45,815 results found for (Supercritical Fluids 2015-2016)

Dynamical crossover in supercritical core-softened fluidsOriginal Research Article  April 2016Eu. A. Gaiduk, Yu. D. Fomin, V.N. Ryzhov, E.N. Tsiok, V.V. Brazhkin
Abstract
   It is well known that some liquids can demonstrate an anomalous behavior. Interestingly, this behavior can be qualitatively reproduced with simple core-softened isotropic pair-potential systems. Although the anomalous properties of liquids are usually manifested at low and moderate temperatures, it has recently been recognized that many important phenomena can appear in supercritical fluids. However, studies of the supercritical behavior of core-softened fluids have been not yet reported. In this work, we study dynamical crossover in supercritical core-softened systems. The crossover line is calculated from three different criteria, and good agreement between them is observed. It is found that the behavior of the dynamical crossover line of core-softened systems is quite complex due to its quasi-binary nature.

Process integration for turmeric products extraction using supercritical fluids and pressurized liquids: Economic evaluationOriginal Research Article  April 2016，J. Felipe Osorio-Tobón, Pedro I.N. Carvalho, Mauricio A. Rostagno, M. Angela A. Meireles
Abstract
   An economic evaluation of an integrated process to produce products derived from turmeric was performed. Process integration of supercritical fluid extraction (SFE), pressurized liquid extraction (PLE), and supercritical antisolvent process (SAS) has been investigated in order to obtain turmeric essential oil (TEO) and powdered curcuminoid-rich extract (PCE). Scale-up led to a decrease in the cost of manufacture (COM) for both the products. Volatile oil and powdered curcuminoid-rich extract COMs decreased from US$ 112.70 kg−1 to US$ 85.58 kg−1 and from US$ 174.80 kg−1 to US$ 141.63 kg−1, respectively, when a raw material costing US$ 7.27 kg−1 was used, and the capacity of the system increased from 2× 50 L to 2× 500 L. The raw material cost had a significant effect on the process expenses. When the capacity of the system was 2× 50 L, and the raw material cost decreased from US$ 7.27 kg−1 to US$ 1.59 kg−1, the COM of volatile oil and powdered curcuminoid-rich extract decreased from US$ 112.70 kg−1 to US$ 64.97 kg−1 and from US$ 174.80 kg−1 to US$ 140.96 kg−1, respectively. The economic evaluation results of this study clearly demonstrate that the integrated process is a feasible alternative and an attractive option to produce derivatives from turmeric.

Asymmetric catalytic synthesis of functionalized tetrahydroquinolines in supercritical fluidsOriginal Research Article March 2016, Evgeniya V. Filatova, Olga V. Turova, Ilya V. Kuchurov, Alexey A. Kostenko, Albert G. Nigmatov, Sergei G. Zlotin
Abstract
   Bifunctional tertiary amine-catalysed Michael-initiated asymmetric domino-reactions are accomplished for the first time in supercritical fluids (sc-CO2 and sc-CHF3). In the proposed conditions, o-N-tosylaminophenyl α,β-unsaturated ketones react with α-nitroalkenes to afford valuable to pharmacology densely functionalized chiral tetrahydroquinolines in moderate to high yields and with very high diastereo- (dr > 99:1) and enantioselectivity (up to 98% ee).

Fabrication of high aspect ratio copper nanowires using supercritical CO2 fluids electroplating technique in AAO templateOriginal Research Article, April 2016, Ho-Chiao Chuang, Guan-Yi Hong, Jorge Sanchez

Oxidative dehydrogenation of isobutane catalyzed by an activated carbon fiber cloth exposed to supercritical fluidsOriginal Research Article，August 2015, Nicolas Martin-Sanchez, O.S.G.P. Soares, Manuel F.R. Pereira, M.Jesus Sanchez-Montero, José L. Figueiredo, Francisco Salvador
Abstract
   Modifications that supercritical fluids promote in the surface chemistry of carbon materials are scarcely investigated. Due to this lack of knowledge, carbon materials exposed to supercritical fluids have not been tested in any catalytic application. Here, we present the oxidative dehydrogenation of isobutane catalyzed by an activated carbon fiber cloth previously exposed to supercritical carbon dioxide, supercritical water and nitric acid. The role of carbonyl–quinone groups as active sites is confirmed by their direct correlation with catalytic activity. The ability of the active sites to produce isobutene is hindered by the presence of acidic groups. Supercritical treatments develop microporosity, while removing acidic oxygen surface groups and incorporating carbonyl–quinone groups, so they are appropriate methods to develop efficient carbon catalysts for this reaction. Coke deposits formed during reaction modify the surface chemistry and porosity of the catalysts. Samples presenting high surface areas are deactivated by coke deposition more slowly. Thanks to it, fibers exposed to supercritical water showed the best performance.

Chapter 3 - Biocatalysis in Organic Solvents, Supercritical Fluids and Ionic Liquids, 2016, Chen Cao, Tomoko Matsuda
Abstract
   Biocatalysis in nonaqueous solvents has promoted green chemistry by controlling reactions as well as by simplifying the work-up procedure. Biocatalysis in nonaqueous solvents such as organic solvents, supercritical fluids, and ionic liquids is described in this chapter to provide theoretical information and practical examples. Biocatalysis in biphasic solvent systems comprising aqueous – organic, aqueous – supercritical fluids, aqueous – ionic liquids and ionic liquids – supercritical fluids are also discussed.

Revisiting complete miscibility between silicate melts and hydrous fluids, and the extreme enrichment of some elements in the supercritical state — Consequences for the formation of pegmatites and ore depositsOriginal Research Article, January 2016, R. Thomas, P. Davidson
Abstract
   Using water and major and trace element data obtained from melt inclusions primarily in pegmatite quartz we have shown in this, and previous papers, that melt–melt–fluid immiscibility is widespread and an important process during the generation of granitic pegmatites. Furthermore we have shown that the formation of pegmatites actually begins in the supercritical melt/fluid stage. In this study we extend previous work, and in particular explore the behavior of 10 different elements (Be, F, P, S, Cl, As, Rb, Sn, Cs, and Ta) in the supercritical range. From preliminary studies we suggest that other elements such as B, Na, K, Zn, Nb, and Sb will behave similarly near the solvus crest of a generalized pseudo-binary melt–water system. This provides important evidence that pegmatite-forming processes have already begun at high temperatures, in the range of 850–750 °C, and that may require a re-think on the partitioning behavior of metals in late stage residual melts exsolved from granitic magmas. The existence of this parental supercritical silicate melt/fluid, although derived from granitic magmas, imposes significant constraints of its own, so drawing conclusions about pegmatite-forming processes from data gained from slightly modified granite compositions becomes highly problematic.
We propose that the extremely high concentration of some elements over a small but well defined water concentration range, symmetrically distributed around the critical point of the pseudo-binary solvus, must be derived from the unusual properties of the near-critical or supercritical phases. These unusual properties include extremely low density, viscosity and surface tension, and high diffusivity, reactivity and mobility. These are exactly the qualities that make such supercritical fluids an excellent medium for the formations of pegmatites by reactions with the existing matrix melt + crystal mush, and for the extreme enrichment of some ore-forming elements, highly soluble in alkali- and water-rich supercritical fluids.
A very important point in mineral crystallization is the non-uniform local enrichment of rare and economically significant elements at specific locations in pegmatites, granites and other rocks. Given the properties of the supercritical phase identified from melt inclusions the process of Ostwald ripening can operate very effectively. The driving force for Ostwald ripening arises because the concentration of solute in the vicinity of small crystals or clusters is greater than, and in the vicinity of larger crystals or clusters less than the average supersaturation. The solute in the supercritical fluid therefore flows from the small crystals to the larger crystals, and permits the growth of very large crystals at the expense of smaller ones, this is favored by the extraordinary properties of supercritical fluids. Given the low surface tension the supercritical fluid can move also through grain boundaries and small channels or dislocation pipes, aiding incompatible element transport. Additionally, their consequences for the formation of some important granite-related ore deposits are briefly outlined.

Shale gas and non-aqueous fracturing fluids: Opportunities and challenges for supercritical CO2Original Research Article，June 2015,Richard S. Middleton, J. William Carey, Robert P. Currier, Jeffrey D. Hyman, Qinjun Kang, Satish Karra, Joaquín Jiménez-Martínez, Mark L. Porter, Hari S. Viswanathan
Abstract
   Hydraulic fracturing of shale formations in the United States has led to a domestic energy boom. Currently, water is the only fracturing fluid regularly used in commercial shale oil and gas production. Industry and researchers are interested in non-aqueous working fluids due to their potential to increase production, reduce water requirements, and to minimize environmental impacts. Using a combination of new experimental and modeling data at multiple scales, we analyze the benefits and drawbacks of using CO2 as a working fluid for shale gas production. We theorize and outline potential advantages of CO2 including enhanced fracturing and fracture propagation, reduction of flow-blocking mechanisms, increased desorption of methane adsorbed in organic-rich parts of the shale, and a reduction or elimination of the deep re-injection of flow-back water that has been linked to induced seismicity and other environmental concerns. We also examine likely disadvantages including costs and safety issues associated with handling large volumes of supercritical CO2. The advantages could have a significant impact over time leading to substantially increased gas production. In addition, if CO2 proves to be an effective fracturing fluid, then shale gas formations could become a major utilization option for carbon sequestration.

Improved dissolution and bioavailability of silymarin delivered by a solid dispersion prepared using supercritical fluidsOriginal Research Article，June 2015, Gang Yang, Yaping Zhao, Nianping Feng, Yongtai Zhang, Ying Liu, Beilei Dang
Abstract
   The objective of this study was to improve the dissolution and bioavailability of silymarin (SM). Solid dispersions (SDs) were prepared using solution-enhanced dispersion by supercritical fluids (SEDS) and evaluated in vitro and in vivo, compared with pure SM powder. The particle sizes, stability, and contents of residual solvent of the prepared SM-SDs with SEDS and solvent evaporation (SE) were investigated. Four polymer matrix materials were evaluated for the preparation of SM-SD-SEDS, and the hydrophilic polymer, polyvinyl pyrrolidone K17, was selected with a ratio of 1:5 between SM and the polymer. Physicochemical analyses using X-ray diffraction and differential scanning calorimetry indicated that SM was dispersed in SD in an amorphous state. The optimized SM-SD-SEDS showed no loss of SM after storage for 6 months and negligible residual solvent (ethanol) was detected using gas chromatography. In vitro drug release was increased from the SM-SD-SEDS, as compared with pure SM powder or SM-SD-SE. In vivo, the area under the rat plasma SM concentration-time curve and the maximum plasma SM concentration were 2.4-fold and 1.9-fold higher, respectively, after oral administration of SM-SD-SEDS as compared with an aqueous SM suspension. These results illustrated the potential of using SEDS to prepare SM-SD, further improving the biopharmaceutical properties of this compound.

