Kinetics and Mechanism of Alkaline Hydrolysis of [(Methoxy)(p-substituted styryl)-carbene] Pentacarbonyl Chromium(0) Complexes in Aqueous Acetonitrile

신갑철,황재영,양기열,구인선,Ikchoon Lee 대한화학회 2005 Bulletin of the Korean Chemical Society Vol.26 No.12

Kinetic studies have been performed for alkaline hydrolysis of a series of [(methoxy)(p-substituted styryl)carbene]pentacarbonyl chromium(0) complexes ((CO)5Cr=C(OCH3)CH=CHC6H4X, X = p-OCH3, p-CH3, H, p-Cl, p-NO2). Second-order rate constants (kOH-) for the alkaline hydrolysis in 50% acetonitrile-water (v/v) were determined spectrophotometrically at various temperatures. At a low pH region (pH < 7.5), the observed rate constant (kobs) remained constant with a small value, while in a high pH region (pH > 9.5), kobs increases linearly with increasing the pH of the medium. The second-order rate constants (kOH-) increase as the substituent X changes from a strong electron donating group to a strong electron withdrawing group. The Hammett plot obtained for the alkaline hydrolysis is consisted of two intersecting straight lines. The nonlinear Hammett plot might be interpreted as a change in the rate-determining step. However, the fact that the corresponding Yukawa-Tsuno plot is linear with  and r values of 0.71 and 1.14, respectively indicates that the nonlinear Hammett plot is not due to a change in the rate-determing step but is due to ground-state stabilization through resonance interaction. The positive value suggests that nucleophilic attack by OH – to form a tetrahedral addition intermediate is the rate-determining step. The large negative S¹ value determined in the present system is consistent with the proposed mechanism.

Styryl diphenyl phosphine oxide의 가수분해 반응메카니즘에 관한 연구

신갑철,김학진,이광일 慶尙大學校 1985 論文集 Vol.24 No.1

The rate constants for the hydrolysis of p-substituted styryl diphenyl phosphine oxide(p-H, p-Cl, p-CH_3, p-OCH_3) were determined at various pH and rate equations which can be applied over wide pH range were obtained; below pH 5.0 the rate of hydrolysis of p-substituted styryl diphenyl phosphineoxide were catalyzed by hydronium ion and above pH 8.0, the specific base catalysis were observed. However, in the range of pH 5.0-8.0 the rate of hydrolysis were independent on the pH change andno general base catalysis were observed at pH 4.75. The substituent effects on the hydrolysis of styryl diphenyl phosphine oxide derivatives were also studied. On the basis of these results, the hydrolysis mechanism of p-substituted styryl diphenyl phosphine oxide were proposed.

Phenyl Isocyanides의 가수분해반응 메카니즘과 속도론적 연구

신갑철,성정완,박경곤,전혁제 慶尙大學校 기초과학연구소 1992 基礎科學硏究所報 Vol.8 No.-

Phenyl isocyanaide(PIC) and its derivatives were prepared from the corresponding anilines by the Ugi's method and were identified by the melting point and spectral data. The rate constants for the hydrolysis of PIC and its derivatives (p-Cl, p-Br, m-Cl, p-NO_2) were determined by ultraviolet spectrophotometry at various pH and a following general rate equation which can be applied over a wide pH range were derived. K_t=K_10+K_OH[OH^-] On the bases of this rate equation, general base and substituent effect, identification of final product, and Hammett's plots, plausible mechanisms for the hydrolysis of phenyl isocyanides were proposed.

Methylvinlketone에 對한 Mercaptans의 添加反應에 관한 速度論的 硏究

姜大鎬,申甲鐵 慶尙大學校 1975 論文集 Vol.14 No.-

The rate constants for the addition of n-propyl- and n-butylmercaptan to methylvinylketone were determined by iodometry at various pH and temperatures. From these rate constants, we obtained a rate equation K??=k??+k'[OH??]=??????????=k'[OH??] which can be applied over wide pH range. We also calculated the activation parameters(△H??, △S??) From the values obtained above, we reached the conclusion as follows: 1. The reaction is initiated by addition of n-propyl- and n-butylmercaptan molecule below pH 4. 2. The reaction is proceeded by the n-propyl- and n-butylmercaptied ion above pH 6. 3. At pH 4-6, the complex addition reaction mechanism can also be fully explained by the equation obtained. 4. The mercaptan having longer carbon chain has the smaller nucleophilicity, which is based on the values of calculated activation parameters, and this result is in accord with our expectation.

K+-Dibenzo-18-Crown-6 착물의 안정도에 미치는 용매효과

張珠晥,申甲鐵 慶尙大學校 1980 論文集 Vol.19 No.1

The stability constants of the complexation of KSCN with dibenzo-18-Crown-6 was determined conductometrically at constant ionic strength of∼10-3M and at 10°, 25°, 40° and 60℃ in aprotic solvents which were poor anion solvating solvent; N, N'-dimethylformamide N.N'-dimethylacetamide and dimethylsufoxide. The magnitude of the stability constants were obtained by the order of DMF>DMA>DMSO. This order was dependent on the solvent property as function donocity. From the stability constants, the thermodynamic parameters-enthalpy change and entropy change for the complexation were evaluated.

