• Bulletin of the Korean Chemical Society
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• v.23 no.1
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• pp.112-118
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• 2002

Good-to-excellent yields of 2,3-Disubstituted norbornenes (or norbornanes) were obtained using a Pd/Cu catalyzed three-component ternary coupling reaction of aryl halides, norbornadiene (or norbornene), and alkynols in toluene at $100{\circ}C$ in the presence of 5.5 M NaOH as a base and benzyltriethylammonium chloride as a phase transfer catalyst. The results of experiments using various aromatic halides suggest that the ternary coupling reaction is promoted by bromide.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.83-84
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• 2008

바이오 디젤은 석유기반 연료들을 대신할 수 있는 대체연료일 뿐만 아니라 재생가능자원으로부터 얻을 수 있다는 장점을 가지고 있다. 바이오 디젤은 동 식물성 유지를 이용해서 알코올과 촉매 존재하에서 제조되며, 주로 KOH, NaOH 등 균질촉매를 이용하여 제조하는데 이는 폐수 발생이 많고 공정 비용이 많이 든다는 단점이 있다. 따라서 최근에는 폐기물 발생이 없고 촉매의 제거가 편리한 비균질촉매의 개발이 이루어지고 있다. 본 연구에서는 NaX 제올라이트 촉매에 KOH를 담지시켜 염기도의 증가에 따라 바이오디젤의 제조특성에 미치는 촉매특성을 조사해 보았다. NaX 제올라이트 촉매에 KOH 담지량이 증가와 반응시간이 증가함에 따라 바이오디젤 생성량은 증가하였다.

• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.20-27
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• 2021

Effects of the etching treatment of SAPO-34 catalyst were investigated to improve the catalytic lifetime in DTO reaction. The aqueous NH3 solution was a more appropriate treatment agent which could control the degree of etching progress, compared to that of using a strong acid (HCl) or alkali (NaOH) solution. Therefore, the effect on characteristics and lifetime of SAPO-34 catalyst was observed using the treatment concentration and time of aqueous NH3 solution as variables. As the treatment concentration or time of aqueous NH3 solution increased, the growth of erosion was proceeded from the center of SAPO-34 crystal plane, and the acid site concentration and strength gradually decreased. Meanwhile, it was found that external surface area and mesopore volume of SAPO-34 catalyst increased at appropriate treatment conditions. When the treatment concentration and time were 0.05 M and 3 h, respectively, the lifetime of the treated SAPO-34 catalyst was the longest, and was significantly enhanced by ca. 36% (based on DME conversion of > 90%) compared to that of using the untreated catalyst. The model for the etching progress of SAPO-34 catalyst in a mild treatment process using aqueous NH3 solution was also proposed.

• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.600-606
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• 2018

The influence of acidity in MTT zeolite of different Si/Al molar ratio's on the catalyst activity in methanol-to-olefin (MTO) reaction has been investigated. The Si/Al ratio was controlled with the Al content in the gel when N,N,N',N'-tetramethyl-1,3-diaminopropane was used as a structure directing agent (SDA). The gel composition was controlled to $20SiO_2$ : 30SDA : x (=0.25~1.25)$NaAlO_2$ : 2NaOH : $624H_2O$, which was subject to the hydrothermal synthesis at 433 K for 4 days. As the composition of sodium aluminate decreased, the particle size of MTT zeolite increased, and also the amount of acid sites decreased. To investigate the catalytic performance, MTO reaction was carried out at 673 K with $1.2h^{-1}$ WHSV. It was found that the H-MTT (1.00Al) catalyst with a Si/Al molar ratio of 24 maintained the methanol conversion over 90% for 900 min.

• Korean Chemical Engineering Research
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• v.48 no.3
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• pp.322-326
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• 2010

Stability of sodium borohydride solution during storage was studied. In order to enhance the $NaBH_4$ stability, NaOH and KOH were added to the $NaBH_4$ solution. The effect of concentration of the borohydride and alkaline solution, temperature and materials of storage vessels on the rate of borohydride hydrolysis was investigated. The rate of hydrogen evolution decreased as the concentration of alkaline increased due to increase of $NaBH_4$ stability in the solution. The stability of $NaBH_4$ solution decreased when the borohydride concentration raised from 10 to 15 wt% and then increased when the $NaBH_4$ concentration increased above 15 wt% due to increase in the pH of the concentrated solution. The activity coefficient of hydrolysis of $NaBH_4$ solution(NaOH 3.0 wt%, $NaBH_4$ 25 wt%) was 115.1 kJ/mol and this value was 1.5~4.0 times higher than that of hydrolysis of $NaBH_4$ solution with catalyst. The borohydride solutions in glass and stainless-steel vessel were more stable than the solution in plastic(PE) vessel.

