• Macromolecular Research
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• 제12권5호
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• pp.501-506
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• 2004

We have investigated the spectral properties of DNA, including its electric absorption, circular and linear dichroism (CD and LD), and fluorescence emission, in the DNA-linear polyethyleneimine (LPEI) and DNA-branched polyethyleneimine (BPEI) complexes at various polymer concentrations. The spectral properties of both complexes are similar. We observed a relatively moderate change in the absorption and CD spectra at low amine/DNA phosphate (NIP) ratios (< 0.5), followed by a drastic collapse within the N/P range from 0.8 and 1.0. The absorption and CD spectra recovered as the N/P ratio increased to ca. 1.2. In contrast, the LD and emission of ethidium intercalated between the DNA bases decreased almost linearly at N/P ratios between 0.0 and 1.0. These spectra never recovered at higher N/P ratios. We believe that the moderate changes in the spectrum at low N/P ratios occurred because of electrostatic interactions between DNA and BPEI, while the collapsed spectra at N/P ratios between 0.5 and 1.5 occurred because of condensation/aggregation of the DNA. Considering the structure of the polymers, we suggest that the secondary amino group of LPEI and all three amino groups of BPEI are equally involved in DNA condensation.

• 한국응용과학기술학회지
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• 제25권1호
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• pp.65-72
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• 2008

The ion exchangers supported on silica gel containing primary, secondary, or tertiary amine groups show a behaviour that is weakly acidic, while the quaternary salts are strongly acidic. These properties change according to the hydrophilicities of the modifier functional groups. Ammonium salt derivatives supported on silica gel were prepared from silica modified with 3-Aminopropyltriethoxysiliane and N-3-(Trimethoxysilyl)propylehtylene diamine. The preparation and the ion exchange properties of two systems were discussed. Two systems have different hydrophilicities and contain ammonium chloride derivatives of 3-amminopropyltriethoxysilane and N-3-(triehtoxysilyl)propyl ethylene diamine supported on silica gel, $SA^+/Cl^-$ and $SA^+/Cl^-$, respectively. The high affinity to perchlorate ion presented by the $SA^+/Cl^-$ through the equilibrium studies of ion exchange led us to its application as an ion selective electrode for the perchlorate ion. The determination of the perchlorate ion in the presence of other anions and in complexes is very difficult. Few analytical methods are available and most of them are indirect. Both materials showed potential use as an ion exchanger; they are thermically stable, achieve equilibrium rapidly in the presence of suitable exchanger ions, and are easily recovered.

• 한국환경과학회지
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• 제12권5호
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• pp.551-557
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• 2003

An experimental study of the absorption of CS$_{2}$ in the secondary amine diethanolamine(DEA) was performed in this work. The primary objectives were to investigate an analogy between N2O and CS$_{2}$ permitting estimation of the physical solubility and diffusivity of the sulfur gases in the reacting amino solutions. The solubilities of CS$_{2}$ in water at 25, 40 and 6$0^{\circ}C$ has been measured. The data show fair agreement with previous literature values. The solubility of CS$_{2}$ in 5-25 weight % polyethylene glycol has been measured in order to investigate a possible analogy between CS$_{2}$ and N$_{2}$O The diffusivities of CS$_{2}$ in water and the reaction rate between CS$_{2}$ and DEA has been measured at 25 and 4$0^{\circ}C$, using a wetted sphere apparatus operated at approximately 1/3 atmospheres pressure, which is a previously untried method.

• 대한화학회지
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• 제36권6호
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• pp.933-940
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• 1992

Calix[6]arene을 포름알데히드와 이차아민과 반응시키면 물에 녹는 칼릭세린 염기가 얻어진다. 이를 메틸요오드로 처리하여 암모늄 염을 만들고 다양한 친핵성 물질과 반응시키면 칼릭세린의 파라위치에 작용기가 포함된 calix[6]arene이 얻어진다. Calix[6]arene도 포름알데히드와 이차의 아릴아민과 반응시켜 물에 녹는 칼릭세린 아민을 만들었다. 이렇게 합성된 칼릭세린중 물에 녹는 아민과 산기가 포함된 calix[6]arene과 calix[8]arene을 운반체로 이용하여 중성의 방향족 물질들을 통과시키는 연구를 U 형태의 유리관을 이용하여 수행하였다. 방향족 기질들로는 나프탈렌, 안트라센, 파이렌, 풀우란텐 등의 고체물질을 사용하였다.

• Bulletin of the Korean Chemical Society
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• 제28권2호
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• pp.220-224
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• 2007

Second-order rate constants (kN) have been determined spectrophotometrically for reactions of 2,4-dintrophenyl 2-furoate (2) with a series of alicyclic secondary amines in 80 mol % H2O/20 mol % dimethyl sulfoxide (DMSO) at 25.0 oC. The furoate 2 is more reactive than 2,4-dintrophenyl benzoate (1) toward all the amines studied. The higher acidity of 2-furoic acid (pKa = 3.16) compared with benzoic acid (pKa = 4.20) has been suggested to be responsible for the reactivity order, at least in part. The Brønsted-type plots for the reactions of 1 and 2 are curved downwardly, indicating that the aminolyses of both 1 and 2 proceed through a zwitterionic tetrahedral intermediate (T±) with a change in the rate-determining step on changing the amine basicity. Dissection of the kN values into their microscopic rate constants has revealed that the pKao and k2/k-1 ratios for the reactions of 1 and 2 are identical, indicating that the nature of the nonleaving group (i.e., benzoyl and 2-furoyl) does not affect the reaction mechanism. The k1 values have been found to be larger for the reactions of 2 than for those of 1, which is fully responsible for the fact that the former is more reactive than the latter.

