• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.537-541
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• 2010

Pt-Sn with various ratios was supported on carbon black after pretreatment in an acidic solution by a reduction method. The Pt/Sn ratio was controlled by varying the concentration of each component in the solution, and the influence of the composition on the electrocatalytic activities was investigated. The crystallinity of the synthesized materials was investigated by XRD (X-ray Diffraction), and the oxidation states of both the platinum and tin were determined by XPS (X-ray Photoelectron Spectroscopy). SEM (Scanning Electron Microscopy)-EDS (Energy Dispersive Spectroscopy) was utilized to examine the morphology and composition of the synthesized electrode, and the particle size of the Pt-Sn was analyzed by TEM (Transmission Electron Microscopy). The electrocatalytic activity for oxygen reduction was evaluated in a 0.5 M $H_2SO_4$ solution using a rotating disk electrode system. The activity and stability were found to be strongly dependent on the electrode composition (Pt/Sn ratio). The catalytic activity and stability for methanol oxidation were also measured using cyclic voltammetry (CV) in a mixture of 0.5 M $H_2SO_4$ and 0.5 M $CH_3OH$ aqueous solution. The addition of proper amount of Sn was found to significantly improve both catalytic activity and stability for methanol oxidation.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.106.2-106.2
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• 2010

동식물성 기름과 메탄올의 전이에스테르화 반응에 의해 생산되는 바이오디젤은 환경친화성과 지속가능성이 인정됨에 따라 그 생산량이 급격히 증가하고 있어 대두유, 유채유, 팜유 등의 원료유 부족과 가격 상승, 수급 불안정 등의 문제가 대두되고 있다. 이를 해결하기 위한 방안으로 유리지방산 함량이 높은 저가유지 자원(폐식용유, 폐돈지, 폐우지, soapstock, trapped grease)과 새로운 오일 작물을 이용한 생산 기술 연구가 활발히 진행되고 있다. 본 연구에서는 비활용 해외 열대작물 씨앗에서 착유한 식물성 오일을 정제하여 바이오디젤 원료유를 생산하는 과정에서 발생하는 폐기물(폐유, 폐수)의 경제적 처리 방안으로 유화유 제조 원료(벙커C유, 물)와 유화유 제조 첨가제(무기계, 유기계)로 활용 가능성을 검토하였다. 열대작물 오일의 물성 분석 결과 고형물, 수분, 인지질(phospholipid), 유리지방산(free fatty acid) 함량이 기존 원료유보다 매우 높게 나타났다. 인지질은 바이오디젤 제조 반응후 에스테르와 글리세린의 층분리를 방해하고 유리지방산은 염기촉매와 결합하여 지방산염을 생성해 생산 수율을 감소시킨다. 고형물과 수분 역시 촉매반응에 악영향을 가지나 여과와 감압증발에 의해 쉽게 제거가 가능하다. 유리지방산은 산촉매 에스테르화 반응에 의해 제거가 가능하다. 인지질은 탈검(degumming) 과정을 통해 제거하며 탈검은 수용성 탈검, 산 탈검, 세정 공정으로 구성된다. 착유한 원료유의 고형물을 제거 후 물과 수세하여 수용성 인지질을 수화하여 층 분리해 제거하고 상층의 오일은 추가적인 산 탈검을 수행한다. 그 뒤 세정을 통해 사용된 탈검제인 산과 추가적으로 수화된 인지질을 제거하게 된다. 이러한 3단계의 탈검 과정에서 하층으로 오일과 물이 폐기물로서 배출되며 본 연구에서는 배출 폐기물을 다시 층분리하여 오일층과 물 층으로 구분하여 유화유 제조에 사용되는 벙커C유, 물, 그리고 기존 유기계 및 무기계 유화제의 대체 가능성을 조사하였다. 유화 연료유는 기름과 물을 균일한 분산상으로 혼합한 연료유로 연소시 오일계 성분의 미연분을 감소시켜 연료 효율 제고와 배출가스 성상을 개선하기 위해 개발되어 왔다. 본 발표에서는 다양한 종류의 상용 첨가제 및 바이오디젤 원료유 생산 폐기물을 활용해 유화 연료유를 제조하였으며 각 유화유의 장시간의 상(phase) 안정성을 비교하였다. 바이오 폐기물 중에는 천연 계면활성제(surfactant)인 인지질이 다량 함유되어 있어 기존의 무기계 및 유기계 유화제보다 상 안정성이 우수하게 나타났으며 바이오디젤 원료유 생산 공정의 폐기물인 폐유과 폐수의 활용이 가능한 것으로 나타났다.