친핵성 첨가반응에 대한 용매효과 (I) Phenylvinylketone에 대한 아민의 첨가반응속도에 미치는 용매의 극성효과

신갑철,김태린,Gap-Cheol Shin,Tae-Rin Kim 대한화학회 1992 대한화학회지 Vol.36 No.2

여러 가지 용매에서 phenylvinylketone에 대한 아민(piperidine 및 diethyl-amine)의 친핵성 첨가반응 속도 상수를 $25^{\circ}C$에서 분광광도법으로 측정한 결과 그의 첨가반응 속도상수는 용매의 극성에 비례함을 알았고 이것을 Kirkwood식으로 잘 설명할 수 있었다. 즉, 이 반응은 고리형 구조의 zwitter ion 중간체를 거쳐 일어남을 알 수 있었다. 또 phenylvinylketone에 대한 아민의 첨가반응에서 3차 아민은 1차 및 2차 아민에서 보다 반응이 훨씬 느리게 진행되었으며 이것은 1차 및 2차 아민에서는 고리형 구조의 zwitter ion 중간체를 형성할 수 있고 또한 음전하의 비편재화 및 엔올형의 구조까지 가능하지만 3차 아민에서는 위의 구조들이 불가능하기 때문에 1차 및 2차 아민에서 보다 느리게 진행된다고 생각된다. The rate constants of the nucleophilic addition reaction of amines (piperidine and diethylamine) to phenylvinylketone in various solvents have been determined by UV spectrophotometry at $25^{\circ}C$. On the basis of the high sensitivity of the rate to the polarity of the medium, it may be concluded that the reaction intermediate has zwitterionic character. The effect of the solvents on the rate of the bimolecular nucleophilic addition reaction is described well by the Kirkwood equation: The transition state of the reaction has a cyclic structure formed through an intramolecular hydrogen bond. The addition reaction of primary and secondary amines to phenylvinylketone in all solvents take place considerably faster than that of tertiary amine and this results also can be explained by the intermediate products in the reaction have a cyclic structure formed through an intramolecular hydrogen bond for the primary and secondary amines but not for the tertiary amine.

화약발파(火藥發破) : 기술해설(技術解說) ; 화약기술계(火藥技術界)의 대부(代父) ; -지산허전박사화갑기념집(智山許塡博士華甲記念集)에서 발췌-

申甲澈,李永煥 대한화약발파공학회 1987 화약발파 Vol.5 No.1

Malonic acid Benzylidene Diethyl Ester에 대한 Amines의 친핵성 첨가반응에 관한 속도론적 연구

신갑철,정강원 慶尙大學校 1984 論文集 Vol.23 No.2

The kinetic studies on the addition of amines(primary, secondary and tertiary) to Malonic acid Benzylidene Diethyl Ester(MBDE) and Ethylcinnamate(EC) have been carried out in several solvents (MeOH, EtOH and n-PrOH) and at various temperatures. The order of reactivity in solvents was MeOH>eToh>N-PrOH, this result could be explained by the thermodynamic parameters and the dielectric constant of solvents. From the kinetic data, the following reactivity of amines has been derived ; piperidine>n-butylamine>diethylamine>benzylamine. This result was concurred with the Bronsted relationship, expect the deviation of diethylamine which might be resulted from its steric hinderance. It was found that the 3。 amines was less reactive than that of 1。 and 2。 amines toward MBDE. It was therefore suggested that the reactivity of amines was influenced by the formation of intramolecular hydrogen bond. The difference of reactivity between MBDA and EC could be explained by the neighboring group effect.

Sodium Ethylenediaminetetraacetatocobaltate(Ⅲ)와 Potassium Trimethylenediaminetetraacetatocobaltate(Ⅲ)Complex의 Chloride ion첨가에 관한 분광학적 고찰

신갑철,오창언 慶尙大學校 1976 論文集 Vol.15 No.-

As the Sodium ethylenediaminitetraacetatocobaltate(Ⅲ) takes form five membered chelate ring, more strain is found in out-plane than in-plane. By the result of it the complex is unstable and therefore ligand, chloride ion, can attack this complex easily. But the potassium trimethylenediaminetetraacetatocobaltate(Ⅲ) form six membered chelate ring, so the structure is stable. As a conseguence of the above, the attack of chloride ion as lignad is found to be difficult.

酸性溶媒속에서 Diethylitaconate에 對한 n-Propylmercaptan의 添加反應에 關한 反應速度論的 硏究

申甲澈,吳昌彦 慶尙大學校 1974 論文集 Vol.13 No.-

The rate constants for the addition reaction of n-propylmercaptan to Diethylitaconate are determined by iodometry at various PH and a rate equation which can be applied over wide pH range is obtained. The rate euqtion reveals that below pH4, the addtion reaction is started by the addition of the n-propylmercaptan molecule and above pH 6, this additionof n-prophymercaptan and n-propymercaptan and n-proylmercaptide ion occures. This complex addition reaction mechanism can be fully explained by the rate euqation obtained.