcinogen.

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Rudy Baskette, Supercritical Fluid Technologies, Inc

Sunflower seeds contain a high concentration of Vitamin E rich oil.The oil is advantageous for human consumption due to the high vitamin E content and the low amounts of saturated fat. The active component of Sunflower Oil Vitamin E is α-Tocopherol, an antioxidant that defends against ROS (reactive oxygen species). The α-Tocopherol is fat soluble and specifically prevents ROS damage during oxidations of polyunsaturated fatty acids in lipids. 

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Rudy Baskette, Supercritical Fluid Technologies, Inc

Dark chocolate bars consist of fat, sugar, and cocoa.  In production, clean roasted cocoa beans are ground and stored in a hanging bag within a heated room.  Cocoa fat drips down; the remaining bagged components are the cocoa powder solids. This is referred to as the Broma method.  This cocoa fat is re-introduced with sugar to the cocoa powder in later stages to produce dark chocolate. 

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Rudy Baskette, Supercritical Fluid Technologies, Inc

Abstract

Benzophenone is a white crystalline organic substance with a slightly sweet rose geranium scent.  In industry it is typically utilized as a photo-initiator, since it breaks down UV light into free radicals when exposed to light. Benzophenone’s protects a range of products from inks, perfumes, cleaning products, to pharmaceuticals, and soaps. Adding  benzophenone to clear plastic packaging such as food containers prevents UV damage to the contents inside. Benzophenone has also been utilized as biochemical probe to map certain peptide interactions.

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Rudy Baskette, Supercritical Fluid Technologies, Inc

Abstract

As traditional oil reserves become limited, investigation into alternative energy sources becomes increasingly important.  Microalgae are a versatile, renewable resource.  Certain species can produce large amounts of lipids that can be converted to fatty acid methyl ethers (FAME) for biodiesel.

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Yiwen Li,a Hua Jiang,a* Binbin Hana and Yang Zhangb

Abstract
BACKGROUND: The effects of the conditions for the supercritical carbon dioxide (scCO2) drying of cellulose nanocrystal (CNC) wet gel were investigated on the residual solvent content, the shrinkage and the microstructure of the ensuing aerogel.

RESULTS: The scCO2 drying of CNCwet gel could be divided into a spillage phase and an extraction phase. In the first phase, just a very short time after the beginning of drying, shrinkage occurred andmore than half of the solvent was removed. No further shrinkage was observed thereafter, but the solvent continued to be exponentially removed. Increasing pressure, temperature and timewere favorable for solvent removal and the reduction of aerogel shrinking. The shrinkage increased the pore size inside the aerogel andmade the outer surface of the CNC aerogel much denser than its interior. To preserve the original microstructure of the wet gel, the optimal drying was performed at 11.04MPa and 40 ∘C for 120 min. At these conditions, the shrinkage ratio was only inversely proportional to the CNC content in the wet gel.

CONCLUSION: CNC aerogel was obtained with a shrinkage ratio of 3.1%, a surface area of 387m2 g−1 and an average pore size of 7.2 nmusing 3.0% (w/w) CNC wet gel. © 2019 Society of Chemical Industry

Rotana Hay, Kemal Celik*

Division of Engineering, New York University Abu Dhabi, Abu Dhabi, P.O. Box 129188, United Arab Emirates

Reactive magnesium oxide cement (RMC) has the potential to become a sustainable alternative to ordinary Portland cement (OPC). In this study, an approach utilizing supercritical CO2 (scCO2) was investigated to accelerate carbonation of an RMC-based composite and to overcome its long carbonation process under the natural environment. It was found that scCO2 led to an extremely rapid strength gain of the composite, with a mature strength level achievable within a period of hours. CO2 sequestration factors were also increased by three folds as compared to samples cured under a 20% CO2 concentration environment for 28 days. It was also revealed that the carbonation phases under scCO2 were dominated by nesquehonite followed by hydromagnesite and some other intermediate hydrated magnesium carbonates (HMCs). More uniform carbonation within the matrix was also attained under the scCO2 condition. Despite the promising outcomes, technical and cost challenges would need to be resolved before a possible scale-up.

Arda Tuhanioglu and Ali Ubeyitogullari*

ACS Food Sci. Technol. 2022, 2, 12, 1879–1887
Publication Date:November 24, 2022
https://doi.org/10.1021/acsfoodscitech.2c00266
Copyright © 2022 American Chemical Society

Sorghum bran, containing high-value lipids and phenolic compounds, is an underutilized food processing byproduct. This study developed and optimized a green method based on a sequential pure supercritical carbon dioxide (SC–CO2) and ethanol/water-modified SC–CO2 extraction to extract wax-rich lipids and phenolic compounds from sorghum bran in a single step. The extraction conditions, namely, temperature (20–100 °C), pressure (20–40 MPa), extraction time (0.5–5 h), and cosolvent type (ethanol or ethanol–water), were optimized for the highest wax-rich lipids and phenolics extraction yields. In the first part, neat SC–CO2 at 40 MPa and 60 °C resulted in the highest lipid yield (6.2%, w/w dry basis), which contained ∼5% (w/w) high-melting point waxes. The purified wax fractions containing phytosterols showed high melting points of 57–87 °C. In the second part, the highest total phenolics and flavonoids yields were achieved at 40 MPa and 40 °C via 15% (w/w) ethanol–water (1:1, v/v) modified SC–CO2 by 150 ± 3 mg of gallic acid equivalent (GAE)/100 g of bran (dry basis) and 99.6 ± 4 mg of catechin equivalent (CAE)/100 g of bran (dry basis), respectively. Overall, this study provides a novel single-step extraction approach based on SC–CO2 to extract and fractionate lipids and phenolic compounds from sorghum bran.

