• 한국식품과학회지
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• 제22권3호
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• pp.332-336
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• 1990

레놀레산이 함유된 액상 모델시스템에 있어서 지방산의 산화반응에 미치는 양조간장(분말)의 항산화 특성에 대한 일련의 연구를 행하여 다음과 같은 결과를 얻었다. 양조간장은 산화반응 과정 중 과산화물 생성을 억제하였으며, 반응에 첨가된 양조간장의 함량이 높을수록 항산화 작용이 더 큰 결과를 보였다. 이를 기존 항산화제와 비교하였을 때 알파-토코페롤0.05% 첨가수준의 항산화성은 양조간장 분말 $0.2{\sim}0.5%$ 범위에 있었다. 그리고 10ppm의 염화제일철이 함유된 산화반응에 있어서 양조간장은 미량금속의 산화촉진작용을 저하시켰으며 구연산과 공존할 때 항산화작용의 상승효과도 있었다. 또한, 양조간장은 oxidative free radical과 반응하였을때 수소공여성이 인정되었으며 리놀레산 혼합물의 리폭시제나이제 촉매적 산화반응을 억제하는 효과도 보였다.

• 대한화학회지
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• 제10권2호
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• pp.76-90
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• 1966

Ammonium sulfate synthesized by the air oxidation methods without catalyst using the reaction vessel which was fitted with fritted glass at the bottom of it and introducing, through the bottom, ammonia and air with constant flow rates to sulfurous acid solution of constant concentrations at the given temperatures. The experiment showed that the oxidation process was accelerated in accord with the increase of the air flow rates when the ammonia flow rate was constantly kept at ca. 100ml/min. in high temperatures. When the pH of the solution reached 9.0, the oxidation was nearly completed. It is assumed that in the process of reaction, $[O_{2}{\to}HSO_{3}^-]^{\neq}$ would be produced as an activated complex and the reaction was thought to be first order. The experiment indicated that the 0.5M sulfurous solution could be oxidized up to 98.54% at the flow rates of ammonia and air, 100ml/min., and 4l/min., respectively at $50^{\circ}C$.

• Preventive Nutrition and Food Science
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• 제2권1호
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• pp.6-10
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• 1997

The reaction mechanisms and kinetics of tertiary butylhydroquinone(TBHQ) as an antioxidant in soybean oil oxidation were studied. The oxidation reaction of soybean oil at 55, 60 and $65^{\circ}C$ was a first order. The activation energies of soybean oil containing 0, 25, 50, and 75ppm TBHQ were 12.15, 6.05, 6.15 and 6.17kcal/mole. respectively. The addition of THQ to soybean oil containing 0, 25, 50, and 75ppm TBHQ were 1.88$\times${TEX}$10^{7}${/TEX}, 4.10$\times${TEX}$10^{2}${/TEX}, 4.32 $\times${TEX}$10^{2}$p/TEX} and 3.97$\times${TEX}$10^{2}${/TEX}, respectively. The decrease of frequency factor rather than the activation energy. The effects of antioxidants on the temperature dependecy of lipid oxidation could be effectively evaluated by measuring their effects on the activation energy of lipid oxidation.

• 공업화학
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• 제31권4호
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• pp.368-376
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• 2020

본 연구에서는 SO₂를 제어하기 위한 산화 촉매에서 platinum (Pt)을 활성금속으로 하는 촉매의 반응특성에 관한 분석을 수행하였다. Titania (TiO₂) 지지체에 다양한 precursor 형태의 Pt를 사용하여 Pt/TiO₂ 촉매를 제조하여 실험에 사용하였다. Pt/TiO₂ 상의 Pt²⁺ 또는 Pt⁴⁺와 같은 Pt valence state에 따른 SO₂ 산화의 성능 차이는 나타나지 않으며, PtCl_x과 같은 Pt chloride species는 전체적으로 SO₂ 산화 성능을 감소시킨다. 또한, XPS 분석을 수행하여 SO₂ 산화 반응 전/후의 촉매상의 valence state를 분석한 결과 SO₂ 산화반응 이후 lattice oxygen의 감소 및 surface chemisorbed oxygen의 증가를 확인할 수 있다. 따라서 Pt/TiO₂ 촉매의 SO₂의 산화 반응은 PtOx에 해당하는 lattice oxygen의 반응과 oxygen vacancy에 의한 산화-환원 반응이 진행되는 Mar-Van Krevelen 메커니즘이 주요한 SO₂ 산화 반응임을 판단할 수 있으며, 이러한 결과를 통하여 촉매 상에 존재하는 PtOx (Pt²⁺ 또는 Pt⁴⁺)의 oxygen species가 주요한 활성 site로 작용함을 확인할 수 있다.

