• 한국염색가공학회지
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• 제24권1호
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• pp.39-44
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• 2012

To improve flame retardation of poly(ethylene terephthalate) (PET) against burning, resorcinol bis(diphenyl phosphate) (RDP), phosphorous containing flame retardant, was incorporated into PET backbone by radical reaction pathway. Radical endcapping of PET with RDP was confirmed by spectroscopic and thermal analysis. From 400 MHz $^{31}P$ solid state FT-NMR spectrum of PET with RDP (PET-RDP), phosphorus spectra peak in RDP was found at ca. -10 ppm. Furthermore, P-C bond stretching vibration peaks were found ca. $530cm^{-1}$ in FT-IR spectrums of PET-RDP. These results indicated that RDP can be chemically bound at the ends of PET by radical addition method. Thermal characteristics of pure PET (pPET) and PET-RDP were measured and evaluated by TGA thermal analysis. There was not significant changes in thermal characteristics of PET-RDP compared to that of pPET.

• 약학회지
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• 제30권5호
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• pp.203-207
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• 1986

2-Aminobenzamide reacts with not only keton radical but also carbonyl group in carboxylic acid, to form easily -N-C-N-novel ring cyclization as a result I and V. In addition, it reacts with 1, 2-cyclohexadione or benzil, whitch are both 1, 2-diketone compounds, at the both ketone radical sites to give V or VII respectively. On the reaction with dimethone, however, which has 1, 3-diketone radical, it reacted with only one carbanyl group and VI was produced. We investigated the reaction with cr-ketoester such as ethyl pyruvate and diethyl rnesoxalate. In the reaction with ethylpyruvate, amine group in 2-aminobenzamide reacted not with ketone radical but carbonyl group in ester (product VIII). On the other hand, diethyl measoxalate reacted at the ketone radical site rather than the ester site (product IX).

• Bulletin of the Korean Chemical Society
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• 제29권2호
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• pp.319-322
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• 2008

The viability of acetylene addition in each step of aromatic formation initiated by vinyl radical and acetylene also with its competition with structure rearrangement is investigated by determining optimal geometries and barrier and reaction energies using quantum mechanical methods. In principle, the addition reaction has more difficult in term of free energy and enthalpy compared to geometry arrangement. Under combustion conditions, i.e. T = 1200 K, acetylene addition is unfavorable mechanism as the barrier energy values rise much higher than that of geometry arrangement. However, in longer chain hydrocarbon case, e.g. n-CxHx+1 where x ³ 8, C-C bond rotation is rather difficult and requires high energy to form a ring structure, elongation chain is preferable.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제10권S_3호
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• pp.127-137
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• 2001

The sonochemical Process has been applied as a treatment method and was investigated its effect on the decomposition of humic substances(HS). The reaction kinetics and mechanisms in the Process of sonochemical treatment for humic substances(HS) in wastewater have also been discussed. It was observed that the metal ions such as Fe(II) and Mn(II) showed catalytic effects, while Al(III), Ca(II), and Mg(II) had inhibitory effects on the decomposition of humic substances in sonochemical reaction with hydrogen peroxide. Experimental results also showed factors such as hydrogen peroxide dose affected the formation of disinfection by-products. Two trihalomethanes, chloroform and dichlorobromomethane were formed as major disinfection by-products during chlorination. The mechanism of radical reaction is controlled by an oxidation process. The radicals are so reactive that most of them are consumed by HS radicals and hydroxyl radicals can be acted on organic solutes by hydroxyl addition, hydrogen abstraction, and electron transfer. The depolymerization and the radical reaction of HS radicals appear to occur simultaneously. The final steps of the reaction are the conversion of organic acids to carbon dioxide.

• 한국환경보건학회지
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• 제35권6호
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• pp.532-537
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• 2009

The tropospheric ozone production mechanism for the gas phase additive oxidation reaction of hydroxyl radical (OH) with isoprene (2-methyl-1,3-butadiene) has been studied using cavity ring-down spectroscopy (CRDS) at total pressure of 50 Torr and 298 K. The applicability of CRDS was confirmed by monitoring the shorter (~4%) ringdown time in the presence of hydroxyl radical than the ring-down time without the photolysis of hydrogen peroxide. The reaction rate constant, $(9.8{\pm}0.1){\times}10^{-11}molecule^{-1}cm^3s^{-1}$, for the addition of OH to isoprene is in good agreement with previous studies. In the presence of $O_2$ and NO, hydroxyl radical cycling has been monitored and the simulation using the recommended elementary reaction rate constants as the basis to OH cycling curve gives reasonable fit to the data.