Safoura Ahmadzadeh 1, Ali Ubeyitogullari 2

Affiliations
1Department of Food Science, University of Arkansas, Fayetteville, AR 72704, USA.
2Department of Food Science, University of Arkansas, Fayetteville, AR 72704, USA; Department of Biological and Agricultural Engineering, University of Arkansas, Fayetteville, AR 72701, USA. Electronic address: uali@uark.edu.
PMID: 36436852 DOI: 10.1016/j.carbpol.2022.120296

A new approach via extrusion-based 3D food printing (3DP) was developed to fabricate porous spherical beads from corn starches with different amylose contents (i.e., 25, 55, and 72 %). The effects of amylose content and drying method, i.e., freeze-drying and supercritical carbon dioxide (SC-CO2), on the structural properties of the starch beads were investigated. The shape and size of the 3D-printed beads highly depended on the starches’ amylose content as it affected the rheological properties of the inks. The smallest 3D-printed bead size was ∼980 μm generated from high amylose (72 %) corn starch. 3DP of starch with high amylose content along with SC-CO2 drying resulted in starch beads with superior properties. The SC-CO2-dried beads showed a significantly higher surface area (175 m2/g) than the freeze-dried ones (<1 m2/g).

Ali Ubeyitogullari 1 and Syed S. H. Rizvi1,2*
1 Department of Food Science, Cornell University, Ithaca, NY 14850
2 School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY 14850

ABSTRACT

A new strategy to concentrate phospholipids from buttermilk powder was developed using a food-grade green method based on ethanol-modified supercritical carbon dioxide (SC-CO2) extraction. The effects of extraction conditions, namely temperature (50 and 60°C), pressure (30 and 40 MPa), and ethanol concentration (10, 15, and 20%, wt/wt), on the total lipid yield and phospholipid content were investigated. The ethanol concentration had a more significant effect on the total lipid yield and phospholipid content than the temperature and pressure within the ranges studied. The highest phospholipid recovery was achieved at 60°C, 30 MPa, and 15% (wt/wt) ethanol with a total lipid yield of 6.3% (wt/wt), of which 49% (wt/wt) were phospholipids composed of dihydrosphingomyelin (5%), sphingomyelin (24%), phosphatidylethanolamine (22%), phosphatidylserine (2%), phosphatidylinositol (3%), and phosphatidylcholine (44%). The triacylglycerol compositions of extracts obtained by Folch and ethanol-modified SC-CO2 extractions were similar. A sequential pure SC-CO2 and ethanol-modified SC-CO2 extraction was carried out to separate nonpolar lipids in the first fraction, thereby concentrating phospholipids in the second fraction. This sequential extraction produced a highly concentrated phospholipid extract (76%, wt/wt). To the best of our knowledge, this is the highest phospholipid concentration reported from buttermilk powder. Thus, this phospholipid-rich extract
can be used in the development of functional foods as a food-grade emulsifier with potential health-promoting effects.

Key words: buttermilk, phospholipid, supercritical carbon dioxide, ethanol, extraction

Diana E. Sepulveda 1,2, Kent E. Vrana 1, Nicholas M. Graziane 1,2,* and Wesley M. Raup-Konsavage 1,*

1 Department of Pharmacology, Penn State College of Medicine, Hershey, PA 17033, USA
2 Department of Anesthesiology & Perioperative Medicine, Penn State College of Medicine,
Hershey, PA 17033, USA
* Correspondence: ngraziane@pennstatehealth.psu.edu (N.M.G.);
wkonsavage@pennstatehealth.psu.edu (W.M.R.-K.); Tel.: +717-531-8433 (N.M.G.); +717-531-4172 (W.M.R.-K.)

Abstract: Neuropathic pain is a condition that impacts a substantial portion of the population and is expected to affect a larger percentage in the future. This type of pain is poorly managed by current therapies, including opioids and NSAIDS, and novel approaches are needed. We used a cisplatin-induced model of neuropathic pain in mice to assess the effects of the cannabinoids THC and CBD alone or in varying ratios as anti-nociceptive agents. In addition to testing pure compounds, we also tested extracts containing high THC or CBD at the same ratios. We found that pure CBD had little impact on mechanical hypersensitivity, whereas THC reduced mechanical hypersensitivity in both male and female mice (as has been reported in the literature). Interestingly, we found that high CBD cannabis extract, at the same CBD dose as pure CBD, was able to reduce mechanical hypersensitivity, although not to the same level as high THC extract. These data suggest that, at least for CBD-dominant cannabis extracts, there is an increase in the anti-nociceptive activity that may be attributed to other constitutes of the plant. We also found that high THC extract or pure THC is the most efficacious treatment for reducing neuropathic pain in this model.

Keywords: neuropathic pain; tetrahydrocannabinol; cannabidiol; cannabinoids; cannabis

Jiakai Zhang a, John Anawati a, Gisele Azimi a,b,*

a Laboratory for Strategic Materials, University of Toronto, Department of Chemical Engineering and Applied Chemistry, 200 College Street, Toronto, Ontario M5S 3E5,
Canada
b Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario M5S 3E4, Canada

There is a significant global push towards recycling of waste electrical and electronic equipment (WEEE) to enable the circular economy. In this study an environmentally sustainable process using supercritical carbon dioxide as the solvent, along with a small volume of tributyl-phosphate-nitric acid (TBP-HNO3) adduct as the chelating agent, is developed to extract rare earth elements (REEs) from fluorescent lamp waste. It is found that mechanical activation using oscillation milling improves extraction efficiency. To elucidate the process mechanism, an in-depth characterization of solids before and after the process using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) is performed. Furthermore, UV visible spectroscopy is performed to determine the coordination chemistry of the rare earths of interest, i.e., yttrium, europium, and terbium during the complexation with TBP-HNO3 adduct. It is found that Al3+ and Ca2+ cations from the aluminium oxide (Al2O3) and hydroxyapatite (Ca5(PO4)3OH) present in the fluorescent lamp waste compete with REEs in reacting with TBP-HNO3 adduct; hence, REE extractions from real fluorescent lamp waste is less than previously reported extractions from synthetic feeds. Not only can management of fluorescent lamp waste help conserve natural resources and protect ecosystems, but it can also facilitate efficient utilization of materials and promote the circular economy.

