• 약학회지
• /
• 제35권2호
• /
• pp.119-122
• /
• 1991

A convenient method for the synthesis of ibuproxam, which is a non steroidal antiinflammatory agent, is reported. Friedel-Crafts reaction of isobutylbenzene with ethyl $\alpha$-chloro-$\alpha$-(methylthio)acetate (3) gives ethyl $\alpha$-methylthio-(p-isobutylpheny) acetate (4). Ethyl 2-methylthio-2-(4-isobutylphenyl) propionate (5) is obtained from methylation of the compound (4) with NaH and Mel. lbuproxam (7) is easily synthesized by reductive desulfurization of the compound (5) with zinc dust-acetic acid or Raney nickel, followed by treatment of the resultant ethyl 2-(4-isobutyl-pheny) propionate (6) with H$_{2}$NOH-HCI.

• 약학회지
• /
• 제35권2호
• /
• pp.131-134
• /
• 1991

A new method for the synthesis of butibufen, which is a non steroidal anti-iriflammatory agent, is described. Friedel-Crafts reaction of isobutylbenzene with ethyl $\alpha$-chloro-.alpha.-(methylthio) acetate (1) gives ethyl $\alpha$-methylthio-(p-isobutylphenyl)acetate (2). Ethyl 2-methylthio-2-(4-isobutylphenyl)butyrate (3) is obtained from treatment of the compound (2) with NaH and Etl. Butibufen (5) is synthesized by reductive desulfurization of the compound (3) with zinc dust-acetic acid or Raney nickel, followed by hydrolysis of the resultant ethyl 2-(4-isobutylphenyl)butyrate (4).

• Bulletin of the Korean Chemical Society
• /
• 제24권5호
• /
• pp.539-540
• /
• 2003

• Bulletin of the Korean Chemical Society
• /
• 제22권4호
• /
• pp.375-378
• /
• 2001

The palladium catalyzed dehalogenative homocoupling of haloarylsulfonates under reductive conditions has proceeded selectively depending on the type of the halogen. Thus, an iodo or a bromo leaving group of haloarylsulfonates was homocoupled to gi ve symmetrical biaryls in good yields with the sulfonate group intact, whereas a chloro leaving group gave no reaction under the conditions used. When the more reactive nickel catalyst was employed instead of the palladium catalyst in the reaction, both dehalogenative and desulfonative homocouplings of haloarylsulfonates occurred regardless of the type of the halogen used.

• 대한화학회지
• /
• 제59권6호
• /
• pp.493-498
• /
• 2015

The reductive amination of cyclohexanone with ammonia over Cu-Cr-a/γ-Al₂O₃ was investigated. It was found that a proper solvent with high solubility of ammonia and 4Å molecular sieves for the elimination of generated water contributed to the formation of cyclohexylamine in the premixing process. In addition, the addition of ammonia in the fixedbed reactor could obviously improve the conversion of cyclohexanone to cyclohexylamine. Finally, reaction conditions including reaction temperature, hydrogen pressure and charging rate of the premix were optimized. Under the optimized conditions, cyclohexylamine was obtained in 83.06% yield.

• 한국세라믹학회지
• /
• 제56권4호
• /
• pp.387-393
• /
• 2019

A N₂H₄-Cu(I)-HNO₃ solution was used to dissolve magnetite powders and a simulated oxide film on Inconel 600. The addition of Cu(I) ions to N₂H₄-HNO₃ increased the dissolution rate of magnetite, and the reaction rate was found to depend on the solution pH, temperature, and [N₂H₄]. The dissolution of magnetite in the N₂H₄-Cu(I)-HNO₃ solution followed the contracting core law. This suggests that the complexes of [Cu⁺(N₂H₄)] formed in the solution increased the dissolution rate. The dissolution reaction is explained by the complex formation, adsorption of the complexes onto the surface ferric ions of magnetite, and the effective electron transfer from the complexes to ferric ions. The oxide film formed on Inconel 600 is satisfactorily dissolved through the successive iteration of oxidation and reductive dissolution steps.

