• Korean Journal of Agricultural Science
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• v.10 no.2
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• pp.354-364
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• 1983

Confonmation of (Z)-cinnamonitrile have been studied by molecular orbital theoretically using extended Huckel theory(EHT) and CNDO/2 molecular orbital calculation methods. The results indicate that the stability of conformation is(Z)-gauch>(Z)-planar. The rate constants for alkalie hydrolysis of cinnamonitrile at pH 7.0-14.0 range have been determined by ultra-violet spectrophotometry in 50% methanol at $25^{\circ}C$ and the following rate equation which can be applied over wide pH range was obtained; $${\therefore}k=({\frac{1.41{\times}10^{-14}+1.21{\times}10^7/[H_3O^+]}{2.65{\times}10^{-7}+1.64/[H_3O^+]})+9.14{\times}10^9/[H_3O^+]$$ The rate equation reveals that, at pH 7.0-10.0, the reaction is initiated by the addition of water molecule to unsaturated cabon-carhon double bond of cinnamonitrile and ${\alpha}C-{\beta}C$ bond scission follow subsequently in neutral and alkalie media. At pH 12.0-14.0, in strong alkalie solution, that so-called Michael type nucleophilic addition that the over-all rate constants is only dependent upon the concentration of hydroxide ion occurs competitively and are very complicated. Hence, the reaction mechanism of alkalie hydrolysis of cinnamonitrile which did not carefully before can be fully explained.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.213-216
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• 2008

2차원 전극의 RhB 분해 성능은 Pt(+)-Pt(-) > Pt(+)-Sus(-) > Sus(+)-Sus(-) 전극의 순으로 나타났다. 3차원 전극은 Pt-ACF-Pt 전극만 2차원 전극보다 초기 반응속도가 낮고 최종 RhB농도가 높은 것으로 나타났으나 다른 전극은 충전물 종류에 관계 없이 2차원 전극보다 초기 반응속도가 높은 것으로 나타났다. 음극의 종류에 관계없이 3차원 전극의 충전물에 따른 RhB 분해는 GAC > Nonwoven fabric fiber > ACF로 나타났다. GAC 충전량이 50 g 이상에서 RhB 분해속도는 거의 유사한 것으로 나타났으나 전력을 고려한 단위 W당 시간당 RhB 농도 감소를 나타내었다. 그림에서 보듯이 최적 GAC 충전량은 50 g로 사료되었다. 최적 전류는 2.5 A로 사료되었다.

• Journal of the Korean Ceramic Society
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• v.25 no.5
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• pp.50-50
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• 1988

The controlled Ti(CO2H5)4 hydrolysis reactions for the synthesis of Spherical Monodispersed Titania powders are described. Increasing the concentration of TEOT and the molar ratio of water to TEOT in alcohol solution decrease the reaction time and the particle size. The reaction time is delalyed by increasing the chain length and the number of carbon branches of alcohol as a solvent. The prepared powders with an average diameter of 0.8μ and the spherical monodispersed transfer to Rutile phase at 550℃.

• Journal of the Korean Chemical Society
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• v.43 no.5
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• pp.505-510
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• 1999

$TiO_2$ powders were prepared via hydrolysis of titanium n-butoxide in n-butanol and hydrolysis mechanism of titanium n-butoxide was studied using UV-Vis spectrometer. Hydrolysis reactions were controlled to proceed to pseudo-first order reaction in the presence of excess water. The phases of $TiO_2$ powders, prepared under the these conditions, were identified by XRD and reaction rates were calculated by Gugggenheim method. Prepared powders were noncrystalline states in their initial stage of formation but transformed to crystalline rutile structure by heating. Reaction mechanism of titanium n-butoxide was proposed as Interchange-Associative(Ia) mechanism, based on the data of n-value and termodynamic parameters which were determined from the rate constants.

