• KSBB Journal
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• 제18권3호
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• pp.222-228
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• 2003

당알콜인 D-sorbitol을 화학 촉매 p-toluenesulfonic acid(p-TSA)를 이용하여 탈수반응을 수행하여 고리구조의 1,4-sorbitan을 제조 후 효소적으로 고정화 리파제 Novozym 435를 이용하여 아크릴산과 에스테르화 반응을 수행한 결과 아래와 같은 결론을 얻었다. D-Sorbitol을 p-TSA를 화학촉매로 하여 탈수반응을 통한 고리화 반응의 생성물인 1,4-sorbitan의 최대수율을 얻을 수 있는 최적조건은 1% (w/w)의 p-TSA를 이용하여 200 mmHg의 감압조건에서 13$0^{\circ}C$에서 150분 반응 후 약 90%의 1,4-sorbitan을 얻을 수 있었으며, 부산물과 미반응의 D-sorbitol의 양을 최소화시킬 수 있었다. 화학적 촉매반응의 생성물로 얻은 1,4-sorbitan을 고정화 리파제 (Novozym 435)를 이용하여 반응매질 t-butanol에서 아크릴산과의 에스테르화 반응을 수행한 결과, 5$0^{\circ}C$에서 고정화효소는 최대 활성을 보였으며, 최적 첨가량은 3% (w/v)이었다. 또한 초기농도가 반응의 전환율에 미치는 영향을 조사한 결과 1,4-sorbitan 50 8/L의 초기농도에서 55.8%의 최대 전환율을 얻었으며, 63.5%의 반응수율을 보인 1:3의 몰비가 최적으로 조사되었다.

• 공업화학
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• 제26권3호
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• pp.347-350
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• 2015

본 논문에서는 친환경 촉매 중 하나인 이온성액체를 이용한 이소부탄 알킬레이션 반응에 대해서 연구하였다. 산성 이온성액체 중 하나인 1-Octyl-3-methylimidazolium-bromide-aluminum chloride를 촉매로 사용하였다. 최적의 반응조건을 규명하기 위하여 액체공간속도, 반응온도 및 이온성액체의 조성에 따른 반응성능에 대하여 조사하였다. 일정한 실험 조건에서 반응온도의 경우 $80^{\circ}C$에서 최적의 반응성능을 보였고 이온성액체의 조성은 음이온 비가 0.56인 경우 우수한 반응특성을 보였다. 또한 반응조건에 따른 생성물의 수율을 예측할 수 있는 모델식을 통계학적 접근을 통해 완성하였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.124.1-124.1
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• 2010

The impurities in the methanol fuel that is used for direct methanol fuel cell (DMFC) could greatly affect the performance of membrane electrode assemblies (MEA). The most common impurities in the commercial methanol fuel are mainly ethanol, acetone, acetaldehyde, or ammonia. In this study, the effect of impurities in methanol fuel was investigated on the performance of MEA. The MEA for DMFC were prepared using a semi-automatic bar-coating machine, which can prepare the catalyst layer with uniform thickness for MEA. As a result, a single cell supplied with one of the 6 different kinds of methanol fuels showed a significant degradation of the fuel cell performance. The most common impurities in the commercial methanol fuel is mainly ethanol, acetone, acetaldehyde, or ammonia. The effects of the kind and the concentration of impurities in the methanol fuels were investigated on the performance of MEA for DMFC. We will propose the optimum compositions and limit concentration of impurities in methanol fuel for high performance of MEA for DMFC.