Nattanai Kunanusonta, Jiakai Zhangb, Kimberly Watadab, Yusuke Shimoyamaa, Gisele Azimib,⁎

a Department of Chemical Science and Engineering, Tokyo Institute of Technology, S1-33, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8550, Japan
b Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada

Abstract
Supercritical fluid extraction is receiving growing attention for the enhanced extraction and separation of metals. A metal must be charge neutral and coordinatively ready to dissolve in non-polar supercritical carbon dioxide (sc-CO2). This can be accomplished by bonding the metal with a combination of negative and neutral ligands. Here, we investigate the effect of four organophosphorus reagents including triethyl phosphate (TEP), tri-n-butyl phosphate (TBP), tributyl phosphine oxide (TBPO), and trioctyl phosphine oxide (TOPO), on the extraction of neodymium from a neodymium-iron-boron magnet in sc-CO2. The COSMO-vac model is used to predict the solubility of these reagents in sc-CO2 showing the order of TEP > TBPO ~ TBP > TOPO. The stoichiometry of Nd-ligand complexes is determined via UV-Vis spectroscopy, showing a 1:1 Nd–TEP, 1:3 Nd–TBP, 1:3 Nd-TBPO, and 1:4 Nd–TOPO complex chemistry Highest neodymium extractions are achieved with TEP followed by TBP, TBPO, and TOPO, respectively. This is due to the increase in coordination number which results in more hydrophobic interactions between aliphatic functionalities, leading to larger micellar assemblies with lower solubility in sc-CO2, which result in lower extraction efficiency.

Jiakai Zhang a, Gisele Azimi a,b,*

a Laboratory for Strategic Materials, University of Toronto, Department of Chemical Engineering and Applied Chemistry, 200 College Street, Toronto, Ontario, M5S 3E5,
Canada
b Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario, M5S 3E4, Canada

Abstract
The widespread utilization of lithium-ion batteries (LIBs) will lead to multimillion tons of end-of-life LIBs. The batteries comprise high content of valuable metals including lithium, cobalt, nickel, and manganese; hence, their recycling is imperative. This study develops a supercritical fluid extraction process using supercritical CO2 solvent with tributyl phosphate–nitric acid and hydrogen peroxide adduct to recover the four metals from the LIBs of electric vehicles. A full factorial design of experiment is utilized to determine the effect of temperature, pressure and adduct to solid ratio on the extraction. The extraction is optimized using empirical models, leading to 90% metal extraction. The addition of hydrogen peroxide improves the extraction by reducing metals to more soluble forms in supercritical CO2. A systematic investigation is performed to elucidate the process mechanism. The developed process can help management of end-of-life LIBs, conserve of natural resources, and promote the circular economy.

Yuxiang Yao,† Nina F. Farac,† and Gisele Azimi*,†,‡

†Laboratory for Strategic Materials, Department of Chemical Engineering and Applied Chemistry, 200 College Street, Toronto,
Ontario M5S 3E5, Canada
‡Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario M5S 3E4, Canada

ABSTRACT:

Today’s world relies upon critical green technologies that are made of elements with unique properties irreplaceable by other materials. Such elements are classified under strategic materials; examples include rare earth elements that are in increasingly high demand but facing supply uncertainty and near zero recycling. For tackling the sustainability challenges associated with rare earth elements supply, new strategies have been initiated to mine these elements from secondary sources. Waste electrical and electronic equipment contain considerable amounts of rare earth elements; however, the current level of their recycling is less than 1%. Current recycling practices use either pyrometallurgy, which is energy intensive, or hydrometallurgy that rely on large volumes of acids and organic solvents, generating large volumes of environmentally unsafe residues. This study put emphasis on developing an innovative and sustainable process for the urban mining of rare earth elements from waste electrical and electronic equipment, in particular, a nickel metal hydride battery. The developed process relies on supercritical fluid extraction utilizing CO2 as the solvent, which is inert, safe, and abundant. This process is very efficient in the sense that it is safe, runs at low temperature, and does not produce hazardous waste while recovering ∼90% of rare earth elements. Furthermore, we propose a mechanism for the supercritical fluid extraction of rare earth elements, where we considered a trivalent rare earth element state bonded with three tri-n-butyl phosphate molecules and three nitrates model for the extracted rare earth tri-n-butyl phosphate complex. The supercritical fluid extraction process has the double advantage of waste valorization without utilizing hazardous reagents, thus minimizing the negative impacts of process tailings.

KEYWORDS: Rare earth elements, Supercritical fluid extraction, Recycling, Urban mining, Waste electrical and electronic equipment, Nickel metal hydride battery

Jiakai Zhang,† John Anawati,† Yuxiang Yao,† and Gisele Azimi*,†,‡

†Department of Chemical Engineering and Applied Chemistry, Laboratory for Strategic Materials, 200 College Street, Toronto,
Ontario M5S 3E5, Canada
‡Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario M5S 3E4, Canada

ABSTRACT:

There is a global need for efficient and environmentally sustainable processes to close the life cycle loop of waste electrical and electronic equipment (WEEE) through recycling. Conventional WEEE recycling processes are based upon pyrometallurgy or hydrometallurgy. The former is energy-intensive and generates greenhouse gas (GHG) emissions, while the latter relies on large volumes of acids and organic solvents, thus generating hazardous wastes. Here, a novel “aeriometallurgical” process was developed to recycle critical rare earth elements, namely, neodymium (Nd), praseodymium (Pr), and dysprosium (Dy), from postconsumer NdFeB magnets utilized in wind turbines. The new process utilizes supercritical CO2 as the solvent, which is safe,
inert, and abundant, along with the tributyl-phosphate−nitric acid (TBP−HNO3) chelating agent and 2 wt % methanol as a cosolvent. Nd (94%), Pr (91%), and Dy (98%) extraction was achieved with only 62% iron (Fe) coextraction and minimal waste generation. Fundamental investigations into the extraction mechanism demonstrated that metal ion charge has an important impact on the extraction efficiency. Fundamental investigations indicate that extraction proceeds by corrosion of the magnet particle’s surface layer. This work demonstrates that supercritical fluid extraction would find widespread applicability as a cleaner, a more sustainable option to recycle value metals from end-of-life products to enable the circular economy.

