자연과학대학, 화학과

이종팔,엄태섭,성대동 東亞大學校 大學院 1988 大學院論文集 Vol.13 No.-

The nucleophilic substitution reaction of p-substituted anilines and solvolyses of various substrates in tetrahydrofuran and methanol binary solvent mixtures have been investigated by means of conduct metrically. In order to investigate solvent effect on the rate of reaction, the solvatochromic parameters of tetrahyd rofuran and methanol bianry solvent mixtures have been determined by mean of UV-vis. sepctrophotometer. From the results of rate constants the following conlution have been obtatined. The values of solvatochromic parameters, α,βand π?? values increased with the methanol content, the increase in the αvalues being the greatest. And hence the solvent effect is controlled mainly by αvalues, i.e., hydrogen bond donor ability, of the transition state and the reactants. As the substituent of benzenesulfonyl chloride is varied from one of electorn donating to that of withdrowing, ???? values increase, while the variation of the substituent in aniline to one of electron donating caused ?? values to increase. The reaction center, sulfer atom has shown to develope negative charge and nitogen atom on the nucleophile has shown to develope positie charge in the transition state. From application of potential energy surface model, teh reacton are shown to proceed by an associative S??2 reaction which is in between the S??N and S??2 mechanism.

정수처리공정에서 소독부산물인 트리할로메탄의 생성모델

이성식,성낙창,이종팔,박현석,정미은,이상준,윤태경 한국환경과학회 2004 한국환경과학회지 Vol.13 No.3

We have been proposed model equation which is able to predict the trihalomethane producing concentration formation, that is one of byproduct, in the water treatment processes. In proposed model, the effects of trihalomethane factors like chlorine contact time, pH, temperature, TOC and UV-254 are considered. The concentration of the trihalomethane produced is proportion to the contact with chlorine, pH of water, temperature of water TOC and UV-254, respectively. This proposed model could be predicted the formed concentration of trihalomethanes by trihalomethane factors.

S-(4-methylphenyl)-4-chlorothiobenzoate의 아민 첨가 분해 반응

이종팔,전정남 東亞大學校附設基礎科學硏究所 1995 基礎科學硏究論文集 Vol.12 No.1

We have been studied for the aminolysis of s-(4-methylphenyl)-4-methylthiobenzoate with secondary alicyclic amines in water and at 40℃, 0.2M ionic strength with KCI by spectrophotometric method. The Bronsted plot for the second order rate constant is biphases with slopes β₁=0.12 and β₂=0.41 at high and low pKa region, respectively. The curved Bronsted plot can be explained by the exitance of a Zwitterionic tetrahedral intermediate in the reaction path and a change in the rate determing step. We found, when the nucleophile is weakly basic than the leaving group, the second step(breakdown of intermediate) should be rate determing step and, the nucleophile is strong base, such like piperidine, the first step(formation of intermediate) should be rate determing step.

DANSYL, BANSYL 및 DABSYL Chlorides의 가용매분해 반응에서의 용매화거동

李鍾八,成大東,金明淑 東亞大學校 1994 東亞論叢 Vol.31 No.1

The bimolecular nucleophilic substitution reactions of DABSYL and BANSYL chlorides have investigated by kinetic method and discussed with solvent dynamics that has been proved by means of laser flash photolysis. The results are as follows, 1. The rate constants of nucleophilic substitution reaction of BANSYL chloride show higher than those of DABSYL chloride in MeOH-MeNO2 binary solvent mixtures. The reactions proceed through an orbital-controlled reaction mechanism. 2. The phenomena of rate maxima show at 70% (v/v) content of MeOH in the solvolyses of DABSYL chloride and BANSYL chloride. The rate maximum is caused by the sum of the hydrogen bond donor acidity(α) and the polarity-polarizability parameter of solvent(π') as shown in the specific solvent effect as a general isodielectric solvent systems. 3. The laser flash photolyses of DABSYL chloride and BANSYL chloride are observed the fluorescent emission spectra which are generated by exciting of the two molecules. 4. The recovery life times of BANSYL chloride and DABSYL chloride are detected similar and the values of τ1 and τ2 are shown as shortest. 5. Rearrangement of the substrates in the content of 60% (v/v) of MeOH is depending on the rotation of the substrates on the surface of solvents by analysis of the rearrangement time.

