반 양성자성 용매에서 1,5-디페닐 카보하이드라지의 환원파에 대한 폴라로그래피적 거동

최칠남,송기동,윤석진 조선대학교 기초과학연구소 1985 自然科學硏究 Vol.8 No.1

아세트니트릴 50%와 물 50%의 혼합용액 중에서 1, 5-diphenylcarbohydrazide(DPH)의 폴라로 그래프법적 성질을 직류 폴라로 그래프법에 의해서 조사하였다. 각 환원파의 환원전류가 어떤 유형인가를 조사하기 위하여 수은주의 높이, 용액의 온도, DPH의 농도에 따른 한계전류의 변화를 측정하였다. 그 결과 3.3×10^-2M-NaClO_4의 용액 속에서 1,5-DPH의 환원은 1전자 2단계의 환원과정을 거쳐 아민 화합물로 환원되었다. 각 환원파는 확산 지배적이었고 가역적이었다. The polarographic behavior of 1,5-diphenyl carbohydrazide in acetonitrile 50% and water 50% mixture solution has been investigated by direct current polarography. In order to investigate the type of reduction current at every reduction step, dependence of limiting current on the height of mercury head, solution temperature, and concentration of 1,5-diphenylcarbohydrazide have been examined. The results were shown that the reduction of 1,5-diphenylcarbohydrazide in 3.3×10^-2M sodium perchlorate solution procedes along one, two-electron steps to give the corresponding amine compounds. Every reduction wave was diffusion controlled and considerably reversible.

Cd(Ⅱ) 폴라로그람의 異常波에 關한 硏究

崔七男,朴聖珪,丁梧鎭,문경국 조선대학교 기초과학연구소 1984 自然科學硏究 Vol.7 No.1

pH 6.0∼12.0 範圍에서 0.15M 타르타르 酸鹽支持溶液 속에서 Cd(Ⅱ) Polarogram을 25℃에서 二段還元波를 調査한 결과 pH8.2部分 까지는 限界電流 및 半波電位값이 一定하며 한편 같은 濃度의 窒酸鹽 支持溶液을 사용하였을 때에 比하여 一段還元波의 半波電位값은 0.03volt 陰의 電位값으로 移動하고, 限界電流 값은 21% 減少되었다. pH8.2 部分 以上부터 限界電流 값이 急激하게 增加하다가 pH8.9 以上부터는 다시 急激하게 減少하는 現象을 보여 주었다. 한편 pH8.2 以上부터는 半波電位가 pH11.0에서는 -1.37volt로 되었다. 可能한 電極反應을 假定하여, pH11.0에 이르기까지의 還元波移動의 原因을 檢討하였다. The second reduction waves of the polarogram of Cd(Ⅱ) in 0.15M sodium tartrate solution were investigated in the range of pH from 6.0 to 12.0 at 25 C. Up to pH 8.2, the limiting current and the half wave potential were found to be constant, and when compared with the nitrate solution equal to the concentration of sodium tartrate, the limiting current of the first reduction wave has been decrease 21% and the half wave potential of the first reduction wave shifted by -0.03 volt. The values of limiting current were sharply increased above pH 8.2, and maximum value was obtained at pH 9.8. The half wave potentials were gradually proceeded in negative direction with increasing pH and the half wave potential of -1.37 volt was obtained at the pH 11.0. Suggesting possible mechanisms of electrode reactions, the anomalous behavior of reduction waves of Cd(Ⅱ) in sodium tartrate solution up to pH 11.0 was discussed.

科學敎育을 개선을 위한 硏究 : 美國의 North Carolina州를 中心으로 With Reference to the North Carolina Provrince in U.S.A