• Journal of the Korean Electrochemical Society
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• v.12 no.2
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• pp.173-180
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• 2009

In order to develop a novel polymer electrolyte membrane for direct methanol fuel cell (DMFC), styrene monomer was graft-polymerized into poly(tetrafluoroethylene perfluoropropyl vinyl ether) (PFA) film followed by a sulfonation reaction. The graft polymerization was prepared by the $\Upsilon$-ray radiation-grafting method. Subsequently, sulfonation of the radiation-grafted film was carried out in a chlorosulfonic acid/1,2-dichloroethane (2 v/v%) solution. The chemical, physical, electrochemical and morphological properties of the radiation-grafted membranes (PFA-g-PSSA) were characterized by fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The water uptake, ionic conductivity, and methanol permeability of the PFA-g-PSSA membrane were also measured. The cell performances of MEA prepared with the PFA-g-PSSA membranes were evaluated and the cell resistances were measured by an impedance analyzer. The MEA using PFA-g-PSSA membranes showed superior performance for DMFCs in comparison with the commercial Nafion 112 membrane.

• Korean Chemical Engineering Research
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• v.46 no.4
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• pp.727-731
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• 2008

Mesoporous Pt-Au alloy films were successfully fabricated on ITO-coated glass by electrodeposition method using tri-blockcopolymer (P123) as a templating agent. The electrolyte consisted of 10 mM hydrogen hexachloroplatinate ($H_2PtCl_6$), 10 mM hydrogen tetrachloroaurate ($HAuCl_4$), and proper amount of P123. For comparison, control samples were electrodeposited without $HAuCl_4$ and P123. Film composition was determined by EDS(Energy Dispersive X-ray Spectroscopy), and the mesoporous structure was confirmed by TEM(Transmission Electron Microscopy). SEM(Scanning Electron Microscopy) was utilized to examine surface morphology, and it was observed that the addition of P123 affected the particle growth, resulting in the significant change of surface morphology. Methanol oxidation and CO oxidation were carried out to investigate electrocatalytic activities of synthesized samples. It was observed that the catalytic activity was strongly dependent on the film compositions. Compared with nonporous electrode prepared without P123 templating, mesoporous films prepared with P123 templating showed much higher catalytic activities and stability for both methanol oxidation and CO oxidation. These enhanced electrocatalytic activities were due to the high surface area and facilitated charge transfer of mesoporous films.

• Korean Chemical Engineering Research
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• v.50 no.2
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• pp.217-222
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• 2012

The synthesis of dimethyl carbonate(DMC) is a promising reaction for the use of naturally abundant carbon dioxide. DMC has gained considerable interest owing to its versatile chemical reactivity and unique properties such as high oxygen content, low toxicity, and excellent biodegradability. In this study, the synthesis of DMC through the transesterification of ethylene carbonate(EC) with methanol was investigated by using ionic liquid and metal oxide catalysts. The screening test of different catalysts revealed that choline hydroxide ([Choline][OH]) and 1-n-butyl-3-methyl imidazolium hydroxide([BMIm][OH]) had better catalytic performance than metal salts catalysts such as MgO, ZnO and CaO. The effects of reaction parameters such as reaction temperature, MeOH/EC mole ratio, and carbon dioxide pressure on the reactivity of [Choline][OH] catalyst were discussed. High temperature and high MeOH/EC mole ratio were favorable for high conversion of EC. However, the yield of DMC showed a maximum when carbon dioxide pressure was 1.34 MPa, and then it decreased for higher carbon dioxide pressure. Zinc chloride($ZnCl_2$) was used as co-catalyst with the ionic liquid catalyst. The mixed catalyst showed a synergy effect on the EC conversion and DMC yield probably due to the acid-base properties of the catalysts.