• Korean Chemical Engineering Research
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• v.49 no.5
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• pp.516-520
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• 2011

Sodium borohydride, $NaBH_4$, shows a number of advantages as hydrogen source for portable proton exchange membrane fuel cells (PEMFCs). The hydrogen yield of sodium borohydride hydrolysis reaction was studied. The effect of temperature, $NaBH_4$ concentration, NaOH concentration and catalyst type on the hydrogen yield from $NaBH_4$ hydrolysis reaction were measured. The catalysts of Co-P/Cu, Co-B/Cu and Co-P-B/Cu were used in this study and there was no different effect of these catalysts on the hydrogen yield from $NaBH_4$. Under the temperature of $60^{\circ}C$, the hydrogen yield decreased as $NaBH_4$ concentration increased due to formation of gel with by-products and reactants. The gel formed during $NaBH_4$ hydrolysis reaction diminished the hydrogen evolution rate and total volume of hydrogen. Addition of NaOH stabilizer enhanced the formation of gel and then decreased the hydrogen yield.

• 한국전기화학회:학술대회논문집
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• 2005.07a
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• pp.341-346
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• 2005

펄스 도금 조건이 Co 도금층의 미세 구조 및 알칼리 $NaBH_4$ 용액의 수소발생특성에 미치는 영향을 조사하였다. 펄스 주기 및 최대전류밀도가 증가함에 따라 polyhedral 형상의 Co 결정립이 triangular형상으로 변화하였으며, 점차 결정립이 조대화 되어, 촉매 표면적이 감소하였다. 결국 알칼리 $NaBH_4$ 용액 내에서 가수분해반응에 참여하는 촉매 site가 감소하여 수소발생속도가 낮아졌다. 펄스도금시간이 증가함에 따라 Co 결정립의 크기가 점차 증가하여 촉매 표면적이 감소하였고, 가수분해반응에 참여하지 못하는 CO의 양이 증가하여 수소발생속도가 크게 감소하였다. 최대전류밀도 $0.1\;A/cm^2$, 펄스 주기 2 mS에서 10 s 동안 펄스 도금 시, $25^{\circ}C\;1\;wt.\%\;NaOH\;+\;10\;wt.\%\;NaBH_4$ 용액에서 $2140\;ml/min{\cdot}g-catalyst$의 높은 수소발생속도를 가지는 것으로 나타났다.

• Journal of Environmental Science International
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• v.19 no.10
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• pp.1247-1256
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• 2010

Since biodiesel as bioenergy is defined as ester compounds formed by esterification of animal/vegetable oils, in this study three vegetable cooking oils (market, waste and refined waste ones) were esterified by reactions of alkali catalyst and immobilized enzyme. The fatty acid composition of the formed ester compounds was analyzed to investigate the feasibility of biodiesel production. By lipolysis (i.e, hydrolysis of Triglyceride (TG)), all three vegetable oils used in this study were found to produce Diglyceride (DG), Monoglyceride (MD) and Fatty acid ethylester (FAEE). However, the amount of produced FAEE (which can be used as an energy source) was in the increasing order of market cooking oil, waste one and refined waste one. With NaOH catalyst, FAEE was produced about 24.92, 17.63 and 11.31 % for the respective oils while adding Lipozyme TL produced FAEE about 43.54, 38.16 and 24.47 %, respectively. This indicates that enzyme catalyst is more effective than alkali one for transesterification. In addition, it was found that the composition of fatty acids produced by hydrolysis of TG was unchanged with alkali and immobilized enzyme reactions. Thus it can be expected that stable conditions remain in the course of mixing with gasoline whose composition is similar to that of the fatty acids.

• Transactions of the Korean hydrogen and new energy society
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• v.35 no.2
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• pp.152-161
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• 2024

In this study, a fuel cell system for future defense unmanned vehicles was designed and validated. A Co/Al₂O₃-Ni foam catalyst for NaBH₄ hydrolysis was characterized using several analytical methods. A NaBH₄ hydrogen generation system with the Co/Al₂O₃-Ni foam catalyst continuously generated hydrogen at elevated reaction temperatures. The fuel cell system with the NaBH₄ hydrogen generation system was designed and tested. The performance of the fuel cell system was comparable to that of the fuel cell system using pure hydrogen. Therefore, the fuel cell system with the NaBH₄ hydrogen generation system is a suitable power source for future defense unmanned vehicles owing to its easy refueling and simple system.

• Journal of the Korean Wood Science and Technology
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• v.41 no.6
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• pp.583-593
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• 2013

The based-catalyzed depolymerization (BCD) of kraft lignin isolated from black liquor which the chemical pulping of a mixture of various Southeast Asia hardwood chips was carried out in a batch reactor in the presence of different NaOH concentrations with supercritical methanol. The S:G ratio of the kraft lignin determined by pyrolysis-GC/MS analysis turned out roughly 1.4:1 and main products were vanillic acid, syringol and 3-methoxy catechol. The diethyl ether extracts as phenolic monomers from BCD reaction were produced similar yield among different NaOH concentrations. The 21 compounds were identified by GC/MS analysis in all experiments and major products were catechol, 3-methoxycatechol, 4-methylcatechol, syringol and isovanillic acid. However, it had been shown to be different monomer contents depending on the dosage of NaOH. Catechol, 4-methylcatechol and 3-methoxycatechol were shown to be the dominant monomer from BCD reaction using 7.5 and 3.25% of NaOH concentration whereas syringol, isovanillic acid, 3-methoxycatechol and 4-methylcatechol were determined to be the most typical products under the condition of 1.63% NaOH.