• Bulletin of the Korean Chemical Society
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• v.3 no.4
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• pp.144-148
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• 1982

The kinetic study on the bromine-exchange reaction of antimony tribromide with t-butyl bromide in nitrobenzene or 1,2,4-trichlorobenzene has been carried out, using Br-82 labelled antimony tribromide. The results show that the exchange reaction is first order with respect to t-butyl bromide and 1.5th order with respect to antimony tribromide. It is assumed that the 1.5th order indicates the coexistance of first- and second-order kinetics. Reaction mechanisms for the exchange reaction are proposed.

• 월간산업보건
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• s.192
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• pp.22-24
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• 2004

• 월간산업보건
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• s.190
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• pp.33-35
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• 2004

• 월간산업보건
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• s.191
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• pp.11-13
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• 2004

• Applied Chemistry for Engineering
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• v.10 no.7
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• pp.1079-1085
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• 1999

An investigation was made of the effect of various transition metal catalysts, ligands, and a promoter on the synthesis of N,N'-diphenylurea(DPU) from nitrobenzene, aniline, and carbon monoxide. Homogeneous Pd and Ni catalysts were found to be highly efficient, giving almost quantitative isolated DPU yields at 100% nitrobenzene conversion. Bidentate ligand, 1,3-bis(diphenylphosphino)proane(dppp) showed much improved activity and significantly different reactivity relative to the usual monodentate $PPh_3$ ligand in the presence of Ni and Pd catalysts. These results were inferred to the effect of the cis coordination of bidentate dppp ligand on the metal. The use of a promoter $Et_4NCl$ was indispensable in the case of $PPh_3$, yet inhibited the reaction if used with dppp. It was possible to reuse the Pd-dppp catalyst system, although the catalytic activity was reduced slowly.

• Journal of the Korean Chemical Society
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• v.43 no.2
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• pp.161-166
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• 1999

Transfer of lanthanide ions across the liquid/liquid interface facilitated by ionopore ETH4120 has been studied by using cyclic voltammetry (CV) and chronopotentiometry with cyclic linear current-scanning (CPCLCS) under the condition where the concentration of ETH4120 in nitrobenzene was much smaller than the concentration of lanthanide ions in aqueous solution. One cathodic current peak (transfer from aqueous to nitrobenzene phase) and two anodic current waves (transfer from nitrobenzene to aqueous phase) were observed. The cathodic wave was due to the formation of 1:1 (metal:ligand) complex and two anodic waves showed successive formation of 1:2 and 1:3 complexes in nitrobenzene solution. But there was no cathodic wave corresponding to two anodic waves. The ion transfer mechanism has also been discussed.

• Journal of the Korean Chemical Society
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• v.26 no.5
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• pp.326-332
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• 1982

The structure of the complex extracted from an aqueous solution containing methylene blue and tetrafluoroborate with 1,2-dichloroethane has been investigated by comparing IR spectrum of the extract with those of pure components and appeared to be an 1 : 1 contact ion-pair between monovalent ions of opposite charge. The extraction constant obtained from the absorbance data measured at 658nm in 1,2-dichlorethane has a value of 1.1${\times}$at$10^4M{-1}$ 25$^{\circ}$C in the range from 1.43${\times}10^{-2}$ to 2.86${\times}10^{-1}$M HF. In the solvent extraction with nitrobenzene, the identical experiments show that extraction constants are increased with HF concentration possibly due to dissociation of the ion-pair in nitrobenzene.

• Journal of the Korean Chemical Society
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• v.24 no.4
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• pp.302-309
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• 1980

The solubilities of n-propyl bromide in nitrobenzene and in 1,2,4-trichlorobenzene have been measured at 19, 25 and $40^{\circ}C$ in the presence and absence of gallium bromide. When gallium bromide does not exist in the system, the solubility of n-propyl bromide in nitrobenzene is greater than in 1,2,4-trichlorobenzene, indicating a stronger interaction of n-propyl bromide with nitrobenzene than with 1,2,4-trichlorobenzene. In the presence of gallium bromide, 1: 1 complex $n-C_3H_7Br\cdotGaBr_3$ is formed in the solution. The instability constant K of the complex was evaluated. $$n-C_3H_7Br\cdotGaBr_3 \rightleftarrows n-C_3H_7Br ＋ \frac{1}{2Ga_2Br_6 }$$The change of enthalpy, free energy and entropy for the dissociation of the complex were also calculated. It seems that the stabilities of the complex, gallium bromide with alkyl bromide, are relatively concerned with the stabilities of the alkyl ion.

• Journal of the Korean Chemical Society
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• v.15 no.5
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• pp.228-235
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• 1971

The solubilities of n-butyl bromide in nitrobenzene and in 1,2,4-trichlorobenzene have been measured at $19^{\circ},\;25^{\circ},\;and\;40^{\circ}C$ in the presence and absence of gallium bromide. When gallium bromide does not exist in the system, the solubility of n-butyl bromide in nitrobenzene is greater than in 1,2,4-trichlorobenzene, indicating a stronger interaction of n-butyl bromide with nitrobenzene than with 1,2,4-trichlorobenzene. In the presence of gallium bromide, complex of n-butyl bromide with gallium bromide, 1:1 complex, $n-C_4H_9Br{\cdot}GaBr_3$, is formed in the solution. The instability constant K of the complex was evaluated. $n-C_4H_9Br{\cdot}GaBr_3{\rightleftharpoons}n-C_4H_9Br+\frac{1}{2}Ga_2Br_6$ The changes of enthalpy, free energy and entropy for the dissociation of the complex were also calculated.

• Journal of the Korean Chemical Society
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• v.21 no.6
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• pp.404-412
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• 1977

Electrochemical reduction of nitrobenzene (${\phi}NO_2$) and its derivatives on Pb electrode was studied by means of galvanostatic measurements and coulometric electrolysis in ethanol-water solvent. In acidic solutions phenylhydroxyl amine and aniline ethanol-water solvent. In acidic solutions phenylhydroxyl amine and aniline were produced while nitrosobenzene and coupled products such as azo-and hydrazobenzene were produced in basic solutions. Nitrosobenzene (${\phi}NO$) was not found to be an intermediate in the reduction reactions of ${\phi}NO_2$ in acidic solutions. No direct coupling between ${\phi}NO\;and\;{\phi}NHOH$ was observed to occur in the electrolyte solutions used. Mechanisms of the production of phenylhydroxylamine and nitrosobenzene are deduced from Tafel slope, pH dependence and reaction order with respect to nitrobenzene. Mechanism for the reduction of substituted nitrobenzenes seems to be identical to that of nitrobenzene.