• Bulletin of the Korean Chemical Society
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• 제30권7호
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• pp.1573-1578
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• 2009

A computational study of the reactions between Zn-containing species, the products of the thermal decomposition of diethylzinc (DEZn) and water was investigated. The Zn-containing species – $C_2H_5)_2,\;HZnC_2H_5,\;and\;(ZnC_2H_5)_2$ – were assumed to react with water during ZnO metal organic chemical vapor deposition (MOCVD). Density functional theory (DFT) calculations at the level of B3LYP/6-311G(d) were employed for the geometry optimization and thermodynamic property evaluation. As a result dihydroxozinc, $Zn(OH)_2$, was the most probable reaction product common for all three Zn-containing species. A further clustering of $Zn(OH)_2$ was investigated to understand the initial stage of ZnO film deposition. In experiments, the reactions of DEZn and water were examined by in-situ Raman scattering in a specially designed MOCVD reactor. Although direct evidence of $Zn(OH)_2$ was not observed, some relevant reaction intermediates were successfully detected to support the validity of the gas phase reaction pathways proposed in the computational study.

• Applied Science and Convergence Technology
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• 제23권1호
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• pp.14-26
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• 2014

Copper is an important component from coin metal to electronic wire, integrated circuit, and to lithium battery. Copper oxides, mainly including $Cu_2O$ and CuO, are important semiconductors for the wide applications in solar cell, catalysis, lithium-ion battery, and sensor. Due to their low cost, low toxicity, and easy synthesis, copper oxides have received much research interest in recent year. Herein, we review the crystallization of copper oxides by designing various chemical reaction routes, for example, the synthesis of $Cu_2O$ by reduction route, the oxidation of copper to $Cu_2O$ or CuO, the chemical transformation of $Cu_2O$ to CuO, the chemical precipitation of CuO. In the designed reaction system, ligands, pH, inorganic ions, temperature were used to control both chemical reactions and the crystallization processes, which finally determined the phases, morphologies and sizes of copper oxides. Furthermore, copper oxides with different structures as electrode materials for lithium-ion batteries were also reviewed. This review presents a simple route to study the reaction-crystallization-performance relationship of Cu-based materials, which can be extended to other inorganic oxides.

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1794-1796
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• 2012

• Bulletin of the Korean Chemical Society
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• 제32권spc8호
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• pp.3145-3148
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• 2011

• Bulletin of the Korean Chemical Society
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• 제30권12호
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• pp.3082-3084
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• 2009

• Bulletin of the Korean Chemical Society
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• 제14권1호
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• pp.32-38
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• 1993

3-(3-Bromotetrahydrofuran-2-yl)-3-cephem 7 was obtained from 3-(2-hydroxyethyl)vinyl-3-cephem 6 by the cyclization reaction using N-bromosuccinimide. Compound 5 was prepared by Wittig reaction, namely a coupling of cephem-derived triphenylphosphonium salt 3 with aldehyde component 4 in the presence of base.

• Bulletin of the Korean Chemical Society
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• 제13권2호
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• pp.184-187
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• 1992

Regeneration methods of oximes, hydrazones, and N,N-dimethylhydrazones to the related carbonyl compounds were effected using various dicarbonyl compounds which are activated with electron withdrawing substituents such as trifluoromethylated $\beta-diketones$, $\beta-acylpyruvates$, and $\alpha-diketones$ via an equilibrium exchange reaction. The chemical transformations of the dicarbonyl compounds in the exchange reaction were investigated by various spectroscopic methods.

• KSBB Journal
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• 제19권5호
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• pp.385-389
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• 2004

In this research, the chemo-enzymatic synthesis of sorbitan methacrylate was investigated to optimize reaction conditions. Firstly, sorbitan was manufactured by sorbitol cyclic reaction in the presence of p-toluenesulfonic acid (p-TSA) as catalyst material. Secondly, sorbitan methacrylate was synthesized by immobilized lipase Novozyme 435 with acyl donors in t-butanol. As a result of enzymatic synthesis of sorbitan methacrylate, the conversion yield reached about $65\%$ in the condition of initial sorbitan conc. 50 g/L, enzyme content $3\%$ (w/v) , molar ratio 1:3, reaction temperature 50^{circ}C and reaction time 42 hrs using methyl methacrylate as acyl donor. Comparing with acyl donors and reaction temperature, the conversion yield reached about 18, 65 and $80\%$ with methacrylic acid, methyl methacrylate and vinyl methacrylate as acyl donor, respectively. And optimum reaction temperature was 60, 50, and 50^{circ}C, respectively

• 공업화학
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• 제10권6호
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• pp.885-888
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• 1999

본 연구에서는 $Na_2B_4O_7{\cdot}10H_2O/Na_2B_4O_7{\cdot}5H_2O$ 반응계의 열분해 탈수반응에 의한 반응속도상수를 결정하고 반응계의 재현성 및 화학축열재의 반복사용에 따른 내구성을 검토하였다. 반응계의 열분해 탈수반응의 차수는 1차이었고, 열분해 탈수 반응속도는 수증기의 분압차에 정비례하였다. 반응계의 반응속도상수는 약 0.27이었고, 반응속도상수와 반응차수에 대한 반응의 재현성이 우수하였다. 또한 화학축열재의 내구성은 연속적으로 반복 사용하여도 활성변화는 ${\pm}5%$ 범위 내에 있었다.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제2권1호
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• pp.79-84
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• 1998

The rates of absorption of carbon dioxide into aqueous solutions of 2-amino-2-methyl-1-propanol (AMP) were measured using a semibatch stirred vessel with a plane gas-liquid interface at $25^{\circ}C.$ The absorption rates under the fast reaction regime were analysed using chemical absorption theory. The reaction was found to be first order with respect to both $CO_2$ and the amine.