• Bulletin of the Korean Chemical Society
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• 제20권8호
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• pp.935-938
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• 1999

Reactivity and reaction mechanism for the reactions of 1,1'-(azodicarbonyl) dipiperidine with triphenylphosphines are investigated using kinetic method. The cation radical, Ph3P and the anion radical, -N-N - are produced during the course of the reaction. The cation radical is formed by the transfer of an electron from phosphorus to the nitrogen atom. The anion radical is formed by the addition of the one electron to the azo rad-ical. The rate constants are decreased by electron withdrawing groups while they are increased by electron donating groups present in triphenylphosphine. The electron density increases on nitrogen, while positive charge is developed on phosphorus in the transition state.

• Korean Chemical Engineering Research
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• 제51권4호
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• pp.523-526
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• 2013

본 연구에서는 수질정화 기술개발을 위하여 수산화라디칼 및 오존 발생기를 이용하여 수중에 존재하는 천연 지방산 분해 제거 연구를 수행하였다. 천연 지방산은 수산화라디칼 및 오존에 의하여 1차 분해반응 형태로 제거되었으며, 천연 지방산의 분해반응에서 수산화라디칼 단독으로 사용하는 것 보다 오존과 함께 사용한 경우 분해 효율을 크게 향상시킬 수 있음을 알 수 있었다. 또한, 천연 지방산이 수산화라디칼과 오존에 의해 분해되는 화학반응 기구를 제안하였다.

• 대한화학회지
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• 제26권1호
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• pp.1-6
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• 1982

Thiophenol이 ${\alpha}$-methylstyrene에 부과되는 반응에 대하여 CNDO/2 방법을 써서 분자궤도론적으로 고찰하였다. 전체 부가반응은 두 단계, 즉 (1)티오페놀이 분해하여 Phenylthiyl 라디칼이 되는 단계와 (2)이 라디칼이 ${\alpha}$-methylstyrene에 부가되어 새로운 단위체 라디칼이 되는 단계로 되어 있으나 부가반응속도를 결정하는데 지배적인 과정은 첫째 (1)과정임을 계산결과로 알 수 있었다. 이것이 바로 thiyl라디칼의 치환기에 대한 Hammertt관게에서 陰의 ${\rho}$값이 실험적으로 얻어진 이유이다. ${\rho}$-chlorophenylthiyl 및 m-trifluoromethyl phenylthiyl 라디칼이 ${\rho}$-methoxy-${\alpha}$-methylstyrene에 부가될 때 Hammett 직선관계로 부터 벗어나는 이유는 전체 반응속도에 미치는 부가반응단계 (2)의 기여가 증가하였기 때문이라고 설명 할 수가 있었다.

• Korean Chemical Engineering Research
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• 제53권1호
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• pp.83-90
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• 2015

본 연구에서는 multi-walled carbon nanotube (MWCNT) 표면에 자유 라디칼 중합 가능한 methacrylate기를 다량으로 도입하기 위한 연구를 수행하였다. 먼저, MWCNT 표면에 카르복실기(-COOH)를 도입하기 위하여 황산과 질산의 혼산으로 초음파로 처리하면서 2시간 산화시켜 MWCNT-COOH를 합성하였다. 합성된 MWCNT-COOH를 염화티오닐(thionyl chloride)와 반응시켜 MWCNT-COCl을 합성하고, triethylenetetramine (TETA)와 반응시켜 MWCNT-$NH_2$를 합성하였다. 합성된 MWCNT-$NH_2$와 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM)의 투입 몰 비를 변화시키면서 Michael 부가 반응으로 MWCNT 표면에 methacrylate기가 도입된 MWCNT-AHM을 합성하였다. MWCNT의 표면 개질정도는 fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA)와 원소분석(elemental analysis, EA) 분석을 통해 개질 반응의 진행 정도와 최적 개질 조건을 확인하였다. 그 결과 MWCNT-$NH_2$에 접목되어 있는 TETA에 대하여 AHM의 반응 몰 비를 1:10로 하고 8시간 반응시켰을 때 methacrylate기가 가장 많이 도입되는 조건임을 확인하였다.

• 대한화학회지
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• 제24권1호
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• pp.34-43
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• 1980

아세토니트릴 용매에 녹은 티안트렌 양이온 자유라디칼 과염소산염과 티오크잔틴을 반응시키면 티안트렌과 티오크잔틴 양이온 라디칼 대신에 티오크잔틸이움 이온이 생성된다. 이 혼합물에 아니솔, 아닐린, N,N-디에틸아닐린, 카테콜, 에틸벤젠 등을 가해 줌으로서 각각 9위치에 치환기를 가진 티오크잔틴을 얻었다. 디벤조-18-크라운-6-에테르, 디페닐수은과 삼페닐포스핀과의 반응에서도 같은 유형의 생성물이 얻어진다. 그러나 전자받게를 가진 방향족 화합물과의 반응은 너무 느리거나 반응이 일어나지 않았다.