• Bulletin of the Korean Chemical Society
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• 제31권11호
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• pp.3366-3370
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• 2010

The specific rates of solvolysis of t-butyl fluoroformate (1) have been measured at $40.0^{\circ}C$ in 21 pure and binary solvents. These give a satisfactory correlation over the full range of solvents when the extended Grunwald-Winstein equation, with incorporation of the solvent nucleophilicity and the solvent ionizing power, is applied. The actual values are very similar to those obtained in earlier studies of the solvolyses of isopropyl chloroformate and ethyl chlorothioformate in the more ionizing and least nucleophilic solvents, which are believed to proceed by an ionization pathway. The small negative values for the entropies of activation are consistent with the ionization nature of the proposed rate-determining step. These observations are also compared with those previously reported for the corresponding primary and secondary alkyl haloformate esters.

• 대한화학회지
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• 제13권4호
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• pp.303-307
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• 1969

酸性溶液中에서 重金屬 이온의 沈澱劑로 널리 使用되는 Nitrosophenyhydroxylamine(Cupferron)의 非可逆電極反應의 電流電壓曲線과 酸性 및 알카리性에서의 還元反應機構 및 反應速度 그리고 pH變化에 따른 관여전자수, 活性化 energy를 Delahay 方法을 利用하여 구하였다.

• 대한화학회지
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• 제34권3호
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• pp.297-303
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• 1990

<ㅆㄸㅌ>$VO^{2+} 촉매가 존재하는 수용매에서 과산화수소에 의한 n-부틸아민의 산화반응은 n-부틸아민, 산 및 촉매인 VO^{2+}$농도에 대해서 각각 일차의존성을 보여주었다. 이 산화반응은 처음에는 이민중간물질이 생성된 다음에 가수분해되어 부틸알데히드와 암모니아를 생성한다. 이 반응의 속도결정단계는 n-부틸아민의 탈수소화반응이 일어나 이민이 생성되는 과정임을 제시한다.

• 대한화학회지
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• 제39권1호
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• pp.29-34
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• 1995

구리(II)-아민류 착물에 의한 l-ascorbic acid의 산화반응속도를 pH 4.6에서 Onishi 방법으로 측정하였다. 이 반응의 메커니즘은 l-ascorbic acid가 구리(II) 착물에 배위된 다음 속도결정단계에서, 전자이동이 일어나는 내부권 메커니즘에 따라 반응이 진행됨을 알았다.

• 대한화학회지
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• 제21권2호
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• pp.83-88
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• 1977

2,4-이니르로 염화벤젠과 p-톨루이딘, 아닐린 및 p-염화아닐린간의 반응속도론적인 연구를 메탄올-아세트니트릴 혼합용매에서 실시하였다. 알코올의 수소에 의한 특수용매화로 실험결과를 해석하였으며, 용매의 변화에 따라 반응메카니즘이 변함을 알았다.

• Bulletin of the Korean Chemical Society
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• 제24권1호
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• pp.91-94
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• 2003

Kinetic studies of the reaction of O-methyl-S-phenylthiocarbonates with benzylamines in methanol at 45.0 ℃ have been carried out. The reaction proceeds by a stepwise mechanism in which the rate-determining step is the breakdown of the zwitterionic tetrahedral intermediate, $T^{\pm}$, with a hydrogen-bonded four-center type transition state (TS). These mechanistic conclusions are drawn based on (ⅰ) the large magnitude of ${\rho}_X\;and\;{\rho}_Z$, (ⅱ) the normal kinetic isotope effects $(k_H/k_D\;>\;1.0)$ involving deuterated benzylamine nucleophiles, (ⅲ) the positive sign of ${\rho}_{XZ}$ and the larger magnitude of ${\rho}_{XZ}$ than that for normal $S_N2$ processes, and lastly (ⅳ) adherence to the reactivity-selectivity principle (RSP) in all cases.

• 한국지능시스템학회논문지
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• 제18권1호
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• pp.133-138
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• 2008

In this paper, we propose a novel anchor shot detection system, named to MASD (Multi-phase Anchor Shot Detection), which is a core step of the preprocessing process for the news video analysis. The proposed system is composed of four modules and operates sequentially: 1) skin color detection module for reducing the candidate face regions; 2) face detection module for finding the key-frames with a facial data; 3) vector representation module for the key-frame images using a non-negative matrix factorization; 4) one class SVM module for determining the anchor shots using a support vector data description. Besides the qualitative analysis, our experiments validate that the proposed system shows not only the comparable accuracy to the recently developed methods, but also more faster detection rate than those of others.

• Bulletin of the Korean Chemical Society
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• 제24권7호
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• pp.925-930
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• 2003

Kinetic studies of the reaction of Z-aryl cyclopropanecarboxylates with X-pyridines in acetonitrile at 55.0 ℃ have been carried out. The reaction proceeds by a stepwise mechanism in which the rate-determining step is the breakdown of the zwitterionic tetrahedral intermediate, $T^{\pm}$. These mechanistic conclusions are drawn base on (i) the large magnitude of ρx and ρz, (ii) the positive sign of ρxz and the larger magnitude of ρxz than normal $S_N2$ processes, (iii) a small positive enthalpy of activation, Δ$H^≠$, and a large negative, Δ$S^≠$, and lastly (iv) adherence to the reactivity-selectivity principle (RSP) in all cases.

• 대한화학회지
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• 제35권1호
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• pp.16-23
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• 1991

폴리스틸렌 수지에 트리에틸렌테트라아민을 반응시켜 선형과 집게형의 킬레이트 수지를 합성하였으며, 이들 수지에 지지된 아민은 주로 적외선 스펙트럼으로 확인하였고, 전이금속이 수지에 흡착되는 속도를 측정하였다. 이 결과에서 얻어진 확산계수 및 활성화엔트로피 등이 보고된다. 흡착과정의 속도결정 단계는 입자를 통한 확산과정이다.

• Bulletin of the Korean Chemical Society
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• 제5권1호
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• pp.41-44
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• 1984

The oxidation of carbon monoxide has been investigated on Ni-doped ${\alpha}-Fe_2O_3$ catalyst at 300 to $450^{\circ}$. The oxidation rates have been correlated with 1.5-order kinetics; first with respect to CO and 1/2 with respect to $O_2$. Carbon monoxide is adsorbed on lattice oxygen of Ni-doped ${\alpha}-Fe_2O_3$, while oxygen appears to be adsorbed on oxygen vacancy formed by Ni-doping. The conductivities show that adsorption of CO on O-lattice produces conduction electron and adsorption of $O_2$ on O-vacancy withdraws the conduction electron from vacancy. The adsorption process of CO on O-lattice is rate-determining step and dominant defect of Ni-doped ${\alpha}-Fe_2O_3$ is suggested from the agreement between kinetic and conductivity data.