• 멤브레인
• /
• 제13권1호
• /
• pp.54-63
• /
• 2003

피리디니움 (pyridunium) 그룹을 포함한 음이온교환막의 제조 및 전기화학적 특성 평가를 수행하였다. 실험 결과, 제조된 피리디니움 음이온교환막은 상용막과 대등한 전기저항 ($3.0 {\Xi}cm^2$>, in 0.5 mol $dm^{-3}$ NaCl) 및 높은 이온선택도 ($Cl^-$ 이온수송수 약 0.97)의 우수한 전기화학적 특성을 나타내었다. 또한 피리니디움 그룹을 함유한 음이온교환막에서의 물분해는 상용막 (AM-1, Tokuyama Corp., Japan)에 비해 동일한 전류밀도 하에서 약 100배 내지 1000배 가량 낮게 측정되었는데 이는 4차 아로마틱 피리디니움 그룹의 공명효과 (resonance effect)가 이온교환기의 분자구조적 안정성에 영향을 미쳤기 때문으로 사료되었다. 또한 피리디니움 음이온교환막의 전기투석 특성이 semi-pilot 스케일에서 평가되었다.

• 한국막학회:학술대회논문집
• /
• 한국막학회 1994년도 춘계 총회 및 학술발표회
• /
• pp.61-62
• /
• 1994

In order to prepare polyion complex membranes useful for the separation of water-alcohol by pervaporation, k-carrageenan containing artionic sulfate groups in the backbone and good hydrophilicity was selected for the polyanion membrane material and poly{1,3-bis[4-butyl pyridinium] propane. bromide}, one of the polycations synthesized in our lab and containing cationic pyridinium groups., was used. The polyion complex membranes were prepared by the ion complex formation between kcarrageenan films and poly{1,3-bis[4-butyl pyridinium] propane. bromide}. On the formation process of polyion complex membranes, the way of potyion complex formation was carefully studied. In order to study the effect of the morphology on the permeation properties of the polyion complex membranes, which is one of the important factors affecting on the permeation properties of membranes but rarely studied, the microstructure behaviors of the polyion complex mem6ranes in methanol-water mixtures with different compositions Were also studied with x-ray diffractometry and polarizing microscopy.

• 공업화학
• /
• 제16권1호
• /
• pp.153-157
• /
• 2005

$H_2O$ 용매하에서 4-(dimethylamino)pyridine과 chromium(VI) trioxide의 반응을 통하여 4-(dimethylamino)pyridinium dichromate를 합성하여, IR, EA 및 ICP 등으로 구조를 확인하였다. 여러 가지 용매하에서 4-(dimethylamino)pyridinium dichromate를 이용하여 벤질 알코올의 산화반응을 측정한 결과 유전상수 값이 큰 용매 순서인 시클로헥센 < 클로로포름 < 아세톤 < N,N-디메틸포름아미드 용매에서 높은 산화반응성을 보였다. 산 촉(HCl)를 이용한 N,N-디메틸포름아미드 용매하에서 4-(dimethylamino)pyridinium dichromate는 벤질 알코올과 그의 유도체들($p-CH_3$, H, m-Br, $m-NO_2$)을 효과적으로 산화시켰다. 그리고 전자받개 그룹들은 반응속도가 감소한 반면에 전자주개 치환체들은 반응속도를 증가시켰다. 또한 Hammett 반응상수 $\rho$값은 -0.70(303 K)이였다. 그러므로 본 실험에서 알코올의 산화반응 과정은 먼저 크토메이트 에스테르 형성과정을 거친 후, 속도결정단계에서 양성자 전이가 일어나는 메카니즘임을 알 수 있었다.

• 한국막학회:학술대회논문집
• /
• 한국막학회 2002년도 춘계 총회 및 학술발표회
• /
• pp.65-68
• /
• 2002

• 한국산학기술학회논문지
• /
• 제14권1호
• /
• pp.499-505
• /
• 2013

6M-HCl 용매 하에서 헤테로고리 화합물인 4-(dimethylamino)pyridine과 chromium(VI) trioxide의 반응을 통하여 4-(dimethylamino)pyridinium chlorochromate[$C_7H_{10}N_2HCrO_3Cl$] 착물을 합성하여, 적외선분광광도법(IR), 유도결합 플라즈마(ICP) 등으로 구조를 확인하였다. 여러 가지 용매 하에서 4-(dimethylamino)pyridinium chlorochromate를 이용하여 벤질알코올의 산화반응을 측정한 결과 유전상수(${\varepsilon}$) 값이 큰 용매 즉, 시클로헥센<클로로포름<아세톤$H_2SO_4$)를 이용한 N,N'-디메틸포름아미드 용매 하에서 4-(dimethylamino)pyridinium chlorochromate는 벤질 알코올과 그의 유도체들(p-$OCH_3$, m-$CH_3$, H, m-$OCH_3$, m-Cl, m-$NO_2$)을 효과적으로 산화시켰다. 그리고 전자받개 그룹들은 반응속도가 감소한 반면에 전자주개 치환체들은 반응속도를 증가시켰다. 또한 Hammett 반응상수(${\rho}$) 값은 -0.68(303K) 이었다. 그러므로 본 실험에서 알코올의 산화반응 과정은 속도결정단계에서 수소화 전이가 일어나는 메카니즘임을 알 수 있었다.