N-테노일 이미다졸 유도체의 가수분해반응

이종팔,성대동,엄태섭 東亞大學校 大學院 1994 大學院論文集 Vol.19 No.-

The oseudo first order rates for hydrolses of N-thenoylimidazole(N-TI), N-thenoylbenzimidazole and N-thenoyl-2-phenylimidazole(N-TPI) have been determined at over all pH range with the ionic strength of 0.5M KCl at 40℃ by spectrometry. Hydronium ion and hydroxide in catalyzed reaction observed. The reaction of the diprotonated species occured at pH=3.5 in N-TI and at less than pH=6 in N-TPI. Metal ion catalyses were observed very weakly in hydrolyses of these compounds in the presence of divalent metal ions Cu², Ni², or Zn². We have observed that metal ion promoted hydronium ion catalyzed reaction. Saturation effects were observed only in the metal ion catalyzed hydrolysis of N-TI.

세라믹 정밀여과막과 한외여과막을 이용한 광촉매로 전처리된 아크릴 폐수의 처리

이광현,김종팔,강병철 대한상하수도학회 2002 상하수도학회지 Vol.16 No.4

The application of ceramic microfiltration membrane and ceramic ultrafiltration membrane and reverse osmosis membrane using acrylic wastewater pretreated by photocataiyst was discussed with the variation of appled pressure and temperature. Turbidity were shown high removal efficiency in ceramic microfiltration membrane and ceramic ultrafiltration membrane process using acrylic wastewater pretreated by photo-catalyst. Ceramic microfiltration membrane and ceramic ultrafiltration membrane using acrylic wastewater pretreated by photo-catalyst was shown that COD and T-N were not highly affected with the variation of appled pressure and temperature. It was shown that removal efficiency of COD and T-N with ceramic microfiltration membrane and ceramic ultrafiltration membrane was low. Removal efficiency of COD with reverse osmosis membrane was better with permeate by ceramic ultra filtration membrane than with permeate by ceramic microfiltration membrane. T-N and TDS were shown high removal efficiency in reverse osmosis membrane.

술핀아미드의 가수분해반응에 미치는 산 및 친핵체의 촉매작용

李鍾八,嚴泰燮 東亞大學校附設基礎科學硏究所 1997 基礎科學硏究論文集 Vol.14 No.1

술핀아미드류의 가수분해반응에 미치는 산 및 친핵체의 촉매작용을 25℃, 이온세기 0.1 M(NaClO₄)로 조절된 수용액에서 UV/VIS 분광광도법으로 조사하였다. 산 촉매반응은 벤젠술핀아미드의 이탈기 아닐린에 전자주게 치환기를 가진 반응기질과 벤젠술피닐기의 치환기가 전자주게인 반응기질 모두 pH 3 부근에서 가수분해반응속도상수의 대수값이 현저한 차이를 보였다. 이와 같은 현상은 위와 같은 반응기질이 산 촉매가 수분해될 때 초원자가중간체를 거쳐 진행된다는 사실의 속도론적 증거가 됨을 알았다. 반면, 벤젠술핀아미드의 치환기가 전자받게기인 경우는 pH 3 부근에서 변곡점이 생기지 않음을 보였다. 할로겐화이온에 의한 촉매반응은 Br?이 Cl?보다 크게 나타났으며 이때 반응속도는 반응용액의 산의 농도에 영향을 받음을 보였다. 술핀아미드의 치환기효과로부터 얻은 Hammett의 반응상수 ρ값으로부터 예상되는 할로겐화이온에 의한 촉매반응메카니즘은 술포늄 양이온을 거쳐 진행될 것으로 예상할 수 있었다. We have been kinetically studied on acid and nucleophile catalysis for hydrolysis of sulfinamides at 25℃ in aqueous solution at the ionic strength of 0.1M with NaClO₄by spectrophotometrically. The substrates which the leaving group aniline has electron donating group were shown a breakdown of pH-rate profile at near pH 3 as well as the substrate having electron donating group at benzenesulfinyl group. The break is ascribed to a change in the rate determining step of the reaction involving a hypervalent intermediate. However, the substrates which have the leaving group with electron withdrawing group were not observed a breakdown of pH- rate profile at pH3. Catalysis of halide ion was observed in the hydrolysis of sulfinamides. The nucleophile reactivity observed was in the order of Br?>Cl?, but also found to depend upon the acid concentration of solution. From the Hammett's reaction constant ρ values which were obtained by effect of substituent of sulfinamides, we expect that the reaction mechanism may proceed via sulfonium cation.

