S-(4-Chlorophenyl)-4-methylthiobenzoate와 이차아민과의 반응

엄태섭,이종팔 東亞大學校 1997 東亞論叢 Vol.34 No.-

The reaction of s-(4-chlorophenyl)-4-methylthiobenzote with secondary alicyclic amines are subjected to a kinetic investigation in water 40℃, ionic strength 0.2M (with KCl). Under amine excess, pseudo-first order rate constants(Kobs) are obtained, which are linearly proportional to the total amine concentration. The second-order rate constants (Kobs) are calculated as the slope of these plots. The Bronsted plot obtained is biphasic with slopes β₁=0.1(high pKa), β₂=0.4(low pKa). This plot is consistent with the existence of a zwitterionic tetrahedral intermediate(T±) on the reaction pathway whereby expulsion of leaving group (ShpCl) from T±is rate determining step (k₂step) at low pKa, and there is a change to rate-limiting formation of T±(k₁step) at high pKa.

술핀아미드의 가수분해반응에 미치는 친핵체의 촉매작용

嚴泰燮,李益春,李鍾八,成大東 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

2배위 및 3배위 황화합물들이 가수분해될 때 무기산이나 할로겐화 이온과 같은 친핵체에 의해 촉매작용을 받는다는 사실이 알려져 있다. 이들 화합물들의 산촉매 가수분해반응 메카니즘은 식(1)에서 보는 바와 같이 반응 중심인 황 원자 주위에 다섯 개의 전자쌍이 관련된 초원자가 중간체(hypervalent intermediate)가 관련된다는 사실이 흥미의 대상이 되어 오고 있다.

트리플루오르에탄올 混合溶媒系에서 염화나프토일 分解反應의 Sn2轉移狀態 變化

嚴泰燮,成大東,柳俊夏 東亞大學校 大學院 1982 大學院論文集 Vol.6 No.-

The solvolytic rate constants of l-naphthoyl, and 2-naphthoyl chloride in TFE-EtOH and TEF-H₂O binary solvent mixtures have been measured at various temperatures. The rate constants for solvolysis in TFE-H₂O solvent mixtures are observed higher than in TFE-EtOH solvent mixtures. In the transition state naphthoyl chlorides have not peri-hydrogen dffect and also the l value of 2-naphthoyl chloride has lager one, therefore this reaction proceeds SAN reaction mechanism as shown in the potential surface diagram. It is in accord with that the reaction proceeds through the transition state of tetrahedral intermediate. The rate constants in TFE-EtOH solvent mixtures have shown higher in lager content of ethanol.

염화나프탈렌 술포닐의 친핵성 치환반응에 관한 연구

엄태섭 東亞大學校 1978 東亞論叢 Vol.15 No.2

The kinetics for solvoysis of 1-naphthalenesulfonyl chloride and 2-naphthalenesulfonyl chloride in ethanol-water and acetone-water mixtures have been studied. The nucleophilic substitution reactions of para-substit-uted anilines with the two substrates have been investigated by means of conductometry. The reactivity and mechanism fo solvolysis have been discussed in terms of solvent composition and activation parameters, but bond-breaking increased with the increase of water content. The reaction rate of 2-naphyhyl compound in solvent was faster than that of 1-naphthyl compound due to the peri-hydrogen effect in the transition state and the ground state stabilization effect. Pseudo-first order rate constants Kobs were determined for the reactions of naphthalenesulfonyl chlorides with para-substituted anilines. The second order rate constants K₂ and third order catalytic constants k₃ were then determined from kobs. For 1-naphthyl compound in this reaction peri-hydrogen effect was also observed. The large Bronsted coefficient βand large negative slope ρfor the Hammett plots were obtained. These results together with the unusually low valuses of activation paremeters were consistent with the SAN-elimination mechanism, but these could be equally well interpreted with the associative SN2 mechanism.

혼합용매의 비직선형 용매화 에너지 상관관계

嚴泰燮,成大東,李鍾八,朴現錫,金良姬 東亞大學校 大學院 1989 大學院論文集 Vol.14 No.-

Solvoltic rates for 1-adamantyl chloride and 1-adamantyl bromide were determined for methanol-mitromethane and methanol-nitrobenzene. Solvent ionizing power was estimated for two mixtures. Two solvent mixtures were shown that uncleophilic solvent assistant was in relation to the general use of the Grunwald-Winstein equation. Also, there is no evidence to support ail earlier suggestion that 1-adamantyl derivatives are procedeed by S( )1 absolutely, wherein they can be interpreted as evidence for dessociative S( )2 from the results of double difference method and Berry's pseudo rotation process diagram.

