• Title, Summary, Keyword: hydrogenation

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Hydrogenation of trans-Cinnamaldehyde with Hydrido-Carbonyl Osmium(II) Complexes of Chelating Phosphine Ligands

  • 정민교;허성;이원용;전무진
    • Bulletin of the Korean Chemical Society
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    • v.18 no.8
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    • pp.806-810
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    • 1997
  • A series of new hydridocarbonyl osmium(Ⅱ) complexes, OsHCl(CO)(PPh3)(L-L)[L-L=Ph2P(CH2)nPPh2 (n=1 (1), 2 (2), 3 (3), cis-Ph2PCH=CHPPh2 (4), and Fe(η5-C5H4PPh2)2 (5)] has been synthesized from OsHCl(CO)(PPh3)3 and chelating diphosphines. These complexes have been characterized by IR, 1H NMR and elemental analysis. The catalytic activities of these complexes both for the transfer hydrogenation of trans-cinnamaldehyde with 2-propanol as the hydrogen donor, and for the selective hydrogenation of trans-cinnamaldehyde with H2, have been examined. Complexes (1)-(5) were shown to have higher selectivities for the transfer hydrogenation of the C=O bond of aldehyde than for the transfer hydrogenation of the C=C bond of aldehyde. The selectivities for the transfer hydrogenation with 2-propanol as well as for the hydrogenation with H2 have been found to decrease in the order 3 > 5 > 2 > 4 > 1. Complex (3) has shown to possess almost 90% of the selectivity to cinnamyl alcohol for transfer hydrogenation. It is also found that there is a correlation between the ν(CO) of each complex and the hydrogenation, of the C=O bond of trans-cinnamaldehyde. Overall, the selectivities with the complexes (1)-(5) are greater for the transfer hydrogenation with 2-propanol than for the hydrogenation with H2.

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Volume Expansion of TiMn2-type Hydrogen Storage Alloy with Hydrogenation (TiMn2계 수소저장합금의 수소화에 따른 부피팽창)

  • PARK, CHOONG-NYEON
    • Transactions of the Korean hydrogen and new energy society
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    • v.28 no.5
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    • pp.459-464
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    • 2017
  • The volume expansions of $Ti_{0.95}Zr_{0.05}V_{0.4}Mn_{1.45}Fe_{0.1}Cr_{0.05}$ alloy during hydrogenation with various conditions have been investigated. The theoretical volume expansion measured with XRD for this alloy with hydrogenation was 21%. The apparent volume expansion of this alloy ingot with hydrogenation was composed of two effects. One is a hydrogenation and the other is a pulverization. The apparent volume of free alloy powder was 1.8 times greater than that of an ingot, implying the pulverization effect on the apparent volume expansion is 80%. The apparent volume expansion of the alloy ingot with hydrogenation under a unconstrained condition was about 80 (${\pm}15$)%, much smaller than that of free alloy powder which expected as 118%. In addition, The apparent volume expansion of the alloy ingot with hydrogenation under a constrained condition(Al container) was about 50%, much smaller than that of the unconsrained. This reduced apparent volume expansion of the alloy ingot could be attributed to an arrangement of alloy powder keeping its original shape of the ingot even after hydrogenation.

Hydrogenation of Arenes with Metallic Iridium and Rhodium Powders Prepared from Iridium(Ⅰ) and Phodium(Ⅰ)-COD Complexes under Mild Conditions

  • 진종식;이병노;문지중;송중호;박용선
    • Bulletin of the Korean Chemical Society
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    • v.16 no.6
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    • pp.528-533
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    • 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.

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Cataytic Hydrogenation of o-Nitrochlorbenzene to 3,3'-Dichlorobenzidine

  • Shen, Kaihua;Li, Shude;Choi, Dong-Hoon
    • Bulletin of the Korean Chemical Society
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    • v.23 no.12
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    • pp.1785-1789
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    • 2002
  • 2,2'-Dichlorohydroazobenzene was prepared by selective hydrogenation of o-nitrochlorobenzene with hydrogen in the presence of 0.8% and 5% Pd/C catalyst. O-Chloroaniline was a minor product in the catalytic hydrogenation of o-nitrochlorobenzene. The effects of base, Pd/C catalyst, and co-catalyst were discussed on catalytic hydrogenation. 2,2'-Dichlorohydroazobenzene, as an intermediate, was rearranged to 3,3'-dichlorobenzidine after reacting with HCl. It was shown that selectivity of catalytic hydrogenation of o-nitro-chlorobenzene is affected strongly by concentration of base, Pd/C catalyst, and co-catalyst. $^1Hand^{13}C$NMR spectroscopy confirmed the chemical structures of 2,2'-dichlorohydrazobenzene and 3,3'-dichlorobenzidine.