崔七南,曺在興,尹晳珍 조선대학교 교육연구소 1987 교과교육연구 Vol.10 No.-

타르타르산 용액속에서 카드뮴착물에 대한 폴라로 그래피적 거동

崔七男 조선대학교 기초과학연구소 1984 自然科學硏究 Vol.7 No.1

pH6.0∼12.0 범위에서 0.5M 타르타르산염지지용액 속에서의 Cd(Ⅱ) 폴라로그램의 연속해리 상수를 25℃에서 조사하였다. 반파전위는 pH6.0∼8.0, pH9.0∼10.0, pH11.0∼12.0에서 각각 -1.940v, -1.944v로 일정해 감을 알았고 Peak Current는 pH에 따라 일정한 규칙성을 보였다. -1.8v 이상에서 반파전위를 측정할 수 있었다. 전극반응기구라 보고 pH6.0∼12.0에서 타르타르산 지지용액 속에서 Cd(Ⅱ)의 환원파의 연속해리 상수는 Kd_1 6.4×10^-1, Kd_2 5.6×10^-9 Kd_4 1.3×10^-8라고 결론지을 수 있다. The polarograms of Cd(Ⅱ) in 0.15M tartrate solution were investigated by the method of the determination of consecutive dissociation constants in the range of pH values from 6.0 to 12.0 at 25℃. Half wave potentials were found to be constant at -1.940V, -1.948V, and -1.944V at the pH range 6.0∼8.0, 9.0∼10.0 and 11.0∼12.0 respectively, and peak currents were showed regularlity of the pH values. It was found possible to estimate the half-wave potential in a given experiment over the range of -1.8 V. Suggesting possible mechanisms of electrode reactions, consecutive dissociation constants of reduction waves of Cd(Ⅱ) in tartrate solution to pH value of 6.0∼12.0 are estimated as Kd_1, Kd_2, Kd_3 and consecutive constants of 6.4×10^-9, 1.3×10^-8 respectively.

A Study on the Electronic Properties and Redox Reaction of Molybdenum (Ⅵ) and Tungsten (Ⅵ)-N,N-Diethyldithiocarbamate Complexes

Choe, Chil Nam CHOSUN UNIVERSITY 1997 Basic Science and Engineering Vol.1 No.1

The chemical behavior of Mo(VI) and W(VI) complexes with the ligand has been investigated by UV/vis-spectrophotometric, magnetic, and electrochemical methods. Three energy absorption bands are observed in the spectra of these complexes. The crystal field splitting energy, spin pairing energy, and bond strength were obtained from the spectra of complexes. The electronic properties of the complexes are found to be delocalized, and low-spin state. The correlation between ligand and metals was strong bonding strength and diamagnetics. The redox processes of these complexes are a one-electron one step reaction. Mo(VI) complex exhabits irreversible, quasi-irreversible, and irreversible of three redox waves. But W(VI) complex can be observed irreversible in the single redox wave.

陰ion 交換樹指에 依한 國內産 Monazite 모래 中 稀土類 元素分離

崔七男,朴聖珪,丁梧鎭,최훈 조선대학교 기초과학연구소 1983 自然科學硏究 Vol.6 No.1

An anion exchange method for separating the individual rare earth elements in monazite producted in Woong Chun area, Chung-nam, Korea and Bo Sung River area, Chun-Nam Korea has been developed. The rare earth complex ions with D.T.P.A at pH 8.3 pass through the anion resin bed. The absorption order of the complex ionts was in accordance with that of the stability constants of the complexes. The elution of a mixture of all the rare earths oxides through an ion exchange bed with an ammonia-buffered solution of D.T.P.A indicated having the monazite of Bo Sung River area and Woong Chun area been decomposed with 95%-sulfuric acid into the sample solution was absorbed into the Amberlite CG-400 anion exchange resin. The fraction of the rare earth elements was eluted with ammonia alkaline solution of 0.025M-D.T.P.A. Rare earths oxides in the effluent were precipitated with oxalic acid and the precipitate was ignited to obtain oxides. Y, La and Ce in the oxides were determined by X-ray fluorescence method. And the other oxides were determined by gravimetic method. The amount of the rare earth elements was determined by Atomic Absorption Spectrophotometer. The Lanthanide oxalate hydrate was determined by X-ray diffractometer. The Lanthanide oxalate hydrate was determined by X-ray diffractometer and was measured by thermal analyser. Changes of structure of the Lanthanide oxalate hydrate in accordance to heating condition were identified by electron microscope.