• 한국응용과학기술학회지
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• 제22권2호
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• pp.136-141
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• 2005

This paper presents applicability of Fenton oxidation to perchloroethylene(PCE) contaminated soil. The initial concentration of PCE was 187mg/kg and Fenton oxidation conditions were 1.0M $H_2O_2$ and 0.5M $Fe^{2+}$. More than 97% of PCE decomposition and 98% of dechlorination were obtained within 5 hrs. It was found that the decomposition of PCE by Fenton oxidation was followed pseudo first order and its reaction coefficient was 0.78 $hr^{-1}$. GC-MS and GC-ECD analysis of reaction intermediates confirmed only the presence of trichloroacetic acid(i.e., 1.0% of initial PCE concentration). Under Fenton oxidation conditions, it was proposed that PCE was decomposed not simultaneously but one by one.

• Carbon letters
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• 제9권2호
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• pp.121-126
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• 2008

High modulus pitch based carbon fibers (HM) were exposed to isothermal oxidation using tube furnace in carbon dioxide gas to study the oxidation kinetics under the temperature of $800-1100^{\circ}C$. The kinetic equation $f=1-{\exp}(-at^b)$ was introduced and the constant b was obtained in the range of 1.02~1.42. The oxidation kinetics were evaluated by the reaction-controlling regime (RCR) depending upon the apparent activation energies with the conversion increasing from 0.2 to 0.8. The activation energies decrease from 24.7 to 21.0 kcal/mole with the conversion increasing from 0.2 to 0.8, respectively. According to the RCR, the reaction was limited by more diffusion controlling regime for the HM fibers with the conversion increasing. Therefore, it seems that the oxidation which is under the diffusion controlling regime takes place continuously from the skin to the core of the fiber.

• Bulletin of the Korean Chemical Society
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• 제33권1호
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• pp.35-38
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• 2012

Room temperature oxidation of organic sulfides with polyvinylpyrrolidone-supported hydrogen peroxide (PVP-$H_2O_2$) in the presence of Mn(III) complexes of meso-tetraphenylporphyrin, Mn(TPP)X (X = OCN, SCN, OAc, Cl) and imidazole (ImH) leads to the highly chemoselective (ca. 90%) oxidation of sulfides to the corresponding sulfoxide. The efficiency of reaction has been shown to be influenced by different reaction parameters such as the nature of counterion (X) and solvent as well as the molar ratio of reactants. Using Mn(TPP)OCN and ImH in 1:15 molar ratio and acetone as the solvent leads to the efficient oxidation of different sulfides.

• 한국표면공학회지
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• 제34권1호
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• pp.25-32
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• 2001

$TiB_2$ ceramics were oxidized at 800, 900 and $1000^{\circ}C$ in air for 40 hr, and their oxidation property was investigated using TGA, XRD, SEM and EPMA. The oxidation resistance decreased with an increase in oxidation temperature. The scale was essentially composed of $TiO_2$ only. $B_2$$O_3$ formed during oxidation escaped from the $TiO_2$ oxide scale owing to its high vapor pressure. This made the oxide scale highly porous and thick. The oxidation reaction was mainly governed by the inward transport of oxygen.$ TiO_2$ existing at the outermost scale grew into peculiarly shaped blades, as the reaction progressed.

• 대한화학회지
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• 제56권2호
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• pp.212-216
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• 2012

The kinetics of oxidation of nicotinic acid by peroxomonosulfate (PMS) has been studied in acetate buffers. Stoichiometry of the reaction corresponds to the reaction of one mole of the oxidant with a mole of nicotinic acid. N${\rightarrow}$O product has been confirmed both by UV visible and IR spectroscopy. The reaction is second order viz. first order with respect to each reactant. Activation parameters have also been evaluated. A plausible reaction mechanism is mentioned and the derived kinetic rate law accounts for experimental observations.

• 한국대기환경학회지
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• 제6권1호
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• pp.57-72
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• 1990

The oxidation of carbon monoxide on a catalyst, $LaSrNiCoO_3$ was investigatigated with a plug flow system. Kinetic quantities such as reaction-rate, reaction order and Arhenius-parameters at various reactor temperature from 200$^\circ$C to 300$^\circ$C were determined. Also, the optimum condition for the oxidation of carbon monoxide with this catalyst was determined and are as follows. Partial pressure of oxigen ; 428mmHg Partial pressure of carbon monoxide ; 332mmHg Mixed moral ratio of oxigen and Carbon monoxide ; 1.3 : 1 Total gas flow ; 224ml/min Reaction temperature ; 340$^\circ$C The reaction kinetic equation at the optimum condition, temperature range from 200$^\circ$C to 340$^\circ$C, are as follow. $$ $v = Ae^{6.5Kcal/RT} [CO]^{0.93 \sim 0.98} [O_2]^{0.42 \sim 0.50}$ $$ In addition to this, numerical calculation were performed to evaluate the mass and heat transfer effect on this system.