Rates of hydrogenation of cycloalkenes from the liquid phase on platinum-alumina catalysts

Hussey, Allen S.; Keulks, George W.; Nowack, Gerhard; Baker, Robert H.

doi:10.1021/jo01266a029

Cited by 39 publications

(20 citation statements)

References 1 publication

(1 reference statement)

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“…Methanol (Sigma-Aldrich, Chromasolv Plus), methionine (Sigma-Aldrich, C98 %), cysteine (SigmaAldrich, C98 %), tryptophan (Sigma-Aldrich, C98 %), threonine (Sigma-Aldrich, C98 %), thiamine HCl (SigmaAldrich, C98 %), biotin (Sigma-Aldrich, C98 %), niacin (Sigma-Aldrich, C98 %), and p-aminobenzoic acid (SigmaAldrich, C98 %) were used as purchased. Cyclohexene is known to undergo auto-oxidation in air [26,27], and these oxidation products have a detrimental effect on catalyst stability. Thus, the reactions performed here used cyclohexene containing butylated hydroxytoluene as an oxidation inhibitor (Sigma-Aldrich, C99 %).…”

Section: Reaction Kinetics Measurementsmentioning

confidence: 99%

Inhibition of Metal Hydrogenation Catalysts by Biogenic Impurities

2014

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We show that supported Ni, Pt, and Pd catalysts used for liquid phase hydrogenation are inhibited by the biogenic impurities present in biologically-derived feedstocks used to produce high-value chemicals. The effects of thiamine HCl, cysteine, methionine, biotin, tryptophan, niacin, threonine, and p-aminobenzoic acid were elucidated by collecting adsorption isotherms of these species and by quantifying their influence on the rate of cyclohexene hydrogenation at 323 K. Inhibition increases in the order of Pd \ Pt \ Ni and generally correlates with the binding energies of sulfur and nitrogen. The equilibrium constants reported here for adsorption of these species on Ni, Pt, and Pd can facilitate the design of separation systems and new catalysts used for upgrading biologically-produced platform molecules.

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Section: Reaction Kinetics Measurementsmentioning

confidence: 99%

Inhibition of Metal Hydrogenation Catalysts by Biogenic Impurities

2014

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“…This argument may be viewed as an explanation of the role of oxygen as an activator following Poltorak and Boronin ( 1966). Hussey et al (1968) reported reaction rates for the liquid phase hydrogenation of cyclohexene on platinum/ aluminum oxide catalysts using cyclohexane as the solvent. Unfortunately, the surface area of platinum metal was not given by these authors who also acknowledge the possibility of mass transfer effects in their work.…”

Section: Page 904mentioning

confidence: 99%

“…The deactivation of supported platinum catalysts has been noticed when cycloalkenes have been used, and hydroperoxides have been stated to be the main cause of poisoning (Hussey et al, 1968;Price and Shiewetz, 1957). The cyclohexene was purified by passing it through dry 300 m2g-1 surface area q-7 transitional alumina powder ( Kaiser Chemicals) activated at 673°K in flowing helium (Liquid Carbonic, 99.995% pure) which was first passed over copper turnings at 673°K and a trap at 80°K.…”

Section: Page 906mentioning

confidence: 99%

“…The hydrogenation rates on platinum/silica catalysts obtained by Dmitrienko et al are at least one order of magnitude lower than those obtained by us. Dmitrienko et al observed that the order of reaction with respect to cyclohexene was zero order only up to 50% conversion; this could mean that owing to poisons present in the liquid reagents, the activity of the catalyst decreased as the hydrogenation reaction progressed (Hussey et al, 1968 …”

Section: +'mentioning

confidence: 99%

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Catalytic hydrogenation of cyclohexene: Part II. Liquid phase reaction on supported platinum in a gradientless slurry reactor

