• Bulletin of the Korean Chemical Society
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• v.15 no.6
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• pp.456-460
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• 1994

Catalytic effects of various cobalt phenylporphyrin compounds on the reduction of thionyl chloride at glassy carbon electrode have been evaluated by determining kinetic parameters with cyclic voltammetric techniques. The concentration of catalysts and the electrode immersion time have been found to affect the catalyst performance strongly, leading to a conclusion that the compounds are first adsorbed at the electrode surface and act as catalysts. Significant improvements in cell performance have been noted in terms of both exchange rate constants of up to 3 times and current densities of up to 150% at glassy carbon electrode.

• Bulletin of the Korean Chemical Society
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• v.19 no.12
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• pp.1355-1359
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• 1998

The treatment of 1,1-bis(phenylthio)-2,2,3,3,3-pentafluoropropylbenzene (1) with 2 equiv. of phenyllithium in THF at -78 ℃ resulted in the formation of isomeric mixture (70: 30) of trifluoromethylated 1,2-diphenylvinyl sulfide 2 in 87% yield. The further oxidation of 2 with m-chloroperbenzoic acid in methylene chloride afforded isomeric mixture (70:30) of trifluoromethylated 1,2-diphenylvinyl sulfone 3 in 87% yield. When 3 was reacted with carbon nucleophiles such as methyllithium, n-butyllithium, phenyllithium and lithium octylide, the corresponding addition-elimination adducts 4, 5, 6 and 7 were obtained in moderate to good yields. The reaction of 3 with 4 equiv. of tributyltin hydride in benzene at reflux temperature provided isomeric mixture (90 : 10) of trifluoromethylated 1,2-diphenylvinyl stannane 8 in 41% yield. The reaction of 8 with methyllithium in the presence of trimethylsilyl chloride gave isomeric mixtures (90: 10) of trifluoromethylated 1,2-diphenylvinyl silane 9 in 88% yield. Finally, the treatment of 8 with Br2 and 12 resulted in the formation of isomeric mixtures (90: 10) of trifluoromethylated 1,2-diphenylvinyl bromide 10 and iodide 11 in 72% and 90% yields, respectively.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.286-290
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• 2010

The reaction of carboxylic acid derivatives such as esters, acid chlorides and acid anhydrides with alkynyl lithiums in the presence of lithium morpholinide and $BF_3{\cdot}OEt_2$ gave alkynyl ketones in good yield (73-96%).

• Textile Coloration and Finishing
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• v.7 no.4
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• pp.54-60
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• 1995

Cellulose(cell)/dimethylacetamide(DMAc)/lithium chloride(LiCl) solutions were prepared and spun to fibers in coagulants. Then, obtained fibers were annealed in appropriate chemicals. The fibers from cell/DMAc/LiCl showed cell III morophology prior to annealing without differenciating the kind of coagulants. Morphology of crystallite, however, was affected by annealing. Annealed fibers at 17$0^{\circ}C$ showed cell IV morphology and had better mechanical properties than others.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.977-982
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• 2013

Cellulose mixed esters (CME), substituted by various fatty acyl chains, are renewable bio-based polyesters. It has lots of potential due to the biodegradable property. In this study, Alpha cellulose was activated for 2h at $40^{\circ}C$ in deionized water prior to synthesis. Homogeneous esterification of CME was accomplished with water-activated alpha cellulose, various saturated fatty acids and acetic anhydride in lithium chloride/N,N-dimethylacetamide (LiCl/DMAc) medium. CME was obtained after 5 hr at $120^{\circ}C$. The filtrated products were characterized using TGA, FT-IR, 1H-NMR and FE-SEM, and the influence of water activation on the total degree of substitution was investigated.

• Solar Energy
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• v.18 no.3
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• pp.185-195
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• 1998

The high viscosity of a LiCl(lithium chloride) solution as an absorbent in a solar energy regenerator causes a channeling phenomenon on the solar powered absorber plate surface when the solution is trickling down for regenerating itself. As this channeling phenomenon affects badly the heat and mass transfer, it is pertinent that this phenomenon be studied. Since regenerating performance of the solar energy regenerator depends on how the solution uniformly flows on the plate surface, an experiment on the structure of the plate surface for a model regenerator was conducted. Various shapes and structures of the plat surface down which the LiCl solution trickled were tested, and it was found that a tiered surface showed the highest water evaporation rate leaving more potential energy concentrating LiCl on the plate. It was also observed that the water evaporation rate depended largely on the pitch and height of the disturbing rods. In addition, the wider the contact area is and the longer the solution's flow time, the better the solar energy regenerator's performance.

• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.226-230
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• 2005

Chitosan derivatives, 6-amino-6-deoxychitosan (6A6DC) was successively prepared as a reactive carbohydrate for the stabilization of epidermal growth factor (EGF) by the reactions of chitosan with tosyl chloride, sodium azide, and lithium aluminum tetrahydride. The structure of 6A6DC was confirmed by EA, FT-IR, $^1H-NMR$ and $^{13}C\{^1H\}-NMR$. The degree of substitution (ds) of amino groups in 6A6DC was determined to be 0.7. 6A6DC did not show any cytotoxicity on the normal human dermal fibroblast (NHDF) proliferation at least in the range tested (0.3 g/mL 600 g/mL) and was considered as a suitable material for the stabilization of EGF against proteolytic degradation due to its non-cytotoxicity and high reactivity.

