• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.3252-3260
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• 2012

2,2'-Bipyridinium chlorochromate[$C_{10}H_8N_2HCrO_3Cl$] was synthesized by the reaction of 2,2'- bipyridine with chromium(VI) trioxide in 6M HCl. The structure was characterized by IR and ICP analysis. The oxidation of benzyl alcohol using 2,2'-bipyridinium chlorochromate in various solvents showed that the reactivity increased with the increase in the order of the dielectric constant(${\varepsilon}$), in the order: cyclohexene< chloroform$p-CH_3$, H, m-Br, $m-NO_2$) in N,N'-dimethylformamide. Electron-donating substituents accelerated the reaction, whereas electron acceptor groups retarded the reaction. The Hammett reaction constant(${\rho}$) was -0.64(303K). The oxidation reactivity of alcohols can be a useful factor to study about physical properties such as thermal stability, when the polysilsesquioxane solution is ready for an applying coating agent. The observed experimental data was used to rationalized the hydride ion transfer in the rate-determining step.

• Bulletin of the Korean Chemical Society
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• v.26 no.10
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• pp.1525-1528
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• 2005

The synthesis and characterization of ${K_3[Ru(C_2O_4)3]{\cdot}4H_2O\;(C_2O_4}^{2-}$ = oxalato anoin) complex are described, and its redox properties (in buffer solution of pH = 12) have been investigated. This complex is used for in situ generation of oxoruthenates complexes which have been characterized by electronic spectroscopy. Reaction of ${K_3[Ru(C_2O_4)3]{\cdot}4H_2O$ with excess ${S_2O_8}^{2-}$ in molar KOH generates trans-${[RuO_3(OH)_2]^{2-}/S_2O_8}^{2-}$ reagent while with excess ${BrO_3}^-$ in molar $Na_2CO_3$ generates ${[RuO_4]^-/BrO_3}^-$ reagent. Avoiding the direct use of [$RuO_4$] the organic-soluble $(n-Pr_4N)^+[RuO_4]^-$, (TPAP) has been isolated by reaction of $K_3[Ru(C_2O_4)3]{\cdot}4H_2O$ with excess ${BrO_3}^-$ in molar carbonate and n-$Pr_4$NOH. In a mixture of $H_2O/CCl_4$ ruthenium tetraoxide can be generated by reaction of $K_3[Ru(C_2O_4)3]{\cdot}4H_2O$ with excess ${IO_4}^-$. The catalytic activities of oxoruthenates that have been made from $K_3[Ru(C_2O_4)3]{\cdot}4H_2O$ towards the oxidation of benzyl alcohol, piperonyl alcohol, benzaldehyde and benzyl amine at room temperature have been studied.

• Journal of the Korean Chemical Society
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• v.32 no.3
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• pp.179-185
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• 1988

The reaction of VO_2\;^+$ with benzyl alcohol in perchloric acid and aqueous dimethylformamide leads to the formation of $VO^{2+}$ and benzaldehyde. The products, $VO^{2+}$ and benzaldehyde, are identified by infrared spectroscopy and gas chromatography. Kinetic studies on the reaction of VO_2\;^+$ with benzyl alcohol have been carried out using visible spectroscopy. The empirical rate equation can be expressed as $-d[VO_2\;^+]/dt=2\{\\{k_O+k_H[HClO_4]\}\[VO_2\;^+][C_6H_5CH_2OH]$ The rate determining step for the reaction is the process for the formation of $VO^{2+}$ and $C_6H_5CHOH$. The activation parameters are ${\Delta}H^{\neq}=13.32{\pm}1.73\;kcalmol^{-1}$ and ${\Delta}S^{\neq}=-31.02{\pm}0.09\;calmol^{-1}K^{-1}$ for the oxidation of benzyl alcohol in aqueous dimethylformamide.