A high-pressure high-temperature setup for in situ Raman spectroscopy of supercritical fluidsOriginal Research Article, May 2015, Marion Louvel, Amélie Bordage, Cécile Da Silva-Cadoux, Denis Testemale, Eric Lahera, William Del Net, Olivier Geaymond, Jean Dubessy, Roger Argoud, Jean-Louis Hazemann
Abstract
   A high-pressure/high-temperature cell dedicated to Raman spectroscopy is presented. The P and T ranges are optimized for the study of supercritical fluids (T ≤ 975 K, P ≤ 200 MPa); the P and T parameters are controlled independently. The autoclave was adapted from a previous cell (designed for X-ray absorption and scattering spectroscopies) to answer the specific requirement of Raman spectroscopy. Original high pressure windows and sample cell have been developed to ensure both pressure resistance and transparency for the optical laser and Raman scattering beams. An optical integration of the autoclave in the Raman spectrometer setup was designed to perform in situ Raman experiments on fluids. The spectroscopic measurements can be combined with visual observation, which is particularly useful for the study of multi-phasic systems. As examples of the efficiency of the set-up and its scientific opportunities, we present Raman measurements on water, carbon dioxide and mixed H2O–CO2 system obtained from ambient to supercritical conditions.

Growth factors delivery from hybrid PCL-starch scaffolds processed using supercritical fluid technologyOriginal Research Article，May 2016, Luis Diaz-Gomez, Angel Concheiro, Carmen Alvarez-Lorenzo, Carlos A. García-González Close abstractGraphical abstractResearch highlights Purchase PDF - $35.95 Supplementary content
Abstract
   Synthetic polymeric scaffolds to be used as surrogates of autologous bone grafts should not only have suitable physicochemical and mechanical properties, but also contain bioactive agents such as growth factors (GFs) to facilitate the tissue growth. For this purpose, cost-effective and autologous GFs sources are preferred to avoid some post-surgery complications after implantation, like immunogenicity or disease transmission, and the scaffolds should be processed using methods able to preserve GFs activity. In this work, poly(ɛ-caprolactone) (PCL) scaffolds incorporating GFs were processed using a green foaming process based on supercritical fluid technology. Preparation rich in growth factors (PRGF), a natural and highly available cocktail of GFs obtained from platelet rich plasma (PRP), was used as GF source. PCL:starch:PRGF (85:10:5 weight ratio) porous solid scaffolds were obtained by a supercritical CO2-assisted foaming process at 100 bar and 37 °C with no need of post-processing steps. Bioactivity of GFs after processing and scaffold cytocompatibility were confirmed using mesenchymal stem cells. The performance of starch as GF control release component was shown to be dependent on starch pre-gelification conditions.

High performance by N-doped graphene via supercritical fluid processing using an oxime nitrogen sourceOriginal Research Article，March 2016，S.Suresh Balaji, A. Elavarasan, M. Sathish
Abstract
   Heteroatom doped graphene has been proved for its promising applications in electrochemical energy storage systems. Here, nitrogen (N) doped graphene was prepared via two different techniques namely supercritical fluid assisted processing and hydrothermal heat treatment using dimethylglyoxime (DMG) as an oxime nitrogen precursor. The FT-IR and Raman spectra showed the N-containing functional group in the graphene. The XRD analysis revealed the complete reduction of graphene oxide during the supercritical fluid processing. The elemental analysis and X-ray photoelectron spectroscopy revealed the amount and nature of N-doping in the graphene, respectively. The surface morphology and physical nature of the samples were analyzed using scanning and transmission electron microscopic analysis. The electrochemical performance of prepared electrode materials was evaluated using cyclic voltammetry, galvanostatic charge-discharge analysis and electrochemical impedance spectroscopy. The N-doped graphene prepared via supercritical fluid assisted processing exhibit enhanced capacitive behaviour with a maximum specific capacitance of 286 Fg−1 at a current density of 0.5 A/g. The cycling studies showed 98% specific capacity retention with 100% coulombic efficiency over 1000 cycles at 5 A/g. The enhanced specific capacitance of N-doped graphene prepared via supercritical fluid heat treatment over the hydrothermal heat treatment is ascribed to the nature of N-doping in the graphene.

Prediction of heat transfer to supercritical fluids by the use of Algebraic Heat Flux ModelsOriginal Research Article, February 2016, Andrea Pucciarelli, Medhat Sharabi, Walter Ambrosini
Abstract
   The paper discusses capabilities and limitations of Algebraic Heat Flux Models in predicting heat transfer to supercritical fluids. The model was implemented in a commercial code and used as a basis for obtaining an advanced definition of the turbulent Prandtl number and an improved estimate of the buoyancy production of turbulence kinetic energy. A comparison between the obtained results and experimental data available in literature is performed highlighting promising features, in particular when dealing with trans-pseudo-critical conditions. Experimental conditions using different fluids where analysed showing improvements with respect to two-equation turbulence models; a reference DNS calculation is considered as well for comparison. Calculated wall temperature values are in general well reproduced by the methodology and sensitivity analyses show that improvements may be obtained in future works by selecting case-specific AHFM parameters in association with different turbulence models.

Determination and correlation of infinite dilution binary diffusion coefficients for aluminum acetylacetonate in supercritical and liquid fluidsOriginal Research Article，January 2016,Chang Yi Kong, Kou Watanabe, Toshitaka Funazukuri
Abstract
   The infinite dilution binary diffusion coefficients D12 for aluminum acetylacetonate in supercritical CO2 were determined at 308.15–333.15 K and at 7.80–40.00 MPa by the chromatographic impulse response (CIR) method. And, the diffusion measurements in liquid ethanol were carried out at 300.15–333.15 K and at 0.10 and 30.00 MPa by the Taylor dispersion method. It was found that the D12 values measured in supercritical CO2 show slowing down in the region of near critical point. The determined activation energies of diffusion were 23.0, 13.7, 12.0, 11.3 kJ/mol at 12.00, 20.00, 25.00, 35.00 MPa in supercritical CO2 and 19.1 kJ/mol at 0.10 MPa in liquid ethanol, respectively. All determined 90 diffusion data in this study can be correlated with the equation of D12 [m2/s] = 1.558 × 10−14 T [K] η [Pa s]−0.761 with average absolute relative deviation (AARD) of 5.6% over a wide fluid viscosity range from 2.462 × 10−5 to 1.258 × 10−3 Pa s.

Microbial Inactivation by Ultrasound Assisted Supercritical FluidsOriginal Research Article, 2015, Jose Benedito, Carmen Ortuño, Rosa Isela Castillo-Zamudio, Antonio Mulet
Abstract
   A method combining supercritical carbon dioxide (SC-CO2) and high power ultrasound (HPU) has been developed and tested for microbial/enzyme inactivation purposes, at different process conditions for both liquid and solid matrices. In culture media, using only SC-CO2, the inactivation rate of E. coli and S. cerevisiae increased with pressure and temperature; and the total inactivation (7-8 log-cycles) was attained after 25 and 140 min of SC-CO2 (350 bar, 36 °C) treatment, respectively. Using SC-CO2+HPU, the time for the total inactivation of both microorganisms was reduced to only 1-2 min, at any condition selected. The SC-CO2+HPU inactivation of both microorganisms was slower in juices (avg. 4.9 min) than in culture media (avg. 1.5 min). In solid samples (chicken, turkey ham and dry-cured pork cured ham) treated with SC-CO2 and SC-CO2+HPU, the inactivation rate of E. coli increased with temperature. The application of HPU to the SC-CO2 treatments accelerated the inactivation rate of E. coli and that effect was more pronounced in treatments with isotonic solution surrounding the solid food samples. The application of HPU enhanced the SC-CO2 inactivation mechanisms of microorganisms, generating a vigorous agitation that facilitated the CO2 solubilization and the mass transfer process. The cavitation generated by HPU could damage the cell walls accelerating the extraction of vital constituents and the microbial death. Thus, using the combined technique, reasonable industrial processing times and mild process conditions could be used which could result into a cost reduction and lead to the minimization in the food nutritional and organoleptic changes.

A new equation of state for gaseous, liquid, and supercritical fluidsOriginal Research Article，February 2016, N. Farzi, P. Hosseini
Abstract
   In the present study, a new equation of state (EOS) was derived by using the thermodynamic equation of state and the intermolecular potential (3, 9, 12). It was shown that the EOS is applicable in low and high ranges of temperature, pressure and density for gaseous, liquid and supercritical fluids and even in liquid–gas phase transition region. The new EOS is applicable for a variety of fluids such as polar, nonpolar, rare gases, short-chain and long-chain hydrocarbon fluids. The absolute percent deviation of the calculated density for gaseous, liquid and supercritical fluids is very low. The common bulk modulus point and the common compression point regularities were predicted by the new EOS. The new EOS was compared with some equations of state which had been derived similarly. It is shown that the repulsive potential used in the EOS derivation is effective in predicting correct fluid properties.

Supercritical fluids as a green technology for the pretreatment of lignocellulosic biomassOriginal Research Articl
, January 2016, L.V. Daza Serna, C.E. Orrego Alzate, C.A. Cardona Alzate
Abstrac
   One of the main drawbacks for using lignocellulosic biomass is related to its recalcitrance. The pretreatment of lignocellulosic biomass plays an important role for delignification and crystallinity reduction purposes. In this work rice husk (RH) was submitted to supercritical pretreatment at 80 °C and 270 bar with the aim to determine the effect on lignin content, crystallinity as well as enzymatic digestibility. The yields obtained were compared with dilute sulfuric acid pretreatment as base case. Additionally a techno-economic and environmental comparison of the both pretreatment technologies was performed. The results show a lignin content reduction up to 90.6% for the sample with 75% moisture content using a water–ethanol mixture. The results for crystallinity and enzymatic digestibility demonstrated that no reductions were reached. Supercritical pretreatment presents the best economical and environmental performance considering the solvents and carbon dioxide recycling.

Formation of zinc oxide thin film using supercritical fluids and its application in fabricating a reliable Cu/glass stackOriginal Research Article，June 2015, Mitsuhiro Watanabe, Shigeaki Tamekuni, Eiichi Kondo
Abstra
   This paper demonstrates zinc oxide (ZnO) film formation by using supercritical fluid chemical deposition and the application of the ZnO films in improving the adhesion of Cu/glass stacks. Bis(2-methoxy-6-methyl-3,5-heptanedionate)zinc(II) was used as a precursor, and the deposition was carried out at different oxygen contents and temperatures. When oxygen content was high and/or deposition temperature was high, white polycrystalline ZnO films were deposited; otherwise, the films were brown and had a higher carbon content. XPS analyses revealed that the white ZnO films had less carbon contamination. A significant improvement in the adhesion of the Cu/glass stacks was observed when the fabricated ZnO film was inserted between Cu and glass.