KEYWORDS: Supercritical fluid extraction, Waste electrical and electronic equipment recycling, Tributyl-phosphate-HNO3, NdFeB magnets

Yuxiang Yao a, Erin Chau a, Gisele Azimi a,b,⇑

a Laboratory for Strategic Materials, Department of Chemical Engineering and Applied Chemistry, 200 College Street, Toronto, Ontario M5S 3E5, Canada
b Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario M5S 3E4, Canada

Abstract:

Polyethylene (PE) and polypropylene (PP) feedstock contain various additives, such as fillers and colorants, which either degrade or carry through the depolymerization process; thereby causing intense dark colors and a pungent petroleum odor. The combination of color and odor imposes several challenges, limiting the potential markets of the wax products. This study put emphasis on the development of an innovative and environmentally sustainable process based on supercritical fluid extraction (SCFE) to remove organic and inorganic contaminants that cause color and odor in waxes derived from recycled polymers. In terms of organic impurity removal, for PE 81% and for PP 97% removal efficiency was achieved. The color of PE and PP in terms of lightness under CIELAB (lightness, green-red, blue-yellow) color space was improved by 13 and 40 units, respectively. The purified waxes could be utilized in a variety of market segments, including color masterbatch, roofing shingles, rubber, and coatings. Compared with traditional purification technologies based on solvent extraction and absorbent filters, SCFE process offers exceptional advantages, including fast reaction rates, little liquid waste, ease of separation of solutes, and fewer separation stages. This novel process enables producing high-value water white waxes from reclaimed polymeric feedstock with a focus on clean technologies and enhanced resource efficiency.

Thesis Submitted to The School of Engineering of the UNIVERSITY OF DAYTON In Partial Fulfillment of the Requirements for The Degree of Master of Science in Bioengineering
By Sally Louis Homsy
Dayton, Ohio
August, 2012

ABSTRACT

PROCESSING ALGAL BIOMASS TO RENEWABLE FUEL: OIL EXTRACTION AND HYDROTHERMAL LIQUEFACTION
Name: Homsy, Sally Louis
University of Dayton
Advisor: Dr. Sukh S. Sidhu

Since the industrial revolution the world’s reliance on fossil fuels has been increasing at an accelerated rate. The negative environmental effects of burning fossil fuels and the demand for energy security have increased interest in renewable fuels technology. Using biomass as a feedstock for energy generation has emerged as an area of interest, and the focus of this study is on the sustainable production of a crude oil from the algal species Chlorella vulgaris. The derived crude oil is to serve as a feedstock for renewable diesel production. The constituents of this algae derived oil must be similar in structure and low in impurities, especially nitrogen and sulfur content, to allow for the economical upgrade of this oil to renewable diesel. Two methods for the generation of the crude oil were explored: direct oil extraction from the algal biomass and hydrothermal liquefaction of the algal biomass. Total algal lipid extraction from both dry and wet algal biomass was studied and multiple solvents, procedures and cell pretreatment methods were compared; this includes solvents at ambient conditions, supercritical carbon dioxide, liquefied dimethyl ether, ultrasonication, mechanical disruption and steaming. It was determined that pretreatment of the Chlorella vulgaris biomass is not necessary for total oil extraction, that total oil extraction from dry algae can be achieved by using a 95% ethanol solvent and that total oil extraction from wet algae can be achieved by using a 6:77:17 w/w/w ratio of water to ethanol to hexane. The optimal oil extraction procedure was scaled up and a process was developed to fractionate the algal biomass and isolate the lipid fractions conducive to upgrading to renewable diesel. The crude oil produced through this method was analyzed and found to be suitable for economical upgrade to renewable diesel. However biomass conversion to oil was low; only about 13.5% of the biomass could be converted to oil due to the relatively low lipid content of the Chlorella vulgaris (about 18% lipids on a dry weight basis). The hydrothermal liquefaction of the Chlorella vulgaris biomass was capable of converting about 44% of the initial Chlorella vulgaris biomass to bio-crude. However, the quality of the oil produced was not ideal for upgrading to renewable diesel due to the high nitrogen and sulfur content of the oil and the diverse molecular structures of the oil constituents. In conclusion, it was recommended that a method to enhance Chlorella vulgaris lipid content, such as nitrogen starvation or the introduction of sugars in the growth media, should be adopted prior to harvest and that the developed oil extraction procedure should be used to produce a renewable upgradable crude oil.

Shun Yao a, Dongdong Hu a, Zhenhao Xi a, Tao Liu a, Zhimei Xu a, Ling Zhao a,b,*
a Shanghai Key Laboratory of Multiphase Materials Chemical Engineering, East China University of Science and Technology, Shanghai, 200237, PR China
b College of Chemistry and Chemical Engineering, Xinjiang University, Urumqi, 830046, PR China

Abstract

Currently Polyethylene terephthalate (PET) foam is the most promising structural core materials, and the tensile mechanical properties are one of its important application indicators. Herein, environmental-friendly supercritical CO2 (ScCO2) extrusion foaming was adopted to prepare PET foam. Aiming at investigating the influence of crystals on the mechanical properties, isothermal treatment in the post-process was used to improve the crystallization process of PET foams. Due to the crystal perfection proceeds via migration and rejection of the structural defects at the crystallites induced by slow crystallization, the crystallinity increased rapidly with the rise of isothermal temperature, especially above the glass transition temperature (Tg). Qualitatively, it can be concluded that the crystalline phase contents have an intimate positive correlation with the tensile modulus, meanwhile, the shape ratio of the crystal have no significant effects on the tensile modulus. In addition, a coupling scheme of aggregate two-layered composite inclusion model and Simone-Gibson equation was first proposed to quantify the mathematical relationship between crystallization and tensile modulus of PET foam, which realized basic agreement.