• Applied Chemistry for Engineering
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• v.28 no.5
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• pp.597-600
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• 2017

$(C_{10}H_8N_2H)_2Cr_2O_7$ was synthesized by reacting 4,4'-bipyridine and chromium (VI) trioxide. The structure of the product was characterized with FT-IR (infrared spectroscopy) and elemental analysis. The oxidation of benzyl alcohol using $(C_{10}H_8N_2H)_2Cr_2O_7$ in various solvents showed that the reactivity increased with the increase of the solvent dielectric constant, in the order of DMF (N,N'-dimethylformamide) > acetone > chloroform > cyclohexane. In the presence of DMF, an acidic catalyst such as $H_2SO_4$ $(C_{10}H_8N_2H)_2Cr_2O_7$ oxidized benzyl alcohol (H) and its derivatives ($p-OCH_3$, $m-CH_3$, $m-OCH_3$, m-Cl, $m-NO_2$). Electron donating substituents accelerated the reaction rate, whereas electron acceptor groups retarded the reaction rate. Hammett reaction constant (${\rho}$) was -0.70 (308 K). The observed experimental data were used to rationalize the hydride ion transfer in the rate determining step.

• Elastomers and Composites
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• v.55 no.1
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• pp.51-58
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• 2020

In this study, the thermal oxidation of raw natural rubber (NR) was investigated under controlled conditions by optical image and fourier transform infrared (FT-IR) analysis. The thermal oxidation was performed on a transparent thin film of raw NR coated on a KBr window in a dark chamber at 80℃ under low humidity conditions to completely exclude moisture and restrict light oxidation. Images of the thin film of raw NR were obtained before and after thermal oxidation. FT-IR absorption spectra were measured in the transmission mode at different thermal exposure times. The thermal oxidation of NR was examined by the changes in the absorption peaks at 3449, 1736, 1447, 1377, 1242, 1072, and 833 cm^-1, which corresponded to a hydroxyl group (-OH), a carbonyl group (-C=O) from an aldehyde and a ketone, a methylene group (-CH₂-), a methyl group (-CH₃), a carbon-oxygen single bond (-C-O) from an epoxide, a carbon-oxygen bond (-C-O) from an ether, an alcohol, a peroxide, or a cyclic peroxide, and a cis-methine group (cis-CCH₃=CH-), respectively. In the initial stage of thermal oxidation, two different types of free radicals were produced quickly and randomly by the homolytic cleavage of a double bond and allylic hydrogen abstraction. Aldehydes and ketones were formed from chain scissions of the double bonds and alcohols were produced from allylic hydrogen abstraction at the methylene or methyl groups. Two reactions seemed to proceed competitively with each other. At a later stage, oxidative crosslinks seemed to dominate through the combination of free radicals such as an allyl radical (CH=CHCH₂·), alkoxy radical (RO·), and peroxy radical (ROO·) and the reaction of a hydroperoxide (-ROOH) with a double bond. The image obtained after thermal oxidation showed hardening without cracks. Based on these observations, a plausible two-step mechanism was suggested for chain hardening caused by the thermal oxidation.

• Journal of the Korean Chemical Society
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• v.31 no.4
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• pp.359-363
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• 1987

Sonic waves (50KHz) was accelerated the oxidation reaction of primary, benzyl and secondary alcohol with $BaMnO_4\;and\;KMnO_4-CuSO_4{\cdot}5H_2O$ to give the corresponding aldehyde and ketone at $30^{\circ}C/1$ atm. in high yields compared to stirring or refluxing condition.

• Korean Journal of Food Science and Technology
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• v.33 no.1
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• pp.40-44
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• 2001

The effects of TEMPO and NaBr concentration, and temperature on the selective oxidation of primary alcohol groups in corn starch were examined. Reaction time decreased with the increased levels of TEMPO, NaBr and temperature up to 1.7 mM and 100 mM per 100 mM anhydroglucose unit(AGU) and $14^{\circ}C$, respectively, and did not change appreciably at the higher levels. Yield decreased with the increased NaBr levels and was not affected TEMPO level and the temperature. NaBr level and temperature showed negative effects on the selectivity. But the selectivity was not affected by NaBr level and temperature until 100 mM/100 mM AGU and $6^{\circ}C$. TEMPO had no effect on the selectivity significantly.