Molecular simulations of supercritical fluid systemsReview Article，February 2016, John M. Stubbs
Abstract
   Molecular simulation has become increasingly common as a means to study properties of pure supercritical fluids (SCFs) as well as their solutions. With the large number of studies, and wide range of properties reported, it is advantageous to summarize the current approaches. To this end, both Monte Carlo and molecular dynamics molecular simulation methods are briefly introduced together with important points of molecular models. Subsequently, water and carbon dioxide SCFs are focused on both neat and in mixtures, and an overview of reported properties, including select descriptions of the methods used to determine them, is given. This work serves as a starting point to understanding and carrying out molecular simulations on SCFs
　

Bio-based polymers, supercritical fluids and tissue engineeringReview Article, May 2015,
Aurelio Salerno, Concepción Domingo Pascual
Abstract

Tissue engineering and health care involve the diagnosis, treatment, and prevention of diseases with the ultimate goal to improve people's quality of life by developing advanced materials and therapeutic approaches based on scaffolds and drug delivery. Bio-based polymers are excellent candidate materials for these purposes as, for example, they provide biophysical and biochemical properties able to induce the correct biological response for both in vitro and in vivo applications. This review aims to provide the reader with an overview of the use of bio-based polymers, as well as their blends and composites, for tissue engineering and health care purposes. Special emphasis is given to supercritical fluid processing of bio-based polymers for drug delivery and scaffold fabrication, as they enable the preparation of biomedical systems and avoid the use of chemicals potentially harmful to cells and living tissues. The last part of this review highlights some significant in vitro and in vivo applications of bio-based polymeric scaffolds for the regeneration of specific tissues, namely bone, cartilage, blood vessel, nerve, skin and dermis.

Scale-up study of supercritical fluid extraction process for Baccharis dracunculifoliaOriginal Research Article, January 2016, Julia T. Paula, Ana C. Aguiar, Ilza M.O. Sousa, Pedro M. Magalhães, Mary A. Foglio, Fernando A. Cabral
Abstract
   To evaluate the effects of the bed geometry on the scale-up of fixed bed extractors and on the cost of supercritical extracts from Baccharis dracunculifolia leaves (local name in Brazil: alecrim-do-campo), supercritical CO2 (scCO2) extraction curves at 50 °C and 300 bar at different heights (H) and bed diameter (D), at H/D ratio ranging from 1.86 to 5.2 were obtained. The global yield in all experiments was around 4.6%, and the scale-up criterion adopted was maintain constant the solvent flux. Five phenolic compounds of interest, caffeic acid, p-coumaric acid, trans-cinnamic acid, artepillin C, and kaempferide were quantified by high-performance liquid chromatography. The fractions exhibited high kaempferide levels, which varied from 29.07 to 46.47 mg kaempferide per gram of extract. The optimal manufacturing cost has been estimated at US $ 171.12/kg at 80 min, which shows the possibility of obtaining B. dracunculifolia extracts at an industrial level.

Molecular composition of oxygenated compounds in fast pyrolysis bio-oil and its supercritical fluid extractsOriginal Research Article，May 2016, Tingting Cheng, Yehua Han, Yanfen Zhang, Chunming Xu
Abstract
   A three-step supercritical CO2 extraction was used for selective fractionation of fast pyrolysis bio-oil. Oxygen-containing compounds in bio-oil and its fractions were characterized using infrared spectroscopy (IR), 1H nuclear magnetic resonance spectroscopy (NMR), gas chromatography–mass spectrometry (GC–MS) and negative-ion electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). With appropriate optimization of extraction parameters, lipids, hemicellulose, lignin and condensed aromatics were found enriched in three different fractions. The molecular composition and compound classes were identified by combined analytical techniques, and the selectivity of the fractionation was proved. The compound-type-specific fractionation also facilitated the following characterization and provided insights into the chemical composition of bio-oil. Results indicated that CO2 supercritical fluid extraction was potential for bio-oil preprocessing.

Fluid phase equilibria and mass transfer studies applied to supercritical fluid extraction of Illicium verum volatile oilOriginal Research Article，June 2016, Pages 203-211
Rodrigo Scopel, Caroline Finkler da Silva, Aline Machado Lucas, José Jacques Garcez, Alexandre T. do Espirito Santo, Rafael Nolibos Almeida, Eduardo Cassel, Rubem M.F. Vargas
Abstract
   Supercritical fluid extraction (SFE) is one of the techniques used to obtain Illicium verum volatile oil, however, solubility of the volatile oil in CO2, one of the most important process variables from the SFE, is still unknown. In this work, vapor liquid equilibria experiments (VLE) were conducted in order to verify solubility of the major compound in the I. verum volatile oil, E-anethole, in CO2. In addition, SFE was carried with 750 g/h and 1500 g/h of CO2 at 308.15 K and 8000 kPa, 9000 kPa, 10,000 kPa and the antioxidant activity of the volatile oil accessed by the DPPH method. The VLE experimental data was modeled using the Peng–Robinson EOS (PR-EOS) with three mixing rules (vdW1, vdW2 and MKP). Moreover, SFE process was simulated using the equation proposed by Sovová and solubility data was compared with the values obtained by the PR-EOS.

Natural convection in shear-thinning fluids: Experimental investigations by MRIOriginal Research Article
, April 2016, Mohamed Darbouli, Christel Métivier, Sébastien Leclerc, Chérif Nouar, Mondher Bouteera, Didier Stemmelen
Abstract
   An experimental investigation of the Rayleigh–Bénard convection in shear-thinning fluids using MRI technics is presented. The experimental setup consists on a cylindrical cavity defined by a finite aspect ratio A = D/d = 6. Qualitative and quantitative results are provided. Flow structure is determined from velocity mapping for a Newtonian fluid, Glycerol and for shear-thinning fluids, Xanthan gum aqueous solutions with weight concentrations ranging from 0.1% to 0.2%. In the case of the Glycerol and the Xanthan solution at 0.1%, one recovers similar results in terms of criticality with Rac ≈ 1800 and patterns since the convection is characterized by rolls. When the Xanthan concentration is increased, the critical Rayleigh number is not modified, however the onset occurs with hexagonal pattern. Because the critical temperature differences increase with the concentrations due to an increase in viscosity, one can think that hexagonal patterns are due to variations of physical properties with temperature (non Oberbeck–Boussinesq effects). Similarities with some results obtained in the Newtonian case are highlighted. We have observed a transition from hexagonal patterns to rolls by increasing the Rayleigh number. This pattern transition is characterized by a discrepancy in the maximal velocity values. By using shear-thinning fluids, results show an increase in the intensity of convection compared with the Newtonian case.

Effect of solvent type and ratio on betacyanins and antioxidant activity of extracts from Hylocereus polyrhizus flesh and peel by supercritical fluid extraction and solvent extractionOriginal Research Article，July 2016, Farahnaz Fathordoobady, Hamed Mirhosseini, Jinap Selamat, Mohd Yazid Abd Manap
Abstract
   The main objective of the present study was to investigate the effect of solvent type and ratio as well as the extraction techniques (i.e. supercritical fluid extraction (SFE) and conventional solvent extraction) on betacyanins and antioxidant activity of the peel and fresh extract from the red pitaya (Hylocereus polyrhizus). The peel and flesh extracts obtained by SFE at 25 MPa pressure and 10% EtOH/water (v/v) mixture as a co-solvent contained 24.58 and 91.27 mg/100 ml total betacyanin, respectively; while the most desirable solvent extraction process resulted in a relatively higher total betacyanin in the peel and flesh extracts (28.44 and 120.28 mg/100 ml, respectively). The major betacyanins identified in the pitaya peel and flesh extracts were betanin, isobetanin, phyllocactin, butyrylbetanin, isophyllocactin and iso-butyrylbetanin. The flesh extract had the stronger antioxidant activity than the peel extract when the higher proportion of ethanol to water (E/W) was applied for the extraction

Assessment of ultra high performance supercritical fluid chromatography as a separation technique for the analysis of seized drugs: Applicability to synthetic cannabinoidsOriginal Research Article，April 2016, Stephanie Breitenbach, Walter F. Rowe, Bruce McCord, Ira S. Lurie
Abstract
   The recent development of modern methods for ultra high performance supercritical fluid chromatography (UHPSFC) has great potential for impacting the analysis of seized drugs. In the separation of synthetic cannabinoids the technique has the potential to produce superior resolution of positional isomers and diastereomers.
    To demonstrate this potential we have examined the capability of UHPSFC for the analysis of two different groups of synthetic cannabinoids. The first group was a mixture of 22 controlled synthetic cannabinoids, and the second group included JWH018 and nine of its non-controlled positional isomers The clear superiority of UHPSFC over other separation techniques was demonstrated, in that it was capable of near baseline separation of all 10 positional isomers using a chiral column. In total we examined four achiral columns, including Acquity UPC2 Torus 2-PIC, Acquity UPC2 Torus Diol, Acquity UPC2 Torus DEA and Acquity UPC2 Torus 1-AA (1.7 μm 3.0 × 100 mm), and three chiral columns, including Acquity UPC2 Trefoil AMY1, Acquity UPC2 Trefoil CEL1 and Acquity UPC2 Trefoil CEL2 (2.5 μm 3.0 × 150 mm), using mobile phase compositions that combined carbon dioxide with methanol, acetonitrile, ethanol or isopropanol modifier gradients. Detection was performed using simultaneous PDA UV detection and quadrupole mass spectrometry. The orthogonality of UHPSFC, GC and UHPLC for the analysis of these compounds was demonstrated using principal component analysis. Overall we feel that this new technique should prove useful in the analysis and detection of seized drug samples, and will be a useful addition to the compendium of methods for drug analysis.

A closer study of methanol adsorption and its impact on solute retentions in supercritical fluid chromatographyOriginal Research Article，April 2016, Emelie Glenne, Kristina Öhlén, Hanna Leek, Magnus Klarqvist, Jörgen Samuelsson, Torgny Fornstedt
Abstract
   Surface excess adsorption isotherms of methanol on a diol silica adsorbent were measured in supercritical fluid chromatography (SFC) using a mixture of methanol and carbon dioxide as mobile phase. The tracer pulse method was used with deuterium labeled methanol as solute and the tracer peaks were detected using APCI-MS over the whole composition range from neat carbon dioxide to neat methanol. The results indicate that a monolayer (4 Å) of methanol is formed on the stationary phase. Moreover, the importance of using the set or the actual methanol fractions and volumetric flows in SFC was investigated by measuring the mass flow respective pressure and by calculations of the actual volume fraction of methanol. The result revealed a significant difference between the value set and the actually delivered volumetric methanol flow rate, especially at low modifier fractions. If relying only on the set methanol fraction in the calculations, the methanol layer thickness should in this system be highly overestimated.
   Finally, retention times for a set of solutes were measured and related to the findings summarized above concerning methanol adsorption. A strongly non-linear relationship between the logarithms of the retention factors and the modifier fraction in the mobile phase was revealed, prior to the established monolayer. At modifier fractions above that required for establishment of the methanol monolayer, this relationship turns linear which explains why the solute retention factors are less sensitive to changes in modifier content in this region.