• 대한화학회지
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• 제41권5호
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• pp.246-250
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• 1997

히드록실아민이 존재하는 붕산염 매질에서 루테늄(III)은 수은 표면에 사전농축이 잘 되었고 이 피흡착질의 환원 생성물에 의한 촉매 수소 전류를 측정함으로써 혼적량 루테늄을 정량할 수 있었다. 순환 전압전류법으로 산화환원 및 흡착 누적 특성을 조사하였다. 최적 조건은 다음과 같다: 붕산염 0.015 M, pH 2,5, 히드록실아민 0.55 M, 누적 전위 -0.70 V, 그리고 시차 펄스 모드에서 주사속도 5 mV/s이었다. 이 조건에서 검출한계는 $3{\times}10^{-10}$(7분 수집)이었다. 방해 가능한 다른 백금족 금속이온들의 허용량도 조사하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.677-682
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• 2001

Catalytic combustion is the environmental-friendly technology, which has been applied to a variety of areas for industrial and domestic use in recent years. Accordingly, this study performed the development of the catalytic manufacturing technology for the high temperature and of the catalytic combustor in priority, which were aimed to be applied to a commercialized boiler. Paliadium(Pd) of a noble metal was used as a catalyst for the high temperature and supported on alumina($Al_[2}O_{3}$) and zirconia($ZrO_{2}$) in constant weight ratio. Activity of Pd catalysts is compared and analyzed in the catalytic combustion of natural gas. The ratio of $Pd/Al_{2}O_{3}=4$ was found to be better than any other weight ratios in activity and durability. The performance examination of catalysts and of combustion through the plate-type combustor made it possible to be developed the cylindrical-type combustor which has increased combustion area. Catalytic combustion boiler of 25,000 kcal/hr class was also developed, which had the optimum combustion condition at the nozzle of 5.95mm and the orifice of 21mm. This condition was determined through the performance experiments of catalytic combustion boiler to which the cylindrical-type catalytic combustor was applied.

• Bulletin of the Korean Chemical Society
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• 제28권10호
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• pp.1661-1664
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• 2007

Direct reaction of elemental silicon with a gaseous mixture of isopropyl chloride (1) and hydrogen chloride in the presence of copper catalyst using a stirred bed reactor equipped with a spiral band agitator gave isopropyldichlorosilane having a Si-H bond (2a) as a major product and isopropyltrichlorosilane (2b) along with chlorosilanes, trichlorosilane and tetrachlorosilane. A process for production of 2a was maximized using the 1:0.5 mole ratio of 1 to HCl and smaller size of elemental silicon at a reaction temperature of 220 °C. When a reaction was carried out by feeding a gaseous mixture of 1 [12.9 g/h (0.164 mol/h)] and HCl [2.98 g/h (0.082 mol/h)] to a contact mixture of elemental silicon (360 g) and copper (40 g) under the optimum condition for 45 h, 2a among volatile products kept up about 82 mol % until 35 h and then slowly decreased down 68 mol % in 45 h reaction. Finally 2a was obtained in 38% isolated yield (based on 1 used) with an 85% consumption of elemental silicon in a 45 h reaction. In addition to 2a, 2b was obtained as minor product along with chlorosilanes, trichlorosilane, and tetrachlorosilane. The decomposition of 1 was suppressed and the production of 2a improved by adding HCl to 1.

• 한국환경과학회지
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• 제14권9호
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• pp.889-896
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• 2005

The nanosized $TiO_2$ photocatalysts were prepared by the hydrolysis of $TiCl_4$ and calcined at different temperatures. The resulting materials were characterized by TGA, DSC, XRD, and TEM testing techniques. XRD, TEM, and BET measurements indicated that the particle size of $TiO_2$ was increased with rise of calcination temperature and surface area was decreased with rise of it. The prepared $TiO_2$ photocatalysts were used for the photocatalytic degradation of congo red. The effects of calcination temperature, $TiO_2$ loading, the initial concentration of congo red, and usage frequencies were investigated and the rate constants were determined by regressing the experimental data. Calcination is an effective treatment to increase the photo activity of nanosized $TiO_2$ photocatalysts resulting from the improvement of crystallinity. The optimum calcination temperature of the catalyst for the efficient degradation of congo red was found to be $400^{\cric}C$. The rate constant was decreased with increase in the initial concentration of congo red and increased with increase in the $TiO_2$ loading. In the case of $TiO_2$ photocatalysts, the photocatalytic activity wasn't greatly affected by the usage frequencies.

