• Advances in environmental research
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• v.7 no.1
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• pp.39-52
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• 2018

Direct membrane filtration (DMF) of wastewater has many advantages over conventional biological wastewater treatment processes. DMF is not only compact, but potentially energy efficient due to the lack of biological aeration. It also produces more biosolids that can be used to produce methane gas through anaerobic digestion. Most of ammoniacal nitrogen in wastewater is preserved in effluent and is used as fertilizer when effluent is recycled for irrigation. In this study, a technical feasibility of DMF was explored. Organic and nitrogen removal efficiencies were compared between DMF and membrane bioreactor (MBR). Despite the extremely high F/V ratio, e.g., $14.4kg\;COD/m^3/d$, DMF provided very high COD removal efficiencies at ~93%. Soluble microbial products (SMP) and extracellular polymeric substances (EPS) were less in DMF sludge, but membrane fouling rate was far greater than in MBR. The diversity of microbial community in DMF appeared very narrow based on the morphological observation using optical microscope. On the contrary, highly diverse microbial community was observed in the MBR. Microorganisms tended to form jelly globs and attach on reactor wall in DMF. FT-IR study revealed that the biological globs were structurally supported by feather-like materials made of secondary amines. Confocal laser scanning microscopy (CLSM) study showed microorganisms mainly resided on the external surface of microbial globs rather than the internal spaces.

• Korean Journal of Crystallography
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• v.10 no.1
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• pp.88-93
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• 1999

The complex [Ni(L)](ClO4)2 (1) (L=2,13-bis(2-pyridylmethyl)-3,14-dimethyl-2,6,13,17-tetraazatricyclo[14,4,01.1807.12]docosane) has been synthesized and characterized by X-ray crystallography. (1) crystallizes in the triclinic, space group P, with a=10.948(2), b=10.948(2), c=14.911(4) , α=93.73(2), β=93.77(2), γ=99.29(2)o, V=1754.8(7) 3, Z=2, R1(wR2) for 5217 observed reflections of [I>2σ(I)] was 0.048(0.099). The coordination environment around nickel(II) ion shows a distorted octahedron with four secondary and tertially amines of the macrocycle and two nitrogen atoms of pyridylmethyl groups.

• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.933-940
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• 1992

Calix[6]arene react with formaldehyde and secondary amines to yields water soluble Mannich bases which can be converted to the corresponding quaternary salts. Treatment of the quaternary salts with a nucleophile such as cyano, ethoxy, and hydride yields p-substituted calix[6]arenes. Calix[8]arene too react with formaldehyde and diallyl amine to yield a water soluble Mannich base. The transport of neutral arenes through an aqueous phase along a concentration gradient mediated by those of water soluble calixarenes as molecular carrier was studied in a U-type cell. Naphthalene, anthracene, pyrene, and fluoranthene are tested as a neutral solid guest compounds for the transport experiment.

• Journal of the Korean Chemical Society
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• v.57 no.2
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• pp.234-240
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• 2013

The synthesis of title compounds were accomplished by synthetic sequence shown in Scheme 1. Chalcones on cyclocondensation with thiourea in ethanol and potassium hydroxide under reflux yielded the respective dihydropyramidin-2(1H)-thiones. Each of the dihydropyrimidin thiones was, then subjected to the Mannich condensation in alkaline medium using three different secondary amines, viz., dimethylamine, diethylamine and morpholine to obtain a new series of S-Mannich bases. All the synthesised compounds ($C_1-C_{15}$) were evaluated for their antiulcer and antibacterial activities. Compounds $C_4$, $C_5$, $C_6$, $C_{14}$ and $C_{15}$ exhibited relatively more potent antiulcer activity but not comparable to the standard; Omeprazole, while $C_1$, $C_2$, $C_3$ and $C_{13}$ were moderate in activity at 100 mg/kg p.o. All the compounds ($C_1-C_{15}$) showed mild to moderate activity against both Gram-positive (S.aureus, L.delbrueckii) and Gram-negative (P.vulgaris, E.coli) bacteria. Amongst the compounds tested, only $C_6$, $C_9$, $C_{12}$ and $C_{15}$ were found to be potent.

• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2269-2273
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• 2012

Pseudo-first-order rate constants $k_{amine}$ have been measured spectrophotometrically for the reactions of benzyl 4-pyridyl carbonate 6 with a series of alicyclic secondary amines in $H_2O$ at $25.0^{\circ}C$. The plots of $k_{amine}$ vs. [amine] curve upward, indicating that the reactions proceed through a stepwise mechanism with two intermediates, a zwitterionic tetrahedral intermediate $T^{\pm}$ and its deprotonated form $T^-$. This contrasts to the report that the corresponding reactions of benzyl 2-pyridyl carbonate 5 proceed through a forced concerted pathway. The $k_{amine}$ values for the reactions of 6 have been dissected into the second-order rate constant $Kk_2$ and the thirdorder rate constant $Kk_3$. The Br${\o}$nsted-type plots are linear with ${\beta}_{nuc}=0.94$ and 1.18 for $Kk_2$ and $Kk_3$, respectively. The $Kk_2$ for the reaction of 6 is smaller than the second-order rate constant $k_N$ for the corresponding reaction of 5, although 4-pyridyloxide in 6 is less basic and a better nucleofuge than 2-pyridyloxide in 5.