염화나프탈렌술포닐의 親核性 置換反應에 미치는 溶媒效果

嚴泰燮 東亞大學校 1981 東亞論叢 Vol.18 No.1

The solvolysis of 1-naphthalene and 2-naphthalene sulfonyl chloride have been studied for the solvent effect on rates in various solvant mixtures: acetonitrile-dimethyl sulfoxide(DMSO), acetone-DMSO, dioxane-DMSO, methanol-DMSO, ethanol-DMSO. Transition state variation caused by the changes solvent composition of the solvent mixture has shown the More O'Ferrall plots. The results of nucleophilic displacement reaction are preceded by a dissociative S?2 mechanism in higher aprotic solvent and DMSO solvent mixture and in higher dielectric constant aprotic solvent and DMSO mixtures. Structure-reactivity interaction on nucloephilic displacement reaction of naphthalene sulfonyl chlorides with substituded anilines has been observed associative S?2 mechanism. And it has been shown that DMSO solvent is a very strong uncleophile in each solvent mixture.

學校實驗室廢水에 대한 調査 硏究 : 하단캠퍼스를 中心으로 Around the Hadan Compus of Dong-A University

엄태섭,박유미,이종팔 동아대학교 환경문제연구소 1986 硏究報告 Vol.9 No.1

The monthly estimation of the waste water components effluenced from the laboratories of Colleges in Dong-A University has been determined and the laboratory waste water and the sewage in university also analyzed to survey and study for the present situation and disposal treatment plan to get as the basic data It has been come to a conclusion as follows 1) The waste matter of laboratories in University has composed the organic chemical waste of 48% and the inorganic chemical waste of 52%. The large amount of effluence are Cu of 35% Cr of 27% in inorganic chemical waste and there are a little bit amount of Pb As. Fe CN etc. 2) The pollution level of metal ions for each college laboratory has shown the highest in the college of Natural Sciences and October in each month. This view seems that the frequency in use of laboratory are the highest and the laboratories have many students in laboratory of general physics. laboratory of general chemistry and laboratory of general biology. 3) From the analysis and determination the sewage in university has shown the average pH 7.2 as to be neutrality and COD. BOD and the contamination level have shown lower the maximum permissible limit. 4) The components of waste water of college laboratories have diversity. It seems to be proper that the blanket treatment system which recollect separately to treat each component different from the industrial waste disposal treatment because there are many the effluent outlets.

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.

Nucleophilic Substitution Reaction of Dabsyl Chloride with p-Substituted Anilines

嚴泰燮,崔舜圭,成大東,韓性彬 東亞大學校 大學院 1985 大學院論文集 Vol.10 No.-

염화답실과 치환아닐린과의 친핵성 치환반응을 여러 용매계에서 진행시키고 이때의 반응속도 상수를 결정하였다. Br?nsted β값과 Hammett ρ?값들의 결과로부터 전이상태에서 결합파괴보다 결합형성이 우선함을 알 수 있었다. 분광용매화 상관관계식으로부터 용매의 수소결합주게(HBD) 산도 값(α)의 기여도 보다 용매의 편극-극성값(π?)의 기여도가 더 크게 작용함으로서 전이상태에서 결합 형성에 용매의 작용이 큼을 알았다. 또한 Dansyl과 Bansyl의 산 염화물보다 속도상수값이 크게 관측되어지는데 이것은 친핵체가 반응기질의 평면에 수직되게 공격함으로써 전이상태가 더욱 안정화되기 때문이며 이느 Marcus의 전이상태이론에서 concerted mechanism이 작용함을 의미한다 하겠다.

TFE-EtOH와 TFE-H₂O 混合溶媒속에서 2-염화테노일의 親核性 置換反應

尹庠基,嚴泰燮,成大東 東亞大學校 大學院 1981 大學院論文集 Vol.5 No.-

For solvolysis of 2-thenoyl chloride we discussed the solvent effects on rates in TFEEtOH, THE-H₂O solvent mixtures. We have used the More O' Ferrall plots show that transition state variation caused by solvent, changes is consistent with an associative Sn2 mechanism for THE-EtOH binary solvent mixtures and an Sn2 mechanism for THE-H₂O in the solvolysis of 2-thenoyl chloride.