• Bulletin of the Korean Chemical Society
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• v.4 no.1
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• pp.3-9
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• 1983

Lithium n-butylborohydride was prepared from borane-dimethylsulfide (BMS) and n-butyllithium, and the approximate rates and stoichiometrics of its reactions with selected organic compounds containing representative functional groups were studied in THF at room temperature. Phenol and benzenetiol liberated hydrogen quickly and quantitatively, and the reactions of primary alcohols, 2,6-di-ter-butylphenol and 1-hexanethiol liberated hydrogen quantitatively within 3 hrs, whereas the reactions of secondary and tertiary alcohols were very slow. Aldehydes and ketones were reduced rapidly and quantitatively to the corresponding alcohols. Cinnamaldehyde utilized 1 equiv. of hydride rapidly, suggesting the reduction to cinnamyl alcohol. Carboxylic acids evolved 1 equiv. of hydrogen rapidly and further reduction was not observed. Anhydrides utilized 2 equiv. of hydride rapidly but further hydride uptake was very slow, showing a half reduction. Acid chlorides were reduced to the alcohol stage very rapidly. All the esters examined were reduced to the corresponding alcohol rapidly. Lactones were also reduced rapidly. Expoxides took up 1 equiv. of hydride at a moderate rate to be reduced to the corresponding alcohols. Nitriles and primary amides were inert to this hydride system, whereas tertiary amide underwent slow reduction. Nitroethane and nitrobenzene were reduced slowly, however azobenzene and azoxybenzene were quite inert. Cyclohexanone oxime evolved 1 equiv. of hydrogen rapidly, but no further reduction was observed. Phenyl isocyanate and pyridine N-oxide were proceeded slowly, showing 1.74 and 1.53 hydride uptake, respectively in 24 hours. Diphenyl disulfide was reduced rapidly, whereas di-n-butyl disulfide, sulfone and sulfonic acids were inert or sluggish. n-Hexyl iodide and benzyl bromide reacted rapidly, but n-octyl bromide, n-octyl chloride, and benzyl chloride reacted very slowly.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2017.10a
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• pp.74-74
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• 2017

Electrorefining is a key step in pyroprocessing. The electrorefining process is generally composed of two recovery steps - the deposit of uranium onto a solid cathode and the recovery of the remaining uranium and TRU elements simultaneously by a liquid cadmium cathode. Uranium deposit recovered from the solid cathode is a dendritic powder. It is necessary to separate the adhered salt from the deposits prior to the consolidation of uranium deposit. The adhered salt is composed of lithium, potassium, uranium, and rare earth chlorides. Distillation process was employed for the cathode processing. One of the operation methods is distillation of the salt at low temperature ($900^{\circ}C$), and then melting of the deposit at high temperature to avoid a backward reaction. For the development of the salt distiller, the distillation behavior of the low vapor pressure chlorides should be studied. Rare earth chlorides in the adhered salt of uranium deposits have relatively low vapor pressures compared to the process salt (LiCl-KCl). In this study, the evaporation rates of the lanthanum and neodymium chlorides were measured for the salt separation from electrorefiner uranium deposits in the temperature range of $825{\sim}910^{\circ}C$. The evaporation rate of both chlorides increased with an increasing templerature. The evaporation rate of lanthanum chloride varied from 0.12 to $1.68g/cm^2/h$. Neodymium chloride was more volatile than lanthanum chloride. The evaporation rate of neodymium chloride varied from 0.20 to $4.55g/cm^2/h$. The evaporation rate of both chlorides are more than $1g/cm^2/h$ at $900^{\circ}C$. Even though the evaporation rates of both chlorides were less than that of the process salt, the contents of the lanthanide chlorides were small in the adhered salt. Therefore it can be concluded that $900^{\circ}C$ is suitable for the operation temperature of the salt distiller.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.2
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• pp.271-278
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• 2021

In this study, a chlorination technique for recycling Li₂ZrO₃, a reaction product of ZrO₂-assisted rinsing process, was investigated to minimize the generation of secondary radioactive pyroprocessing waste. It was found that the reaction temperature was a key parameter that determined the reaction rate and maximum conversion ratio. In the temperature range of 400-600℃, an increase in the reaction temperature resulted in a profound increase in the reaction rate. Hence, according to the experimental results, a reaction temperature of at least 450℃ was proposed to ensure a Li₂ZrO₃ conversion ratio that exceeded 80% within 8 h of the reaction time. The activation energy was found to be 102 ± 2 kJ·mol^-1·K^-1 between 450 and 500℃. The formation of LiCl and ZrO₂ as reaction products was confirmed by X-ray diffraction analysis. The experimental results obtained at various total flow rates revealed that the overall reaction rate depends on the Cl₂ mass transfer rate in the experimental condition. The results of this study prove that the chlorination technique provides a solution to minimize the amount of radioactive waste generated during the ZrO₂-assisted rinsing process.