• 대한화학회지
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• 제12권3호
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• pp.106-113
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• 1968

여러 酸性溶媒 속에서 3,4-methylenedioxy-${\beta}$-nitrostyrene에 대한 n-butylmercaptan의 親核性 添加反應速度常數를 측정하여 넓은 pH범위에서 잘 맞는 反應速度式을 구하였다. 이 식에 의하면 pH3이하에서는 mercaptan분자가 첨가하며 pH6이상에서는 mercaptide ion이 첨가함을 알 수 있고 이 중간 pH범위에서 일어나는 복잡한 반응 메카니즘도 이 식에 의해 정량적으로 잘 설명할 수 있음을 알았다.

• Bulletin of the Korean Chemical Society
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• 제18권4호
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• pp.374-379
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• 1997

The rate constants for the nucleophilic addition of thiophenol derivatives (p-OCH3, H, p-CH3, m-CH3, p-Br and p-NO2) to 4'-[N-(9-acridinyl)]-1'-(N-methanesulfonyl)-3'-methoxyquinonediimide (AMQD) were determined by ultraviolet spectrophotometer in water at 5 ℃, and rate equations which can be applied over a wide pH range were obtained. On the basis of pH-rate profile, Bronsted plot, adduct analysis, general base catalysis and substituent effect, a plausible mechanism of this addition reaction was proposed: Below pH 2.5, the reaction proceeded by the addition of thiophenol molecule to 6'-position of quinonoid after protonation at the acridinyl nitrogen. Above pH 6.2, the addition of sulfide anion to 6'-position of quinonoid was rate controlling. However, in the range of pH 3.0-6.0, these two reactions occured competively.

• 대한화학회지
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• 제16권4호
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• pp.232-240
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• 1972

Ethylacrylate에 대한 n-butylmercaptan의 첨가반응속도상수를 iodometry로 측정하여 넓은 pH범위에서 잘 맞는 속도식을 구하였다. 이 식에 의하면 pH 4 이하에서는 n-butylmercaptan분자가 첨가하여 pH 7 이상에서는 n-butylmercaptide ion이 첨가함을 알 수 있고 pH 4∼7 사이에서 일어나는 복잡한 첨가반응 메카니즘도 이 식으로 잘 설명 될 수 있음을 알았다.

• 대한화학회지
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• 제13권4호
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• pp.289-296
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• 1969

Ethylcinnamate에 대한 ethylmercaptan의 첨가반응속도상수를 idodometry로 측정하여 넓은 pH범위에서 잘 맞는 속도식을 구하였다. 이 식에 의하면 pH3이하에서는 ethymercaptan분자가 첨가하여 pH7이상에서는 ethylmercaptide ion이 첨가함을 알 수있고 pH3-7사이에서 일어나는 복잡한 첨가반응 메카니즘도 이식으로 잘 설명될 수 있음을 알았다.

• Asian-Australasian Journal of Animal Sciences
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• 제23권12호
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• pp.1594-1600
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• 2010

A study was conducted to determine the dietary effects of a clay mineral (sodium bentonite, NaB) on manure gas emission, health, production, and meat characteristics of Hanwoo steers. Two diets fed to steers included a control diet (concentrate mix and rice straw) and a treatment diet (control diet+1.0% clay mineral/concentrate mix). Dietary NaB addition considerably reduced concentrations of gases ($H_2S$, $SO_2$ and $NH_3$) in the manure of Hanwoo steers. Growing steers fed NaB had similar blood profiles with the exception of lower (p<0.05) concentrations of blood alkaline phosphatase and lactate dehydrogenase. Dietary NaB addition tended to increase (p = 0.10) live weight by 30 kg at slaughtering and did not affect carcass yield and quality traits. Dietary NaB addition increased concentrations of P (p<0.01), Mg (p<0.01), Na (p<0.01), Zn (p<0.005), K (p = 0.08), Fe (p = 0.08) and Cu (p = 0.07) in the longissimus muscle compared to the control but did not affect (p>0.05) fatty acid composition. The study demonstrated that the dietary addition of a clay mineral could be effective in improving mineral bioavailability to Hanwoo steers, which could be one of the reasons for their improved performance.