• Applied Chemistry for Engineering
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• v.25 no.1
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• pp.116-120
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• 2014

Light cycle oil (LCO), one of the by-products of the catalytic cracking gasoline manufacturing process, contains a lot of valuable aromatics. In particular, 2,6-dimethylnaphthalene (2,6-DMN) contained in LCO has been becoming important as the basic material of polyethylene naphthalate plastic and liquid crystal polymer, etc. If it were possible to separate and purify the valuable aromatic hydrocarbons (such as 2,6-DMN) from LCO, which have only been used as fuel mixed with heavy oil, it would be very meaningful in terms of the efficient use of resources. We investigated the high-purity purification of 2,6-DMN by the combined method of melt crystallization (MC) and solute crystallization (SC). The enriched DMN isomer mixtures (concentration of 2,6-DMN : 10.43%) recovered from LCO by distillation-extraction combination and the crystal recovered by MC used as raw materials of MC and SC, respectively. The solvent of SC used was a mixture of methanol and acetone (60 : 40 wt%). The crystal of 2,6-DMN with a high-purity of 99.5% was recovered by MC-SC combination. We confirmed that the MC-SC combination was one of the very useful combinations for the high-purity purification of 2,6-DMN contained in the enriched DMN isomer mixtures.

• Journal of the Society of Disaster Information
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• v.17 no.1
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• pp.10-24
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• 2021

Purpose: The purpose of this study is to determine the dangers of biodiesel and general diesel mixtures currently used as alternative fuels by equipment (tag method and penski Marten method) and to determine the difference between flash point and combustion point (closed, open) according to test methods. It is intended to be used as a reference material for identification and evaluation of firecausing substances by confirming the risk of mixtures by comparative analysis and measurement, and establishing a risk assessment method for chemical substances. Method: Flash point test method and result treatment were tested based on ASTM and KS M mode, which are tag sealing and pen schematense test methods used as flash point and combustion point test methods for crude oil and petroleum products. The manufacturer of the equipment used in this experiment was a test equipment that satisfies the test standards of KS M 2010 with equipment produced by TANAKA of Japan. The flash point and combustion point were measured, and the flash point according to the test method of biodiesel and general diesel mixture ( Closed, open), and the ignition point of a mixture of biodiesel and general diesel was compared and analyzed for ignition risk compared with conventional diesel. Results: Looking at the experimental results, first, as an analysis of the risk of flammability of the mixture, the flash point of a substance containing 70% biodiesel was found to be about 92℃ based on general diesel with a flash point of 64.5℃, and gasoline and biodiesel or When the biodiesel mixture was synthesized, it was confirmed that the flash point tends to decrease. In addition, the difference between the flash point and the combustion point was analyzed as about 20 ~ 30℃, and when a small amount of gasoline or methanol was mixed, the flash point was lowered, but it was confirmed that the combustion point was similar to that of the existing mixture. Conclusion: In this study, in order to secure the effectiveness of the details of the criteria for judging dangerous materials in the existing Dangerous Materials Safety Management Act, and to secure the reliability and reproducibility of the judgment of dangerous materials, we confirm the criteria for judging the risk of the mixture through an experimental study on flammable mixtures. It will be able to provide reference data for experimental criteria for flammable liquids that are regulated in the field. In addition, if this study accumulates know-how on experiment by test method, it is expected that it can be used as a basis for research on risk assessment and research on dangerous goods.