• Bulletin of the Korean Chemical Society
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• v.30 no.10
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• pp.2208-2212
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• 2009

Oxidation of cycloalkenes with $O_2$ promoted by heterogeneous bis(acetylacetonato) cobalt (II) complex catalyst which can be recycled has been performed under mild conditions. It was found that $\beta$-ionone, cyclohexene, 1-methylcyclohexene, and $\alpha$-ionone were efficiently oxidized with $O_2$ in the presence of Co (II) complex and butyraldehyde at $55\;{^{\circ}C}$. A simple treatment of the resulting products led to epoxides as predominant products and a small amounts of allylic oxides, the chemoselectivity for the former being 82.1 - 90.8% with a 70.6 - 98.6% substrate conversion. On the other hand, oxidation of 1-phenylcyclohexene, 1-cyclohex-1-enylethan-1-one, $\alpha$-pinene, and $\beta$-pinene gave allylic oxides as major products.

• Bulletin of the Korean Chemical Society
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• v.23 no.4
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• pp.626-628
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• 2002

• Bulletin of the Korean Chemical Society
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• v.33 no.7
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• pp.2251-2254
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• 2012

A rapid and practical green route for N-formylation of primary and secondary amines with formic acid at room temperature under the solvent-free conditions using HEU zeolite as a heterogeneous, reusable and highly efficient catalyst is described. The process is remarkably simple and environmentally benign. Excellent chemoselectivity was observed for the conversion of primary amines in the presence of secondary amines.

• Bulletin of the Korean Chemical Society
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• v.18 no.12
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• pp.1269-1273
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• 1997

The system which employs iron, palladium, molecular oxygen and hydrogen as a model mono-oxygenase, has been investigated to develop a new method for selective cyclohexane oxidation uner mild conditions. This system provides much higher yield and selectivity for the formation of cyclohexanol and cyclohexanone compared to that of the existing industrial method. When the catalytic system, FeCl2-Pd/alumina, was employed, the oxidation system required acetone as a solvent to be efficient and acidifying the solvent by a little addition of acetic acid or HCl made the system more efficient. The Pd catalyst was recyclable without a significant deactivation but the recycling of ferrous chloride showed the decrease in the activity. On the other hand, the heterogeneous catalytic system, Pd/Fe2O3 could be recovered easily and reused after drying treatment.

• Bulletin of the Korean Chemical Society
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• v.15 no.7
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• pp.563-567
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• 1994

The electroreduction of dioxygen at glassy carbon electrodes with irreversible self-assembly of N-hexadecyl-N'-methyl viologen $(C_{16}VC_1)$ proceeds at potentials more positive than those where the reduction occurs at bare electrodes. The electrocatalyzed reduction takes place at potentials well ahead of those where the catalyst is reduced in the absence of dioxygen and the limiting currents observed at rotating disk electrodes did not deviate from the thoretical Levich line up to 6400 rpm, indicating that the electrocatalysis is extremely rapid. The rate constant for the heterogeneous reaction between $C_{16}V^+C_1$ immobilized on the electrode surface and $O_2$ in solution was estimated to be ca. $10^8\;M^{-1}s^{-1}$. The half-wave potential of dioxygen reduction was independent of solution pH.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.253-261
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• 2005

Catalytic wet oxidation of ppm levels of trichloroethylene (TCE) in water has been conducted using $TiO_2$-supported cobalt oxides at a given temperature and weight hourly space velocity. 5% $CoO_x/TiO_2$ might be the most promising catalyst for the wet oxidation at $36^{\circ}C$ although it exhibited a transient behavior in time on-stream activity. Not only could the bare support be inactive for the wet decomposition reaction, but no TCE removal also occurred by the process of adsorption on $TiO_2$ surface. The catalytic activity was independent of all particle sizes used, thereby representing no mass transfer limitation in intraparticle diffusion. Characterization of the $CoO_x$ catalyst by acquiring XPS spectra of both fresh and used Co surfaces gave different surface spectral features of each $CoO_x$. Co $2p_{3/2}$ binding energy of Co species exposed predominantly onto the outermost surface of the fresh catalyst appeared at 781.3 eV, which is very similar to the chemical states of $CoTiO_x$ such as $Co_2TiO_4$ and $CoTiO_3$. The spent catalyst possessed a 780.3 eV main peak with a satellite structure at 795.8 eV. Based on XPS spectra of reference Co compound, the TCE-exposed Co surfaces could be assigned to be in the form of mainly $Co_3O_4$. XRD measurements indicated that the phase structure of Co species in 5% $CoO_x/TiO_2$ catalyst even before reaction is quite comparable to the diffraction lines of external $Co_3O_4$ standard. A model structure of $CoO_x$ present on titania surfaces would be $Co_3O_4$, encapsulated in thin-film $CoTiO_x$ species consisting of $Co_2TiO_4$ and $CoTiO_3$, which may be active for the decomposition of TCE in a flow of water.

