• Clean Technology
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• 제16권4호
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• pp.239-244
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• 2010

The carboxylation of the fluorenyl epoxide with a spiro framework, 9,9'-Bis(4-oxiranylmethoxyphenyl) fluorine (2) was catalyzed by some onium salts such as quaternary ammonium and phosphonium salts to produce the corresponding five-membered cyclic carbonate (3) in an efficient and environmentally benign fashion. The coupling reactions depend greatly on the kind of the halide anions and alkyl chain length of the onium salts. While the reaction was sensitive to the reaction temperature, the reaction trends suggest that the catalytic efficiency of the quaternary ammonium halides may correlate strongly with the melting points of the halides. The reactions using a catalytic amount (2 mol %) of quaternary ammonium bromide with an n-butyl chain at 75.9 bar of $CO_2$ and 393 K give the highest yield of the cyclic carbonate (92%).

• Journal of the Korean Chemical Society
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• 제37권9호
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• pp.837-844
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• 1993

N-Arylmethylideneglycine N-oxide alkyl esters(1) were alkylated with alkyl halides in THF using lithium hexamethyldisilazide as a base, followed by hydroxylaminolysis to give N-hydroxy-${\alpha}$-amino acid esters(7).

• Bulletin of the Korean Chemical Society
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• 제33권8호
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• pp.2642-2646
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• 2012

Pretreatment of spent FCC catalyst and its application in remove trace olefins in aromatics were investigated in this research. The most effective pretreatment route of spent FCC catalyst was calcining at $700^{\circ}C$ for 1 h, washing with 5% oxalic acid solution in ultrasonic reactor and dried. Treated spent FCC catalyst was modified with metal halides, then to prepare catalyst to remove trace olefins in aromatics. X-ray diffraction, Pyridine-FTIR, $N_2$ adsorption-desorption and inductively coupled plasma optical emission spectrometer (ICP-OES) were used to investigate the pretreatment process. The result showed that the performance of the treated spent FCC catalyst was much greater than that of the spent FCC catalyst, which indicted the possibility and improvement of this research.

• Journal of the Korean Chemical Society
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• 제13권2호
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• pp.103-108
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• 1969

전보에 이어 90% 에탄올 용액에서의 염화 벤질 및 브롬화 벤질과 요오드화 이온 간의 교환반응을 연구하였다. HSAB이론을 도입하여 할로겐화 이온의 pb혼합 궤도가 서로 겹치는 전이 상태로서 실험 결과를 설명하였다.

• Journal of the Korean Chemical Society
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• 제13권2호
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• pp.115-120
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• 1969

Kinetics of reactions of halide ions with 1-naphthyl methyl halide have been investigated in anhydrous acetone. Semi-quantitative analysis of the results shows that if the softness of the substrate increases remarkably, the nucleophilicity order of halide ions is $I^- > Br^- > Cl^-$ even in dipolar aprotic solvent. But for 1-naphthyl methyl bromide, though the reaction center which was made soft by symbiosis of bromine atom raises the reactivity of soft nucleophile, nucleophilicity order indicates that soft-soft interaction is interfered by perihydrogen.

• Ceramist
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• 제10권3호
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• pp.48-54
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• 2007

Glass-ceramics transparent above $10\;{\mu}m$ in the infrared, have been synthesized. They are based on germanium and antimony sulphides or selenides associated to alkali halides. They are prepared by heating glass samples at temperatures above the glass transition, as a function of time. Ceramisation can be controlled, so that sub-100 nm crystals are generated in the glass matrix. Then, low light scattering is achieved and the transparency window of the original glass is maintained. When gallium sulphide is added, glass ceramics can be doped with rare-earth ions. Emissions from the $^4F_{3/2}$ and $^4I_{13/2}$ of $Nd^{3+}$ and $Er^{3+}$ ions, respectively, are more intense in glass-ceramics, as compared to their vitreous counterpart. Examination of band profiles and decaytimes show that rare-earth ions are embedded in both crystalline and glassy environments.

• YAKHAK HOEJI
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• 제52권4호
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• pp.311-315
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• 2008

The synthesis of 7-arylidene cephalosporanates for ${\beta}-lactamase$ inhibitor was described. The reactions of substituted benzyl halides $[1]{\sim}[3]$ with triphenylphosphine gave triphenylphcsphonium chlorides $[4]{\sim}[6]$. These phosphonium salts were treated with n-butyllithium to give ylides, which were reated with 7-oxocephalosporanate [7] by Wittig reaction to afford the 7-exomethylene cephalosporanates $[8]{\sim}[10]$. These cephalosporanates were oxidized to cephalosporanate sulfones $[11]{\sim}[13]$ with mCPBA. The deprotection of benzhydryl cephalosporanate $[8]{\sim}[13]$ with $AlCl_3$ and $NaHCO_{3}$ gave sodium salts of 7-arylidene cephalosporanates $[14]{\sim}[19]$.

• Bulletin of the Korean Chemical Society
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• 제34권3호
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• pp.820-822
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• 2013

N,N,N',N'-Tetrabromobenzene-1,3-disulfonamide (TBBDA)/$PPh_3$ and N,N,N',N'-tetrachlorobenzene-1,3-disulfonamide (TCBDA)/$PPh_3$ are two highly reactive reagent systems for the conversion of alcohols corresponding into alkyl chlorides and bromides in moderate to excellent yields in dichloromethane at room temperature under mild and neutral conditions.

• The Korean Journal of Ceramics
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• 제1권3호
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• pp.152-154
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• 1995

A non-hydrolytic sol-gel process was developed to fabricate low-hydroxyl hard gels. The reaction of tert-butyl alcohol with silicon halides provided transparent low-hydroxyl hard gels. Some properties such as transparency, density, and refractive index was successfully doped into the hard gel matrices. The absorption spectrum of an erbium-doped methylsilsesquioxane was investigated to decide the pumping wavelength of an argon laser. The luminescence of the erbium-doped gel at 664 nm seems to be due to $4^F{9/2}\to 4^I_{15/2}$ transition.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.1013-1016
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• 2003

A new route for the synthesis of silver doped of zinc sulfide phosphor by combustion method has been investigated. Silver nitrate was decomposed with urea or carbohydrazide to give small size particles in presence of alkali metal halides at low temperature compared to the conventional method. The high temperature inherent to the highly exothermic nature of redox reaction leads to well-crystallized powder in short time. The phosphors thus obtained were further heated at $1050^{\circ}C$ in an inert atmosphere for 3hrs to get better luminescence properties.