• Bulletin of the Korean Chemical Society
• /
• v.16 no.6
• /
• pp.528-533
• /
• 1995

Metallic iridium and rhodium powders prepared from the reactions of [M(COD)(PhCN)2]ClO4 (M=Ir(1), Rh(2); COD=1,5-cyclooctadiene) with hydrogen at room temperature in methylene chloride show catalytic activities for hydrogenation of arenes at room temperature under atmospheric pressure of hydrogen. Most substituents (CH3, COOH, NO2, CH2OH, CHO, OPh, OCH3, C=C, halogens and CH2Cl) on aromatic ring suppress the rate of the hydrogenation of the aromatic ring while the aromatic ring hydrogenation of phenol and 1,4-dihydroxobenzene is faster than that of benzene over these metallic powders. Hydrogenation of benzoic acid occurs only at the aromatic ring leaving the COOH group intact over iridium metal powders while benzoic acid is not hydrogenated at all over rhodium metal powders. Carbonyl, nitro, acetylenic and olefinic groups on an aromatic ring are hydrogenated prior to the aromatic ring hydrogenation. Hydrogenolysis of OH groups of phenol, benzyl alcohol and 1,4-dihydroxobenzene, and hydrodehalogenation of halobenzenes, benzyl halides and cinnamyl chloride also occur along with the hydrogenation of aromatic ring.

• Journal of Korean Society for Atmospheric Environment
• /
• v.15 no.2
• /
• pp.183-190
• /
• 1999

Magnetite was synthesized with $FeSO_4$, and NaOH for the decomposition of carbon dioxide and for the study of the methane formation. The chemical equivalent ratio was changed from 0.5 to 1.50 for the magnetite synthesis. The chemical equivalent ratio was fixed in 1.00, and Nickel chloride and Rhodium chloride equally added and synthesized with the ratio was of 0.10~10.00 mole%. The crystal strucure of the synthesized magnetite was measured XRD. Putting synthesized magnetite in the reactor and using hydrogen gas oxygen-deficient magnetite was made. Injecting carbon dioxide in the reactor, the decomposition reaction was experimented. The formation of methane was confirmed injecting hydrogen gas in the reactor after carbon dioxide was decomposed.

• Bulletin of the Korean Chemical Society
• /
• v.18 no.8
• /
• pp.824-827
• /
• 1997

Bis(ethylene)rhodium(Ⅰ) chloride dimer reacted with vinylcyclopropane to give σ,η3-allylrhodium(Ⅲ) complex 3. Complex 3 underwent C-C bond cleavage of 8-quinolinyl ethyl ketone 11, to form η3-1,3-dimethylallylrhodium(Ⅲ) complex 8, which was reductively eliminated by trimethyl phosphite to give 8-quinolinyl-1-methylbut-2-enyl ketone (10). More sterically hindered 8-quinolinyl alkyl ketones were allowed to react with complex 3 to afford corresponding alkenes as well as a mixture of complex 8 and η3-1-ethylallyl rhodium(Ⅲ) complex 19, identified as 10 and 8-quinolinyl-pent-2-enyl ketone (20) after reductive elimination. 8-Quinolinyl alkyl ketone bearing a sterically hindered alkyl group showed less reactivity for C-C bond cleavage and higher 20/10 ratio compared with those having a less sterically hindered alkyl group, such as 8-quinolinyl ethyl ketone (11).

