Low temperature hydrogenation of tetralin over supported rhodium catalysts in supercritical carbon dioxide solvent

Hiyoshi, Norihito; Mine, Eiichi; Rode, Chandrashekhar V.; Sato, Osamu; Shirai, Masayuki

doi:10.1016/j.apcata.2006.05.040

Cited by 24 publications

(14 citation statements)

References 14 publications

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“…As the CO 2 pressure increased, the selectivities to cis-and trans-4-tert-butylcyclohexanol decreased, whereas the selectivity to 4-tert-butylcyclohexanone increased due to the higher solubility of the intermediate product 4-tert-butylcyclohexene-1-ol at higher CO 2 pressures, resulting in its further hydrogenation to 4-tert-butylcyclohexanone [39]. The similar effect also appeared in hydrogenation of naphthalene and tetralin in scCO 2 [40][41][42]. In addition, the adsorption mode of the reactants on the surface of the catalysts can be tuned through changing CO 2 pressure, resulting in a variation in product distribution.…”

Section: Effect Of Co 2 Pressuresupporting

confidence: 53%

Selective hydrogenation of citral over Au-based bimetallic catalysts in supercritical carbon dioxide

Liu

Zhao

2010

Sci. China Chem.

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Selective hydrogenation of citral was investigated over Au-based bimetallic catalysts in the environmentally benign supercritical carbon dioxide (scCO 2 ) medium. The catalytic performances were different in citral hydrogenation when Pd or Ru was mixed (physically and chemically) with Au. Compared with the corresponding monometallic catalyst, the total conversion and the selectivity to citronellal (CAL) were significantly enhanced over TiO 2 supported Pd and Au bimetallic catalysts (physically and chemically mixed); however, the conversion and selectivity did not change when Ru was physically mixed with Au catalyst compared to the monometallic Ru/TiO 2 , and the chemically mixed Ru-Au/TiO 2 catalyst did not show any activity. The effect of CO 2 pressure on the conversion of citral and product selectivity was significantly different over the Au/TiO 2 , Pd-Au/TiO 2 , and Pd/TiO 2 catalysts. It was assumed to be ascribed to the difference in the interactions between Au, Pd nanoparticles and CO 2 under different CO 2 pressures.

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Section: Effect Of Co 2 Pressuresupporting

confidence: 53%

Selective hydrogenation of citral over Au-based bimetallic catalysts in supercritical carbon dioxide

Liu

Zhao

2010

Sci. China Chem.

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“…Similarly, it was reported in the literature that the cis isomer of decalin has a much higher rate for hydrogen production than the trans decalin due to the facile dehydrogenation of the cis isomer by the flat surface. 35,36 It is anticipated that the rates for cis isomer hydrogenation and dehydrogenation are higher than those of trans in our system. To conclude, in the view of these findings, an efficient catalyst should have a high hydrogenation/dehydrogenation activity to switch between the 9-ethylcarbazole and 9-ethyl-perhydrocarbazole (cis-Pl 12 [B]) on the surface reversibly in a fast manner without forming any kinetically stable intermediates or isomer products.…”

Section: Product Concentration Timementioning

confidence: 93%

Comparative Study of Catalytic Hydrogenation of 9-Ethylcarbazole for Hydrogen Storage over Noble Metal Surfaces

Eblagon

Tam

et al. 2012

J. Phys. Chem. C

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The use of liquid organic hydrides (LOH) as a chemical hydrogen store to supply hydrogen gas for a polymer electrolyte membrane fuel cell (PEFC) is explored. In the present work, hydrogenation of 9-ethylcarbazole is particularly investigated in the liquid phase over different unsupported noble metal powders. The kinetics obtained from the hydrogenation of the substrate over these catalytic systems are modeled, and the derived fundamental rate constants are systematically compared. It is found that the differences in activity and product distribution of the reaction over different metal surfaces depend critically on the electronic structures of the metals. From the prospective application of 9-ethyl-carbazole, an effective catalyst should be able to convert the substrate to the fully hydrogenated cis product without forming any kinetically stable intermediates. Ruthenium is the most active catalyst among all the metals studied for this reaction. However, this catalyst suffers from relatively low selectivity with the accumulation of large quantities of partially hydrogenated intermediates due to weak adsorption and poor surface diffusion of the intermediates for further hydrogenation.

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“…Ru was 10.4 and 6.0 times more active than Rh in tetralin and toluene hydrogenations, respectively. Rh has been reported to have the highest activity toward the hydrogenation of aromatic hydrocarbons [19][20][21][22][23]. Reports have suggested that Pt and Pd catalysts on acidic supports displayed higher activity than Rh because spillover hydrogen was used to hydrogenate additional acidic sites [21,24,25].…”

Section: Resultsmentioning

confidence: 99%

“…Our experimental results may also be explained by the ability of adsorbed oxygen to suppress H 2 adsorption, retard the mobility of adsorbed hydrogen, or suppress the adsorption of aromatic hydrocarbons. The adsorption of aromatic molecules is possibly affected by steric hindrance, because these molecules adsorb on the catalyst in parallel configuration through p-electrons [19,34,35]. Therefore, a small amount of adsorbed oxygen may cause a serious retardation on hydrogenation reaction rates.…”

Section: Mechanism Of the Retardation Of Hydrogenation By Oxygenmentioning

confidence: 99%

Influence of trace oxygen on the hydrogenation activity of Ru/Al2O3 catalysts

Seki

Ohshima

Kurokawa

et al. 2010

Reac Kinet Mech Cat

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The influence of trace oxygen on the catalytic activity of alumina supported Ru in the liquid phase hydrogenation of aromatic hydrocarbons was studied. The catalytic activity of Ru increased remarkably and the reproducibility was improved by removing dissolved oxygen from the reactant mixture and carefully refining the catalyst transfer procedure into the reactor to avoid exposure to air. Trace oxygen affected Ru very severely, but did not affect Rh, Pd, and Pt much. The activity of Ru was lower than those of Rh, Pd, and Pt in the presence of oxygen as reported in the literature; however, it was the highest when oxygen was removed carefully. Measurements of the adsorbed oxygen suggested that the activity seriously decreased when only the part of Ru surface was covered by oxygen. Bimetallic Pt-Ru catalysts demonstrated high activity even in the presence of oxygen.

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Low temperature hydrogenation of tetralin over supported rhodium catalysts in supercritical carbon dioxide solvent

Cited by 24 publications

References 14 publications

Selective hydrogenation of citral over Au-based bimetallic catalysts in supercritical carbon dioxide

Selective hydrogenation of citral over Au-based bimetallic catalysts in supercritical carbon dioxide

Comparative Study of Catalytic Hydrogenation of 9-Ethylcarbazole for Hydrogen Storage over Noble Metal Surfaces

Influence of trace oxygen on the hydrogenation activity of Ru/Al2O3 catalysts

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