• Clean Technology
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• v.21 no.2
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• pp.130-139
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• 2015

The NO oxidation process has been applied to improve a removal efficiency of NO included in exhaust gas. In this study, to produce a dry oxidant for the NO oxidation process, the catalytic H₂O₂ decomposition method was proposed. A variety of the heterogeneous solid-acidic Mn-based catalysts were prepared for the catalytic H₂O₂ decomposition and the effect of their physico-chemical properties on the catalytic H₂O₂ decomposition were investigated. The results of this study showed that the acidic sites of the Mn-based catalysts has an influence on the catalytic H₂O₂ decomposition. The Mn-based catalyst having the abundant acidic sites within the wide temperature range in NH₃-TPD shows the best performance for the catalytic H₂O₂ decomposition. Therefore, the NO oxidation efficiency, using the dry oxidant produced by the H₂O₂ decomposition over the Mn-based catalyst having the abundant acidic properties under the wide temperature range, was higher than the others. As a remarkable result, the best performances in the catalytic H₂O₂ decomposition and NO oxidation was shown when the Mn-based Fe₂O₃ support catalyst containing K component was used for the catalytic H₂O₂ decomposition.

• Clean Technology
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• v.19 no.3
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• pp.313-319
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• 2013

To produce biodiesel efficiently from fish oil containing 4% free fatty acid, esterification and trans-esterification were carried out with Vietnam catfish oil, which was kindly provided from GS-bio company. Heterogeneous solid acid catalysts such as Amberlyst-15 and Amberlyst BD-20 and sulfuric acid as homogeneous acid catalyst were used for the esterification of free fatty acids in the fish oil. Sulfuric acid showed the highest removal efficiency of free fatty acid and the shortest reaction time among three acid catalysts. The base catalysts for trans-esterification such as KOH, $NaOCH_3$ and NaOH were compared with each other and KOH was determined to be the best transesterification catalyst. Some solid material, which assumed to be saponified product from glycerol and biodiesel, were observed to form in the fish oil biodiesel when using $NaOCH_3$ and NaOH as the transesterification catalyst. The initial acid value of fish oil was proven to have a negative effect on biodiesel conversion. Of the three catalysts, KOH catalyst transesterification was shown to have high content of FAME and the optimal ratio of methanol/oil ratio was identified to be 9:1.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.119-124
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• 2018

The production of methyl N-phenyl carbamate by an oxidative carbonylation method of aniline and methanol is of great interest as an environmentally friendly process that can replace the monomer production process of a polymer produce using conventional phosgene. In this study, heterogeneous catalysts were prepared by using Y-zeolite, $SiO_2$, $Al_2O_3$ as support, and oxidative carbonylation continuous operation from aniline and methanol was attempted using the prepared heterogeneous catalyst. Batch reactor was used to determine the support, and various reaction conditions such as reaction temperature, reaction pressure, and effect of promoter were established using palladium catalyst. A reaction kinetics study was conducted under optimum reaction conditions. The basic data for carbamate process development were obtained by performing continuous operation for a long time under established reaction condition.

• Applied Chemistry for Engineering
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• v.5 no.2
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• pp.230-237
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• 1994

The reaction conversions of n-butyl acetate in the alkaline hydrolysis of n-butyl acetate by Aliquat 336 were measured in a flat agitator and a dispersion agitator. These measured data was used to analyze the complicated reaction mechanism of the liquid-liquid heterogeneous reaction by a phase transfer catalyst with a pseudo-first order reaction model, a interfacial reaction model and a bulk-body reaction model. The pseudo-firsts order reaction model and the interfacial reaction model could be explained by the experimental data from the dispersion agitator and the bulk-boby reaction model could be explained by those from the flat agitator and the reaction rate constants were $3.1{\times}10^{-4}$, $7.3{\times}10^{-4}$, $6.6m^3/kmol.s$ from these models at $25^{\circ}C$, respectively.