• 대한화학회지
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• 제41권6호
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• pp.299-303
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• 1997

4-치환 Phenyl ethyl benzylphosphonate의 알칼리 가수분해 반응에 대한 속도 상수($k_{OH}$)를 UV-Vis 분광 광도계로서 결정하였다. 활성화 엔트로피(${\Delta}S^{\neq}$)값은 큰 음의 값을 가졌으며 이 결과는 활성화 엔트로피가 양의 값이나 작은 음의 값으로 기대되는 해리 반응(EA)과 일치하지 않았고 좋은 Hammett 상관 관계식으로부터 속도결정단계에서 이탈기에 의해 음의 전하가 거의 발생하지 않는 회합성(AE) 메커니즘이 일어남을 강력히 암시하고 있다. 반응속도론적 연구 결과에 의하면 4-치환 Phenyl ethyl benzylphosphonate의 가수분해 반응은 해리 메커니즘으로 진행되지 않음을 알 수 있었다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.360-363
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• 2005

This study was a method that used a hydrolysis for increasing the efficacy of alcohol decrease from Hovenia dulcis extract. The best pH was 2.0 to obtain a maximum activity at fixed reaction temperature and time. At pH 2.0, reaction temperature $80^{\circ}C$ and reaction time 4 hr gave the highest activity which was 124.2% of control. This is very simple and efficient method to increase the efficacy of alcohol decrease from Hovenia dulcis extract. The mechanism that increases the efficiency of alcohol decrease be examined through hydrolysis.

• 생명과학회지
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• 제20권12호
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• pp.1906-1909
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• 2010

Benzenesulfinamide류의 가수분해반응에서 산 및 할라이드 이온의 촉매작용을 속도론적으로 조사하였다. 반응속도는 산 및 할라이드 이온의 농도가 증가함에 따라 증가하였고, benzenesulfinyl group에 전자주게기와 이탈기에 전자받게기를 가진 반응기질에서 빠르게 나타났다. 할라이드 이온의 반응성은 브롬 이온이 염소이온 보다 크게 나타남을 알 수 있었다. 반응 메카니즘은 초원가 중간체와 술포늄 양이온을 거쳐 진행 될 것으로 예상 할 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제15권1호
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• pp.40-47
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• 2005

Modeling and simulation for simultaneous saccharification and fermentation (SSF) process in bioconversion of paper mill sludge to lactic acid was carried out. The SSF process combined the enzymatic hydrolysis of paper mill sludge into glucose and the fermentation of glucose into lactic acid in one reactor. A mathematical modeling for cellulose hydrolysis was developed, based on the proposed mechanism of cellulase adsorption deactivation. Another model for simple lactic acid fermentation was also made. A whole mathematical model for SSF was developed by combining the above two models for cellulose hydrolysis and lactic acid fermentation. The characteristics of the SSF process were investigated using the mathematical model.

• 한국응용과학기술학회지
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• 제6권2호
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• pp.67-74
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• 1989

The Kinetics of the Hydrolysis of benzalacetophenone derivatives has been investigated by ultraviolet spectrophotometry in 5% dioxane - $H_2O$ at $50^{\circ}C$. A rate equation which can be applied over wide pH range was obtained. The substituent effect on the hydrolysis of benzalacetophenone derivatives were facilitated by electron attracting groups. Based on the rate equation, substituent effect, general base effect, activation parameters and final product, the hydrolysis of benzalacetophenone derivatives seems to be initiated by the netural molecule of $H_2O$ which does not dissociate at below pH 9.0 but proceeded by the hydroxide ion at above pH 11.0. In the range of pH $9.0{\sim}11.0$ these two reactions occur competitively.

• 한국응용과학기술학회지
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• 제10권1호
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• pp.75-81
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• 1993

The hydrolysis kinetics of 2-furyl chalcone derivatives $[I]{\sim}[V]$ was investigated by ultraviolet spectrophotometery in 30% dioxane-$H_{2}O$ at $25^{\circ}C$ and the structure of these compounds were ascertained by means of ultraviolet, infrared and NMR spectra. The rate equations which were applied over a wide pH range(pH $1.0{\sim}12.0$) were obtained. The substituent effects on 2-furyl chalcone derivatives $[I]{\sim}[V]$ were studied, and the hydrolysis were facilitated by the electron attrecting groups. On the basis of the rate equation, substituent effect, general base effect and final product. the plausible hydrolysis mechaism was proposed: Below pH 4.0, it was only proportional to concentration of hydronium ion, at pH $4.0{\sim}9.0$, neutral $H_{2}O$ molecule competitively attacked on the double bond. By contrast, above pH 9.0, it was proportional to concentration of hydroxide ion.