• Archives of Pharmacal Research
• /
• 제9권4호
• /
• pp.229-232
• /
• 1986

Three inexpensive oxidation reagents, namely pyridinium chlorochromate, chromium trioxide-dipyridine and nicotinium dichromate were utilized for oxidation of carbohydrates in 78-92% yield. Hydration could be eliminated in the oxidation of pentopyranosides and hexopyranosides, while pentofuranosides had a tendency to be easily hydrated during the oxidation. In the carbon-13 n. m. r. study, the carbonyl function resulted from the oxidation affected on the chemical shifts of $\alpha$- and $\beta$-carbons of methyl 3. 4-O-isopropylidene-$\beta$-D-arabinopyranosid-2-ulose (8) and 1,2 : 4, 5-di-O-isopropylidene-$\beta$-D-erythro-2, 3-hexodiulo-2, 6-pyranose (10) to slightly down fields (0.7-2.6 p. p. m.) compared with the chemical shifts before oxidation. While the carbonyl groups of 1. 2-O-isopropylidene-5-O-ethyloxycarbonyl-$\alpha$-D-erythro-pentofuran-3-ulose (4) and methyl 3, 5-0-isopropylidene-$\alpha$-D-threo-pentofuranosid-2-ulose (6) pushed the $\alpha$-carbons to up fields (3, 2-18.3 p. p. m. However, the order of signals on the spectra before and after oxidation remained unaltered.

• 한국막학회:학술대회논문집
• /
• 한국막학회 1998년도 춘계 총회 및 학술발표회
• /
• pp.1-6
• /
• 1998

To change permselectivity between anions through the anion exchange membrane in electrodialysis, the various modified anion exchange membranes were prepared: highly crosslinked anion exchange membranes, anion exchange membranes having benzyl trialkylammonium groups with different carbon number of alkyl chain as anion exchange groups and anion exchange membranes having pyridinium groups with a hydrophilic or hydrophobic substituent at a different position as anion exchange groups. It became clear from the evaluation of these membranes that the degree of the hydrophilicity of the anion exchange membranes greatly affects the permselectivity between two artions. To increase the hydrophiticity of the anion exchange membranes further, electrodialysis was carried out in the presence of ethylene glycols and the permeation of strongly hydrated anions increased and that of less-hydrated anions decreased. It became clear that the change in the permselectivity between two artions is due to the change in the affinity of anions to the membranes, not the change in mobility ratio of the anions in the membranes phase.

• 약학회지
• /
• 제40권6호
• /
• pp.621-624
• /
• 1996

Betaine was treated with hydrochloric acid and then with sodium borohydride to give a hydroxy compound 2. The reaction of 2 with thionyl chloride followed by thiourea led a comp ound 5. Oxidation of compound 2 with pyridinium dichromate(PDC) and succesive treatment with Lawesson's reagent also afforded the same compound 5. Cleavage of N-C14 bond compound of 7 was carried out via two reaction sequence from the compound 4. Finally, compound 10 was sythesized by a series of transformations from the compound 4.

• 한국식품영양과학회지
• /
• 제26권3호
• /
• pp.475-479
• /
• 1997

A decrease in the circulating levels of estrogen, occuring as a consequence of post menopausal decline or from surgical ovariectomy, results in an accelerated loss of bone. Estrogen has been shown to stimulate lysyl oxidase activity, and the treatment with estrogen increased the pyridinium content of cortical bone. a trivalent mature cross-links collagen fibrils named pyridinoline, which is especially abundant in collagen of cartilage and bone, markedly increases with growth in humans and rats. The main aim of this study was to examine the increased bone loss caused by ovariectomy through monitoring the concentrations of the collagen and the pyridinium cross-links of collagen, pyridinoline. The ovariectomized rats, 4 weeks old, were divided at random into two or three groups of 5. Ovariectomies were carried out on both of the saline-treated group(OVX(NH)) and the estrogen-treated group(OVX(H)) using the dorsal approach and sham operations were performed on the sham-operated group(sham). They were maintained under identical conditions for 4 or 8 weeks and were allowed free access to food and water. it was observed that there was no significant difference between the control group and the sham-operated group, however, the control group had a higher content of collagen than the saline-treated group after 4 weeks and 8 weeks. Based on these results, iot is supposed that estrogen can enhance collagen synthesis and affects the pyridinoline formation in collagen fibrils through stimulating lysyl oxidase activity.

• Bulletin of the Korean Chemical Society
• /
• 제8권3호
• /
• pp.168-170
• /
• 1987

The reaction between 1-benzyl-3-carbamoyl-1,4-dihydropyridine (BNAH) 1 and various 1-arylpyridinium salts 2, and the reaction between 1-(4-methylphenyl)-1,4-dihydropyridine 4b and 1-aryl-3-carbamoylpyridinium (1-arylnicotinamide) salts 5 were carried out. The extents of reaction in equilibrium were estimated by nmr integration data. The equilibrium constants for the reactions, K, and the standard Gibbs free energy changes for the reduction of the pyridinium salts to the corresponding 1,4-dihydropyridines ${\Delta}G^{\circ}'$ were evaluated. The Hammett plot of log K for the reaction between 1 and 2, and ${\Delta}G^{\circ}'$ against ${\sigma}_p$ of the substituents in 1-aryl moiety shows linear correlation with the reaction constant ${\rho}$ of 9.4 (for log K vs ${\sigma}_p$) and -54.5 KJ/mole (for ${\Delta}G^{\circ}'$ vs ${\sigma}_p$). It was found that 1-aryl-1,4-dihydropyridines have much higher reducing power than the corresponding 1-aryl-1,4-dihydronicotinamides, and the power is affected greatly by the electron-withdrawing ability of the substituents in aryl group. The reactions were utilized for preparation of 1,4-dihydropyridines bearing highly electron-withdrawing groups such as 4-nitrophenyl and 2,4-dinitrophenyl, which could not be obtained by conventional dithionite reduction of the corresponding pyridinium salts due to the base-labile nature of the salts.