Supercritical fluid extraction vs conventional extraction of myrtle leaves and berries: Comparison of antioxidant activity and identification of bioactive compoundsOriginal Research Article, July 2016, Paula Pereira, Maria-João Cebola, M. Conceição Oliveira, M. Gabriela Bernardo-Gil
Abstract
   In this work, the antioxidant capacity of extracts of Portuguese myrtle (Myrtus communis L.) is being studied over a period of three years. The samples were leaves of myrtle collected at the flowering stage and berries sampled at an early ripened stage. Supercritical fluid extraction (SFE) extracts were obtained at 23 MPa, 45 °C and a CO2 flow of 0.3 kg h−1 using ethanol as co-solvent with a flow rate of 0.09 kg h−1. Hydrodistillation was carried out in a Clevenger type apparatus and the aqueous phase was extracted with diisopropylether having obtained what is hereby designated as liquid phase extract (LPE).
    The antioxidant capacity of all the extracts was determined by using three different methods: the Folin–Ciocalteu, the Trolox Equivalent Antioxidant Capacity (TEAC) and the Oxygen Radical Absorbance Capacity (ORAC). The results show that the SFE extracts present a significantly higher antioxidant capacity. The extracts were characterized and quantified by HPLC-DAD-MS/MS methods. The bioactive compounds identified in all the extracts were phenolic acids (only in the LPE extracts), flavonoids and anthocyanins (only in the SFE extracts). The results indicate that the higher antioxidant capacity of the SFE myrtle extracts is mainly correlated with the concentration of flavonol glycosides, the myricetin-O-glycosides.

Fast and sensitive supercritical fluid chromatography – tandem mass spectrometry multi-class screening method for the determination of doping agents in urineOriginal Research Article，April 2016, Lucie Nováková, Vincent Desfontaine, Federico Ponzetto, Raul Nicoli, Martial Saugy, Jean-Luc Veuthey, Davy Guillarme
Abstract
   This study shows the possibility offered by modern ultra-high performance supercritical fluid chromatography combined with tandem mass spectrometry in doping control analysis. A high throughput screening method was developed for 100 substances belonging to the challenging classes of anabolic agents, hormones and metabolic modulators, synthetic cannabinoids and glucocorticoids, which should be detected at low concentrations in urine. To selectively extract these doping agents from urine, a supported liquid extraction procedure was implemented in a 48-well plate format. At the tested concentration levels ranging from 0.5 to 5 ng/mL, the recoveries were better than 70% for 48–68% of the compounds and higher than 50% for 83–87% of the tested substances. Due to the numerous interferences related to isomers of steroids and ions produced by the loss of water in the electrospray source, the choice of SFC separation conditions was very challenging. After careful optimization, a Diol stationary phase was employed. The total analysis time for the screening assay was only 8 min, and interferences as well as susceptibility to matrix effect (ME) were minimized. With the developed method, about 70% of the compounds had relative ME within the range ±20%, at a concentration of 1 and 5 ng/mL. Finally, limits of detection achieved with the above-described strategy including 5-fold preconcentration were below 0.1 ng/mL for the majority of the tested compounds. Therefore, LODs were systematically better than the minimum required performance levels established by the World anti-doping agency, except for very few metabolites.

A rapid method for the separation of vitamin D and its metabolites by ultra-high performance supercritical fluid chromatography–mass spectrometryOriginal Research Article，April 2016, Firas Jumaah, Sara Larsson, Sofia Essén, Larissa P. Cunico, Cecilia Holm, Charlotta Turner, Margareta Sandahl
Abstract
   In this study, a new supercritical fluid chromatography–mass spectrometry (SFC–MS) method has been developed for the separation of nine vitamin D metabolites within less than eight minutes. This is the first study of analysis of vitamin D and its metabolites carried out by SFC–MS. Six columns of orthogonal selectivity were examined, and the best separation was obtained by using a 1-aminoanthracene (1-AA) column. The number and the position of hydroxyl groups in the structure of the studied compounds as well as the number of unsaturated bonds determine the physiochemical properties and, thus the separation of vitamin D metabolites that is achieved on this column. All D2 and the D3 forms were baseline separated with resolution values > 1.5. The effects of pressure, temperature, flow rate and different gradient modes were studied. Electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) were compared in positive mode, both by direct infusion and after SFC separation. The results showed that the sensitivity in APCI+ was higher than in ESI+ using direct infusion. In contrast, the sensitivity in APCI+ was 6-fold lower than in ESI+ after SFC separation. The SFC–MS method was validated between 10 and 500 ng/mL for all analytes with coefficient of determination (R2) ≥ 0.999 for all calibration curves. The limits of detection (LOD) were found to range between 0.39 and 5.98 ng/mL for 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) and 1-hydroxyvitamin D2 (1OHD2), respectively. To show its potential, the method was applied to human plasma samples from healthy individuals. Vitamin D3 (D3), 25-hydroxyvitamin D3 (25OHD3) and 24,25(OH)2D3 were determined in plasma samples and the concentrations were 6.6 ± 3.0 ng/mL, 23.8 ± 9.2 ng/mL and 5.4 ± 2.7 ng/mL, respectively.

Fast separation of triterpenoid saponins using supercritical fluid chromatography coupled with single quadrupole mass spectrometryOriginal Research Article，March 2016, Yang Huang, Tingting Zhang, Haibo Zhou, Ying Feng, Chunlin Fan, Weijia Chen, Jacques Crommen, Zhengjin Jiang
Abstract
   Triterpenoid saponins (TSs) are the most important components of some traditional Chinese medicines (TCMs) and have exhibited valuable pharmacological properties. In this study, a rapid and efficient method was developed for the separation of kudinosides, stauntosides and ginsenosides using supercritical fluid chromatography coupled with single quadrupole mass spectrometry (SFC-MS). The separation conditions for the selected TSs were carefully optimized after the initial screening of eight stationary phases. The best compromise for all compounds in terms of chromatographic performance and MS sensitivity was obtained when water (5–10%) and formic acid (0.05%) were added to the supercritical carbon dioxide/MeOH mobile phase. Beside the composition of the mobile phase, the nature of the make-up solvent for interfacing SFC with MS was also evaluated. Compared to reversed phase liquid chromatography, the SFC approach showed higher resolution and shorter running time. The developed SFC-MS methods were successfully applied to the separation and identification of TSs present in Ilex latifolia Thunb., Panax quinquefolius L. and Panax ginseng C.A. Meyer. These results suggest that this SFC-MS approach could be employed as a useful tool for the quality assessment of natural products containing TSs as active components.

Supercritical fluid chromatography coupled with in-source atmospheric pressure ionization hydrogen/deuterium exchange mass spectrometry for compound speciationOriginal Research Article，March 2016,Yunju Cho, Man-Ho Choi, Byungjoo Kim, Sunghwan Kim
Abstract
   An experimental setup for the speciation of compounds by hydrogen/deuterium exchange (HDX) with atmospheric pressure ionization while performing chromatographic separation is presented. The proposed experimental setup combines the high performance supercritical fluid chromatography (SFC) system that can be readily used as an inlet for mass spectrometry (MS) and atmospheric pressure photo ionization (APPI) or atmospheric pressure chemical ionization (APCI) HDX. This combination overcomes the limitation of an approach using conventional liquid chromatography (LC) by minimizing the amount of deuterium solvents used for separation. In the SFC separation, supercritical CO2 was used as a major component of the mobile phase, and methanol was used as a minor co-solvent. By using deuterated methanol (CH3OD), AP HDX was achieved during SFC separation. To prove the concept, thirty one nitrogen- and/or oxygen-containing standard compounds were analyzed by SFC-AP HDX MS. The compounds were successfully speciated from the obtained SFC-MS spectra. The exchange ions were observed with as low as 1% of CH3OD in the mobile phase, and separation could be performed within approximately 20 min using approximately 0.24 mL of CH3OD. The results showed that SFC separation and APPI/APCI HDX could be successfully performed using the suggested method.

Chiral separations of cathinone and amphetamine-derivatives: Comparative study between capillary electrochromatography, supercritical fluid chromatography and three liquid chromatographic modesOriginal Research Article，March 2016, Dima Albals, Yvan Vander Heyden, Martin G. Schmid, Bezhan Chankvetadze, Debby Mangelings
Abstract
   The screening part of an earlier defined chiral separation strategy in capillary electrochromatography (CEC) was used for the separation of ten cathinone- and amphetamine derivatives. They were analyzed using 4 polysaccharide-based chiral stationary phases (CSPs), containing cellulose tris(3,5-dimethylphenylcarbamate) (ODRH), amylose tris(3,5-dimethylphenylcarbamate) (ADH), amylose tris(5-chloro-2-methylphenylcarbamate) (LA2), and cellulose tris(4-chloro-3-methylphenylcarbamate) (LC4) as chiral selectors. After applying the screening to each compound, ADH and LC4 showed the highest success rate. In a second part of the study, a comparison between CEC and other analytical techniques used for chiral separations i.e., supercritical fluid chromatography (SFC), polar organic solvent chromatography (POSC), reversed-phase (RPLC) and normal-phase liquid chromatography (NPLC), was made. For this purpose, earlier defined screening approaches for each technique were applied to separate the 10 test substances. This allowed an overall comparison of the success rates of the screening steps of the 5 techniques for these compounds. The results showed that CEC had a similar enantioselectivity rate as NPLC and RPLC, producing the highest number of separations (9 out of 10 racemates). SFC resolved 7 compounds, while POSC gave only 2 separations. On the other hand, the baseline separation success rates for NPLC and RPLC was better than for CEC. For a second comparison, the same chiral stationary phases as in the CEC screening were also tested with all techniques at their specific screening conditions, which allowed a direct comparison of the performance of CEC versus the same CSPs in the other techniques. This comparison revealed that RPLC was able to separate all tested compounds, and also produced the highest number of baseline separations on the CSP that were used in the CEC screening step. CEC and NPLC showed the same success rate: nine out of ten substances were separated. When CEC and NPLC are combined, separation of the ten compounds can be achieved. SFC and POSC resolved eight and three compounds, respectively. POSC was the least attractive option as it expressed only limited enantioselectivity toward these compounds.

