• 한국응용과학기술학회지
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• 제6권2호
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• pp.59-65
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• 1989

The rate constants of the hydrolysis of cinnamanilide derivatives were determined UV spectrometry in $H_2SO_4\;(5{\sim}20N)$, NaOH($5{\sim}11N)\;at\;50{\sim}110^{\circ}C$ and rate equation could be applied over a strong acid and strong base were obtained. Final product of the hydrolysis was a cinnamic acid. The ${\rho}$ values obtained from the slope of linear plots of log $k_{abs}$ vs. Hammet $t{\sigma}$ constants were slightly negatives, Substituents on cinnamanilide showed a relatively small effect, with hydrolysis facilitated be electron donating group. Activation energy(Ea)was also calculated for the hydrolysis of the cinnamanilide. From this reaction rate equation, substituent effect and experimental of rate constants, that the hydrolysis of cinnamanillde was Initiated by the netural molecule of $H_2O$ which do not dissociate at strong acid, and proceeded by hydroxide ion at strong base.

• 상하수도학회지
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• 제32권1호
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• pp.27-35
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• 2018

The stability of liquid ferrate(VI) produced by an innovative method was confirmed and the degradation characteristics of cyclic compounds(Benzene, Aniline, Toluene, 1,4-Dioxane) by liquid ferrate(VI) were investigated under the same reaction conditions. When it was compared with the ferrate manufactured by the wet oxidation method, the liquid ferrate was more stable. And the stability of liquid ferrate was tested at the storage temperature. As a result, only 17.7% of liquid ferrate(VI) has decomposed at the storage temperature($4^{\circ}C$) for 28 days. Among the cyclic compounds, the aniline was rapidly degraded compare to other cyclic compounds, which seems to be due to the electron-donating ability of the substituent, $-NH_2$ group. Especially, when 1,4-dioxane was compared with benzene, the decomposition rate of 1,4-dioxane was lower than that of benzene, suggesting that oxygen atoms hinder the electrophilic reaction. Among 4 cyclic compounds, it was observed that aniline has the highest rate constant than those of other cyclic compounds.

• Bulletin of the Korean Chemical Society
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• 제28권12호
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• pp.2343-2353
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• 2007

We report the application of time-dependent density functional theory (TDDFT) to the calculation of potential energy profile relevant to the excited state intramolecular proton transfer (ESIPT) processes in title molecules. The TDDFT single point energy calculations along the reaction path have been performed using the CIS optimized structure in the excited state. In addition to the Stokes shifts, the transition energies including absorption, fluorescence, and 0-0 transition are estimated from the TDDFT potential energy profiles along the proton transfer coordinate. The excited state TDDFT potential energy profile of SA and 3ASA resulted in very flat function of the OH distance in the range ROH = 1.0-1.6 A, in contrast to the relatively deep single minimum function in the ground state. Furthermore, we obtained very shallow double minima in the excited state potential energy profile of SA and 3ASA in contrast to the single minimum observed in the previous work. The change of potential energy profile along the reaction path induced by the substitution of electron donating groups (-NH2 and -OCH3) at different sites has been investigated. Substitution at para position with respect to the phenolic OH group showed strong suppression of excited state proton dislocation compared with unsubstitued SA, while substitution at ortho position hardly affected the shape of the ESIPT curve. The TDDFT results are discussed in comparison with those of CASPT2 method.

• 대한화학회지
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• 제38권1호
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• pp.21-25
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• 1994

이미다졸 고리를 포함하는 lexitropsin에서, DNA minor grooved의 염기쌍(G-C sequence)과 결합하는 부분인 치환이미다졸의 양성자 친화도를 확장분자궤도함수법으로 조사하였다. 그 결과 메틸이미다졸의 경우 염기중심 질소의 $\alpha$위치에 치환된 이미다졸이 N에 치환된 이미다졸보다 양성자 친화도가 약간 더 크게 나타났으며 다른 치환이미다졸의 경우에는 N에 치환된 이미다졸이 ${\alpha}$위치에 치환된 이미다졸보다 양성자 친화도가 더 크게 나타났다. 예상한 바와 같이 이미다졸의 N에 전자를 미는기가 치환될 때 모두 양성자 친화도가 증가함을 알 수 있었다.

• 대한화학회지
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• 제33권4호
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• pp.413-418
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• 1989

치환 2-phenylethyl tosylate와 치환 피리딘을 아세토니트릴에서, 2-phenylethyl m-nitrobenzenesulfonate(2-PNS)와 치환 피리딘을 아세토니트릴과 메탄올 용매 중에서 각각 반응시켰다. 기질과 친핵체 다같이 전자를 미는 치환기는 반응속도를 증가시켰다. 이들 결과는 전이상태 변화를 예측하는 More O'Ferral과 양자역학적인 모델에서 결합 파괴가 결합형성보다 더 진전된 $S_N2$ 메카니즘으로 진행함을 보였다. 전이상태 변화는 양자 역학적인 모델의 예측이 실험치와 잘 일치하였고 이탈기에서는 More O'Ferral 도시가 잘 맞지 않았다. 2-PNS 와 피리딘류와의 반응에서는 아세토니트릴이 메탄올용매보다 반응이 빨랐다.

