• Applied Chemistry for Engineering
• /
• v.3 no.3
• /
• pp.527-534
• /
• 1992

Raney nickel was used as catalyst in the hydrogen electrode for an alkaline fuel cell. The hydrogen electrode manufactured with the Raney nickel catalyst which was sintered at $700^{\circ}C$ was found to have the highest electrode performance. Using the Raney nickel powder of average particle size $90{\AA}$ for the electrode, the current density which had been measured was $450mA/cm^2$ at $80^{\circ}C$ using 6N KOH solution as an electrolyte. The effects of PTFE addition were investigated with CO-chemisorption, polarization curves and Tafel slope. CO-chemisorption had shown the optimum value when the Raney nickel was mixed with 5wt% of PTFE, but from the current density and Tafel slope at porous Raney nickel electrode, the appropriate value of PTFE addition was 10wt%. Recommendable Ni and Al portion for Raney nickel was 60 : 40 and loading amount was $0.25g/cm^2$. Also the influence of pressing pressure for manufacturing catalytic layer and for junction with gas diffusion layer was examined. The morphology of catalyst surface was investigated with SEM. The influence of reactivation time and heat-treatment temperature were also studied.

• Korean Journal of Materials Research
• /
• v.11 no.8
• /
• pp.703-707
• /
• 2001

The effects of chromium addition on the catalytic activity of Raney nickel in alkaline fuel cell (AFC) have been studied. When the catalysts are prepared from various contents of chromium, the electrochemical characteristics shows the highest mass activity of 3.588 A/g. Operating temperature and electrolyte concentration of half cell were $80^{\circ}C$ and 6N KOH, respectively. With the addition of chromium, the particle size is diminished from 12.11 $\mu\textrm{m}$ to 11.07 $\mu\textrm{m}$ and the decrease of particle size contributes to the enlargement of the specific surface area from 0.653 $\m^2$/g to 0.685$\m^2$/g. The residual aluminium contents of Raney nickel surface are considerably influenced by the particle size and chromium acts as sintering inhibitor.

• YAKHAK HOEJI
• /
• v.35 no.2
• /
• 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).

• Applied Chemistry for Engineering
• /
• v.4 no.2
• /
• pp.373-380
• /
• 1993

The preparation method of Raney nickel catalyst and the effect of promotor for the hydrogen electrode in alkaline fuel cell were investigated with electrochemical methods. The best electrode performance was observed with the Raney nickel which was obtained at $700^{\circ}C$ of sintering temperature and 60:40 of nickel:aluminum. As titanium was added for promotor, the activity of catalyst and characteristic of electrode was improved. Especially, the electrode containing 2w/o of titanium showed the maximum mass activity of 2.4A/g and its mean particle size was $5.7{\mu}m$. The resistance and capacitance of the electrode containing 2w/o of titanium, measured with AC impedance spectroscopy, were calculated to the $0.3{\Omega}cm^2$ and $0.42F/cm^2$, respectively.

• Applied Chemistry for Engineering
• /
• v.8 no.6
• /
• pp.927-933
• /
• 1997

The effects of carbon black on the electrodes performance and on the structure of the catalyst layer in Raney nickel hydrogen electrodes for alkaline fuel cells were investigated by using electrochemical and nitrogen adsorption methods. The optimum content of carbon black in the catalyst layer of Raney nickel hydrogen electrode was 2wt%. The limiting current density was increased by the addition of carbon black due to the enlargement of gas-liquid interface area. The rate determining step at the limiting current density was supposed to be a step where hydrogen dissolves at gas-liquid interfaces.

• YAKHAK HOEJI
• /
• v.35 no.2
• /
• 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.

• 제어로봇시스템학회:학술대회논문집
• /
• 1991.10a
• /
• pp.1085-1090
• /
• 1991

Chemical heat pump is a system to upgrade the low level energy such as industrial waste heat and solar energy by using coupled endothermic and exothermic chemical reactions. Dehydrogenation of 2-propanol can absorb heat near 80.deg. C and is transformed into acetone and hydrogen. Hydrogenation of acetone can liberate heat near 200.deg. C. Dehydrogenation of 2-propanol is difficult around 80.deg. C because .DELTA.G has positive value, but dehydrogenation reaction in liquid phase can overcome this problem because vaporized acetone and hydrogen can be rapidly eliminated. In this work, dehydrogenation of 2-propanol was investigated in liquid phase with Raney nickel catalyst. The energy efficiency of the chemical heat pump was estimated by computer simulation.

• Archives of Pharmacal Research
• /
• v.21 no.2
• /
• pp.187-192
• /
• 1998

The cis- and trans-diastereomers of the 7,8-dihydro-7-deazapurine derivatives were synthesized from the corresponding diastereomers of 4-tran5-cyano-2-methyl-3-phenyl-5-oxopyrrolidine (5), which were reduced from the 2-cis- and 2-tran5-diastereomers of 4-trans-cyano-2-hydroxymethyl-3-phenyl-5-oxopyrrolidine (2) via tosylation, iodination and following elimination respectively. The prepared cis- and ttans-diastereomers of 6-amino-2-mercapto-8-methyl-7-phenyl-7,8-dihydro-7(9H)-deazapurine (8) were transferred to the corresponding 2-methylthio-diastereomers 9 and following desulfurization with Raney-nickel leaded to the cis and trans-diastereomers of 6-amino-8-methyl-7-phenyl-7,8-dihydro-7(9H)-deazapurine (10), respectively. The synthesized 7-deazapurine derivatives were tested for their antibiotic activity by the serial two-fold dilution method.

• Korean Journal of Environmental Agriculture
• /
• v.3 no.1
• /
• pp.36-44
• /
• 1984

Waters, sediments and crucian carps samples collected bimonthly from Nakdong river during- the period of August 1982 to June 1983 were analyzed for organophosphorus pesticide residues by GLC equipped with a flame photometric detector. Among the environmental samples, IBP, diazinon, phenthoate, parathion, malathion and fenitrothion residues were found only in waters and crucian carps and sediments samples were devoid of the residues. In addition, seasonal variations of the residues in waters and crucian carps were observed. Waters and crucian carps samples collected in August, when pesticides are generally in great demand, contained all the organophosphorus pesticide residues while no organophosphorus were detected in waters and crucian carps samples collected in February, April or December. The most abundant residues in the two environmental samples were diazinon and IBP and residue levels of parathion, malathion and fenitrothion were found extremely low.