Chapter Thirteen - Electronic Properties in Supercritical Fluids: The Absorption Spectrum of p-Nitroaniline in Supercritical Water, 2015, Marcelo Hidalgo Cardenuto, Kaline Coutinho, Benedito J.C. Cabral, Sylvio Canuto
Abstract
   Supercritical fluids (SCFs) are of great interest for their remarkable physical–chemical properties. Understanding the properties of SCFs is of industrial and academic interests. Foreign molecules can act as interesting probes giving information from the changes induced by the supercritical environment. The electronic absorption spectrum of p-nitroaniline (pNA) in the environment of supercritical water has been addressed. The thermodynamic condition is assured by Monte Carlo simulation, and quantum mechanical calculations are performed on sampled configurations to obtain the spectrum of pNA in supercritical water. Using the same thermodynamic condition of the experiment (T = 655 K and ρ = 0.12 g/cm3), we analyze the electronic polarization of the p-aniline, the solute–solvent hydrogen bonds, and the red shift of the intense charge transfer π–π* transition. Compared to normal water, the number of solute–solvent hydrogen bonds in supercritical water decreases to essentially one-fifth, from 2.9 to 0.6. The calculated spectrum in supercritical water is obtained using time-dependent CAM-B3LYP/aug-cc-pVDZ and shows a maximum located at 305 nm in good comparison with the experimental maximum observed at 309 nm. In comparison to the results in the vapor phase, the experimental red shift of 17 nm is very well described theoretically with the result of 17 ± 3 nm. A discussion is also presented of the inhomogeneous broadening contribution to the half-width at the absorption maximum.

CFD aided approach to design printed circuit heat exchangers for supercritical CO2 Brayton cycle applicationOriginal Research Article, June 2016, Seong Gu Kim, Youho Lee, Yoonhan Ahn, Jeong Ik Lee
Abstract
   While most conventional PCHE designs for working fluid of supercritical CO2 require an extension of valid Reynolds number limits of experimentally obtained correlations, Computational Fluid Dynamics (CFD) code ANSYS CFX was used to explore validity of existing correlations beyond their tested Reynolds number ranges. For heat transfer coefficient correlations, an appropriate piece-wising with Ishizuka’s and Hesselgreaves’s correlation is found to enable an extension of Reynolds numbers. For friction factors, no single existing correlation is found to capture different temperature and angular dependencies for a wide Reynolds number range. Based on the comparison of CFD results with the experimentally obtained correlations, a new CFD-aided correlation covering an extended range of Reynolds number 2000–58,000 for Nusselt number and friction factor is proposed to facilitate PCHE designs for the supercritical CO2 Brayton cycle application.

Instrument Modifications that Produced Reduced Plate Heights <2 with Sub-2 μm Particles and 95% of Theoretical Efficiency at k = 2 in Supercritical Fluid ChromatographyOriginal Research Article，March 2016,Terry A. Berger
Abstract
   The concept of peak fidelity was shown to be helpful in modeling tubing and detector cell dimensions. Connection tubing and flow cell variances were modeled to determine appropriate internal ID’s, lengths, and volumes. A low dispersion plumbing configuration, based on these calculations, was assembled to replace the standard plumbing and produced the reported results. The modifications made were straightforward using commercially available parts. The full theoretical efficiency of a 3 × 100 mm column packed with 1.8 μm totally porous particles was achieved for the first time in supercritical fluid chromatography (SFC). Peak fidelity of > 0.95 was maintained to below k = 2. A reduced plate height as low as 1.87 was measured. Thus, true “ultra high performance” SFC was achieved, with the results a major improvement from all previous SFC reports.
    Since there were no efficiency losses, none could be attributed to thermal gradients caused by the expansion of the fluid over large pressure drops, under the conditions used. Similarly, changes in diffusion coefficients caused by significant decreases in density during expansion are apparently balanced by the increase in linear velocity, keeping the ratio between the diffusion coefficient and the linear velocity a constant. Changing modifier concentration to change retention was shown to not be a significant problem. All these issues have been a concern in the past.
Diffusion coefficients, and viscosity data needs to be collected at high pressures before the actual limits of SFC can be discovered

Polymers' ultrafine particles for drug delivery systems precipitated by supercritical carbon dioxide + organic solvent mixturesOriginal Research Article, May 2016, Valentina Prosapio, Ernesto Reverchon, Iolanda De Marco
Abstract
   The applicability of supercritical antisolvent precipitation (SAS) is restricted to hydrophobic substances because of the very limited solubility of water in CO2 at ordinary SAS operating conditions (40–60 °C, 10–25 MPa). To overcome this limitation, a technique has been developed, named expanded liquid antisolvent (ELAS), in which mixtures of supercritical carbon dioxide (scCO2) and organic solvents, at expanded liquid conditions, are used as the antisolvent: water solubility is widely enhanced.
    In this work, sodium alginate and polyvinyl alcohol (PVA), two water-soluble polymers, used as carrier for drug delivery systems, were successfully micronized by ELAS. Different antisolvent mixtures were used: scCO2 + ethanol, scCO2 + acetone and scCO2 + isopropyl alcohol. Operating at 15 MPa and 40 °C, varying the organic co-antisolvent, the co-antisolvent mole fraction and the concentration of the polymer in the aqueous solution, nanoparticles (with a mean diameter of about 200 nm), microparticles with smooth surface (with a mean diameter in the range of 0.9–12.5 μm for sodium alginate and 2–9 μm for PVA) and nanostructured microparticles (with a mean diameter of about 11 μm) were produced. XRD analyses on the processed powders revealed that no modifications in the polymer structure were induced by ELAS processing. Solvent residue analyses revealed that the co-antisolvent residue ranged between 50 and 300 ppm depending on the organic solvent used.

Investigation on the fluid selection and evaporation parametric optimization for sub- and supercritical organic Rankine cycleOriginal Research Article，February 2016, Heng Xu, Naiping Gao, Tong Zhu
Abstract
ORC (Organic Rankine cycle) is a promising technology for recovery of low-grade heat. In the previous studies, different conclusions for working fluid selection criterion can be found and relatively few work for supercritical ORC has been made. Therefore, this paper investigates the net power output of ORC utilizing waste flue gas with various evaporation parameters and 12 working fluids in both subcritical and supercritical condition. The results indicate that the variation of the net power output with evaporation pressure is related to the heat source temperature, and the maximum net power output appears at supercritical condition rather than subcritical condition if the heat source temperature is about 25–40 °C higher than the working fluid's critical temperature. Besides, the parametric optimization is performed, and the most suitable working fluids for various flue gas inlet temperature of 150–250 °C have been found. It can be found that the most suitable working fluids have a critical temperature about 40–65 °C lower than flue gas inlet temperature, and the optimum condition is always supercritical. For subcritical ORC, it is better to adopt the working fluids with low evaporation latent heat and high liquid specific heat to pursue a high net power output.

Effect of fluid temperature on the frictional coefficient of supercritical pressure water flowing in adiabatic horizontal tubesOriginal Research Article, July 2016,Qing Zhang, Huixiong Li, Weiqiang Zhang, Liangxing Li, Xianliang Lei
Abstract
   Based on the analysis on sensitivity of the frictional coefficient of supercritical pressure water to the fluid temperature, the conflict of the variation trends of the frictional coefficient with the fluid enthalpy obtained by different researchers was explained. It is shown that both concave curves and convex curves are reasonable for the variation trend of the frictional coefficient with the fluid enthalpy. For the same case, the variation trend of the frictional coefficient with the fluid enthalpy might change from concave curves to convex curves, or, from convex curves to concave curves, when the fluid temperature in the calculation of frictional coefficient is changed by a value as little as only 0.5–1.0 °C. The maximum error in the measured fluid temperature is estimated to be large enough (larger than ±1.0 °C), and might be the main reason for completely different tendencies of the frictional coefficient obtained in different studies.

Evaluation of the response surface and hybrid artificial neural network-genetic algorithm methodologies to determine extraction yield of Ferulago angulata through supercritical fluidOriginal Research Article, March 2016, Gholamhossein Sodeifian, Seyed Ali Sajadian, Nedasadat Saadati Ardestani
Abstract
   In this research, the influence of operational parameters such as pressure, temperature, particle size and dynamic time on the extraction of Ferulago angulata via supercritical carbon dioxide was investigated. Two models, response surface method (RSM) and artificial neural network (ANN), were applied for modeling and predicting of the extraction yield. The capability and sensitivity analysis of two methodologies was evaluated by some statistical parameters including, correlation coefficients (R2), mean square error (MSE), and absolute average relative deviation (AARD). The error values of RSM model (R2 = 0.9645, MSE = 0.0032 and AARD = 3.39) and ANN model (R2 = 0.9971, MSE = 0.0014 and AARD = 1.32) were calculated. Both models showed good agreement with the experimental data, but ANN model was more accurate than the RSM model. RSM and ANN-GA models were subsequently utilized to determine optimal operating conditions in order to gain the maximum yield of Ferulago angulate extraction. The essential oil extraction yield in the optimal conditions was estimated to be 0.851 w/w% and 0.863 w/w% by the RSM and ANN-GA models, respectively. Assessment and evaluation of the above mentioned models were carried out through performing triplicate experiments and finally the average experimental extraction yield was achieved to be 0.867 ± 0.004 w/w% at the best operating conditions 20 MPa, 35 °C, 0.742 mm and 101.3 min.

Ecofriendly pretreatment of grey cotton fabric with enzymes in supercritical carbon dioxide fluidOriginal Research Article， May 2016, Shi-Qi Liu, Zong-Yao Chen, Jian-Ping Sun, Jia-Jie Long
Abstract
   A novel and Ecofriendly process was developed at the first time for the pretreatment of grey cotton fabric by employing enzymes with microemulsion in supercritical carbon dioxide fluid (SCF-CO2). The results show that high efficiency of impurity removal and significant improvement in wettability of treated substrate were achieved with the supposed bioprocess. The fabric weight loss and capillary rise height of substrate were notably influenced by system temperature and pressure, the dosages of enzymes and sodium bis (2-ethylhexyl) sulfosuccinate (AOT), the presence of water and initial pH value, as well as treatment time. An optimized enzymatic and Ecofriendly pretreatment process for desizing and scouring of grey cotton was recommended in supercritical carbon dioxide media with a system temperature at 50.0 °C and a pressure at 13.0 MPa for 60.0 min in the presence of small amounts of ethanol, water, several enzymes and AOT in the reactor at an initial pH value of 7.0–8.0. Moreover, the feasibility and the efficiency of the supposed supercritical bio-pretreatment process were further validated by scanning electronic microscopy (SEM) analysis.