• Resources Recycling
• /
• v.22 no.5
• /
• pp.29-34
• /
• 2013

Solvent extraction experiments were performed to separate platinum and rhodium from mixed chloride solution by using tri 2-ethylhexyl amine (TEHA) and its mixture with TBP and LIX 63. Effects of extraction conditions on the separation of the two metals were investigated as a function of extractant concentration in the HCl concentration range from 1 to 9 M. The concentration of Pt (IV) and Rh(III) was controlled to $1{\times}10^{-3}M$ and $2{\times}10^{-4}M$, respectively. In the extraction with TEHA and its mixture, Pt was quantitatively extracted irrespective of HCl concentration, while the extraction percentage of Rh depended on the extraction condition. When the concentration of HCl in the mixed solution was low, the extraction of Rh was nil and separation of Pt and Rh was possible. Adding TBP to TEHA had little effect on the extraction of both metals, while adding LIX63 to TEHA favored the extraction of Rh.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.7
• /
• pp.1945-1950
• /
• 2010

Solvent extraction experiments of Pt(IV), Pd(II) and Rh(III) by Alamine336 were performed from the mixed chloride solutions. In the HCl concentration range from 1 to 5 M, most of Pt and Pd were extracted from the mixed solutions. However, the extraction percentage of Rh was much smaller than that of Pt and Pd. Lower concentration of Alamine336 in strong HCl solution led to higher separation factor of Rh from Pt and Pd. Adding $SnCl_2$ to the mixed solutions increased the extraction percentage of Rh, while the extraction percentage of Pt and Pd was little affected. Our results showed that selective separation of Rh or coextraction of the three platinum group metals from the mixed solution would be possible by adjusting the extraction conditions.

• Journal of the Korean Institute of Gas
• /
• v.2 no.2
• /
• pp.40-47
• /
• 1998

This study describes a synthesis of spinel-type $Fe_3O_4$ for decomposition of carbon dioxide, using $Fe_3O_4$ $7H_2O$ and NaOH, at $40^{\circ}C$ for 20 h. with change of their chemical equivalent ratio from 0.50 to 0.75, 1.00, 1.25 and 1.50, respectively. Addition of 0.1-1.00 mole percentage $NiCl_2,\;RhCl_3$ to the particles of $Fe_3O_4$, Prepared by reacting chemical equivalent ratio 1.00, afforced spinel $Fe_3O_4$. The structure of $Fe_3O_4$ and $NiCl_2,\;RhCl_3$-added $Fe_3O_4$ was investigated with XRD and SEM, respectively.

• Resources Recycling
• /
• v.27 no.3
• /
• pp.93-99
• /
• 2018

Effective extraction of platinum group elements by dissolving waste platinum scrap from the display industry and solvent extraction, was studied. The extracted platinum solution was prepared as a precursor solution for diesel automotive exhaust gas purification catalyst and its catalytic activity was tested. The behavior of aqueous species of platinum was investigated through solution chemistry and based on the existence and behavior of these chemical species, the possibility of extraction and separation was established. By dissolving waste scrap by electrochemical method, the dissolution time of scrap was shortened and the extraction efficiency was increased. Through separation and removal of rhodium component, solvent extraction by TBP, and stripping by hydrochloric acid, Pt-Chloride-$H_2O$ solution was prepared. And then, an platinum amine complex solution through amination reaction with this solution as a raw material was prepared. The possibility of producing high-value platinum compounds from platinum group waste scrap was investigated by preparing platinum amine complex solution and then examining the catalytic activity with this amine precursor on the combustion reaction of carbon black.

• Bulletin of the Korean Chemical Society
• /
• v.29 no.10
• /
• pp.1920-1926
• /
• 2008

We investigated the C-H bond activation mechanism of aldimine by the [RhCl$(PPH_3)_3$] model catalyst using DFT B3LYP//SBKJC/6-31G*/6-31G on GAMESS. Due to their potential utility in organic synthesis, C-H bond activation is one of the most active research fields in organic and organometallic chemistry. C-H bond activation by a transition metal catalyst can be classified into two types of mechanisms: direct C-H bond cleavage by the metal catalyst or a multi-step mechanism via a tetrahedral transition state. There are three structural isomers of [RhCl$(PH_3)_2$] coordinated aldimine that differ in the position of chloride with respect to the molecular plane. By comparing activation energies of the overall reaction pathways that the three isomeric structures follow in each mechanism, we found that the C-H bond activation of aldimine by the [RhCl$(PH_3)_3$] catalyst occurs through the tetrahedral intermediate.