• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.623-626
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• 2007

킬른형 열분해 반응기를 이용하여 혼합폐플라스틱의 열분해로부터 얻어진 고분자성분의 열적분해 특성에 관한 연구를 TGA와 GC-MS를 이용하여 수행하였다. 열적분해의 속도론적 연구는 $10{\sim}50^{\circ}C/min$ 사이의 여러 가열속도에서 비등온 질량감소 기술을 이용하여 수행하였으며 활성화 에너지 및 반응 차수와 같은 속도 상수들에 대한 정보를 얻기 위하여 문헌에 제시된 여러 가지의 속도론 해석방법을 이용하여 질량감소곡선 및 그 미분 값을 해석하였다. 또한 회분식 열분해 반응기를 이용하여 반응온도에 따른 액상 생성물의 수율변화를 고찰하였으며 GC-MS를 이용하여 액상 생성물의 반응온도 증가에 따른 특성연구를 수행하였다.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.508-508
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• 1986

이온성 계면활성제 존재하에서 유기용매에 물을 첨가하면 물이 계면활성제에 약해 둘러싸이면서 유기용매에 용해되어 의사 이상계가 형성된다. 이러한 계를 역미셀 또는 W/O microemulsion이라고 하며 계면활성제로 둘러 쌓인 물분자 집하체를 water pool이라고 한다. 그런데, 10여년 전 water pool에 bipolymer를 용해시킬 수 있다는 사실이 밟혀짐에 따라 이러한 체계를 생체막을 단순화시킨 모형막으로서 막을 통해 일어나는 여러 가지 현상의 규명에 이용하거나 물에 불용성인 기질의 효소 촉매반응의 반응계로 이용하는 연구가 꾸준히 이루어져 있다. 본 강연은 역미셀계에 리파제를 용해시켜 유지의 가수분해를 유도함으로써 지방산을 생산하는 방법에 관한 연구이다. 역미셀계에서 리파제의 특성은 에멀전계와 비교했을 때 큰 차이가 없었으며 물과 계면활성제의 몰 비율(R값)은 효소의 초기반응 속도에 커다란 영향을 끼치는 인자로 나타났다. 올리브유 농도가 5%(v/v), AOT농도가 0.1M, 초기 물 농도가 1.0M의 조건에서 유지의 회분식 가수분해 실험을 행한 결과 이 기질은 거의 완전히 가수분해되었으며, 이 반응계에서 R값과 초기 물 농도는 반응의 평형에 커다란 영향을 끼치는 것으로 나타났는데 초기 물 농도가 증가할수록 평형 가수분해율은 증가하였단 이러한 결과를 반응속도론 측면에서 분석한 결과 역미셀계에서 리파제 반응은 에멀전계에서와는 달리 2차 반응을 따르는 것으로 나타났다. 물 농도가 평형 가수 분해율과 속도 변수에 끼치는 영향을 수학적으로 표시하기 위하여 2차 가역적 반응 속도론에 근거하여 가수분해율, 평형상수, 속도상수 둥을 나타내는 식을 유도하였고 이를 바탕으로 여러 가지 실험 조건 하에서 리파제 반응의 반응 시간에 따른 가수분해율을 예측한 결과는 실제 실험 결과와 잘 일치하였다(편차는 5%). 또한 속도상수와 R값과의 관계식 및 유도한 방정식을 이용하여 추정한 초기속도와 평형 가수분해율을 최대화하는 R값은 각각 10.4 와 11.4 였다.

• Textile Coloration and Finishing
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• v.10 no.4
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• pp.24-29
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• 1998

11종류의 cellulose에 고착된 vinylsulfone(VS)계 반응성 염료(F-type)의 알칼리 가수분해 거동과 염료와 섬유의 결합 안정성을 cellophane film을 이용한 film권층법에 의하여 조사하였다. F-type은 알칼리욕에서 분해되어 VS type을 생성하고 VS type은 가수분해에 의해 hydroxyethylsulfone(Hy)을 생성하거나 cellulose와 재결합하여 F-type을 생성하였다. F-type은 알칼리 처리에 의해 cellulose의 수산기의 위치에 기인하는 bimodal 가수분해 거동(fast and slow hydrolysis)을 나타내었다. Orange 7과 Yellow 17는 cellulose와의 반응성이 높고 F-type의 초기 분해속도가 빠르며 일반적으로 fast 가수분해속도가 slow 가수분해 속도보다 약 5배정도 큼을 알 수 있었다. 또한 조사된 대부분의 염료의 경우 slow 가수분해 속도는 거의 유사함을 알 수 있었다.

• Journal of the Korean Chemical Society
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• v.38 no.5
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• pp.366-371
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• 1994

The kinetics of the hydrolysis of 5,6-dihydro-1,4-thiazine derivatives was investigated by ultraviolet spectrophotometry in $H_2O$ at 25$^{\circ}C$. A rate equation which can be applied over a wide pH range was obtained. The substituent effects on the hydrolysis of 5,6-dihydro-1,4-thiazine derivatives were studied and the rate of hydrolysis was shown to be accelerated by electron donating groups. Final product of the hydrolysis was 2-(N-acetylaminoethylthio)-acetoacetanilide enol from Judging from the results of the rate equation, general base effect, activation parameters and final products, the hydrolysis of 5,6-dihydro-1,4-thiazine derivatives seemed to be initiated by the neutral $H_2O$ molecule which does not dissociate at pH below 10.0, but proceeded by the hydroxide ion at pH above 11.0, and those two reactions occurred competively at pH 10.0∼11.0 range. On the basis of these findings a plausible mechanism for the hydrolysis of 5,6-dihydro-1,4-thiazine derivative was proposed.

• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.919-924
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• 1992

The kinetics of the hydrolysis of N-benzylidenebenzenesulfonamide derivatives have been investigated by ultraviolet spectrophotometry in $H_2O$ at $25^{\circ}C$. A rate equation which can be applied over a wide pH range was obtained. The substituent effect on the hydrolysis of N-benzylidenebenzenesulfonamide derivatives were studied and rate of hydrolysis is known to be accelerated by electron withdrowing group. Final product of the hydrolysis was benzenesulfonamide and benzaldehyde. Base on the rate equation, substituent effect, general base effect and final products, hydrolysis of N-benzylidenebenzenesulfonamide derivatives seemed to be initiated by the hydronium ion at the pH 0.2${\sim}$2.5 and proceeded by the neutral $H_2O$ molecule at pH 3.0${\sim}$8.0 but proceeded by the hydroxide ion at above pH 8.5.

• Journal of the Korean Chemical Society
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• v.48 no.6
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• pp.561-567
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• 2004

The influence of ultrasound frequency, dissolved gases, and initial concentration on the decomposition of sodium dodecylbenzene sulfonate(DBS) aqueous solution was investigated using ultrasound generator with 200 W ultrasound power. The decomposition rates at three frequencies(50, 200, and 600 kHz) examined under argon atmosphere were highest at 200 kHz. The highest observed decomposition rate at 200 kHz occurred in the presence of oxygen followed by air and argon, helium, and nitrogen. The effect of initial concentration of DBS on the ultrasonic decomposition was decreased with increasing initial concentration and would depend upon the formation of micelle in aqueous solution. It appears that the ultrasound frequency, dissolved gases, and initial concentration play an important role on the sonolysis of DBS. Sonolysis of DBS mainly take place at the interfacial region of cavitation bubbles by both OH radical attack and pyrolysis to alkyl chain, aromatic ring, and headgroup.

• Journal of Soil and Groundwater Environment
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• v.9 no.2
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• pp.20-27
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• 2004

Kinetic characteristics dependent on several factors such as iron mineral and organic solvents were investigated. When F $e^{0}$ , FeS and Fe $S_2$ were used as mediators, minerals affecting reaction rate were in the following order : $Fe_{0}$ 0/ ＞ FeS ＞ $FeS_2$ when in contact $C_2$C $l_{6}$ . The more chloride substituted, the higher reaction rate were observed. The reaction rates were dependent on pH, shaking rate, temperature and specific surface area. 1, 10-phenanthroline and EDTA degradation rates were fast, indicating that they adsorbed on the surface of the iron which makes the electron transfer reaction easy. Nitrate which has $\pi$＊ orbital of molecular can increase electron transfer rate because it is delocalized in its entity. The reaction rates were not affected by hydroquinone. Degradation rates were much enhanced with naturally occurring kaolinite because of the surface corrosion of Fe mineral. However, The reaction rate was not affected by F $e^{2+}$ or S $O_4$$^{2-}$ presented in solution.n.

• Clean Technology
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• v.14 no.3
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• pp.218-223
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• 2008

Decomposition of reactive organic compound dispersed in microemulsion media by hydroxide ions and proton ions generated during electrolysis was tried and the half-lifes for decomposition were compared. Absorbance of p-nitrophenoxide produced from the decomposition of p-nitrophenylacetate (PNPA) was followed to find the rate of decomposition. The applied voltage, temperature, and the amount of substrate were changed to see the effects on the decomposition rate. The advantages of electrolysis in microemulsion system were the high solubilizing capacity of substrate, easy control of decomposition rate, low operation cost, no need for any addition of chemicals, and no byproducts. The mechanism of decomposition and the application to water purification were discussed.

• KSBB Journal
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• v.6 no.2
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• pp.167-174
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• 1991

Enzymatic cellulose hydrolysis depends on the several factors such as the structural features (CrI, particle size and surface area, etc.), the nature of cellulase enzyme system, the inhibitory effects of products, and enzyme deactivation. At the presence of products on the initial hydro- lysis rate of cellulose, cellobiose has more severe inhibitory effect than glucose. Othewise, the inhibition effect of products for adsorbed enzyme is related to the glucose and cellobiose conentration hyperbolically. Enzyme deactivation of FPA and ${\beta}-glucosidase$ were expressed by exponential decay profile.

• Proceedings of the KAIS Fall Conference
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• 2005.05a
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• pp.301-302
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• 2005

PAHs의 분해를 위해 Bacillus subtilis 와 Phanerochaete chrysosporium의 두 미생물을 사용하였고, 이들을 부착시킬 담체로 코르크와 톱밥를 선정하여 미생물을 접종시켰다. Phenanthrene 분해의 경우, 반응 초기에는 분해 속도가 매우 빠르지만 반응 12일째 분해 속도가 떨어졌다. 분해 속도는 1)톱밥에 담지한 Bacillus subtilis, 2)코르크에 담지한 Bacillus subtilis, 3)톱밥에 담지한 Phanerochaete chrysosporium, 4)코르크에 담지한 Phanerochaete chrysosporium의 순으로 나타났다.