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Pure CO2 (pure + co2)
Selected AbstractsPhase behavior on the binary and ternary mixtures of poly(isooctyl acrylate) + supercritical fluid solvents + isooctyl acrylate and CO2 + isooctyl acrylate systemJOURNAL OF APPLIED POLYMER SCIENCE, Issue 2 2008Hun-Soo Byun Abstract Experimental cloud-point data to the temperature of 180 °C and the pressure up to 2000 bar are presented for ternary mixtures of poly(isooctyl acrylate) + supercritical fluid solvents + isooctyl acrylate systems. Cloud-point pressures of poly(isooctyl acrylate) + CO2 + isooctyl acrylate system is measured in the temperature range of 60,180°C and to pressures as high as 2000 bar with isooctyl acrylate concentration of 0,44.5 wt. This system changes the pressure,temperature slope of the phase behavior curves from upper critical solution temperature (UCST) region to lower critical solution temperature (LCST) region as the isooctyl acrylate concentration increases. Poly(isooctyl acrylate) does dissolve in pure CO2 to the temperature of 180°C and the pressure of 2000 bar. The phase behavior for poly(isooctyl acrylate) + CO2 + 9.5, 14.8, 30.6, and 41.9 wt % dimethyl ether (DME) mixture show the curve changes from UCST to LCST as the DME concentration increases. Also, the cloud-point curves are measured for the binary mixtures of poly(isooctyl acrylate) in supercritical propane, propylene, butane, and 1-butene. High pressure phase behaviors are measured for the CO2 + isooctyl acrylate system at 40, 60, 80, 100, and 120°C and pressure up to 200 bar. This system exhibits type-I phase behavior with a continuous mixture-critical curve. The experimental results for the CO2 + isooctyl acrylate system are modeled using the Peng-Robinson equation of state. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 [source] Modeling the phase behavior of ternary systems ionic liquid + organic + CO2 with a Group Contribution Equation of StateAICHE JOURNAL, Issue 5 2009Eliane Kühne Abstract This work presents the results of the use of a Group Contribution Equation of State (GC-EOS) to model experimental data obtained for ternary systems of the type bmim[BF4] + organic solute + CO2 with four different organic compounds, namely acetophenone, 1-phenylethanol, 4-isobutylacetophenone, and 1-(4-isobutylphenyl)-ethanol. Our results show that the GC-EOS is able to qualitatively predict not only L+V,L but also L1+L2,L phase transitions. As the two two-phase boundaries L+V and L1+L2 of the experimentally found three-phase region L1+L2+V almost coincide with the saturated vapor pressure curve of pure CO2, the phase transitions L+V,L1+L2+V and L1+L2+V,L1+L2 have been represented as this vapor-pressure curve by the model. The average absolute deviations between experimental and predicted values for all phase transitions have been found to be very satisfactory. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Vapor,liquid equilibria of mixtures containing alkanes, carbon dioxide, and nitrogenAICHE JOURNAL, Issue 7 2001Jeffrey J. Potoff New force fields for carbon dioxide and nitrogen are introduced that quantitatively reproduce the vapor,liquid equilibria (VLE) of the neat systems and their mixtures with alkanes. In addition to the usual VLE calculations for pure CO2 and N2, calculations of the binary mixtures with propane were used in the force-field development to achieve a good balance between dispersive and electrostatic (quadrupole,quadrupole) interactions. The transferability of the force fields was then assessed from calculations of the VLE for the binary mixtures with n-hexane, the binary mixture of CO2/N2, and the ternary mixture of CO2 /N2/propane. The VLE calculations were carried out using configurational-bias Monte Carlo simulations in either the grand canonical ensemble with histogram,reweighting or in the Gibbs ensemble. [source] Decontamination of organochlorine pesticides in Radix Codonopsis by supercritical fluid extractions and determination by gas chromatographyBIOMEDICAL CHROMATOGRAPHY, Issue 9 