희토류금속(Ⅲ)착물들의 합성과 전자적구조와 전기화학적 거동에 관한 연구(Ⅰ)

崔七男,金世奉,孫孝烈 조선대학교 기초과학연구소 1994 自然科學硏究 Vol.17 No.1

란탄나이드 3가 Pr(Ⅲ),Dy(Ⅲ) 질소주게 리간드인 2,2'-비피리딘을 포함한 착물들을 분광학, 자기학, 그리고 전기화학적 측정 방법에 의해 연구하였다 착물들에 대한 스펙트라, 결합쌍 에너지와, 그리고 스핀상태로부터 얻어진 10D_q의 크기는 Pr^+3와 Dy^+3이온의 에너지 전환으로 부터 얻어졌다. 이들 착물들은 반자기성이며, 비편재화 상태의 낮은 스핀착물을 이루었다. 또한 이들 착물들은 결정장 에너지가 보다 커서 쉽게 결합쌍을 나타내었다. 착물들의 d.c-Polorography와 c.v(Cyolovoltammography)측정결과, 이들 착물들은 2단계의 비가역적 환원과정으로 나타났다. The complexes of trivalent lanthanides, Pr(Ⅲ), Dy(Ⅲ), with nitrogen donor ligands(2,2’-bipyridine) have been studied by spectrophotometry, magnetometry and electrochemistry. The magnitude of 10D_q for the magnetic spectra, the pairing energy, and the spin states of the complexes obtained from energies transfer of the Pr(Ⅲ) and Dy(Ⅲ). These complexes were diamagnetic and low spin complexes of delocalization-states. And also, these complexes have the more easy bonding pairs because these larger than C.F.S.E.(Crystal Field Stabilization Energy) The electrochemical behavior of complexes were imvestigated by the direct current polarography and cyclic voltammetry and it was found that the reduction of these complexes was observed to be irreversible by two steps.

교사교육 개선을 위한 연구 : 미국의 North Carolina 주를 중심으로 with reference to the north carolina province in U.S.A.

최칠남 조선대학교 교육연구소 1989 교과교육연구 Vol.11 No.-

희토류금속(Ⅲ) 착물들의 합성과 전자적구조 그리고 전기화학적 거동에 관한 연구

崔七男,金世奉,金一斗 조선대학교 기초과학연구소 1994 自然科學硏究 Vol.17 No.1

디피바로일메탄올을 가지고, Pr(Ⅲ) 와 Eu(Ⅲ)착물들에 대한 화학적 거동은 U.V/vis 분광분석, 자기학적 그리고 전기화학적 방법으로 조사였다. 착물들의 결정장 갈라짐 에너지 크기와, 스핀 짝지움 에너지 그리고 스핀상태는 스펙트라 로부터 얻었다. 낮은 스핀상태에 있는 두 경우 (4f^2 과 4f^2궤도함수)가 각각 가능했고, 이들 상태는 착물들의 갈라짐 에너지로부터 얻어졌다. Pr(Ⅲ)와 Eu(Ⅲ)의 팔면체 착물들은 ^3F-^3P 와 e_g-b_1g 전위에 일치하는 3개의 스핀 허용 d-d 전위가 나타날 것으로 예상되어진다. 이들 착물들은 상자기성과 비편재화 그리고 낮은 스핀 상태임을 알게 되었다. 착물들의 전기 화학적 거동은 비수용액 속에서 순환 전압 전류법에 의해 관찰 되었다. 이들 환원 피크는 비가역적인 두 단계 환원과정 이었다. The chemical behavior of preseodymium (Ⅲ) and europium (Ⅲ) complexes with dipivaloylmethane was investigated by the use of U,V/vis-spectrophotometry, magnetometry, and electrochemical method. The magnetitude of crystal field splitting energy, the spin pairing energy, and spin state of complexes was obtained from the spectra. For each of the two eases (4f^2 and 4f^6 orbital) where low-spin state are possible, these state were obtained from the splitting energy of complexes. An octahedral complexes of Pr(Ⅲ) and Eu(Ⅲ) would be expected to exhibit three spin-allowed d-d transition, corresponding to the transition ^3F-^3P and e_g-b_1g. These complexes found to be paramagnetics, delocalization, and low-spin state. voltammetry in aprotic media. These reduction peak were irreversible two stop reduction processes.

신·구 교육과정 비교분석(Ⅱ) : 고등학교 화학교과서 실험을 중심으로 Centering on High school chemistry Texts Experiment

최칠남,노봉오,윤석진 조선대학교 교육연구소 1982 교과교육연구 Vol.5 No.-