Yun-Shan Xue,†,‡,# Wei-Wei Cheng,†,# Xi-Ming Luo,† Jia-Peng Cao,† and Yan Xu*,†

†College of Chemical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China
‡School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng, Jiangsu 224002, P. R. China

ABSTRACT: A three-dimensional polymolybdate-based metal−organic framework (POMOF) consisting of Zn-ε-Keggin unit and organic linker, {[PMo8 VMo4 VIO37(OH)3Zn4][BPE]2}·[BPE] (1), was successfully obtained by the hydrothermal method. Compound 1 is composed of Zn-ε-Keggin units and BPE ligands, featuring a fascinating 5-fold interpenetrating framework with dia topology. The catalytic performance of compound 1 was investigated, and experiments showed that 1 could effectively facilitate the cycloaddition reaction of CO2 with epoxides as Lewis acid heterogeneous catalyst. Moreover, compound 1 also was studied as LIBs anode material, and it showed reversible capacity of 546 mA h g−1 at 100th cycle.

Zhonghua Xiang, Xing Zhou, Cuihuan Zhou, Shan Zhong, Xin He, Chengpeng Qin and Dapeng Cao*

Received 13th August 2012, Accepted 7th September 2012
DOI: 10.1039/c2jm35446b

Reducing anthropogenic carbon dioxide emission has become an urgent environmental and climate issue of our age. Here, a series of covalent-organic polymers (COPs) are synthesized, and the adsorption properties of these COPs for H2, CO2, CH4, N2 and O2 are studied. The H2 uptake of COP-2 reaches 1.74 wt% at 77 K and 1 bar, which is among the highest reported uptakes in the field of microporous organic polymers under similar conditions, and CO2 and CH4 adsorption capacities are 594 mg g
1 and 78 mg g
1, respectively, at 298 K and 18 bar. Then, based on the single component isotherm, the dualsite Langmuir–Freundlich (DSLF)-based ideal adsorption solution theory (IAST) is used to predict the selectivity of the COP materials for post-combustion (CO2–N2) and pre-combustion (O2–N2) gas mixtures. The IAST predicted results indicate that COP-1 exhibits significantly higher selectivity compared to COP-2, 3 and 4, due to its smaller pore size. In particular, the adsorption selectivity of COP-1 for the CO2–N2 mixture reaches 91 at a CO2 : N2 ratio of 15 : 85 at 298Kand 1 bar, and 2.38 for the 21 : 79 O2–N2 mixture at 298Kand 1 bar. Furthermore, these COPs also show robust properties for the removal of CO2 from natural gas. The adsorption selectivity of COP-1 for CO2–CH4 is in the range of 4.1–5.0 at a CO2 : CH4 ratio of 15 : 85 at 0 < P < 40 bar.

Zhonghua Xiang, Dapeng Cao*

Three porous luminescent covalent–organic polymers (COPs) have been synthesized through self-polycondensation of the monomers of tris(4-bromophenyl)amine, 1,3,5-tris(4- bromophenyl)benzene, and 2,4,6-tris-(4-bromo-phenyl)-[1,3,5]triazine by using Ni-catalyzed Yamamoto reaction. All the COP materials possess not only high Brunauer–Emmett–Teller (BET) specifi c surface area of about 2000 m 2 g − 1 , high hydrothermal stability, but also graphene-like layer texture. Interestingly, COP-3 and COP-4 show very fast responses and high sensitivity to the nitroaromatic explosives, and also high selectivity for tracing picric acid (PA) and 2,4,6-trinitrotoluene (TNT) at low concentration ( < 1 ppm). In short, the COPs may be a new kind of material for detecting explosives and small organic molecules.

Zhonghua Xiang,† Xuan Peng,‡ Xuan Cheng,† Xiujin Li,§ and Dapeng Cao*,†

†Division of Molecular and Materials Simulation, State Key Laboratory of Organic
Inorganic Composites, ‡College of Information Science, and §Department of Environmental Engineering, Beijing University of Chemical Technology, Beijing 100029, China

ABSTRACT: Effectively separating CO2 from the natural gas, which is one of alternative “friendly” fuels, is a very important issue. A hybrid material CNT@Cu3(BTC)2 has been prepared to separate CO2 from the CO2/CH4 mixture. For comparison of separation efficiency, a series of representative metal
organic frameworks (MOF-177, UMCM-1, ZIF-8, MIL-53 (Al), and Cu3(BTC)2) have also been synthesized by the solvothermal method. Adsorption isotherms of CO2 and CH4 pure gases are measured by Hiden Isochema Intelligent Gravimetric Analyzer (IGA-003). The dual-site Langmuir
Freundlich (DSLF)-based ideal adsorption solution theory (IAST) is used to predict adsorption of each component in the CO2/CH4 mixture. The IAST-predicted results show that the hybrid material CNT@Cu3(BTC)2 exhibits the greatest selectivity among the six materials, and its selectivity keeps in the range of 5.5 to 7.0 for equimolar CO2/CH4 mixture at 1 < p < 20 bar, which is higher than activated carbons. Moreover, the selectivity of CNT@Cu3- (BTC)2 for the CO2/CH4 mixture keeps almost no change with the composition of CH4, which is one of the excellent properties as a promising separation material. In short, this hybrid material CNT@Cu3(BTC)2 shows great potential in separation and purification of CO2 from various CO2/CH4 mixtures by adsorptive processes in important industrial systems.