Patent of cn

Technique and industrial device for refining rice by supercritical polybasic fluid  

Abstract of  CN101554211 (A)

The invention belonges to the field of refining rice by supercritical polybasic fluid. The invention is characterized in that the supercritical polybasic fluid industrial device with carbon-dioxide zero emission, with pressure less than 22 MPa and temperature less than 40 DEG C, pre-breaks wall of brown rice layer to be directly prepared as high-nutrient rice; meanwhile, harmful bacteria, mould and ova are killed, so that freshness date is prolonged and storage loss is reduced; impurities in the brown rice such as pesticide residue, heavy metal and dust are removed via ultrasonic and microwave extraction; the brown rice becomes good-looking and delicious by colouring and aromatizing; besides, anti-free-radical, anti-aging, anti-radiation and immunity-improving natural bioactive substances are uniformly added so as to improve health-care function and added value of the rice, further; thus, fresh and delicious rice with advantages of high nutrient, water saving, washing prevention and rapid cooking is produced, with yield being increased by more than 25%; the invention is executed and popularized widely in rice planting regions, thereby ensuring national food safety and international food safety.

Process for extracting active ingredients of traditional Chinese medicine in unit and combined type and device thereof  

Abstract of  CN101530674 (A)

The invention belongs to highly effective extraction and separation of the active ingredients in field of modernization of Chinese medicine and is characterized in that on the basis of an extraction process and a device consisting of the combination of 3 novel chemical engineering unit operations of water percolation distillation, extractive distillation, and highly efficient az dist azeotropic distilation, the traditional and advanced techniques and devices for water distillation extraction, extraction by semi-bionic method, extraction by ultrasonic waves, extraction by enzyme process, extraction by microbial fermentation and extraction by microwave are preferably selected to constitute the unit and combined type extraction process and the device thereof; the process and the device of the invention is especially suitable for extracting the majority of single Chinese medicine or compound Chinese medicine with both volatile and non-volatile components; in addition the device operates stably with stable parameters; compared with the traditional multifunctional traditional Chinese medicine extracting tank, the tank of the invention features an extraction rate above 95% and energy conservation by over 50%, contraction of the production period by over 50%, reduction of production cost per unit product by 50% and stable content of active ingredients and product quality.

Supercritical fluid drying equipment  
Abstract of  CN105202888 (A)
The invention relates to supercritical fluid drying equipment which comprises a drying body, a filter cavity, a first pipeline and a second pipeline. The drying body comprises a gas drying cavity formed in the upper layer and a heating cavity formed in the lower layer. The bottom layer of the gas drying cavity is obliquely arranged, and a flow channel communicated with the heating cavity is arranged at the bottom of the inclined end. A flow speed induction point, a flow speed control valve and a control valve handle connected with the flow speed control valve are arranged in the flow channel. The control valve handle is arranged on the outer side wall of the drying body. The supercritical fluiddrying equipment comprises the drying body, and is reasonable in structure, good in drying and purifying effect and convenient to maintain.

Supercritical fluid opposite-spraying dyeing device  

Abstract of  CN105200686 (A)

The invention relates to the field of textile dyeing devices, in particular to a supercritical fluid opposite-spraying dyeing device, consisting of a cleaning unit, an opposite-spraying dyeing unit, a rinsing unit, reflux devices, working fluid air seal units, air seal units, a connection plate, a sealing box, a sealing element and a pressure regulator valve; according to a supercritical fluid opposite spraying dyeing process flow, the air seal unit, the working fluid air seal unit, the reflux device, the cleaning unit, the reflux device, the working fluid air seal unit, the reflux device, the opposite-spraying dyeing unit, the reflux device, the working fluid air seal unit, the reflux device, the rinsing unit, the reflux device, the working fluid air seal unit and the air seal unit are arranged in sequence. Supercritical fluid is sprayed to a dyed object from two sides at the same time, the jetting forces of the fluid are offset as 0, the dyeing is uniform, and deformation and tension damage of the dyed object caused by high pressure jetting are eliminated; a level-by-level pressure reducing air seal structure is adopted, so that continuous dyeing is realized, and the device is simple and compact in structure and excellent in manufacturability.
Loquat enzyme nutrient solution and preparation method thereof  

Abstract of  CN105193989 (A)

The invention discloses a loquat enzyme nutrient solution and a preparation method thereof and relates to the technical field of biological fermentation solutions. The loquat enzyme nutrient solution comprises raw materials including loquats, dried loquat leaves, honey, oligosaccharide, dried yeast and water. The preparation method comprises steps as follows: the loquats are subjected to pulp making firstly, the dried loquat leaves are boiled with water, are cooled and then are uniformly mixed with the honey, the oligosaccharide and the dried yeast, water is added, and the mixture is uniformly mixed and placed in a container for sealing fermentation; finally, acquired fermentation broth is processed and extracted with an supercritical fluid extraction and separation technology, and the loquat enzyme nutrient solution is obtained. According to the loquat enzyme nutrient solution and the preparation method thereof, the safe loquat enzyme nutrient solution which is free of side effects and can be taken as a beverage for drinking is prepared with lower cost and the simple method and has remarkable cough relieving and sputum reducing effects.
Purslane extract and preparation method thereof  

Abstract of  CN105193876 (A)

The invention belongs to the technical field of traditional Chinese medicines or cosmetics, and particularly relates to a purslane extract and a preparation method thereof. The extract is prepared by the following steps: drying taken purslane; with 95% ethanol as an entrainer, carrying out CO2 supercritical fluid extraction, adding 1,3-butanediol to an extract, completely recovering a reagent from an organic layer, and drying the reagent to obtain an extract A; carrying out enzyme hydrolysis on residues after supercritical extraction, adding water to extract, filtering and adding activated carbon and clay to the extract liquid, centrifuging and drying the extract liquid to obtain an extract B; and mixing the extract A with the extract B evenly. According to the preparation method provided by the invention, the extract A is rich in alpha-linolenic acid. The polysaccharide content of the extract B is high. Compared with the purslane extract in the prior art, the purslane extract obtained by the extraction method has better antibacterial, anti-inflammatory and anti-irritation effects.
Navel orange enzyme nutrient solution and preparation method thereof  

Abstract of  CN105192830 (A)

The invention discloses a navel orange enzyme nutrient solution and a preparation method thereof and relates to the technical field of biological fermentation solutions. The navel orange enzyme nutrient solution comprises raw materials including navel oranges, dried liquorice, honey, oligosaccharide, dried yeast and water. The preparation method comprises steps as follows: the navel oranges are subjected to pulp making firstly, the dried liquorice is boiled with water, is cooled and then is uniformly mixed with the honey, the oligosaccharide and the dried yeast, water is added, and the mixture is uniformly mixed and placed in a container for sealing fermentation; finally, acquired fermentation broth is processed and extracted with an supercritical fluid extraction and separation technology, and the navel orange enzyme nutrient solution is obtained. According to the navel orange enzyme nutrient solution and the preparation method thereof, the safe navel orange enzyme nutrient solution which is free of side effects and can be taken as a beverage for drinking is prepared with lower cost and the simple method, can replace western medicine, effectively assists a body in automatic regulation of blood pressure and can be used for reducing cholesterol, and hypertension, hyperglycemia and hyperlipemia can be relieved and repaired when the human body is properly supplemented with the orange enzyme.
High-power drafting flame-retardant post-processing method for high-tenacity polyester in supercriticalCO2

Abstract of  CN105177769 (A)

The invention relates to a high-power drafting flame-retardant post-processing method for high-tenacity polyester in supercritical CO2, which comprises the following steps: adding a flame retardant into a closed container, exhausting air at 80-120 DEG C, feeding CO2, increasing the pressure in the container to 8-13MPa to obtain CO2 supercritical fluid, and soaking the primary filament of high-tenacity polyester in the supercritical fluid for swelling; and after swelling, carrying out high-power drafting on the primary filament, and thermoforming to obtain high-tenacity flame-retardant polyester. According to the post-processing method provided by the invention, under the effect of supercritical CO2, the flame retardant can well penetrate to the surface and inside of fiber, and the soaked fiber can be subjected to high-power drafting, so that the tenacity of the polyester fiber is improved while the flame resistance of the polyester fiber is improved. The post-processing method has the advantages of economical efficiency, environmental friendliness, controllable reaction, short reaction time and the like and has great industrial application values. The limited oxygen index of the high-tenacity polyester obtained by the post-processing method provided by the invention is more than 35.0%.
Method for preparing novel nicotianasesterpene H having antiviral activity with supercritical fluidchromatography  

Abstract of  CN105175240 (A)

The invention discloses a sesquiterpenoids compound which is of a novel structure and found in tobacco. The compound is named nicotianasesterpene H, the molecular formula of the compound is C<15>H<20>O<3>, and the structural formula can be found in the specification. The invention further discloses the application of the compound. Activity tests indicate that the compound has a good inhibiting effect on rotavirus and can serve as a lead anti-rotavirus compound for being used in research and development of anti-rotavirus medicinal preparations.
Treatment method for coal-gasification wastewater biochemical sludge  
Abstract of  CN105174675 (A)

The invention provides a treatment method for coal-gasification wastewater biochemical sludge. The method comprises the following steps: 1) transporting the coal-gasification wastewater biochemical sludge into a heating furnace and carrying out preheating; meanwhile, transporting liquid oxygen into a condenser and carrying out heat exchanging and then carrying out transporting into an oxygen buffer tank; 2) respectively allowing the preheated coal-gasification wastewater biochemical sludge and an oxidant from the oxygen buffer tank to enter a supercritical water oxidation reactor, and carrying out oxidation reaction; 3) cooling the oxidized high-temperature fluid via a heat exchanger and then carrying out transporting to a high-pressure gas-liquid separator; 4) discharging a separated liquid-phase product from the bottom part of the high-pressure gas-liquid separator, and transporting a gas-phase product to a dehydrating tower from the top part of the high-pressure gas-liquid separator; 5) cooling the dehydrated gas-phase product through heat exchanging of the condenser, and carrying out transporting to a CO2 purification tower; and 6) discharging the separated liquid-phase CO2 from the bottom part of the CO2 purification tower, and transporting the oxygen in the gas-phase product back to the oxygen buffer tank from the top part of the CO2 purification tower, wherein the oxygen is circularly used as the oxidant. The treatment method for the coal-gasification wastewater biochemical sludge provided by the invention realizes rapid and thorough degradation of organic matters in the coal-gasification wastewater biochemical sludge; meanwhile, cyclic utilization of the oxygen and recovery of the CO2 in the treatment process are realized, so energy is maximumly utilized.
Powdery black food and preparation method thereof  

Abstract of  CN105166900 (A)

