• Bulletin of the Korean Chemical Society
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• v.32 no.3
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• pp.768-778
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• 2011

Calixpyrroles and related macrocycles are non-planer synthetic anion receptors that have attracted considerable attentions in recent years. Although the synthesis of calix[4]pyrrole (known as meso-octamethylporphyrinogen) was reported more than 100 years ago, the anion binding properties were first discovered in 1996. The simple calix[4]pyrroles can be synthesized in single step in high yield by condensation of pyrrole with acetone. The compounds showed preferential binding for halide anions including fluoride, phosphate, carboxylate, and chloride in organic media. Efforts to improve the anion affinity of calix[4]pyrrole and to enhance its selectivity have led to the synthesis of a variety of new calixpyrrole derivatives. Among the various modifications, introduction of straps on one side of the calix[4]pyrroles are the most effective. Incorporation of aromatic rings other than pyrroles also exhibited interesting binding behaviour. Introduction of signalling units as part of the strapping element enable to detect the anions on chromogenic or fluorogenic fashion. Finding of the anion transport properties across the membrane and cytotoxic effects of the calix[4]pyrroles open new window for calixpyrrole-related research. The polymer-incorporated systems have also been employed as anion complexants in solvent-solvent extraction. These old, yet easy-to-make macrocycles have well advanced more recently with the discovery of the ion-pair complexation properties. In this review, the synthetic developments and anion binding properties of calixpyrroles for the last decades will be discussed and will cover the advances in calixpyrrole chemistry.

• Journal of Life Science
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• v.24 no.3
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• pp.234-241
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• 2014

To identify and isolate anticancer active compounds from Solanum nigrum, S. nigrum was extracted with MeOH and then fractionated with various organic solvents ($CH_2Cl_2$, EtOAc, n-BuOH, and $H_2O$). The cytotoxic effects of the MeOH extracts from S. nigrum and its organic solvent-soluble fractions were also tested in HT29 cells. All the MeOH extracts of S. nigrum and its organic-solvent extracts induced cytotoxicity in the HT29 cells. Among the extracts, $H_2O$ was the most effective. The $H_2O$ extract was purified further by repeated silica gel, Sephadex LH-20, Diaion HP- 20, and RP-18 column chromatography. An active anticancer compound, Des-N-26-methylene-dihydrotomatidine, was isolated with a molecular weight of 416 and a molecular formula of $C_{28}H_{48}O_2$. Analysis of the cytotoxic effects of Des-N-26-methylene-dihydrotomatidine on the HT29 cells compared to those of tomatine and tomatidine are similar in its structure, is higher than tomatidine above the 40 ${\mu}g/ml$ concentration, but lower than tomatine. This is the first study to describe the anticancer activity of Des-N-26-methylene-dihydrotomatidin, isolated from S. nigrum. Des-N-26- methylene-dihydrotomatidine seems to have potential as a natural bioactive compound.

• Journal of the Korean Chemical Society
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• v.41 no.8
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• pp.392-398
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• 1997

A method of selective determination of inorganic and organic mercury compounds has been described. The $CHCl_3$ solution of a high molecular quaternary alkylammonium salt, Aliquat 336 was used for the simultaneous preconcentration of both inorganic, $Hg^{2+}$ as its thiocyanate complex, and organic mercury compounds, $CH_3HgCl$ and $C_2H_3O_2$ $HgC_6H_5$ by extraction from their aqueous solution. Selective separation of the inorganic mercury from the extract was followed by stripping with 3 M $HClO_4 $ solution for the subsequent determination by CVAAS. Organic mercury was also determined by CVAAS after removal of $CHCl_3solvent$ from the extract and decomposition of the residue with 4% $KMnO_4 $-1 MH_2$S0_4$. The mixtures of inorganic and organic mercury compounds contained 1.0 $\mug$ as Hg in 50 mL of sample solution(0.02 ${\mu}gHg/mL$) were analysed within ${\pm}6%$ by absolute errors.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.73-76
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• 2000

A novel, continuous bioreactor system combining a bubble column (absorption section) and a two-phase bioreactor (degradation section) has been designed to treat a gas stream containing benzene. The bubble column contained hexadecane as an absorbent for benzene, and was systemically chosen considering physical, biological, environmental, operational and economic factors. This solvent has infinite solubility for benzene and very low volatility. After absorbing benzene in the bubble column, the hexadecane served as the organic phase of the two-phase partitioning bioreactor, transferring benzene into the aqueous phase where it was degraded by Alcaligenes xylosoxidans Y234. The hexadecane was then continuously recirculated back to the absorber section for the removal of additional benzene. All mass transfer and biodegradation characteristics in this system were investigated prior to operation of the integrated unit, and these included: the mass transfer rate of benzene in the absorption column, the mass transfer rate of benzene from the organic phase into the aqueous phase in the two-phase bioreactor, the stripping rate of benzene out of the two-phase bioreactor, etc. All of these parameters were incorporated into model equations, which were used to investigate the effects of operating conditions on the performance of the system. Several experiments were conducted to show the feasibility of this system. This process is believed to be very practical for the treatment of high concentrations of gaseous pollutants.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.04a
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• pp.16-19
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• 1996