Wenkai Zhu . Yang Zhang . Xiaoyu Wang . Yan Wu . Minsu Han .
Jungmok You . Chong Jia . Jeonghun Kim

Abstract Nanocellulose-based materials have attracted significant attention because of their attractive advantages. Particularly, aerogel, a porous nanocellulose material, have been used in diverse applications owing to their unique properties. In this study, short rod-like cellulose nanocrystals (CNCs) and long filament-like cellulose nanofibers (CNFs) were isolated from a eucalyptus pulp source using acidolysis and oxidation/mechanical methods, respectively. Subsequently, two different aerogels were prepared from the CNCs and CNFs using the sol–gel method and their properties were compared. The morphology, chemical structure, chemical composition, shrinkage rate, internal structure, thermal degradation, biophysical properties, and mechanical properties of the as-prepared aerogels were compared. Furthermore, the shrinkage of the CNC and CNF aerogels was effectively controlled using a supercritical CO2 drying process. Additionally, three decomposition regions were observed in the thermogravimetric analysis curves of the aerogels; however, the CNF aerogels exhibited enhanced thermal stability than the CNC aerogels. Further, the CNC and CNF aerogels exhibited a mesoporous structure, and the compressive strength of the CNC and CNF aerogels under 85% strain was 269.5 and 299.5 kPa, respectively. This study provides fundamental knowledge on the fabrication of CNCs, CNFs, and corresponding aerogels from lignocellulosic biomass, and their characteristics.

Chen Wana, Gangwei Sunb, Feng Gaoa, Tao Liua,∗, Mohamed Esseghirc,∗, Ling Zhaoa,Weikang Yuanaa

Shanghai Key Laboratory of Multiphase Materials Chemical Engineering, East China University of Science and Technology, Shanghai 200237, PR Chinab
Dow Chemical China Co. Ltd., Elastomers, Electrical & Telecommunication R&D, Shanghai 201203, PR Chinac
Dow Chemical Company, Elastomers, Electrical & Telecommunication R&D, Collegeville, PA 19426, USAa

Low Density Polyethylene (LDPE) is blended with High Density Polyethylene (HDPE) and three typesof Polypropylene (PP) having different melting index (MI), respectively. The compatibility of LDPE/HDPEblends is characterized by using thermal analysis and rheology methods. Differential scanning calorimeter(DSC) traces and rheology methods confirmed their good compatibility. For LDPE/PP blends, the incom-patibility has been widely acknowledged in the literature. The distribution of the PP phase in the blendis investigated using polarized optical microscopy (POM). It is found that the phase structure is closelyrelated to the blend composition and the viscosity ratio of the blend components. Extrusion foaming ofthe blends is conducted using a single extruder fitted with a CO2gas injection system. Under similar foam-ing conditions, the compatible LDPE/HDPE blends all generated a uniform cell morphology and achievedroughly the same expansion ratio. Although the incompatible interface is beneficial to cell nucleation, theLDPE/PP blends did not achieve satisfactory foaming performance. To determine the differences in thefoaming behavior of the two blends, the viscoelastic properties and diffusion coefficients of supercriticalCO2in the blends, were accurately measured via rheology and magnetic suspension balance (MSB) meth-ods. The results indicate that the viscoelastic properties did not show a dominant role in determining thefoaming behavior, by contrast, CO2 diffusion is found to be the key factor affecting foaming performanceespecially in the case of a co-continuous phase structure.

Yessica Escobedo-Flores, David Chavez-Flores, Ivan Salmeron, Carlos Molina-Guerrero, Samuel Perez-Vega*

School of Chemical Science, Autonomous University of Chihuahua, Circuit 1, New University Campus, CP 31125 Chihuahua, Mexico

This research explores the effects of pressure and temperature on the supercritical extraction of polyphenols, antioxidant capacity, and total polyphenolic content from oats. Ethanol (80% v/v) was used as co-solvent, and experiments were controlled by response surface methodology (RSM). For polyphenols with C6-C1 structures (vanillin and vanillic acid), a maximum yield of 18.2 mg/g oats was obtained. Polyphenols with C6-C3 structures (caffeic, sinapic, coumaric, and ferulic acids) gave up to 1389 mg/g oats; where coumaric and ferulic acids were found in higher quantities. Avenanthramides (AVNs) yielded up to 34.52 mg/g oats, with 2p and 2c being found in higher quantities than 2f. The polyphenols, TPC (1.25 mg GAE/g of oats), and ORAC (117.88 mmol TE/g of oats) gave the highest yields at 38 MPa and 55
C. Quadratic models adjusted very well, and a maximum polyphenol content of 1437.57 mg/g was predicted. Moreover, correlations among the polyphenols and antioxidant capacity were found, especially with the ORAC. As a result, the method here presented can be a new procedure for the extraction of polyphenols from oats.

Kenia Fernandez-Acostaa, Ivan Salmerona, David Chavez-Floresa, Ildebrando Perez-Reyesa,
Victor Ramosa, Michael Ngadih, Ebenezer M. Kwofieb, Samuel Perez-Vegaa,*

a School of Chemical Science, Autonomous University of Chihuahua, Circuit 1, New University Campus, CP 31125, Chihuahua, Mexico
b Bioresource Engineering Department, McGill University, Ste-Anne-de-Bellevue, H9X 3V9, Quebec, Canada

Six variables (temperarure, pressure, static time, dynamic time, chemical pretreatment, and particle size) were evaluated in the supercritical CO2 extraction of oil from oats (Avena sativa L.), by the responses obtained using a Plackett-Burman statistical design, including the mass of oil extracted, main fatty acids (GC-MS), polyphenols (HPLC), antioxidant activity (ORAC), and total phenolic content (TPC). For the mass of oil extracted, pressure (55 MPa) and particle size ( > 250 µm) were significant, with a highest yield of 0.800 g/20 g oat. Oleic acid was the most abundant fatty acid (45-53%), followed by linoleic (36–42%) and palmitic (12-16%). Fatty acid composition was significantly affected by particle size, pretreatment, and temperarure. The polyphenols vanillin (43.33µg/g oil), ferulic acid (53.6 µg/g oil), vanillic acid (0.78 µg/g oil), and coumaric acid (2.2µg/g oil) were detected. Pretreatment and high temperarure were significant for increasing the polyphenol content of the oil fractions. TPC was also increased by temperature and pretreatment (97.1 mg gallic acid equivalents/100 g oil) and showed a good correlation with polyphenols (R2 = 82%). Additionally, ORAC antioxidant activity (265 mmol Trolox equivalents/g oil) was significantly affected by pretreatment, temperature (80 °C), and par­ticle size ( > 250 µm).