The invention discloses a powdery black food. The powdery black food is prepared from the following raw materials in parts by weight: 20-30 parts of black rice, 20-30 parts of rye, 15-20 parts of black soybeans, 10-15 parts of black corns, 5-10 parts of black sesames, 5-8 parts of dried black fungi, 4-6 parts of kelps, 3-5 parts of black dates and 2-4 parts of figs. The powdery black food is prepared by the following preparation steps: (1) metering and weighing according to ratios; (2) finely grinding the metered and weighed raw materials and sieving; and (3) after finely grinding and sieving, and carrying out superfine crushing on the raw materials, wherein in superfine grinding, asupercritical impinging stream crushing technology is adopted, carbon dioxide is used as main fluid, the pressure is 15-20MPa, and the grain diameter of the crushed powdery black food is 15-20 microns. For the powdery black food, the raw materials of the black food are combined with the supercritical impinging stream crushing technology to create a new food preparation technology and the produced food has high nutritive value.
Decoloration method for yak hairs

Abstract of  CN105155254 (A)

The invention relates to a decoloration method for yak hairs. The decoloration method is characterized by comprising the following steps: starching and finishing the yak hairs, then performing ultrasonic treatment, and performing decoloration finishing in supercritical carbon dioxide fluid, wherein the whiteness of yak hair fibers obtained by decoloration is 85-95 percent, and the breaking strength is higher than or equal to 1.60cN/tex.
Supercritical carbon dioxide ox horn button dyeing kettle and dyeing technology  

Abstract of  CN105155177 (A)

The invention discloses a supercritical carbon dioxide ox horn button dyeing kettle and a dyeing technology. The dyeing kettle comprises a kettle body. A carbon oxide fluid and dye inlet and a carbon oxide fluid and dye outlet are formed in the bottom of the kettle body; during the dying, the carbon oxide fluid and dye flow into the kettle body from the bottom to impact the button and drive the button to dye in a non-static way, so the button can move due to air flow impact; and dying flaws of overlapped parts between buttons can be avoided. The cylindrical bottom of the dyeing kettle is in an inverted trapezoidal structure to enable the buttons to have contact with carbon oxide fluid with dying paint and finish dying. Buttons with rich colors can be acquired by the use of the dying technology; dyed products require no cleaning and drying operations; a water-free dying process is achieved; production cost is reduced; and dying quality is improved and environment pollution is reduced.
Preparing method for mulberry fibers

Abstract of  CN105154997 (A)

The invention discloses a preparing method for mulberry fibers. The preparing method includes the steps of impurity removing, bundling, cage loading, chemical preprocessing, supercritical carbon dioxide fluid degumming processing, bio-enzyme degumming processing, washing, dewatering, oil feeding, carding and drying, wherein the chemical preprocessing method includes the steps of pickling processing and alkali-oxygen processing. The mulberry fibers obtained with the preparing method are high in degumming rate, small in damage and high in performance, and meet the modern environment-friendly requirement.
Method for purifying sodium dehydroacetate  

Abstract of  CN105153088 (A)

The invention discloses a process for purifying sodium dehydroacetate by using supercritical fluid crystallization. The process comprises the following steps: (1) spraying neutralized impurity-containing 90 DEG C sodium dehydroacetate solution from the top of an extraction tower by using a feedstock pump, feeding supercritical fluid to the bottom portion of the extraction tower, and controlling the temperature of the supercritical fluid to be 33 to 36 DEG C, the pressure to be 9 to 11MPa and the flow to be 15 to 30m<3>/min; (2) reducing the pressure of high-pressure supercritical fluid containing dissolved sodium dehydroacetate to be below the critical pressure of the supercritical fluid through a throttling valve, and then enabling the supercritical fluid to enter a separation kettle; (3) after extraction of sodium dehydroacetate, enabling the product to sequentially pass through dehydration and drying processes. The process for purifying sodium dehydroacetate has the advantages that the process is simple and the equipment structure is compact; since the crystal layer is formed on the heat transfer surface but is not suspended in liquid during the process, the blockage of the equipment and pipes is avoided, the production faults are reduced, the purity of the product produced by using the process is high, the bioactivity is good and the grain size is uniform.
Nicotianasesterpene-F prepared through supercritical fluid chromatography and application of nicotianasesterpene-F  

Abstract of  CN105152880 (A)

The invention discloses a sesquiterpene compound which is prepared through supercritical fluid chromatography and is novel in structure. The compound is named as nicotianasesterpene-F, wherein the molecular formula of nicotianasesterpene-F is C16H20O2, and the nicotianasesterpene-F has the following structure (please see the structure in the specification). The invention further discloses application of the compound. Activity tests show that nicotianasesterpene-F has a very good restraining effect on tobacco mosaic viruses and can be used for research and development on tobacco mosaic virus prevention pharmaceutic preparations as the lead compound for preventing tobacco mosaic viruses.
Pre-seasoned peanut oil convenient to cook and preparation method of pre-seasoned peanut oil  

Abstract of  CN105145870 (A)

The invention discloses pre-seasoned peanut oil convenient to cook. The pre-seasoned peanut oil consists of the following raw materials in parts by weight: 950-1000 parts of peanuts, 15-20 parts of onion stalks, 8-10 parts of star aniseed, 6-7 parts of Chinese prickly ash, 4-6 parts of cloves, 6-9 parts of angelica dahurica, 6-8 parts of formosan lattuce herb, 4-5 parts of lalang grass rhizomes, 10-12 parts of sweet-scented osmanthuses, 16-18 parts of abelmoschus esculentus, an appropriate quantity of lactic acid bacteria, and an appropriate amount neutral protease. According to the pre-seasoned peanut oil disclosed by the invention, extraction is performed twice, so that the extraction rate of fat in the peanut oil can be increased; peanut meal is puffed, so that the inner part of the peanut meal and the inner parts of other material compositions form porous structures, and extraction of nutrient substances is facilitated; the lactic acid bacteria and the neutral protease which are added can reduce the content of aflatoxin in the peanut oil, and the content of amino acid in the fat can also be increased; a supercritical carbon dioxide fluid extraction technology is adopted, so that not only can the active component be effectively extracted, but also the production cost can also be reduced; seasonings of the onion stalks, the star aniseed, the Chinese prickly ash and the like are added, so that the process of frequently adding seasonings in the cooking process is omitted. The pre-seasoned peanut oil has the advantages of being convenient and simple, adequate in nutrients, unique in fragrance and the like
ISSF 2012(10th International Symposium on Supercritical Fluid)
Welcome
“The Versatility of Supercritical Fluid Technology”

ISSF 2012 is a global conference that brings together an international group of researchers, practitioners, and industrialists who will contribute cutting-edge presentations on emerging applications and processes. The focus of this meeting is to highlight the discovery, development, and production aspects inherent with a wide range of technologies that utilize the unique capabilities of supercritical fluid solvents. This three-day Symposium is structured with parallel sessions packed with plenary, keynote, and contributed talks as well as poster sessions. The official language of the program is English.

Click below to see the Latest News About ISSF 2012
　

ISSF 2012 Preliminary Scientific Program - CLICK HERE 

ISSF 2012 Brochure - CLICK HERE
　

Committees
Executive Committee
Jerry King, University of Arkansas, USA (Chair)；Mark McHugh, Virginia Commonwealth University, USA (Program Chair)；Feral Temelli, University of Alberta, Canada； Keith Hutchenson, DuPont, USA； Ram Gupta, Auburn University, USA；
Organizing Committee
Charles Eckert, Georgia Tech, USA；Robert Enick, University of Pittsburgh, USA；Philip Jessop, Queen’s University, Canada；Keith  Johnston, University of Texas, USA；Erdogan Kiran, Virginia Tech, USA；Christopher Kitchens, Clemson University,USA；Brian Korgel, University of Texas, USA；Michael  Matthews, University of South Carolina, USA；Chris Roberts, Auburn University, USA；Phillip Savage, University of Michigan, USA；Aaron Scurto, University of Kansas, USA；Bala Subramaniam, University of Kansas, USA；Mark Thies, Clemson University, USA；
International Scientific Committee
Tadafumi Adschiri, Tohoku University, Japan； Bushra Al-Duri, University of Birmingham, England；Elisabeth Badens, University Paul Cezanne Aix, France； Gerd Brunner, TUHH, Germany； Susana Bottinni, PLAPIQUI, Argentina； Owen Catchpole, Industrial Research Ltd., New Zealand； Nimir Elbashir, Texas A&M University at Qatar； Jacques Fages, Ecole des Mines d’Albi, France； Neil Foster, University of New South Wales, Australia； Motonobu Goto, Kumamoto University, Japan； Buxing Han, Chinese Academy of Sciences, China； Elena Ibanez, CIAL-CSIC, Madrid, Spain； Zeljko Knez, University of Maribor, Slovenia； Youn-Woo Lee, Seoul National University, South Korea； Angela Meireles, UNICAMP-Campinas, Brazil；Martyn Poliakoff, University of Nottingham, England； Ernesto Reverchon, Universita di Salerno, Italy； Richard Smith, Tohoku University, Japan； Irina Smirnova, TUHH, Germany； Charlotta Turner, Lund University, Sweden； Lourdes Vega, MATGAS, Barcelona, Spain；Nora Ventosa, ICMAB-CSIC, Barcelona, Spain；Ki-Pung Yoo, Sogang University, South Korea；

Topics
Abstracts are encouraged from ALL areas of SCF including, but not limited to:
  Biomass and Energy-Related Conversions
 Nano- and Particle Technology
Polymers/Materials Applications and Processes
Thermodynamics-Phase Equilibria-Fluid Properties
Separation Processes
Reactions in Critical Fluids
CO2 Remediation and Environmental Aspects
Supercritical Fluids-Ionic Liquids/Coupled Media
Natural Products, Nutraceuticals, and Food-Related Materials
Process Design and Economics
Application to Inorganic Materials
Hydrothermal Processing & Inorganic Materials
Pharmaceutical-Medical Applications
Industrial Applications of Critical Fluids
Green Chemistry/Engineering and Supercritical Fluids

NOTE -- the program will end on Wednesday, May 16, at approximately 5:15 p.m.

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Fractionation of thyme (Thymus vulgaris L.) by supercritical fluid extraction and chromatography  Original Research Article
The Journal of Supercritical Fluids, Volume 55, Issue 3, January 2011, Pages 949-954
Mónica R. García-Risco, Gonzalo Vicente, Guillermo Reglero, Tiziana Fornari
Abstract
Supercritical fluid chromatography (SFC) was employed to fractionate thyme (Thymus vulgaris L.) extracts, which were obtained by supercritical carbon dioxide extraction of thyme leaves. First, different supercritical extracts were produced at 313 K and at different pressures (15, 30 and 40 MPa). Thymol, a monocyclic terpenoid with recognized antiseptic, analgesic and anti-inflammatory properties, was identified and quantified in the different samples by GC–MS. Then, the supercritical extracts were fractionated by semi-preparative SFC, and different conditions such as pressure, temperature and amount of cosolvent (ethanol) employed were studied. Around a two fold increase of thymol was achieved at 15 MPa, 50 °C and 3% ethanol cosolvent, recovering 97% of the monocyclic terpenoid extracted.