중금속[Cu(Ⅱ), Zn(Ⅱ)]의 분리 및 농축을 위한 역삼투 판틀형 모듈의 적용

이광현,강병철,이종백,김종팔 한국물환경학회 2004 한국물환경학회지 Vol.20 No.4

This study was focused on experiment for the separation and concentration process of Cu(Ⅱ), Zn(Ⅱ) solution with the variation of applied pressure and concentration using reverse osmosis plate and frame modules. Rejection coefficient and degree of concentration for Cu(Ⅱ) component using single and multi-stage reverse osmosis process were showed 96.3 ~ 97.8%, 0.044 ~ 0.191(in single-stage), 96.3 ~ 98.4%, 0.400 ~ 2.264(in multi-stage) within the range of experimental condition, respectively. Those of Zn(Ⅱ) were 93.3 ~ 97.1%, 0.019 ~ 0.395(in single-stage), 96.3 ~ 98.2%, 0.365 ~ 1.454(in multi-stage), respectively. Degree of concentration of multi-stage were higher than those of single-stage. Heavy metal[Cu(Ⅱ), Zn(Ⅱ)] separation was very efficient in using reverse osmosis plate and frame type modules. Separation efficiency for a mixed solution Cu(Ⅱ) and Zn(Ⅱ) was higher than those of each one of Cu(Ⅱ) and Zn(Ⅱ).

음용수처리공정상 염소소독 부산물의 생성모델 및 특성

이성식,박영민,이종팔,성낙창,박현석 동아대학교 기초과학연구소 2003 基礎科學硏究論文集 Vol.20 No.1

낙동강 상수 원수의 정수 처리시 염소소독시 생성 부산물의 평균농도는 THMs는 16.0~17.4mg/L 그리고 HAAs는 19.9~25.5mg/L의 범위이다. HAAs는 활성탄에 쉽게 흡착처리 되며 Freudlich 흡착등온식 모델에 따른다. 생성 THMs의 농도는 총 트리할로메탄 생성인자(TTF) 와 직선적 상관관계가 있다. log THMs = 0.058TTF + 1.12 여기서 TTF는 온도, pH, UV-254, TOC, 염소농도, 염소접촉시간 등과 다음과 같은 상관관계가 있다. TTF = 0.11 log [(TOC) (UV254)] + 0.391 log (Cl₂)) + 0.265 log(t) + 2.31 log (pH - 2.6) + 3.46 log (Temp) The objectives of this study are to determine the formation concentration of trihalomethane (THMs) and haloacetic acids(HAAs) during the drinking water treatment processes and to suggest the model equation which is able to expect producing concentration of the trihalomethane. The average concentration of THMs and HAAs in the basin of Nakdong River are formed during chlorination are detected from 16.0 to 17.4 and from 19.9 to 25.5 mg/g, respectively There is strong relationship between THMs and trihamethane facter(TTF) which are pH, temperature, UV-254 and total organic carbon of tap water and reaction time with chlorine. The adsorption isotherms of HAAs by adsorption carbon is adapted the Freundlich equation.

N-furoyl-4(5)-nitroimidazole의 가수분해반응에 미치는 촉매효과

이종팔,임춘영 동아대학교 기초과학연구소 2003 基礎科學硏究論文集 Vol.20 No.1

N-furoyl-4(5)-nitroimidazole의 가수분해반응을 25℃에서 분광광도법에 의해 속도론적으로 조사하였다. pH 6.5 이하에서 pH에 무관한 반응과 pH 6.5 이상에서 OH에 의한 촉매반응이 관찰되었다. 가수분해반응속도에 미치는 니트로기의 치환기 효과는 그다지 크게 나타나지 않았다. bifunctional acid & base catalyst 들은 촉매작용은 cacodylate가 가장 효과적이었으며, 염기성형 촉매가 산성형 촉매효과 보다 크게 작용함을 알 수 있었다. 반면 acetate는 촉매효과가 거의 나타나지 않았다. 활성화 엔탈피보다 활성화 엔트로피가 크게 나타났으며 용매동위원소효과가 관찰되었다. The rate constants for the hydrolysis of N-furoyl-4(5)-nitroimidazole are determined in water at the 25℃ under pseudo first order conditions by uv/vis spectrophotometer. The pH independent reaction and the hydroxide ion catalyzed reaction are observed from pH 6.5 to 1.0 and above pH 6.5, respectively. The D₂O solvent isotope effect is observed in the pH independent reaction, that is, k_(0)^(H₂O)/K_(0)^(D₂O)2.0. Activation parameters in the water catalyzed reaction and the hydroxide ion catalyzed reaction are calculated to △H ≠ 9.97 Kcal/mol, △H ≠ 8.51 Kcal/mol and △S ≠ 36.6 e,u., △S ≠-67.1 e.u. respectively. Thus, the water catalyzed reaction and the hydroxide ion catalyzed reaction are more important to nucleophilic attack to the carbonyl carbon than the protonation of the leaving group in the transition state. The most effective catalyst of bifunctional catalysts in the hydrolytic reaction is cacodylate and the base form of this catalyst is more effective, whereas there is no catalytic effect on the acetate.