• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.566-570
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• 2005

The study on the hydrogenation and isomerization of unsaturated bicyclic hydrcarbon compounds using methylcyclopentadiene dimer (MCPD) was carried out. Exo compound was prepared through isomerization reaction after two hydrogenation reaction steps. In the first hydrogenation reaction which needs one mole of hydrogen, the formation rate of monomer was increased as dimer was decomposed at reaction temperature above $100^{\circ}C$. At first hydrogenation, DHDMCPD [dihydrodi(methylcyclopentadiene)] was formed and second hydrogenation was proceeded to produce THDMCPD [tetrahydrodi(methylcyclopentadiene)], the ratio of exo to endo THDMCPD was varied by the control of 2nd hydrogenation temperature. To improve the process, continuous 1st and 2nd hydrogenation conditions were established by using the 2nd stage heat controllable reactor. Also, catalytic activities were compared by the use of halogenized aluminum, metal halides and solid acids catalysts on the isomerization reaction from endo to exo THDMCPD.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.2
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• pp.17-24
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• 2012

Tetrahydrotricyclopentadiene(below THTCPD) isomer is a good candidate materials for the high performance liquid fuel component because of its high density and heat of combustion value. The object of this study was to find out the proper reaction condition to improve the fluidity of THTCPD which is solid state at room temperature. Therefore, we have carried out isomerization reactions using aluminum chloride in the varying reaction condition such as reaction temperature and solvents. The results showed that when using aluminum chloride catalyst, THTCPD isomerization reaction was more active in the polar halogenated reaction media such as dichloromethane(methylene chloride: MC), 1,2-dichloroethane(ethylene chloride: EC) and chloroform than in non-polar hydrocarbon media such as n-Hexnae and toluene and was effected by reaction temperature variation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.800-803
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• 2010

Tetrahydrotricyclopentadiene(below THTCPD) isomer is a good candidate for the high performance liquid fuel component because of high density and heat of combustion value. But it has bad fluidity. The object of this study was to find out the optimal reaction condition to improve the fluidity of THTCPD because initial reactant is solid state, So we have carried out isomerization reactions using aluminum chloride catalyst under varying the reaction condition such as reaction temperature and reaction solvents. The results showed that when using aluminum chloride catalyst, isomerization reaction was more active in dichloromethane(methylene chloride: MC), 1,2-dichloroethane(ethylene chloride: EC) and chloroform than n-hexnae and toluene and was effected by reaction temperature.

• KSBB Journal
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• v.10 no.1
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• pp.9-14
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• 1995

Continuous production of fructooligosaccharides from sucrose by a dual immobilized enzyme system of fructosyltransferase and glucose isomerase was studied in a column reactor. The optimal temperature and pH of the immobilized fructosyltransferase were $65^{\circ}C$ and 5.5, respectively. The activity of glucose isomerase was favorable as temperature and pH were increased within the ranges examined. However, both the immobilized enzymes were thermally unstable over $5^{\circ}C$, suggesting that long-term operation of the dual immobilized enzyme column should be carried out below $50^{\circ}C$. The optimum packing ratio of fructosyltransferase to glucose isomerase was found to be around 5/3. Under the optimized reaction conditions, the dual enzyme column was successfully operated for 40 days without any loss of initial enzyme activities, yielding 66% of fructooligosaccharides. Furthermore, the relative sweetness of fructooligosaccharides produced by a dual emzyme system was enhanced by 6% compared with that of fructosyltransferase alone.

• Applied Chemistry for Engineering
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• v.18 no.1
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• pp.36-40
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• 2007

The study on the isomerization reaction of endo-tetrahydrodicyclopentadiene and endo-tetrahydrodi(methylcyclopentadiene) using heteropolyacid catalyst was carried out. Exo compound was prepared from endo compound through isomerization reaction. To improve the problem of aluminum chloride as an isomerization catalyst, application of heteropolyacid was attempted. In use of Keggin type heteropolyacid, catalytic activity was extremely high at cesium substitution instead of 2.5 hydrogen atoms of $H_3PW_{12}O_{40}$. Using the cesium substituted heteropolyacid, isomerization reaction rate was faster than aluminum chloride and the effect of reaction temperature and times on reactivities were compared in isomerization of tetrahydrodicyclopentadiene and tetrahydrodi(methylcyclopentadiene).

• Korean Journal of Food Science and Technology
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• v.11 no.4
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• pp.249-257
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• 1979

Using the whole cell immobilized glucose isomerase which was prepared in the previous work (Korean J. Food Sci. & Technol., 11(3), 192 (1979), the specific activity of the immobilized enzyme was 48.1 units in the batch reaction system and 114 units in the continuous reaction system per g of matrix, respectively. In the continuous reactor the voidity was 0.36, which was suitable for the packed bed reactor. This immobilized enzyme showed a good operational stability of 115 days of half life which was sufficient for the continuous operation. The experimental result showed that 55 % of the substrate was converted to the product in the packed bed reactor. The productivity was dependent on the flow rate, column geometry, enzyme loading, and substrate concentration. An intrapaticle diffusion was observed by the effectiveness factor of 0.75 and interparticle diffusion by the decrease of Km' with increasing the superficial velocity.

