• 분석과학
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• 제6권5호
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• pp.471-477
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• 1993

새로운 거대고리 리간드인 {(4, 5):(13, 14)-dibenzo-6, 9, 12-trioxa-3, 15, 21, -triazabicyclo [15. 3. 1]heneicosa-(1, 17, 19)(18, 20, 21) triene: HDBPDA}를 합성하여 양성자화 상수를 구하고, 알칼리 및 알칼리 토금속에 대한 안정도상수(pK)를 구하였다. 안정도상수로부터 유도되는 식을 이용하여 분리인자(${\Delta}$)를 구했다. HDBPDA 리간드를 chloromethylated styrene-divinylbenzene(Merrifield resin)에 결합시켜 새로운 이온교환체인 HDBPDA 이온교환체를 만들었다. 그리고 이것을 사용하여 칼람크로마토그래피로 물 속에서 알칼리 금속 및 알칼리 토금속 양이온들을 분리하여 보았으며, 여기서 얻어진 크로마토그램으로부터 알칼리 및 알칼리 토금속 이온들의 선택성(selectivity), ${\alpha}$와 분리도(resolution), Rs를 구하고, HDBPDA 리간드와 알칼리 및 알칼리 토금속 이온과의 안정도상수(pK)를 구한 값으로부터 ${\Delta}$값을 얻어 이들의 관련성을 비교하였다. 이 두 방법으로 구한 분리능(${\Delta}$와 Rs)값이 잘 일치함을 보였다. 알칼리 및 알칼리 토금속 이온들의 이온교환용량을 측정하고, pH의 의존도를 알아보았다.

• 대한화학회지
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• 제37권5호
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• pp.491-495
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• 1993

고분자물질로 지지된 아자크라운 에테르(polymer supported azacrown ether:DBPDA ion exchanger)를 합성하고, 이 이온교환체와 Li, Na, 그리고 K의 피크레이트염과의 이온결합등에 대하여 알아보았다. 그리고, DBPDA 이온교환체와 알칼리 피크린산염의 에테르형 용매내에서 알칼리 금속이온들의 결합상수(binding constant:Kb)를 분광광도법을 통하여 구하였다. 그 결과, 결합상수의 크기는 Li < Na < K 순으로 증가하였으며, 리간드와 1:1 착물을 형성한다는 것을 알 수 있었다. 또한 이들의 Kb값들은 용매 및 온도 등과 같은 것들에 의하여 변화하였으며, 그 값들은 $2{\times}10^3{\sim}4{\times}10^4M^{-1}$ 범위내에 있었다. 한편 이들 착물형성 과정에서의 엔탈피 및 엔트로피 변화, ${\Delta}$H 및 ${\Delta}$S는 10~40$^{\circ}C$ 온도 범위내에서 van't Hoff plot으로부터 구했으며, 이들의 값들은 각각, -2.71∼-3.79 kcal/mol과 -16.52∼-20.57 eu 범위내에 있었다.

• Macromolecular Research
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• 제13권2호
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• pp.141-146
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• 2005

Calix[4]crown-6-2,4-bis(4-aminobutyl ether), which has a crown-6 moiety at the 1,3-position and amino function at the 2,4-position, was prepared as an intermediate for the subsequent synthesis of calix[4]crown-6-containing polyamide and polyimide using adipoyl chloride and 1,2,4,5-benzenetetracarboxylic dianhydride. The chemical structures were characterized by IR, $^{1}H NMR$ spectroscopy and elemental analysis, and some of their physical properties, including their thermal behavior, were examined. The ion binding characteristics of the monomer and polymers for alkali metal and alkali earth metal ions were measured by liquid-liquid extraction from the aqueous phase into the organic phase. It has been observed that polyamide has a high binding ability towards various metal cations as compared to polyimide, which showed cesium ion selectivity.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.332-335
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• 2007

Electron injection improvement in OLED organic layers can be obtained by their doping or using alkaline-earth or alkali metals as electron injection layers (EIL). Common handling problems can be solved by an innovative metal dispensing technology to ensure controlled and reliable metal layers for OLED. Thickness and deposition rate of EIL during the process have been explored to optimize device performances.

• 대한방사성의약품학회지
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• 제7권2호
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• pp.141-146
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• 2021

With increasing interest in fluorinated compounds, nucleophilic fluorination reaction has been generally used for synthesizing fluorine-containing chemicals. However, alkali metal fluorides (MFs) generally have low solubility and reactivity in organic solvent. To overcome these problems, various phase transfer catalysts (PTCs) have been investigated. Calix-arene is known as to capture the metal cation(M⁺), and therefore in this review, we would like to introduce several kinds of calix-arene based PTCs, such as bis-tert-alcohol-functionalized crown-6-calix[4]arene (BACCA), oligo-ethylene glycol linked bis-triethyleneglycol crown-5-calix[4]arene (BTC5A), and ionic liquid functionalized calix-arene based catalyst, as well as ion-pair receptor crown-6-calix[4]arene-capped calix[4]pyrrole.

• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.1951-1956
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• 2011

A kinetic study is reported on nucleophilic substitution reactions of 4-nitrophenyl nicotinate 5 and isonicotinate 6 with alkali metal ethoxide EtOM (M = K, Na, and Li) in anhydrous ethanol at $25.0{\pm}0.1^{\circ}C$. Plots of pseudo-first-order rate constant $k_{obsd}$ vs. EtOM concentration exhibit upward curvature for the reactions of 5 and 6 with EtOK and EtONa but are almost linear for those with EtOLi. Dissection of $k_{obsd}$ into $k_{EtO^-}$ and $k_{EtOM}$ (i.e., the second-order rate constant for the reaction with dissociated $EtO^-$ and ion-paired EtOM, respectively) has shown that $k_{EtOK}$ ${\geq}$ $k_{EtONa}$ > $k_{EtO^-}$ but $k_{EtOLi}$ < $k_{EtO^-}$. It has been concluded that $K^+$ and $Na^+$ ions catalyze the reactions by increasing the electrophilicity of the carbonyl carbon atom through formation of a 4-membered cyclic transition state $TS_3$ or $TS_4$. However, $M^+$ ion catalysis has been found to be much less significant for the reactions of 5 and 6 than for the corresponding reactions of 4-nitrophenyl picolinate 4, which was reported to proceed through a 5-membered cyclic transition state $TS_2$. Although 5 and 6 are significantly more reactive than 4-nitrophenyl benzoate 3, the reactions of 5 and 6 result in smaller $k_{EtOK}/k_{EtO^-}$ ratios than those of 3. The electron-withdrawing ability of the nitrogen atom in the acyl moiety of 5 and 6 has been suggested to be responsible for the increase in reactivity and the decrease in the $k_{EtOK}/k_{EtO^-}$ ratio.

• 공업화학
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• 제29권1호
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• pp.112-116
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• 2018

주조공정 중 주형제조 시 점결제로 사용되는 silicate계 바인더의 주요원료 중 하나인 물유리와 첨가제(Si, 알칼리 금속)의 혼합특성을 살펴보았다. 물유리와 첨가제 그리고 비율에 따라 제조된 혼합물은 FT-IR분석을 통해 분자결합구조를 살펴보았으며, 점도측정으로 분자구조와의 상관관계를 비교하였다. 물유리에 Si 소스의 제공은 물질 내 Si 망상결합을 촉진시켜 점도는 증가하였고, 알칼리 금속을 첨가하였을 경우에 물유리의 Si 망상결합을 억제하여 점도가 낮아졌다. 물유리와 리튬 실리케이트(lithium silicate, LS)의 혼합물의 점도는 LS의 함량이 20 wt% 이하에서는 LS의 함량이 증가할수록 증가하였지만, 20 wt%를 초과할 경우 점차 낮아졌다. 물유리에 KOH를 첨가함으로써 점도를 낮출 수 있었으며, 콜로이달 실리카(colloidal silica, CS) 또는 potassium methyl siliconate (PMS)와의 혼합을 효과적으로 이용하는 데 이용할 수 있다.

• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2215-2218
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• 2010

The series of alkali metal perhalogenates, $MXO_4$ (M=Li, Na, K and X=F, Cl, Br, I) were theoretically studied with the help of MP2 methods. Bidentate as well as tridentate structures were found to be stable minima. The bidentate structures are becoming preferred as the size of halogen increases and as the size of metal decreases. Geometrically, the M-O and M-X distances of both bidentate and tridentate structures, increase with the size of metal. Generally, the M-$O_1$ distances of tridentate forms are longer than the corresponding distances of bidentate forms, while the M-X distances of tridentate forms show the opposite trend. Similarly, the X-O bonds increase with the size of halogens except $MXO_4$ pairs, where the X-O bonds are unusually long due to the enhanced oxygen-oxygen repulsions. In short, the relative energetics as well as the geometrical parameters are found to be strongly dependent on halogen and metal elements.

• Bulletin of the Korean Chemical Society
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• 제23권3호
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• pp.503-506
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• 2002

• 한국진공학회:학술대회논문집
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• 한국진공학회 2003년도 제25회 학술발표회 초록집
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• pp.41-41
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• 2003