• Bulletin of the Korean Chemical Society
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• 제29권4호
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• pp.767-771
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• 2008

Second-order rate constants have been measured spectrophotometrically for the Michael-type reaction of 1-(Xsubstituted phenyl)-2-propyn-1-ones (2a-f) with amines in $H_2O$ at 25.0 ${\pm}$ 0.1 ${^{\circ}C}$. A linear Brønsted-type plot is obtained with ${\beta}_{nuc}$ = 0.25 ${\pm}$ 0.02, a typical $\beta_{nuc}$ value for reactions which proceed through a stepwise mechanism with attack of amine on the electrophilic center being the rate-determining step. Secondary alicyclic amines are found to be more reactive than isobasic primary amines. The Hammett plot for the reactions of 2a-f with morpholine is not linear, i.e., the substrate with a strong electron-donating group (e.g., 4-MeO) exhibits a negative deviation from the Hammett plot. However, the Yukawa-Tsuno plot for the same reactions exhibits an excellent linear correlation with ρ = 0.62 and r = 0.82. Thus, it has been proposed that the nonlinear Hammett plot is not due to a change in the ra te-determining step but due to ground-state stabilization through resonance interactions.

• 한국응용과학기술학회지
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• 제10권2호
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• pp.65-72
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• 1993

The kinetics of the addition of thiourea to cinnamenylisophorone derivatives(X : H, p-Br, $p-CH_3$ $m-CH_3$, $p-OCH_3$) was investigated using ultraviolet spectrophotometry in 20%(v/v) dioxane-$H_2O$ at $25^{\circ}C$. A rate equation which can be applied over wide pH range(pH $1.0{\sim}13.0$) was obtained. In order to investigate the substituent effects of cinnamenylisophorone derivatives. Hammett constant was plotted. As the result, the rate of uncleophilic addition of thiourea to cinnamenylisophorone derivatives was facilitated by electron donating group. It was found that addition of neutral thiourea which was not dissociated at the pH $1.0{\sim}9.0$ was proceeded, the reaction was proceeded by addition of dissociated anion of thiourea above the pH 10.0. On the basis of this kinetic study, the reaction mechanism of nucleophilic addition of thiourea was investigated.

• Elastomers and Composites
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• 제58권3호
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• pp.121-127
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• 2023

The effect of diisocyanate type on the decomposition temperature of polyurethane (PU) hydrolysis was investigated in a subcritical water medium up to 250℃. PU samples were prepared using different types of diisocyanate: two aromatic diisocyanates (4,4'-methylene diphenyl diisocyanate (MDI) and methyl phenylene diisocyanate (TDI)), one unbranched aliphatic diisocyanate (hexamethylene diisocyanate (HDI)), and two cyclic aliphatic diisocyanates (4,4'-methylene dicyclohexyl diisocyanate (H₁₂MDI) and isophorone diisocyanate (IPDI)). The pressure had no effect on hydrolysis in the range of 70-250 bar. The decomposition temperature of the PU samples increased in the following order: TDI-PU (199℃) < H₁₂MDI ≈ IPDI ≈ HDI (218-220℃) < MDI-PU (237℃). This order of increase in temperature is related to the electron-donating ability of the group to connected to the nitrogen of the urethane unit. When the temperature of the (PU + water) mixture reached the specific decomposition temperature, the PU samples hydrolyzed completely within 5 min into primary amine and 1,4-butanediol. The hydrolysis products from MDI-PU and H₁₂MDI-PU were separated into a liquid phase rich in (BD + water) and a solid low phase rich in amine, whereas the products from TDI-, IPDI-, and HDI-PU existed in a single aqueous phase.

• 농약과학회지
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• 제5권3호
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• pp.36-40
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• 2001

기질 화합물로 2-N-benzyl-5-phenoxy-3-isothiazolone 유도체를 합성하고 그들의 반응성과 metalaxyl 살균제에 저항성(RPC)과 감수성(SPC)을 나타내는 고추역병균(Phytophthora capsici)들에 대한 살균활성에 미치는 5-치환-phenoxy기의 영향을 검토하였다. 그 결과, 비치환 기질 화합물은 궤도-조절 반응성이 우세하였고 특히, 4-fluoro-치환체 6은 RPC에 그리고 4-nitro-치환체 3은 SPC에 대하여 뚜렷한 선택성을 보였다. RPC에 대한 살균활성은 HOMO 에너지의 적정값(-9.2137 e.v.)에 그리고 SPC는 MR상수의 적정값($7.37cm^3/mol.$)에 주로 의존적이었다. 그리고 Free-Wilson 분석 결과 SPC에는 모든 치환체가 살균활성에 기여하였으나 RPC의 경우에는 methoxy와 bromo-기만이 기여하는 경향이었다.

• 대한화학회지
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• 제31권2호
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• pp.133-142
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• 1987

시클로로펜타디엔과 메틸기로 치환된 알렌의 산 및 에스테르간의 (4+2)고리화반응에서 입체 선택성을 $\pi$-비결합상호작용($\pi$-NBI)을 적용하여 고찰하였다. 열반응에서는 diene(LUMO)-dienophile (HOMO)만을 고려한 2-FMO방법이, 산촉매반응에서는 diene (HOMO)-dienophile (LUMO)상호작용만을 고려한 2-FMO방법이 이들의 입체선택성의 결정에 중요하였다. cumulated diene계의 친디엔체에서 메틸 치환기는 알렌구조와 through-bond 상호작용에 의해 $\pi$-isoconjugate diene 구조를 형성하여 컨쥬게이션기로 작용하며 FMO의 에너지에 narrowing effect를 주고 있으나 이같은 $\pi$-isoconjugated diene 구조를 만들 수 없는 친디엔체에서는 메틸기가 단순히 전자주는기로 작용한다. 열반응에서 입체선택성은 에틸렌 분자와 마찬가지로 메틸 치환기의 $\pi$-비결합 2차궤도 상호작용($\pi$-NSOI)에 의해서 좌우되었다.