• 센서학회지
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• 제22권3호
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• pp.197-201
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• 2013

This paper describes the fabrication and characterization of graphene based carbon dioxide ($CO_2$) gas sensors. Graphene was synthesized by thermal decomposition of SiC. The resistivity $CO_2$ gas sensors were fabricated by pure graphene and graphene decorated Au nanoparticles (NPs). The Au NPs with size of 10 nm were decorated on graphene. Au electrode deposited on the graphene showed Ohmic contact and the sensors resistance changed following to various $CO_2$ concentrations. Resulting in resistance sensor using pure graphene can detect minimum of 100 ppm $CO_2$ concentration at $50^{\circ}C$, whereas Au/graphene can detect minimum 2 ppm $CO_2$ concentration at same at $50^{\circ}C$. Moreover, Au NPs catalyst improved the sensitivity of the graphene based $CO_2$ sensors. The responses of pure graphene and Au/graphene are 0.04% and 0.24%, respectively, at $50^{\circ}C$ with 500 ppm $CO_2$ concentration. The optimum working temperature of $CO_2$ sensors is at $75^{\circ}C$.

• 한국의류학회지
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• 제10권2호
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• pp.59-67
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• 1986

To control the amounts of formaldehyde released from the cotton fabric finished with N-methylol compounds, glycerol was used as a formaldehyde-scavenging agent. It was observed the effects of catalysts and curing conditions when aftertreated with glycerol on melamine resin finished fabric. The effects of Different processes of glycerol treatment, and different resins, urea resin and melamine resin, were compared. The conclusions obtained from the results are as follows: 1) It was shown hatt the aftertreatment with glycerol (treated without catalyst) was more effective than treated with catalysts in controlling free formaldehyde. 2) The optimum curing temperature and curing time for the glycerol aftertreatment without adversely affecting the other properties of fabric was about $160^{\circ}C$, 3 min. 3) According to the increase of glycerol concentration in both aftertreatment and simultaneous treatment the amounts of free formaldehyde was reduced. The rate of decrease was manifest within the limits of $6\%$ in the case of simultaneous treatment with glycerol ana resins, and $3\%$ in the case of glycerol aftertreatment on resin finished fabrics. 4) Dry wrinkle recovery angle was decreased the increase of glycerol concentration. Melamine resin had a little adverse effect than urea resin, particulary glycerol aftertreatment. 5) The breaking strength was increased with the increase of glycerol concentration.

• 한국의류학회지
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• 제13권3호
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• pp.242-251
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• 1989

The purpose of this study was to investigate the changes in easy-care and strength properties of the wet fixation processed viscose rayon fabrics. Rayon fabrics were treated with mixed resins of melamine formaldehyde (MF) and DMDHEU by one bath and two bath wet fixation processes. The MF/DMDHEU mixed resin concentrations were 50/100, 50/150, 100/100, 100/150 and 150/100(g/1). Magnasium chloride was used as a catalyst. Treated fabrics were evaluated by nitrogen content, DP rating, wrinkle recovery angle, breaking strength, tearing strength and abrasion resistance. The properties were compared to the fabrics treated by conventional Pad-Dry-Cure (PDC) method. Wet fixation processed fabrics showed DP ratings of higher than 3 and higher than 275 degrees of wrinkle recovery angles in all the mixed resin concentrations. Wet fixation processed fabrics showed increase in breaking strength and tearing strength but decrease in abrasion resistance. However, the decrease in abrasion resistance was much less than the conventional PDC treated fabrics. The one bath wet fixation processed fabrics showed better physical properties than the two bath processed fabrics in general. The optimum treatment condition was the mixed resin concentration of MF/DMDHEU, 100/100 g/l in one bath wet fixation process.