• Korean Journal of Crystallography
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• v.9 no.1
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• pp.11-14
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• 1998

The synthesis and characterization of [Cu(L)](NCS)2 (1) (L:2,5,9,12-Tetramethyl-1,4,8,11-tetraazacyclotetradecane) are described. Crystal structure of 1 crystallizes in the monoclinic system, space group P21/a, a=7.622(2)Å, b=17.645(2) Å, c=8.223(3) Å, β=109.99(2)˚ Z=2. Least-squares refinement of 1 led to a R(Rw) factor of 0.087 (0.158) for 1535 observed reflections of F0>40(F0). The complex 1 has a square planar geometry with average Cu-N (secondary amines) bond distance of 2.030(4)Å. The axially disposed thiocyanate anions are not coordinated with Cu-N distances of 2.842(7) Å.

• Archives of Pharmacal Research
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• v.19 no.6
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• pp.535-542
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• 1996

Seven isoazamitosene derivatives, mitomycin analogues, were synthesized and tested for cytotoxicities against leukemia and gastric cancer cell lines. Preparation of a pyrrolo[1, 2-a]benzimidazole (3) (azamitosene ring system) was completed by utilizing the Lewis acid-catalized cyclization, with .omicron.-chloronitrotoluene as the starting material. Nitration of 3 produced a mixtue of two isomers (5-nitro isomer (4) and 7-nitro isomer (5)) in product ratio of 36 : 52. 4 was directly converted into quinone (7) by reduction and Fremy oxidaton. Finally, quinone derivatives (8, 9, 10, and 11) were synthesized by 1, 4-addition of 7 with cyclic secondary amines. From above-mentioned 5, 8-nitro compound (15) was prepared in 4 steps. At pH 3, Fremy oxidation of 15 produced quinone (16), whereas iminoquinone derivatives (17a and 17b) at pH 7. Isoazamitosene derivatives (8, 9, 10, and 11), containing cyclic amino groups at the 7-position, showed potent cytotoxicity on P388, SNU-1, and KHH tumor cell lines. Among them, 8 had stronger cytotoxicity against SNU-1 cell line than mitomycin and adriamycin. Considering these results, isoazamitosene derivatives may had unique cytotoxicity profiles. However, isoiminoazamitosene derivatives (17a and 17b) revealed very weak cytotoxicity.

• Bulletin of the Korean Chemical Society
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• v.18 no.8
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• pp.890-895
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• 1997

The approximate rates and stoichiometry of the reaction of excess lithium tripiperidinoaluminum hydride (LTPDA), an alicyclic aminoaluminum hydride, with selected organic compounds containing representative functional groups under the standardized conditions (tetrahydrofuran, 25°) were examined in order to define the reducing characteristics of the reagent for selective reductions. The reducing ability of LTPDA was also compared with those of the parent lithium aluminum hydride (LAH) and lithium tris(diethylamino)aluminum hydride (LTDEA), a representative aliphatic aminoaluminum hydride. In general, the reactivity of LTPDA toward organic functionalities is weaker than LTDEA and much weaker than LAH. LTPDA shows a unique reducing characteristics. Thus, benzyl alcohol, phenol and thiols evolve a quantitative amount of hydrogen rapidly. The rate of hydrogen evolution of primary, secondary and tertiary alcohols is distinctive. LTPDA reduces aldehydes, ketones, esters, acid chlorides and epoxides readily to the corresponding alcohols. Quinones, such as p-benzoquinone and anthraquinone, are reduced to the corresponding diols without hydrogen evolution. Tertiary amides and nitriles are also reduced readily to the corresponding amines. The reagent reduces nitro compounds and azobenzene to the amine stages. Disulfides are reduced to thiols, and sulfoxides and sulfones are converted to sulfides. Additionally, the reagent appears to be a good partial reducing agent to convert primary carboxamides into the corresponding aldehydes.

• Bulletin of the Korean Chemical Society
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• v.17 no.3
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• pp.234-238
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• 1996

Second-order rate constants have been measured spectrophotometrically for the reaction of p-nitrophenyl acetate (PNPA) with morpholine, piperazine and piperidine in MeCN-H2O mixtures of varying compositions. The rate of the present aminolysis decreases upon additions of MeCN into H2O up to near 30-40 mole % MeCN and remains nearly constant upon further additions of MeCN. The reaction of PNPA with anionic nucleophiles, such as HO-, p-chlorophenoxide and butane-2,3-dione monoximate, has also exhibited two distinguishable reactivity zones. However, the reactivity trend for the anionic nucleophiles is quite different from the one obtained for the amine system, e.g. an initial rate decrease in the H2O-rich region followed by an increasing rate trend upon further additions of MeCN in the MeCN-rich region. The rate behaviors shown by the amine system in the MeCN-rich and by the anionic system in the H2O-rich region are unexpected based on the Hughes-Ingold rules. The present unusual rate trends have been attributed to changes in the solvent structure and pKa of the nucleophiles upon the addition of MeCN into H2O. The effect of solvent appears to be more significant for the TS than the GS, and the TS structure is considered to become tighter in the higher MeCN concentration.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.245-253
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• 1979

Trimethylamine and dimethylamine contents of salted, hot-air dried, sun dried and boiled-dried samples of three commercial fishes, common mackerel, gizzard-shad and sardine, were analyzed and quantitatively compared at two different temperature conditions. The formation of both secondary amines was more rapid at $25^{\circ}C$ than at $10^{\circ}C$. And the content of dimethylamine in small sardine was comparatively higher than that in the other samples at both temperatures. Residual amounts of trimethylamine oxide of Halted common mackerel, gizzard-shad and boiled-dried small sardine were relatively higher than those of the other samples. Trimethylamine contents of sun dried samples were relatively higher than in the other samples, while those of boiled-dried small sardine was comparatively lower than those of the others. Dimethylamine content of sun dried samples were higher than those of the other samples, whereas those of boiled-dried small sardine and salted common mackerel were comparatively lower than those of the other samples.