• 한국주조공학회지
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• 제15권6호
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• pp.558-565
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• 1995

Effects of high Si-P addition on microstructure and mechanical properties of thin ductile cast iron have been investigated. The amount of silicon addition have fixed on 4.0wt% and the amounts of phosphorus addition and thickness of specimen have been varied from 0.05 to 0.8wt% and ${\phi}13mm$, ${\phi}10mm$ and ${\phi}6mm$, respectively. As the casting thickness decreased, the average diameter of spheroidal graphite was decreased and the hardness of the cast iron increased. By adding P, the average diameter of spheroidal graphite was increased and the count of the spheroidal graphite was decreased continuously. And the tensile strength and the elongation was decreased, and the hardness was increased. With the P added more than 0.2wt%, the abraded amount was decreased significantly. The addition of P improved the wear resistance and the hardness of thin ductile cast iron.

• Bulletin of the Korean Chemical Society
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• 제12권3호
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• pp.301-303
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• 1991

The rate constants for the nucleophilic addition of thiophenol to $\alpha$, N-diphenylnitrone and it's derivatives (p-$OCH_3$, p-Cl, p-$NO_2$) were determined from pH 3.0 to 13.0 by UV spectrophotometry and rate equations which can be applied over a wide pH range were obtained. On the basis of rate equation, general base and substituent effect a plausible addition mechanism of thiophenol to ${\alpha}$, N-diphenylnitrone was proposed: At high pH, the addition of sulfide ion to carbon-nitrogen double bond was rate controlling, however, in acidic solution, reaction was proceeded by the addition of thiophenol molecule to carbon-nitrogen double bond after protonation at oxygen of ${\alpha}$, N-diphenylnitrone.

• 한국응용과학기술학회지
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• 제12권2호
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• pp.85-92
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• 1995

The rate constant of the nucleophilic addition of 1-propanethiol to ${\alpha}-phenyl-N-iso-propylnitrone$ derivatives were determined at various pH and a rate equation which can be applied over wide pH range is obtained. Final product of the addition reaction was ${\alpha}-thiopropyl-p-phenylbenzylideneamine$. Base on the rate equation, general base effect, substituent effect and final product, plausible mechanism of addition reaction have been proposed. Below pH 3.0, the reaction was initiated by the addition of 1-propanthiol, and in the range of pH 3.0-10.0, proceeded by the competitive addition of 1-propanethiol and propanethiolate. Above the pH 10.0, the reaction proceeded through the addition of propanethiolate.

• Bulletin of the Korean Chemical Society
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• 제20권6호
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• pp.712-714
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• 1999

The rate constants for the nucleophilic addition of potassium cyanide to α,N-diphenylnitrone and its derivatives (p-OCH3, p-CH3, p-Cl, and p-NO2) were determined by ultraviolet spectrophotometer at 25℃, and the rate equations which can be applied over a wide pH range were obtained. On the basis of pH-rate profile, adduct analysis, general base catalysis and substituent effect, a plausible mechanism of this addition reaction was proposed: At high pH, the cyanide ion to carbon-nitrogen double bond was rate controlling, however, in acidic media, the reaction proceeded by the addition of hydrogen cyanide molecule to carbon-nitrogen double bond after protonation at oxygen of a,N-diphenylnitrone. In the range of neutral pH, these two reactions occured competitively.

• 한국응용과학기술학회지
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• 제10권2호
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• pp.65-72
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• 1993

The kinetics of the addition of thiourea to cinnamenylisophorone derivatives(X : H, p-Br, $p-CH_3$ $m-CH_3$, $p-OCH_3$) was investigated using ultraviolet spectrophotometry in 20%(v/v) dioxane-$H_2O$ at $25^{\circ}C$. A rate equation which can be applied over wide pH range(pH $1.0{\sim}13.0$) was obtained. In order to investigate the substituent effects of cinnamenylisophorone derivatives. Hammett constant was plotted. As the result, the rate of uncleophilic addition of thiourea to cinnamenylisophorone derivatives was facilitated by electron donating group. It was found that addition of neutral thiourea which was not dissociated at the pH $1.0{\sim}9.0$ was proceeded, the reaction was proceeded by addition of dissociated anion of thiourea above the pH 10.0. On the basis of this kinetic study, the reaction mechanism of nucleophilic addition of thiourea was investigated.