Scale-up study of supercritical fluid extraction process for clove and sugarcane residue  Original Research Article
The Journal of Supercritical Fluids, Volume 56, Issue 3, April 2011, Pages 231-237
Juliana M. Prado, Glaucia H.C. Prado, M. Angela A. Meireles
Abstract
Many scale-up criteria for supercritical fluid extraction (SFE) can be found in literature. However, the studies are often divergent and inconclusive; therefore, more studies on this field are needed. The objective of the present work was to study the scale-up of SFE process focusing application to Brazilian raw materials. A laboratory scale equipment (290 mL extraction vessel) and a pilot scale equipment (5.15 L extraction vessel) were used to study scale-up of SFE for clove and sugarcane residue. The scale-up criterion adopted consisted in maintaining solvent mass to feed mass ratio constant. The criterion was successfully used for a 15-fold scale-up of overall extraction curves for both raw materials studied; yields in pilot scale were slightly higher than in laboratory scale. The criterion studied allows a rapid and simple scale-up procedure, which can be very useful for the purpose of developing SFE technology at industrial scale in developing countries where such technology is still not available at industrial level.

Glycerol desorption from ion exchange and adsorbent resin using supercritical fluid technology: An optimization study  Original Research Article
The Journal of Supercritical Fluids, Volume 58, Issue 2, September 2011, Pages 226-232
A.E. Costa, A. Santana, M.B. Quadri, R.A.F. Machado, F. Recasens, M.A. Larrayoz
Abstract
In this study, glycerol desorption from Purolite^® PD206 resin was investigated using conventional and supercritical fluids (SCF) techniques. Untreated biodiesel was purified by dry washing using the resin and, after purification, the glycerol desorption was carried out using absolute ethanol under atmospheric conditions at different mass flows (10–30 g/min) or using ethanol-modified supercritical CO₂ (1:3 molar ratio of ethanol:CO₂), under a pressure of 140 bar, within a temperature range of 106–134 °C and with mass flow rates of 6–34 g/min. The results showed that ethanol is an efficient solvent for this process and that the supercritical desorption is much faster than conventional desorption process. Employing the Response Surface Methodology (RSM) it was found that temperature has the greatest effect on the resin regeneration time using supercritical fluids. Optimum conditions obtained were 106.1 °C and 21.9 g/min, in which the resin was regenerated in only 4.17 min.

Biological activities of Solanum paludosum Moric. extracts obtained by maceration and supercritical fluid extraction  Original Research Article
The Journal of Supercritical Fluids, Volume 58, Issue 3, October 2011, Pages 391-397
Silvia Siqueira, Vivyanne dos Santos Falcão-Silva, Maria de Fátima Agra, Claudio Dariva, José Pinto de Siqueira-Júnior, Maria José Vieira Fonseca
Abstract
Solanum paludosum extracts obtained by maceration (SP-EtOH_CRUDE and SP-EtOH_MARC) and supercritical fluid extraction () were evaluated. Three extracts with distinct chromatographic profiles were obtained: SP-EtOH_CRUDE, with a complex phenolic composition; , containing methoxylated flavonoids; and SP-EtOH_MARC, which bears mainly polar polyphenols. All extracts were strong antioxidants, as measured using the diphenylpicrylhydrazyl (DPPH) method, xanthine/xanthine oxidase/luminol and iron-induced lipid peroxidation systems. Extracts were also evaluated as modifiers of antibiotic activity in strains of Staphylococcus aureus expressing fluoroquinolone, macrolide and tetracycline efflux proteins. Despite their lack of antibacterial activity, all extracts were able to potentiate antibiotics activities by as much as eight fold. Both the maceration and supercritical fluid extraction processes were adequate to obtain extracts with different biological activities according to their patterns of phenolic compounds. The data suggest that S. paludosum could be a valuable source of antioxidants and putative efflux pumps inhibitors.

Determination of sudan dyes in food samples using supercritical fluid extraction–capillary liquid chromatography  Original Research Article
The Journal of Supercritical Fluids, Volume 55, Issue 3, January 2011, Pages 977-982
Mónica Ávila, Mohammed Zougagh, Alberto Escarpa, Ángel Ríos
Abstract
Determination of sudan dyes (Sudan I, Sudan II, Sudan III and Sudan IV) in food samples has been developed by several and different methods. However, sample treatment continues being the most important problem to determine these compounds in real samples. A rapid, sensitive and selective method for the extraction, separation and quantification of sudan dyes in commercial food samples has been developed. The method is based on the combination of a supercritical fluid extraction (SFE) procedure, followed by the analysis of the extracted plug by capillary liquid chromatography (CLC) with diode array detection (DAD). The entire procedure was optimized for the extraction of the samples, separation and detection of the analytes. For the SFE, the effect of CO₂ flow rate, extraction pressure, extraction temperature, equilibration and extraction time and methanol modifier content were studied. Linear responses in the range from 50 to 1000 ng mL⁻¹ with average relative standard deviation lower than 11.6, and detection limits ranging from 23.2 to 42.0 ng mL⁻¹ were obtained for the different sudan dyes. The recoveries were in the range of 91–109% for dyes powder samples.

Supercritical fluid extraction of wormwood (Artemisia absinthium L.)  Original Research Article
The Journal of Supercritical Fluids, Volume 56, Issue 1, February 2011, Pages 64-71
L. Martín, A.M. Mainar, A. González-Coloma, J. Burillo, J.S. Urieta
Abstract
The objective of the work was to optimize the extraction of wormwood oil by supercritical fluid extraction (SFE) of growth-controlled plant material. Different extraction conditions, two growth techniques and various crops were tested and the evolution of the extracted oil composition was screened chromatographically. A comparison with conventional techniques such as hydrodistillation (HD) or organic solvent extraction (OSE) was also presented. Particularly, six CO₂ densities ranging from 285.0 kg/m³ to 819.5 kg/m³ were studied in the range of 9.0–18.0 MPa and 40–50 °C. A systematic study was carried out with plant material from 2005, while SFE of 2006, 2008 and aeroponically grown crops was performed for comparative purposes. The effect of ethanol as a modifier of the supercritical fluid extraction was also studied. The major compounds found in the SFE extracts as well as in the HD essential oils were Z-epoxyocimene, chrysanthenol and chrysanthenyl acetate. A model based on mass transfer equations, the Sovová model, was successfully applied to correlate the experimental data.

Supercritical fluid conversion of graphene oxides  Original Research Article
The Journal of Supercritical Fluids, In Press, Corrected Proof, Available online 29 September 2011
Chang Yi Kong, Wei-Li Song, Mohammed J. Meziani, Kenneth N. Tackett II, Li Cao, Andrew J. Farr, Ankoma Anderson, Ya-Ping Sun
Abstract
In the preparation of graphene sheets for various studies and applications, the indirect route through the reduction of graphene oxides (GOs) has been widely pursued. Exfoliated GOs are shown to be mostly single-layer sheets in aqueous solution, and they are also demonstrated for conversion to recover some of the properties intrinsic to graphene. Beyond the commonly used thermal annealing and chemical reduction methods, several environmentally friendly conversion strategies have been explored in the literature. Reported here is a method of annealing GOs in supercritical fluids (SCFs, including carbon dioxide and ethanol) at relatively lower temperatures (up to only 300 °C) for their conversion to reduced GOs (rGOs). The characteristic properties of SCFs include low densities (thus low viscosity/high diffusivity) and diminished surface tension, which have found successful applications in extraction and the cleaning of fragile electronic devices, and also found to enable lower-temperature crystallization of amorphous nanomaterials in a fluid-assisted calcination process. In this study the same principles for lower-temperature calcination in SCFs were applied to the conversion of GOs. The rGOs thus obtained were characterized, with their electrical and thermal conductive properties evaluated and correlated with the different processing conditions. The benefits and shortcomings of the SCF processing method are discussed.

Coenzyme Q₁₀ nanoparticles prepared by a supercritical fluid-based method  Original Research Article
The Journal of Supercritical Fluids, Volume 57, Issue 1, May 2011, Pages 66-72
Xiaohui Hu, Yanni Guo, Lei Wang, Dan Hua, Yanzhen Hong, Jun Li
Abstract
A supercritical fluid-based method is proposed to produce coenzyme Q₁₀ (CoQ₁₀) nanoparticles. First, CoQ₁₀/polyethylene glycol 6000 composite particles are prepared by a modified PGSS (particles from gas-saturated solutions) process with controlling the flow rate of the gas-saturated solution. Then, CoQ₁₀ nanoparticles are obtained by dissolving the composite particles into water. The effect of experimental variables of the modified PGSS process, including pressure, temperature, flow rate of the gas-saturated solution, and mass fraction of CoQ₁₀, on the CoQ₁₀ particle size and particle size distribution was investigated. Results show that CoQ₁₀ slurry product with a median diameter of 190 nm and yield of 89.8% can be prepared at an optimum condition (operating pressure of 25 MPa, operating temperature of 80 °C, gas-saturated solution flow rate of 1.02 mL/min, CoQ₁₀ mass fraction of 40% and nozzle diameter of 100 μm) via the supercritical fluid-based method.

Formulation development of Carbamazepine–Nicotinamide co-crystals complexed with γ-cyclodextrin using supercritical fluid process  Original Research Article
The Journal of Supercritical Fluids, Volume 55, Issue 3, January 2011, Pages 1070-1078
Abhijat Shikhar, Murali Mohan Bommana, Simerdeep Singh Gupta, Emilio Squillante
Abstract
The objective of the present study was to formulate and characterize co-crystals of Carbamazepine (CBZ) and Nicotinamide (NCT) and inclusion complexes of these co-crystals with γ-cyclodextrin (CD). Gas anti-solvent method of supercritical fluid process (SCF) was used as the method of preparation. Formulations were evaluated by dissolution studies, differential scanning calorimetry, hot stage microscopy, scanning electron microscopy, ¹H NMR and X-ray powder diffraction. The dissolution studies show a 2.5-fold increase in dissolution rate in the case of co-crystals and a 40-fold increase when co-crystals were complexed with CD. A lower melting point (160 °C) was observed in the case of co-crystals and the exothermic peaks were missing for pure CBZ and co-crystals when they were complexed with CD. The absence of the melting peaks indicates complete complexation. Electron microscopy picture shows the absence of crystallinity in case of inclusion complexes and also the change in crystal structure for CBZ and NCT in the case of co-crystals. X-ray powder diffraction patterns of co-crystals and inclusion complexes were distinct from the starting materials and the shift in peaks of ¹H NMR confirmed intermolecular hydrogen bonding and complexation

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