• Bulletin of the Korean Chemical Society
• /
• 제27권11호
• /
• pp.1839-1843
• /
• 2006

Hydrothermal reactions of $Ln(NO_3)_3{\cdot}5H_2O $ (Ln = Eu (1), Sm (2), Ho (3), Dy (4)) with 3,5-pyridinedicarboxylic acid (3,5-pdcH2) in the presence of 4,4'-bipyridine led to the formation of the 3-D Ln(III)-coordination polymers with a formula unit of $[Ln_2(3,5-pdc)_2(C_2O_4)(H_2O)_4]{\cdot}2H_2O$. These polymers contain a bridging oxalate ligand ($C_2O_4\;^2$). On the basis of GCMS study of the mother liquor remaining after the reaction, we proposed that the $C_2O_4\;^2$ formation proceeds in three steps: (1) Ln(III)-mediated decarboxylation of $3,5-pdcH_2$ to give $CO_2$, (2) the reduction of $CO_2$ to $CO_2\;^{\cdot}$ by the Ln(II) species, and (3) the reductive coupling of the two $CO_2\;^{\cdot}$ radicals to the oxalate ($C_2O_4\;^2$) ion. All polymers were structurally characterized by X-ray diffraction.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
• /
• pp.212-212
• /
• 2011

In addition to the catalysts' activity and selectivity, the deactivation of catalysts during use is of practical importance. It is crucial to understand the phenomena of the deactivation to predict the loss of activity during catalyst usage so that the high operational costs associated with catalyst replacement can be reduced. In this study, the activity of Ru catalysts, such as nanoparticles (3~6 nm) and polycrystalline thin film (50 nm), have been investigated under CO oxidation and oxidative/reductive reaction conditions at various temperatures with the ambient pressure X-Ray photoelectron spectroscopy (APXPS). With APXPS, the surface oxides on the catalyst are measured and monitored in-situ. It was found that the Ru film exhibited faster oxidation-and-reduction compared to that of nanoparticles showing mild oxidative-and-reductive characteristics. Additionally, the larger Ru nanoparticles showed a higher degree of oxide formation at all temperatures, suggesting a higher stability of the oxide. These observations are in agreement with the catalytic activity of Ru catalysts. The loss of activity of Ru films is correlated with bulk oxide formation, which is inactive in CO oxidation. The Ru nanoparticle, however, does not exhibit deactivation under similar conditions, suggesting that its surface is covered with a highly active ultrathin surface oxide. Since the active oxide is more stable as nanoparticles than as a film, the nanoparticles showed mild oxidative/reductive behavior, as confirmed by APXPS results. We believe these simultaneous observations of both the surface oxide of Ru catalysts and the reactivity in real time enable us to pinpoint the deactivation phenomena more precisely and help in designing more efficient and stable catalytic systems.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
• /
• pp.218-222
• /
• 2004

Batch slurry experiments were conducted to develop cement/slag/Fe(II) system that could treat hazardous liquid wastes containing halogenated organic solvents. Portland cement in combination with Fe(II) was reported to reductively dechlorinate chlorinated organics in a modified solidification/stabilization process. TCE (trichloroethylene) was used a model halogenated organic solvent. The objectives of this study were to assess the feasibility of using cement and steel converter slag amended with Fe(II) as a low cost abiotic reductive dechlorination and to investigate the kinetics of TCE dechlorination over a wide range of TCE concentration. From the result of screening experiments, cement/slag/Fe(II) system was identified as a potentially effective system to treat halogenated organic solvent. Kinetic studies were carried out to further investigate degradation reaction of TCE NAPL (Non Aqueous Phase Liquids) in cement/slag/Fe(II) systems by using batch slurry reactors. Degradation rate of TCE solution in this system can be explained by pseudo-first-order rate law because the prediction with the rate law is in good agreement with the observed data.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2001년도 총회 및 춘계학술발표회
• /
• pp.49-52
• /
• 2001

An experimental study was conducted to test the feasibility of degradative solidification/stabilization (DS/S) process in treating tetrachloroethylene (PCE) in solid phase systems. The Fe(II)-based ds/s process successfully treated PCE in a soil at the reaction rates that would not allow significant release of the contaminant in the environment. A leach model was also developed that could describe the relative importance of leaching and degradation in ds/s. The first and second Damkohler numbers and dimensionless time were important parameters that determined leaching precesses in wastes treated by ds/s.