• Macromolecular Research
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• v.17 no.12
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• pp.950-955
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• 2009

The physical and rheological properties of thermoplasticized irradiation-crosslinked polyethylene foam using supercritical methanol treatment were investigated by GPC, FTIR, DSC, WAXS, DMTA and UDS. The polyethylene foam was selectively decrosslinked into thermoplasticized polyethylene in an appropriate supercritical methanol condition without any undesirable side reactions such as oxidation and disproportionation. The thermoplasticization was promoted with increasing reaction temperature to reach completion above $380^{\circ}C$. The supercritical reaction condition affected the crystallization behavior, and mechanical and rheological properties of the decrosslinked polyethylene foam, but not its crystallographic structure or crystallinity.

• KSBB Journal
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• v.16 no.3
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• pp.233-236
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• 2001

Because of casehardenign effect of amorphous paclitaxel, residual solvents, methylene chloride and emthanol could not be reduced to the maximum value allowed, 600 ppm and 3,000 ppm, in accord with the guidelines issued by the International Conference on Harmonization (ICH, 1997), using rotary evaporation and successive drying in a vacuum oven. However, methylene chloride and methanol were reduced to 486 ppm and 403 ppm, respectively using supercritical $CO_2$ on purified paclitaxel. The optimum pressure and operating time were 80 bar and 30 min at fixed operating temperature ($40^{circ}C$). This approach serves as a novel application of supercritical fluid extraction to remove residual solvents from active pharmaceutical ingredients.

• Archives of Pharmacal Research
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• v.23 no.2
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• pp.163-166
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• 2000

The effects of modifiers such as methanol, water diethylamine in methanol (10 v/v %), and diethylamine in water (10 v/v %) were investigated at three different concentrations (1, 5, and 10 v/v %) of the modifiers in supercritical $CO_2$ (SC-$CO_2$) in order to enhance the supercritical fluid extraction (SFE) efficiency of cephalotaxine from Cephalotaxus wilsoniana Leaves. Among the modifiers employed, methanol basified with diethylamine was found to greatly enhance the extraction efficiency relative to any other modifiers employed. The results suggest that cephalotaxine in plant matrices may be readily changed from SC-$CO_2$-insoluble salt to SC-$CO_2$-soluble free base by basified modifiers. In addition, SC-$CO_2$modified with basified methanol could enhance the extraction efficiency of cephalotaxine more than 30% when compared to the conventional organic solvent extraction.

• Clean Technology
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• v.13 no.1 s.36
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• pp.46-53
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• 2007

We depolymerized PET in supercritical methanol and observed the yield of DMT at various reaction conditions. At subcritical state below $240^{\circ}C$, the yield of DMT was very low, about only 50%. It increased dramatically to 80% at supercritical state above $260^{\circ}C$, thereafter the increasing rate was reduced significantly. Similarly, at subcritical state of 6.89 MPa, the DMT yield was only 50%, but it increased abruptly to 85% at supercritical state of 10.34 MPa, yielding no further increase above the pressure. Within 10 minutes after the beginning of the reaction, the DMT yield reached 80%, indicating that the significant portion of the reaction has proceeded, and then, the yield increased slowly. The methanol/PET ratio of 8 showed the maximum DMT yield. We found the optimum depolymerization condition fur PET methanolysis is temperature $300^{\circ}C$, pressure 10.34 MPa, reaction time 40 minutes, and methanol/PET ratio of 8.

• KSBB Journal
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• v.15 no.1
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• pp.80-83
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• 2000

Polyacetylenes were extracted from Korean ginseng using supercritical $CO_2$ Yield of extraction of panaxydol and panaxynol was increased as the pressure of supercritical $CO_2$ increased at the range from 200 to 300 bar. The optimal yields of panaxydol and panaxynol was achieved at 65 and $55^{\circ}C$, respectively. Methanol was applied as a modifier. The highest yield of panaxydol and panaxynol were 0.230 and 0.054 mg/g-dry weight at modifier concentration of 10%(w/w), 300 bar, and $65^{\circ}C$. When these results were compared to that of methanol-extraction, the recoveries of panaxydol and panaxynol by supercritical $CO_2$ extraction in SFE were 37.8 and 55.1%, respectively.