Elizabeth Ordoñez‐Quintana1 | Ivan Salmeron1 | David Chavez‐Flores1 | Victor Ramos1 | Nestor Gutierrez1 | Lourdes Morales‐Oyervides2 | Efren Delgado3 | Ebenezer Kwofie4 | Michael Ngadi4 | Samuel B. Perez‐Vega1

1School of Chemical Science, Autonomous University of Chihuahua, Chihuahua, Mexico
2Chemical Engineering Department, Autonomous University of Coahuila, Saltillo, Mexico
3Department of Family & Consumer Sciences, New Mexico State University, Las Cruces, NM, USA
4Bioresource Engineering Department, McGill University, Ste‐Anne‐de‐Bellevue, Quebec, Canada

Abstract

This research explores the effect of temperature, pressure, static time, dynamic time, co‐solvent, pretreatment, and particle size on the supercritical/subcritical extraction of ursolic acid (UA), polyphenols, and their antioxidant activity. Experiments were controlled by a screen‐out (Plackett–Burman) statistical methodology. From the results, it could be observed that similar conditions benefited the extraction of UA and polyphenols. The highest yield of UA (6,117.2 μg/g) was obtained when ethanol (25% w/w), particle size (>250 μm), and temperature (60°C) were at their high boundaries. Phloridzin and epicatechin were identified as the most abundant polyphenols, showing concentrations of 531.4 and 288.3 μg/g, respectively. A maximum oxygen radical absorbance capacity of 113.5 μmol TE/g and total polyphenolic capacity (TPC) of 1.7 mg GAE/g were obtained. As a result, higher yields were strongly related to the effect of variables on diffusion and solubility, leading to a more efficient and sustainable process.

Samuel Perez-Vega, Ivan Salmeron, Ildebrando Perez-Reyes, Ebenezer Kwofie, and Michael Ngadi

S. Perez-Vega (*) · I. Salmeron · I. Perez-Reyes
School of Chemical Science, Autonomous, University of Chihuahua, Chihuahua, Mexico
e-mail: sperez@uach.mx

E. Kwofie · M. Ngadi (*)
Bioresource Engineering Department, McGill University, Ste-Anne-de-Bellevue, QC, Canada
e-mail: michael.ngadi@mcgill.ca

Bioactives are metabolites synthesized by plants, where one of their main objectives is to contribute to the self-defense mechanism. Examples of food bioactives are pigments, carotenoids, omega -3 fatty acids, polyphenols, terpenes, lipids, vitamins, peptides, proteoglycans, and polysaccharides (Puri 2017). These specialty chemicals are typically found in low concentrations compared to macronutrients.
Therefore, they can be used as nutraceuticals in foods to improve the nutritional value or treat diseases.
The introduction of new non-conventional methods for the extraction of food bioactives has been a topic of interest for the last decades; this is necessary for improving traditional extraction. Conventional extraction shows excessive use of solvents, usually compromising yield, separation, toxicity, and environmental effects. As a result, new emerging technologies aim to replace conventional extraction in the coming years. The latter is a great challenge since yield and selectivity play a key role in selecting the most appropriate extraction method. In addition, aspects such as scale-up and cost are crucial when moving into an industrial scale. Therefore, these considerations are essential when selecting an extraction method in the laboratory during the early stages of process development.
For several years, supercritical fluid extraction (SFE) has been employed to extract food bioactives. As a result, it is one of the most common processes employing supercritical fluids (SCF). Recently, there has been an interest in new technologies employing SCF, not only extraction (Asiri 2020). However, this chapter will focus only on SFE and its most significant control variables to successfully remove food bioactives.

Jawaher AlYammahi a,b, Ahmad S. Darwish a,b, Tarek Lemaoui a,c, Inas M. AlNashef a,b,c,
Shadi W. Hasan a,b,c, Hanifa Taher a,d, Fawzi Banat a,b,*

a Department of Chemical Engineering, Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, United Arab Emirates
b Center for Membranes and Advanced Water Technology (CMAT), Khalifa University of Science and Technology, PO Box 127788, Abu Dhabi, United Arab Emirates
c Research & Innovation Center for Graphene and 2D Materials (RIC-2D), Khalifa University, P.O. Box 127788, Abu Dhabi, United Arab Emirates
d Research and Innovation Center on CO2 and H2 (RICH), Khalifa University, Abu Dhabi, United Arab Emirates

Abstract
The extraction of date sugar using supercritical extraction is a process that is still in its formative stages. In this study, a comprehensive parametric analysis of the supercritical fluid extraction (SFE) process using supercritical CO2 with water/ethanol as co-solvents was performed to achieve maximum recovery of date sugar extract. The results showed that the maximum total sugar content (TSC) was 70.45 ± 0.01 g/100 g of DFP. This was made up of 7.42 g/100 g fructose, 6.49 g/100 g glucose, and 56.54 g/100 g sucrose. This was attained with 15 v/v% water as co-solvent, 50 ℃, and 200 bar. In addition, machine learning with non-linear regression and artificial neural network (ANN) ensembles was used for TSC prediction. The ANN results showed a strong correlation between operating parameters and sugar recovery with a total R2 of 0.986 ± 0.010. Compared to conventional hot water extraction method (CHWE), the CO2-SFE process resulted in a 1.4-fold increase in TSC recovery and a 2.1-fold increase in organic acids recovery. CO2-SFE demonstrated comparable TSC results with a difference of only 1.2% when compared to the ultrasound-assisted extraction ‘’USAE’ method. The results of the detailed chemical analysis (HPLC and FT-IR) and morphological analysis (SEM) showed that the USAE and CO2-SFE were more efficient than CHWE. Supercritical extraction with co-solvents is particularly effective in recovering date sugar from date fruit, making it a desirable ingredient in a variety of food products.