• Bulletin of the Korean Chemical Society
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• 제18권8호
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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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• 제19권4호
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• pp.457-462
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• 1998

A chiral pentadentate bis-amide ligand, 1,9-bis(S)-pyrrolidinyl-2,5,8-triazanonane-1,9-dio ne$(S,S-prodienH_2)$ has been synthesized from the reaction of bis(2-aminoethyl)amine(dien) and S-proline, and the structure of $[Co(S,S-prodien)H_2O]ClO_4$ has be en determined by single crystal X-ray diffraction. The geometrical structure of the Co(III) complex has been an αβ -form, where the dien moiety of ligand chelates to a facial in metal center, and the aqua ligand coordinates a cis site to the secondary nitrogen of dien. The Co-N(1), Co-N(3) distances of two amide moiety in S,S-prodien are shorter than the other Co-N(2), Co-N(4), and Co-N(5) distances because of the increased basicity of nitrogen in amide. The complex crystallizes in the monoclinic space group $P2_1$(#4), with a=7.838(1), b=12.675(1), c=9.710(1) Å, β=100.39(1) and z=2. Refinement gives the final R and $R_w$ values of 0.045 and 0.057, respectively for 2130 observed reflections. Based upon the CD and X-ray data, it is identified that the absolute configuration of the αβ -$[Co(S,S-prodien)H_2O]ClO_4$ has a Λ-form.

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.640-647
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• 2023

Material corrosion in nuclear power plant (NPP) is not controlled only by amine injection but also by ion exchange (IX) which is the best option to remove trace Na⁺. This study was conducted to understand the Na⁺ leakage characteristics of IX beds packed with ethanolamine-form (ETAH-form) and hydrogen-form (H-form) resins in the simulated water-steam cycle in terms of intrinsic behaviors of four kinds of cation-exchange resins through ASTM test and Vanselow mass action modeling. Na⁺ was inappreciably escaped throughout the channel created in resin layer. Na⁺ leakage from IX bed was non-linearly raised because of its decreasing selectivity with increasing Na⁺ capture and with increasing the fraction of ETAH-form resin. Na⁺ did not reach the breakthrough earlier than ETAH⁺ and NH₄⁺ due to the increased selectivity of Na⁺ to the cation-exchange resin (H⁺ < ETAH⁺ < NH₄⁺ ≪ Na⁺) at the feed composition. Na⁺ leakage from the resin bed filled with small particles was decreased due to the enhanced dynamic IX processes, regardless of its low selectivity. Thus, the particle size is a predominant factor among intrinsic properties of IX resin to reduce Na⁺ leakage from the condensate polishing plant (CPP) in NPPs.

• 분석과학
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• 제36권5호
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• pp.205-215
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• 2023

In the present study, an analytical method was proposed for detecting trifluralin in aquatic products at trace concentrations. The method employed QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) and gas chromatography coupled with tandem mass spectrometry (GC-MS/MS) as the sample preparation and measurement, respectively. The effect of the aqueous phase volume used in the QuEChERS was demonstrated, and the ratio of 10:10 (mL) between water and acetonitrile phase was used for 5 g of sample. Besides, dSPE using C18 and primary-secondary amine (PSA) was applied to remove the potential interferences from the food matrices, indicating no remarkable analyte loss. The linear range was built up from 0.50 ㎍ L^-1 to 3.0 ㎍ L^-1 (R² = 0.9993). Other criteria, i.e., repeatability (RSD_r = 0.86-1.96 %), reproducibility (RSD_R = 1.09-2.01 %), and recovery (over 90 %), were in accordance with Appendix F of AOAC (2016) for method performance. Although no trifluralin was detected for the commercial samples (fish, shrimp, and breaded shrimp), the spiked samples performed favorable recoveries and precision.

• 대한화학회지
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• 제37권11호
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• pp.967-973
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• 1993

1,6-헥산디올과 1,7-헵탄디올과 같은 ${\alpha},{\omega}$-디올은 180$^{\circ}$C, 24시간, 촉매량의 루테늄 착물존재하에서 이차아민과 반응하여 좋은 수득율로 대응하는 생성물인 디아미노화합물이 얻어졌다. 디아미노화합물의 수득률은 ${\alpha},{\omega}$-디올과 이차아민의 몰비에 의해 영향을 받았으며, 또한 반응은 채택한 포스핀 배위자의 성질에의해 영향을 받았다. 한편으로 디옥산 용매내에서 루테늄-포스핀 촉매와 방향족 일차아민 및 1,2,6-헥산트리올을 180$^{\circ}$C, 3시간 반응시키면 선택적으로 1-치환-2-히드록시 과수소아제핀이 좋은 수득율로 주어졌다. 이 생성물의 선택적 합성은 두 개의 일차히드록시기가 보다 우선적으로 산화함을 보여주고 있다. 수득율은 방향족 아민의 파라-, 메타- 및 오르토 치환기의 순서에 따라 감소하였다.