• The Korean Journal of Ceramics
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• v.5 no.1
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• pp.73-77
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• 1999

Capsule free hot isostatic pressing (HIPing) of 12 mol% $CeO_2-88 mo% ZrO_2 (12CeO_2-88ZrO_2)$ powder was conducted at 1100~$1200^{\circ}C$ using the powder crystallized in supercritical methanol followed by supercritical drying. Porous $12CeO_2-88ZrO_2$ ceramics with ~35% open porosity, micropore diameter of ~23 nm and a narrow pore size distribution were fabricated by capsule free hot isostatic pressing at $1100^{\circ}C$. The porosity increased with decrease in HIPing temperature and was accompanied by a steady decrease in fracture strength.

• Korean Chemical Engineering Research
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• v.50 no.4
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• pp.678-683
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• 2012

Ceria is one of the most important catalytic materials which can be used in three-way catalysts, waste water treatment, petroleum refining, etc. So far, many methods have been studied to produce ceria nanoparticles. In this study, ceria nanoparticles were prepared via solvothermal synthesis using supercritical methanol in short reaction time using a batch reactor. The size of synthesized ceria nanoparticles in supercritical methanol is 6 nm without capping agent, which is smaller than that made in supercritical water at the same conditions of $400^{\circ}C$ and 30 MPa. Size difference results from density and critical point difference between water and methanol and slow reaction rate at the surface of ceria particles in supercritical methanol which reduces crystal growth rate. Several organic compounds were added to modify the surface of ceria nanoparticles, and in-situ surface modification was confirmed by FT-IR and TGA analysis. Surface modified ceria nanoparticles have excellent dispersibility in organic solvent. Size and shape of surface modified ceria particles can be controlled by adjusting molar ratio of modifier to precursor and selection of modifier.

• Korean Journal of Food Science and Technology
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• v.34 no.6
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• pp.1057-1061
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• 2002

Effects of modifier and soaking on extraction of triterpenoid saponin (glycyrrhizin) from liquorice were examined using supercritical $CO_2(SC-CO_2)$ at 50 MPa, $60^{\circ}C$, and flow rate of 3 mL/min, and glycyrrhizin content was analyzed by HPLC. Additon of undiluted methanol, ethanol or isopropanol as modifier to $SC-CO_2$ had little influence on extraction yield of glycyrrhizin. Soaking process using water increased the extraction yield as the sample to solvent ratio was increased. Addition of 70% methanol, ethanol or isopropanol to $SC-CO_2$ significantly increased the extraction yields, with 70% methanol resulting in the highest yield. When water at 90% (w/w) of sample weight was used for soaking, the extraction yield and rate increased, 70% ethanol-modified $SC-CO_2$ was almost equal to that obtained using 70% methanol.

• Journal of the Korean Chemical Society
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• v.58 no.1
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• pp.76-79
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• 2014

Petroleum refinery effluents are waste originating from industries primarily engaged in refining crude oil. It is a very complex compound of various oily wastes, water, heavy metals and so on. Conventional processes are unable to effectively remove the chemical oxygen demand (COD) of petroleum refinery effluents. Supercritical water oxidation (SCWO) was proposed to treat petroleum refinery effluents. In this paper, methanol was used to investigate co-oxidative effect of methanol on petroleum refinery effluents treatment. The results indicated that supercritical water oxidation is an effective process for petroleum refinery effluents treatment. Adding methanol caused an increase in COD removal. When reaction temperature is $440^{\circ}C$, residence time is 20 min, OE is 0.5 and initial COD is 40000 mg/L, and COD removal increases 8.5%.

• KSBB Journal
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• v.16 no.1
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• pp.66-70
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• 2001

Factors affecting the supercritical carbon dioxide extraction of camptothecin(CPT) and 10-hydroxycamptothecin(HCPT) from the dried powder of Cmptotheca acuminata were studied. Only a few amount of CPT and HCPT was extracted with pure supercritical carbon dioxide. Methanol and ethanol were efficient modifiers to extract CPT and HCPT. At $40^{\circ}C$, 250 bar, 1 mL/min flow rate, 41% of CPT and 35% of HCPT were extracted with supercritical carbon dioxide modified with 16% of methanol. The diffusion effect of HCPT on extraction efficiency was studied in this solid-fluid system. Round matrix hot-ball model assumption revealed that the value of D/$r^2$ was 0.0072 $min^{-1}$ which was higher than that of solvent extraction with methanol.