Study on the Hydrogenation and Isomerization Reaction of Dimethylcyclopentadiene (디메틸시클로펜타디엔의 수소화 및 이성화반응 연구)

  • Jeong, Byung Hun;Han, Jeong Sik;Lee, Jeong Ho;Kim, Seong Bo;Lee, Bum Jae
    • Korean Chemical Engineering Research
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    • v.43 no.5
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    • pp.566-570
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    • 2005
  • The study on the hydrogenation and isomerization of unsaturated bicyclic hydrcarbon compounds using methylcyclopentadiene dimer (MCPD) was carried out. Exo compound was prepared through isomerization reaction after two hydrogenation reaction steps. In the first hydrogenation reaction which needs one mole of hydrogen, the formation rate of monomer was increased as dimer was decomposed at reaction temperature above $100^{\circ}C$. At first hydrogenation, DHDMCPD [dihydrodi(methylcyclopentadiene)] was formed and second hydrogenation was proceeded to produce THDMCPD [tetrahydrodi(methylcyclopentadiene)], the ratio of exo to endo THDMCPD was varied by the control of 2nd hydrogenation temperature. To improve the process, continuous 1st and 2nd hydrogenation conditions were established by using the 2nd stage heat controllable reactor. Also, catalytic activities were compared by the use of halogenized aluminum, metal halides and solid acids catalysts on the isomerization reaction from endo to exo THDMCPD.

Hydrogenation and Isomerization of Soybean Oil with Perchloratocarbonylbis-(triphenylphosphine) rhodium (Ⅰ)

  • Jeong, Hyun-Mok;Chin, Chong-Shik
    • Bulletin of the Korean Chemical Society
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    • v.5 no.5
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    • pp.199-201
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    • 1984
  • It has been found that $Rh(ClO_4)(CO)(P(C_6H_5)_3)_2$ catalyzes the hydrogenation and isomerization of soybean oil at room temperature under the atmospheric pressure of hydrogen. The hydrogenation occurs at the olefinic groups to produce saturated groups leaving the ester groups intact, and the isomerization converts $-CH = CH- CH_2-CH = CH-$ units to conjugated dienes and the dienes separated by more than two $-CH_2-$ groups. The rate of the hydrogenation is faster than that of the isomerization.

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Highly Enantioselective Rh-catalyzed Transfer Hydrogenation of α-Functionalized Arylketones

  • Lee, Do-Min;Kwak, Se-Hun;Lee, Kee-In
    • Bulletin of the Korean Chemical Society
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    • v.30 no.6
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    • pp.1317-1324
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    • 2009
  • Asymmetric transfer hydrogenation of α-functionalized arylketones has been studied. The chiral Rh-catalyst effectively performed in transfer hydrogenation of $\alpha$-mesyloxyketones with an azeotropic mixture of formic acid/triethylamine to produce optically active 1-arylethandiols with excellent enantioselectivity.

Efficient Hydrogenation Catalysts of Ni or Pd on Nanoporous Carbon Workable in an Acidic Condition

  • Lee, Dong-Hwan;Kim, Hong-Gon;Kang, Min;Kim, Ji-Man;Lee, Ik-Mo
    • Bulletin of the Korean Chemical Society
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    • v.28 no.11
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    • pp.2034-2040
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    • 2007
  • Efficient catalytic systems, where Ni or Pd is introduced in a supporting material of nanoporous carbon, have been developed for a liquid-phase hydrogenation of carboxylic acids and ketones at room temperature. It has been found that the catalysts reliably show high activities and selectivities for the hydrogenation to alcohols even in acidic conditions, and the catalytic activities depend on the preparative method of catalysts, the hydrogen pressure, the agitation rate, and the catalytic species. The hydrogenation of carboxylic acids and ketones clearly shows that the reaction rate is affected by the electronic and the steric effects, and a plausible reaction mechanism using metal hydrides as catalytic species is proposed.

Hydrogenation of methyl methacrylate under mild conditions using biosynthesis Ru catalyst

  • Zhou, Hongling;Huang, Yangqiang;Cheng, Youwei;Wang, Lijun;Li, Xi
    • Journal of Industrial and Engineering Chemistry
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    • v.47
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    • pp.221-227
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    • 2017
  • Hydrogenation of methyl methacrylate (MMA) was investigated over Ru-based catalyst supported on active carbons (AC), which was prepared by bio-reduction method, using C. Platycladi (CP) leaf extract as reductant. By varying reaction temperature, hydrogen pressure and reaction time, hydrogenation of MMA over the biosynthesis Ru-based catalyst was carried out, and resulted the optimum conditions, $30^{\circ}C$ (room temperature), 2.0 MPa, and 50 min. The as-prepared Ru/AC catalyst showed high catalytic activity towards the hydrogenation of MMA, affording 100% of MMA conversion even under mild conditions without solvent and methyl isobutyrate was the only product.