• Journal of the Korean Chemical Society
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• v.55 no.3
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• pp.346-353
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• 2011

Base hydrolysis of 7-hydroxy-2H-chromen-2-one (HC) and 7-hydroxy-2H-chromen-2-one-4-acetic acid (HCA) in aqueous-methanol and aqueous-acetone mixtures were studied kinetically at temperature range from 283 to 313 K. The activation parameters of the reactions were evaluated and discussed. Moreover, the change in the activation energy barrier of the investigated compounds from water to water-methanol and water-acetone mixtures was estimated from the kinetic data. It is observed that the change in activation barriers is more or less the same for the hydrolysis of HC and HCA. Base hydrolysis of HC and HCA follows a rate law with $k_{obs}=k_2[OH^-]$. The decrease in the rate constants of HC and HCA as the proportion of methanol or acetone increases is due to the destabilization of $OH^-$ ion. The high negative values of entropy of activation support the proposal mechanism, i.e. the investigated reaction takes place via the formation of an intermediate complex. Moreover, these values refer to the rigidity and stability of the intermediate complex. Thus, the ring opening of the intermediate complex would be the rate controlling step.

• Clean Technology
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• v.12 no.3
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• pp.145-150
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• 2006

Electrolysis of aqueous solution produces hydroxide ions and proton ions for the hydrolysis of reactive organic compounds, and oxidizing agent such as hypochlorite ions for the oxidative decomposition of organic chemicals. Electrolytic decomposition of dying chemicals was tested with our custom made system, and analyzed by HPLC and UV-VIS spectrophotometer. The electrolytic system could decompose dying chemicals with very high reactivity and low cost. Disposal of byproduct and refill of reactant during electrolysis was not necessary. Decomposition time of dying chemicals is compared under similar conditions, and application to water purification is discussed.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.1055-1061
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• 2000

The kinetics of tar formation has been studied experimentally and modeled mathematically for waste lubricating oil after pyrolyzed at batch reactor. And stabilization of pyrolyzed oil has been studied. A combination of series and parallel reaction was assumed for the mechanism of tar formation. From the proposed kinetic model, pyrolyzed oil to tar was found to be rate limiting step for tar formation. It was found that the fly ash and coke had the ability to remove materials of tar formation and to protect oxidation of pyrolyzed oil.

• Polymer(Korea)
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• v.32 no.2
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• pp.157-162
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• 2008

To investigate the characteristics of pyrolysis for LDPE, LLDPE and HDPE, the low temperature pyrolysis was carried out in the range of 425 to $500^{\circ}C$ for 35 to 65 min. The liquid products formed during pyrolysis were classified into gasoline, kerosene, light oil and wax according to the distillation temperatures based on the petroleum product quality standard of Korea Petroleum Quality Inspection Institute. TGA experiments for three PE samples showed that the onset temperature of pyrolysis increased with increasing heating rate, and the onset temperature of pyrolysis at a fixed heating rate was in the order of LDPE$475^{\circ}C$. Yields of gasoline and kerosene were highest at $450^{\circ}C$, 65 min and decreased slightly at above $475^{\circ}C$.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.3
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• pp.157-161
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• 2011

This study investigated decomposition the pathway and characteristics of fenitrothion, which is applied on the golf course for pesticide, by ZVI in batch reactor. The removal efficiencies of the pure fenitrothion and the commercial fenitrothion in Smithion by ZVI were compared. The fenitrothion was converted to 3-Methyl-4-nitrophenol and 4-Amino-m-cresol by ZVI. The fenitrothion decomposition rate by ZVI could be expressed by the first order reaction. As increasing the ZVI dosages, the first order rate constants and removal efficiencies increased. The surface area normalized rate constants for the pure fenitrothion and the commercial fenitrothion were 0.0398 and 0.1312 ($L/m^2{\cdot}hr$), respectively. The decomposition of the commercial fenitrothion in Smithion was faster than that of the pure fenitrothion by ZVI, the surfactant in Smithion lead to enhances solubility of fenitrothion and disperse ZVI.

• Proceedings of the KAIS Fall Conference
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• 2008.05a
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• pp.319-322
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• 2008

본 논문은 미분 반응기 및 유동층반응기에서 메탄의 열분해에 의한 수소 생산과 탄소 생성에 대한 연구를 수행하였다. 일반적으로 고온 분해시 사용되는 니켈과 철 성분을 대신할 철광석을 이용하여 분해특성을 고찰하였다. 환경에 대한 영향을 최소화한 상태에서 메탄의 전환반응을 메탄 분해촉매 활성에 영향을 미치는 인자에 대하여 연구하였다. 측정된 압력요동특성치의 해석을 통하여 유동층 열분해촉매의 유동화현상을 측정하였으며, 유동화특성에 따른 메탄열분해능을 측정하였다. 또한 고정층에서 공간속도, 입자크기, 비표면적이 미치는 영향을 고찰하여 철광석의 사용가능성을 타진하였다.