• Journal of the Korean Chemical Society
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• v.45 no.6
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• pp.538-545
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• 2001

The ratio of regioisomers in nitration of biphenyl derivatives containing electron-with-drawing group was examined. The ratio of isomers was determined efficiently by quantitative analysis of $^1$H NMR spectrum of product mixture based on $^1$H NMR spectrum of each isomer. Some isomers were isolated after chemical transformation, nitro to amine or carboxylic acid to its ethyl ester, because direct separation was very difficult. To improve the regiselectivity, representative several reaction conditions were tried and the NMR method was applied to determine regioselectivity in nitration of biphenyl derivatives. It was observed that the regioselectivity depend on not only reaction conditions but also position and kind of substituents.

• Food Industry And Nutrition
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• v.2 no.1
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• pp.7-9
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• 1997

내열설 미생물, Thermus caldophilus CK24에 대한 탄수화물 생합성을 연구하는 과정에서 다양한 탄수화물 관련효소를 탐색하고 그레 대한 생화학적 및 분자생물학적 연구를 수행하고 있다. 일차로 내열성 미생물내 1) 당핵산염 합성효소와 당전이 효소, 2) 탄수화물 대사효소. 3)탄수화물 분해 및 전환효소의 존재를 HPLC/Bio-LC분석을 통하여 확인하고 이들에 대한 연구를 진행하고 있다. 본 연구발표에서는 포도당을 과당으로 전환하는 이성화효소(xylose isomerase), 그리고 맥아당을 트레할로스로 전환하는 트레할로스 합성효소(trehalose synthase)를 소개하고저 한다. 이성화효소는 이미 산업적 과당 생산에서 대규모적으로 사용되고 있는 식품산업효소이다. 본 연구에서는 Thermus caldophilus GK24, Thermus thermophilus HB8, Thermus flavus AT62 3종의 내열성 미생물에 대한 이성화효소 유전자를 클로닝 하고, 각 재조합하고 이성화효소를 대량생산하였다. 이 내열성 이성화효소는 최적 반응 온도가 8$0^{\circ}C$이고, 포도당을 과당으로 전환하는 수유른 55%이었다. 이러한 과당전환률은 이미 산업적으로 사용되고 있는 이성화효소의 과당전환률(43%)보다 훨씬 높은 것으로 과당 생산공정의 단순화의 생산성 향상에 결정적인 요인이라 할 수 있다. 한편 본 이성화효소의 산업적 특성을 증대하기 위하여 구조-기능관계 연구를 착수하였다. 우선 내열성 이산화 효소의 입체 구조를 결정하였고, 구조조정에 따른 기능적 특성을 조사하기 위하여 특정 위치의 선택적 변이 연구를 진행하고 있다. 끝으로 포도당 전이 효소를 추적하던 과정에서 맥아당을 트레할로스로 전환하는 새로운 효소를 Thermus caldo-philus GK24에서 발견하였다. 그 트레할로스 합성효소는 분자량이 약 110kDa이고 최적 반응온도가 75$^{\circ}C$이면, 조효소없이 맥아당을 트레할로스로 80%이상 전환해 주는 가역효소이었다. 본 연구에서는 효소반응의 조건과 특성을 조사하였고, 효소 아미노-밀단의 서열결정정보를 통하여 효소의 유전자를 클로닝 하고 그 유전자의 구조와 발현연구를 진행하고 있다.

• Proceeding of EDISON Challenge
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• 2014.03a
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• pp.371-383
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• 2014

이 연구에서는 팔라듐 착물 $Pd(PPh_3)_2$을 사용한 bromotoluene과 morpholine간의 coupling reaction (Buchwald-Hartwig amination) 반응 메커니즘을 계산화학적 방법을 이용하여 연구하였다. 용매화 자유에너지를 고려한 중간체 에너지를 비교하였으며, 반응물질이 o-bromotoluene 일 때와 p-bromotoluene 일 때, 반응 중간체로 monophosphine 착물이 형성되는 경우와 bisphosphine 착물이 형성되는 경우를 비교하였으며, 반응 중간체로 bisphosphine 착물이 형성되는 경우 cis 이성질체가 중간체인 경우와 trans 이성질체가 중간체인 경우를 비교하였다. 그 결과, 반응물로 p-bromotoluene을 사용할 때 o-bromotoluene을 사용할 때보다 중간체가 상대적으로 더 안정하여 더 좋은 수득률을 얻을 수 있을 것으로 예상되었다. 또한 $Pd(PPh_3)_n(o-tolyl)(N(CH_2CH_2)_2O)$ (n=1 또는 2) 중간체를 제외하고는 모든 경우에서 bisphosphine 중간체가 형성되는 반응경로가 더 안정한 것으로 밝혀졌다. 그리고 $Pd(PPh_3)_2ArBr$의 경우 trans 이성질체가 cis 이성질체보다 안정하지만 $Pd(PPh_3)_2Ar(N(CH_2CH_2)_2O)$의 경우 반대로 cis 이성질체가 trans 이성질체보다 안정한 것으로 나타났다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.193-196
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• 2006

This paper presents the results of catalytic endo- to exo- isomerization of saturated poly cyclic compound. Several zeolites were tested and influences of, Si/Al ratio and Structures of the zeolites on the reaction were investigated. The results showed that Y zeolites were more active than other zeolites, because of its large pore size and relative strong acidity. In all Y zeolites with different Si/Al, Y-5.4 is best. In all the zeolites tested, Y calcined at $450^{\circ}C$ was favorable. Still now the aluminium chloride catalyst is more active than zeolites. However, considering of environmental problems, corrosion, and treatment can make the zeolite catalyst substitute the aluminium chloride catalyst.