Separation with synthetic membrane have become increasingly important processes in many fields. In the most application of membrane process, polymer membrane is used. the main advantage of polymers as a material for membrane preparation is the relative simplicity of this film formation which enables one to obtain rather high permeability rates. However, polymeric membranes have several limitations, such as high temperature instability, swelling and decomposition in organic solvent, et. al.. These limitations can be overcome by inorganic membrane. At the present time, commercially available inorganic membranes have pore diameters ranging 5nm to 50mm, and the predominant flow regime in such membrane is Knudsen diffusion. Since the Knudsen permeability is directly proportional to the molecular velocity, gases can be separated due to their molecular masses. However, this separation mechanism is only of important for light gases such as H2 and He. Other separation mechanisms like surface diffusion, active diffusion can play an important role only with very small pore diameters(2nm) and give rise to large permselectivities. Therefore, preparation of inorganic membrane with nano-sized pore have been attracting more and more attention.

• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.1055-1060
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• 2004

A new inhibitor for peptidylprolyl cis-trans isomerase (PPIase) has been isolated from Ganoderma lucidum and purified to homogeneous state by organic solvent extraction. The purified PPIase inhibitor (GPI) is assumed to be a membrane-associated glycoprotein. GPI inhibits specifically the bovine brain PPIase, a cyclophilin, and has no effect on the FKBP activity. The results of our chemical modification study of GPI indicate the presence of Lys residue(s) at or near its binding site. Like CsA-cyclophilin complex, GPI-bovine brain PPIase complex strongly inhibits the calcineurin activity in vitro, suggesting the possible involvement of GPI in immunomodulating pathway by the formation of PPIase-inhibitor-calcineurin complex.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.51-51
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• 2012

Cellulose is extremely difficult to dissolve cellulose in water and most common organic solvents due to their stiff molecular structure, close chain packing and intermolecular hydrogen bonds. Recently, cellulose solutions using ionic liquids (ILs) as a green solvent have been known to form cholesteric liquid crystalline phase at high cellulose concentration. In this study, the phase transition and rheological behaviors of concentrated cellulose/[AMIM]Cl solution were investigated using polarized optical microscopy and rheometry. Studies were conducted to characterize the influence of cellulose concentration on the phase transition of the cellulose solution and the mechanical properties of the regenerated fibers spun from the anisotropic cellulose/[AMIM]Cl solutions.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.331-331
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• 2006

Polylactic acid (PLA) is a promising polymer because it can be derived from renewable resources and provides a biodegradable alternative to petrochemical based polymers. This research aims to synthesize PLA, through direct polycondensation and also tries to avoid the occurrence of separation by-product and the use of catalysts in the process. The polymerization of lactic acid was done at three different temperatures $150^{\circ}C,\;180^{\circ}C\;and\;200^{\circ}C$ for 90 h without catalysts and organic solvent. The proposed process provides results that are comparable to those that incorporate catalysts; during polymerization temperature was $180^{\circ}C$ the molecular weight of PLA obtained reached 42448 Da. The thermal properties of PLA analysis by Differential Scanning Calorimetry (DSC).

• Bulletin of the Korean Chemical Society
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• v.23 no.3
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• pp.459-468
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• 2002

Literature data measured by the author have been processed to report on the effect of solute structure on gas liquid partition coefficients of eleven normal, branched and cyclic alkanes ranging in carbon number from five to nine in sixty nine low molecular weight liquids. The alkane solutes are n-pentane(p), n-hexane(hx), n-heptane(hp), n-octane(o), n-nonane(n), 2-methylpentane(mp), 2,5-dimethylpentane(dp), 2,5-dimethylhexane(dh), 2,3,4-trimethylpentane(tp), cyclohexane(ch), and ethylcyclohexane(ec). The solvent set encompasses most of those studied by Rohrschneider as well as three homologous series of solvents (n-alkanes, 1-alcohols and 1-nitriles) and several perfluorinated alkanes and highly fluorinated alcohols. An excellent linear relationship was observed between lnK and the carbon number of n-alkanes. The effective carbon numbers of branched and cyclic alkanes were determined in a similar fashion to the method of Kovats index. We found that the logarithm of solute vapor pressure multiplied by solute molar volume was a perfect descriptor for the linear relationship with the median effective carbon number.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1142-1146
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• 1996

Cholesterol-containing surfactant was synthesized, and it was sonicated with monomer in water to form a vesicle solution. This vesicle solution was dried to construct a membrane which had a molecular multilayer structure. Using UV irradiation the monomer in this membrane were polymerized, and then surfactant was extracted by organic solvent. Using a X-ray diffractometer, the thickness of one layer and the regularity of the multilayer were measured. And scanning electron microscopy was conducted for fractured polymer film.