• 대한화학회지
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• 제33권1호
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• pp.120-126
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• 1989

pH 0.0∼14.00 범위에서 styrylphenylsulfone 유도체들의 가수분해반응에 대한 반응속도론적 연구가 25$^{\circ}$C의 50% 메탄올-물속에서 자외선 분광법으로 이루어졌다. 반응속도식과 치환기 효과(${\rho}$=1.85(pH 7.0), ${\rho}$=1(pH 13.0))로부터, pH 11.0이상에서는 전형적인 Michael형의 친핵성 첨가반응, pH 9.0이하에서는 물분자에 의한 일반 염기촉매반응, 그리고 pH 9.0∼11.0사이에서는 이들 두 반응이 경쟁적으로 일어남을 제안하였다.

• EDISON SW 활용 경진대회 논문집
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• 제4회(2015년)
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• pp.91-98
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• 2015

Formamide의 중성가수분해 mechanism은 QM/MM (quantum mecahnics/molecular mechanics) molecular dynamics simulations 및 CPMD과 같은 방법으로 연구되어왔다. 본 연구에서는. Umbrella sampling을 이용한 QM/MM-MD simulation을 사용하여 4가지 반응의 free energy surface를 도출해냈다. 전체적으로, 가장 선호되는 메커니즘은 two step으로 구성된 water assisted stepwise mechanism이었으며 모든 mechanism은 ab-initio calculation과 QM/MM-MD simulation이 수행되었다. water assisted stepwise mechanism을 살펴보면, 첫 번째 step에서 formamide의 carbonyl group이 hydrate되면서 gem-diol intermediate를 형성한다. 다음 step에서, intermediate의 hydroxyl group으로부터 amino group으로 water-assisted proton transfer이 일어난다. 두 반응 모두에서 물이 proton transfer를 직접적으로 도와주는 것을 관찰할 수 있었다. 특히, ab-initio calculation과는 다르게 QM/MM-MD에서는 gem-diol intermediate가 안정화되는 것으로 solvent effect를 잘 보여준다.

• 한국군사과학기술학회지
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• 제3권1호
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• pp.164-175
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• 2000

Three compounds of Cu(II)-loaded N,N,N'-trimethylethylenediaminated Merrifield-type polymers were synthesized with yields higher than 80%, and the hydrolysis reaction rates of O-isopropylmethyl-phosphonofluoridate(GB) and O-pinacolylmethylphosphonofluoridate (GD) catalyzed by them have been surveyed. GB and GD hydrolysis by Cu(II)-loaded polymers occurs via intermediate complex mechanism where rapid equilibrium to form intermediate complex between substrate and Cu(II)-loaded polymers($K_f$) is followed by rate determining hydrolysis step($k_1$). The measured activation parameters for $k_1$ are ${\Delta}H^{\ddag}$ : $17.75{\pm}0.98kJ/mol$ ${\Delta}S^{\ddag}$ / : $-218.42{\pm}3.35J/mol$ K, $E^{\circ}_a$ : $20.22{\pm}0.98kJ/mo1$ for GB and ${\Delta}H^{\ddag}$ / : $11.16{\pm}1.15kJ/mol,$${\Delta}S^{\ddag}$ /: $-258.57{\pm}3.93J/mol$ K, $E^{\circ}_a$ : $13.64{\pm}1.15 kJ/mol$ for GD. Standard enthalpy/entropy changes corresponding to the intermediate complex formation constant $K_f$ are ${\Delta}H^{\circ}$ : $37.05{\pm}2.19 kJ/mo1,$$ {\Delta}S^{\circ}$ : $163.12{\pm}7.49 J/mol$ K and ${\Delta}H^{\circ}$ : 418.59{\pm}2.04 kJ/mol,$ ${\Delta}S^{\circ}$ : 4111.92{\pm}6.98 J/mol$ K for GB and GD, respectively, The electron push-pull mechanism by Cu(II)-loaded polymers lowers the P-F bond breaking energy(~400 kJ/mol) to less than 1/20 compared to the case in which no Cu(II)-loaded resin presents. Analysis of $K_f$ and 4k_1$ over pH=6.5~8.0 range suggest that the GB and GD hydrolysis occurs intramolecularily with $pK_a$ =7.29 for ligated $H_2O$ and $t_{1/2}$=36.9 sec, $pK_a$ = 7.06 and $t_{1/2}$=177.7 sec for GB and GD, respectively.

• 대한화학회지
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• 제36권4호
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• pp.584-588
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• 1992

${\alpha}$-(n-butyl)-N-phenylnitrone 유도체들의 가수분해 반응속도상수를 $25^{\circ}C$의 수용액에서 자외선 분광광도법으로 측정하여 넓은 pH 범위에서 잘 맞는 반응속도식을 구하였다. 반응속도식, 가수분해 생성물, 일반염기(general base) 및 치환기 효과 등의 결과로부터 가수분해 반응메카니즘을 제안하였다. 즉, pH 4.5이하에서의 가수분해는 양성자가 첨가된 nitrone의 ${\alpha}$-탄소에 물분자의 공격에 의해 진행되며, pH 10.0 이상에서는 ${\alpha}$-탄소에 히드록시 이온의 직접 첨가에 의하여 가수분해가 진행된다. pH 4.5∼10.0에서는 nitrone에 물분자가 첨가되는 것이 속도결정단계임을 알았다.