1978

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The areal rate of liquid phase hydrogenation of cyclohexene on supported platinum catalysts does not depend on the nature of the support. Nor does it depend on particle size of the metal. The rate constant is independent of the nature of the solvent when the concentration of hydrogen in it is expressed as its measured or calculated solubility. All observations are compatible with the idea that the measured rate is that of chemisorption of dihydrogen on a metal surface covered with reactive hydrocarbon intermediates. SCOPEThe effect of the dimensions of metallic particles on the catalytic activity of supported metals is of theoretical and practical importance. The present work was undertaken to examine the effect of platinum particle size on the liquid phase hydrogenation of cyclohexene in a rocking slurry reactor. The reaction was studied in a static system at constant hydrogen pressure, normally atmospheric pressure, between 275O and 316OK. As diffusion coefficients in the liquid phase are often two or more orders of magnitude lower than in the vapor phase, diffusional influence can play a substantial role in slurry reactors. It is thus imperative that reactions studied in slurry reactors be examined for diffusional effects and proof be given that observed rates have not been disguised by either intraparticle or interphase mass transport. We set out to obtain true kinetic data devoid of either the influence of transport phenomena or catalyst deactivation during an experimental run.The present study also focused on two important aspects of liquid phase reactions, When heterogeneous catalytic reactions are carried out in the gas phase, ideal gas behavior is ordinarily assumed. However, for kinetics in the liquid phase, as in a slurry or trickle bed reactor, it is necessary first of all to ascertain whether concentrations or activities of dissolved reactants should be used in rate expressions. Second, it is also important to check whether different solvents affect the reaction rate or the rate constant. The literature of catalytic reaction engineering offers few experimental or theoretical guidelines bearing on these two important questions. CONCLUSIONS AND SIGNIFICANCEKinetic data have been obtained for the liquid phase hydrogenation of cyclohexene on supported platinum catalysts in a rocking slurry reactor. First of all, values of the turnover frequency N , defined as molecules reacted per site per second, were obtained on catalysts containing different amounts of platinum of the same dispersion, defined as the ratio of surface metal atoms to total metal atoms. Values of N were found to be identical. As this re- Page 904September, 1978 sult was obtained at two different temperatures, it offers sufficient proof that rates were not masked by artifacts such as the influence of interphase and intraparticle heat and mass transfer, or deactivation and poor contacting of the catalyst by reactants. The main result of this work is that values of N were identical on nine different supported platinum catalysts where the me...

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“…12,14 These catalytic transition metals decrease the activation energy, and thus increase the rate of C-H bond formation. Platinum-group transition metals offer a facile pathway for hydrogen to adsorb and dissociate, and the resulting H atoms can then transfer directly to the alkenes adsorbed on the metal surface.…”

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confidence: 99%

Metal Catalyzed Electrochemical Synthesis of Hydrocarbons from Epitaxial Graphene

Daniels

Obe

Daas

et al. 2016

J. Electrochem. Soc.

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Pt/Au transition metal catalysts are shown to significantly improve the electrochemical hydrogenation of low defect density epitaxial graphene (EG) layers ∼2ML thick on Si-face 6H-SiC Initial experiments using Pt nanoparticles deposited from aqueous solution showed large increases in hydrogenation, however, this method demonstrated large variability, attributed to the aqueous nature of the catalyst deposition, known to change the conductivity and reactivity of graphene, as well as clustering of Pt nanoparticles. To reduce process variability, 20 nm thick evaporated metals were used. From Raman, the average observed hydrogen cluster density ∼10 11 cm −2 was similar to the average densities of intrinsic defects (10 10,11 cm −2 ) and charge impurities (10 11 cm −2 ) consistent with recent reports that these sites play a crucial role in the hydrogenation of EG. Au catalysts (3.23 ± 0.22%wt) showed slightly better H-incorporation than Pt (2.81 ± 0.03%wt), an observation we attribute to the fact that H 2 dissociation is no longer the rate-limiting step, as H + is readily available in the aqueous state. The electrochemical enablement of these hydrogenation pathways using catalysts offers new routes to carbon chemistries for hydrogen storage, bandgap engineered hydrocarbons as well as EG-based battery electrodes.

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Rates of hydrogenation of cycloalkenes from the liquid phase on platinum-alumina catalysts

Cited by 39 publications

References 1 publication

Inhibition of Metal Hydrogenation Catalysts by Biogenic Impurities

Inhibition of Metal Hydrogenation Catalysts by Biogenic Impurities

Catalytic hydrogenation of cyclohexene: Part II. Liquid phase reaction on supported platinum in a gradientless slurry reactor

Metal Catalyzed Electrochemical Synthesis of Hydrocarbons from Epitaxial Graphene

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