2006Chunjie Zhao Abstract A method involving depuration of 12 organochlorine pesticides (OCPs) from Radix codonopsis was developed using supercritical fluid extraction (SFE). The pesticides investigated in the study included , -, , -, , - and , -benzene hexachloride, PCNB (pentachloro-nitrobenzene), PCA (pentachloroaniline), HEPT (heptachlor), MPCPS (methyl-pentachlorophenyl sulfide), pp,-DDE [1,1-dichloro-2, 2-bis(p -chlorophenyl) ethylene], op,-DDT [1,1,1-trichloro-2-(o -chlorophenyl)-2-(p -chlorophenyl)ethane], pp,-DDD [1,1-dichloro-2-2-bis(p -chlorophenyl)ethane] and pp,-DDT [1,1,1-trichloro-2,2-bis(p -chlorophenyl)ethane]. A series of experiments was conducted to optimize the final extraction conditions as follows: pure CO2, extraction pressure 15 MPa, extraction temperature 60°C, extraction time 20 min and flow rate 55 mL/h. A GC method with electron capture detection was employed for the determination of the OCPs in Radix codonopsis. An HPLC method was developed for the quantitative determination of active constituents. SFE was used to remove the organochlorine pesticide from Radix codonopsis. The results showed that at least 93.5% of the organochlorine pesticide residues in the herb sample were removed by SPE, while 95.0% of the active constituent marker (atractylenoide III) remained. Copyright © 2006 John Wiley & Sons, Ltd. [source] Supercritical fluid extraction for the separation of organochlorine pesticides residue in Angelica sinensisBIOMEDICAL CHROMATOGRAPHY, Issue 7 2002Chunjie Zhao A method involving the simultaneous extraction and separation of 12 organochlorine pesticides (OCPs) from Angelicae sinensis was developed using supercritical fluid extraction (SFE). The pesticides in the study were ,-, ,-, ,- and ,-benzene hexachloride, PCNB (pentachloro- nitrobenzene), PCA (pentachloroaniline), HEPT (heptachlor), MPCPS (methyl-pentachlorophenyl sulfide), pp,-DDE [1,1-dichloro-2,2-bis (p -chlorophenyl) ethylene], op,-DDT [1,1,1,-trichloro-2-(o -chlorophenyl)-2-(p -chlorophenyl) ethane], pp,-DDD [1,1-dichloro-2,2-bis(p -chlorophenyl) ethane], and pp,-DDT [1,1,1,-trichloro-2,2-bis (p -chlorophenyl)ethane]. The extraction conditions were optimized as follows: pure CO2, extraction pressure 15 MPa, extraction temperature 60°C, extraction time 20,min, and flow-rate 1.5,mL/min. A GC method with electron capture detection was employed to determine the OCPs in Angelicae sinensis. An HPLC method was developed for the quantitative determination of active constituents. The SFE provided high decontamination rate of OCPs and low loss of active constituents in Angelicae sinensis. Copyright © 2002 John Wiley & Sons, Ltd. [source] Evaluation of CO2 -based cold sterilization of a model hydrogelBIOTECHNOLOGY & BIOENGINEERING, Issue 6 2008A. Jiménez Abstract The purpose of the present work is to evaluate a novel CO2 -based cold sterilization process in terms of both its killing efficiency and its effects on the physical properties of a model hydrogel, poly(acrylic acid- co -acrylamide) potassium salt. Suspensions of Staphylococcus aureus and Escherichia coli were prepared for hydration and inoculation of the gel. The hydrogels were treated with supercritical CO2 (40°C, 27.6 MPa). The amount of bacteria was quantified before and after treatment. With pure CO2, complete killing of S. aureus and E. coli was achieved for treatment times as low as 60 min. After treatment with CO2 plus trace amounts of H2O2 at the same experimental conditions, complete bacteria kill was also achieved. For times less than 30 min, incomplete kill was noted. Several physical properties of the gel were evaluated before and after SC-CO2 treatment. These were largely unaffected by the CO2 process. Drying curves showed no significant change between treated (pure CO2 and CO2 plus 30% H2O2) and untreated samples. The average equilibrium swelling ratios were also very similar. No changes in the dry hydrogel particle structure were evident from SEM micrographs. Biotechnol. Bioeng. 2008;101: 1344,1352. © 2008 Wiley Periodicals, Inc. [source] | ||||||||||