• Journal of the Korean Wood Science and Technology
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• v.9 no.2
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• pp.1-30
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• 1981

To investigate the formation of the chromophoric structures taking place during the alkaline pulping vanillyl alcohol [${\alpha}-^{13}C$] guaiacylglycerol-${\beta}$-aryl ether [${\alpha}-^{13}C$ or ${\gamma}-^{13}C$] and phenylcoumarn [${\alpha}-^{13}C$] units as model lignins were treated with 1N sodium hydroxide at 165$^{\circ}C$ for 1.5-3 hours. From the chemical structures of the isolated products and $^{13}C$-NMR Spectra of the reaction mixtures, the main conclusion is as follows; 1) Condensation products of II-1-5 were identified from the reaction mixture of vanillyl alcohol treated with alkali and theses compounds afforded the quinonmethide structure(Fig. 3-7) by air oxidation. 2) Treatment of guaiacylglycerol-${\beta}$-aryl ether unit gave ${\varphi}$-aryl-${\beta}$-aroxy quinone structures (IV-15, IV-16), diguaiacyl-1, 4-penta-diene ${\beta}$, ${\beta}$'-diaroxyl distyrene methane unit, ${\beta}$-aroxy distyrene methane. These distyrene methanes of the compounds are transformed by air oxidation into the corresponding o-quinonemethide units (V-8, V-9). 3) On the treatment of phenylcoumaran, the stilbene derivative was formed in quantitative yield and dimerized(VI-11) in preference to oxidation to the corresponding extended quinone structures. The chromophoric structures taken place during the alkaline treatment of the model lignins are thought to be some important types in alkaline pulping on the basis of the reaction mechanism in this experiment.

• Applied Chemistry for Engineering
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• v.5 no.2
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• pp.373-377
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• 1994

A mechanism for the synthesis of benzophenone from oxidation of diphenylmethane under Aliquit 336 phase transfer catalyst is investigated in this study. The production rate of benzophenone increased with the increasing amount of Allquat 336 and potassium tert-butoxide. At low concentrations of diphenylmethane and oxygen, the reaction order was first with the concentrations of diphenylmethane and oxygen respectively, but it approached to zero order at high concentrations. Tert-butyl alcohol, by-product of the reaction, inhibited the formation of benzophenone. Experimental results fit fairly well to the following initial reaction rate equation derived from reaction mechanism. $$({\gamma}_{BP})_0={\frac{k_1k_3k_5[QCI]_0[DPM]_0[PTB]_0[O_2]_0}{k_2k_4[TBA]_0+k_2k_5[O_2]_0+k_3k_5[O_2]_0[DPM]_0}}$$

• KSBB Journal
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• v.5 no.1
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• pp.81-85
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• 1990

Lignin was extracted from the rice straw by using the solvent mixture of buthyl alcohol and distilled water. And the experiment of vanillin production from extracted lignin was performed with the oxidation catalysts; CuO, Cu(OH)2 and CuSO4.5H2O. The optimum conditions of lignin extraction are the reaction temperature 12$0^{\circ}C$ and the mixture of 250mL buthyloloohol, 250mL, distilled water and 25g rice straw in the presence of 2.5g p-toluenesulfonic acid. The yield of vanillin from extracted lignin increased linearly with the increase of reaction temperature. And it increased with the order of Cu(OH)<$_2$ CuO$_4\cdot \;5H_2$Oas oxidation catalysts. The maximum yield of vanillin was 9% in the presence of 2.5%(w/v) CuSO$_4\cdot \;5H_2$O under the following conditions: temperature, 18$0^{\circ}C$; pressure, 13atm; pH 4.0 and reaction time, two hours.