Ebru Erol

First published: 01 February 2024 https://doi.org/10.1002/cbdv.202301497

Abstract
Bee bread, a valuable bee product that has recently attracted significant public interest as a nutritional supplement. The aim of this study was to evaluate the presence of phenolic compounds in bee bread samples from the Aegean Region and assess their bioaccessibility using a simulated human digestion model. Various extraction techniques, such as maceration, ultrasound-assisted extraction, and supercritical fluid extraction were employed to obtain extracts of bee bread. The antioxidant capabilities of these extracts were carried out using assays like DPPH⋅, ABTS⋅+, CUPRAC, and β-carotene linoleic acid bleaching, and their effectiveness was quantified through IC50 values. The bioaccessibility of phenolic compounds was analysed by using LC-HRMS in a simulated human digestive system using ethanol extracts obtained from bee bread samples of each season by ultrasound-assisted extraction, which has the highest antioxidant activity. In the Aegean bee bread, a total of 25 phenolic compounds which were major phenolics including quercetin, ascorbic acid, isorhamnetin, kaempferol, and hyperoside were identified and quantified. Also, ascorbic acid was the one of the most bioaccessible compounds with the bioaccessibility index 35.38 % for 2021, 16.79 % for 2022. These findings underscore the substantial transformation of the phenolic profile of bee bread as it traverses the human digestive system.

Graphical Abstract

Bernhard Seifried, Feral Temelli∗
Department of Agricultural, Food and Nutritional Science, University of Alberta, 2-06C Agriculture/Forestry Building, Edmonton, Alberta, Canada T6G 2P5

The density of marine lipids in equilibrium with carbon dioxide (CO2) was determined using a view cell equipped with a novel spring balance based onArchimedes’ principle. The densities of fish oil triglycerides (TG) and fish oil fatty acid ethyl esters (FAEE) were measured at pressures ranging from 0.1 to about 25MPa and temperatures of 40, 55 and 70 ◦C. In the pressure and temperature ranges investigated, the density increased with pressure and decreased with temperature. The density increase from atmospheric pressure to about 25MPa at temperatures of 40, 55 and 70 ◦C was 4.1, 3.2, 2.7% and 5.3, 4.0, 3.6% for TG and FAEE, respectively. Volumetric expansion of fish oil TG and FAEE saturated with CO2 was determined at 40 ◦C and pressures ranging from 0.1 to 22MPa. With increasing pressure a relative volume change of up to 38 and 67% was observed for TG and FAEE, respectively. The density and volumetric expansion of lipids in equilibrium with CO2 are important for optimal design of high pressure processes involving mass and momentum transfer.

Sahena Ferdosh1,2,*, Nurul Ashikin Abdul Bari2, Bulan Wu3 and Md. Zaidul Islam Sarker4

1Western Pacific Tropical Research Center, College of Natural and Applied Sciences, University of Guam, Mangilao, Guam, 96923, USA; 2Department of Plant Science, Faculty of Science, International Islamic University Malaysia, Kuantan Campus, 25200, Kuantan, Pahang, Malaysia; 3Division of Natural Sciences, College of Natural and Applied Sciences, University of Guam, Mangilao, Guam, 96923, USA; 4Cooperative Research, Extension, and Education Services (CREES), Northern Marianas College, P.O. Box 501250, Saipan, MP, 96950, USA

Abstract: Background: Anisophyllea disticha (Jack) Baill. (A. disticha) is a species of the Anisophylleaceae family that has undergone the least investigation despite being widely used in folk medicine to cure a wide range of illnesses.

Objective: The purpose of this study is to examine the impact of various factors on the supercritical fluid extraction of A. disticha in order to maximise recovery of total phenolic content, antioxidant activity, and polyphenol identification. Method: The total phenolic content (TPC) and antioxidant activities of A. disticha were determined using the supercritical fluid extraction (SFE) method and compared with Soxhlet. Box-Behnken design of response surface methodology was performed to examine the effect of independent variables of SFE such as temperature, pressure, and concentration of ethanol as co-solvent on TPC and antioxidant activities of A. disticha stem extracts.

Result: At combined effects of different temperatures, pressure, and co-solvent, the total SFE yield were ranged between 0.65 and 4.14%, which was about half of the Soxhlet extract of 8.75 ± 1.54%. The highest concentration (μg/g) of gallic acid (118.83 ± 1.17), p-coumaric (61.60 ± 0.33), ferulic acid (57.93 ± 1.15), and quercetin (24.16 ± 0.41) were obtained at a temperature of 50°C, the pressure of 25 MPa and co-solvent of 20%, while lowest concentration was found 70°C, 30 MPa, and 20% ethanol.

Conclusion: SFE extracts possessed remarkable TPC and concentration of phenolic compounds, indicating superior recovery of compounds. SFE showed more than two-fold higher ferric-reducing antioxidant power compared to Soxhlet with values of 585.32 ± 17.01 mg Fe (II)/g extract and 203.63 ± 16.03 mg Fe (II)/g extract, respectively. SFE demonstrated a potential alternative to the classical solvent extraction methods.

A R T I C L E H I S T O R Y

Received: April 05, 2023
Revised: May 02, 2023
Accepted: May 12, 2023
DOI:
10.2174/2210315513666230607123047
Keywords: Anisophyllea disticha (Jack)Baill., supercritical fluid extraction, box-behnken design, total phenolic content, antioxidant
activities, soxhlet extract.