A study about the effect of the temperature of hydrogen treatment on the properties of Ru/Al2O3 and Ru/C and their catalytic behavior during 1-heptyne semi-hydrogenation

Lederhos, Cecilia; L’Argentière, Pablo C.; Coloma, Fernando; Fı́goli, N.S.

doi:10.1007/s10562-006-0085-z

Cited by 15 publications

(14 citation statements)

References 25 publications

(24 reference statements)

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“…Samples were prereduced in situ 1 h at 483 K .To correct possible deviations caused by electronic charge on the samples, the Al 2p line was taken as an internal standard at 74.4 eV. The areas under the peaks were estimated by calculating the integral of each peak after subtracting the Shirley background and fitting the experimental peak to a combination of Lorentzian and Gaussian lines of 30-70% proportions [13].…”

Section: Catalyst Characterizationmentioning

confidence: 99%

Kinetic study of the selective hydrogenation of styrene over a Pd egg-shell composite catalyst

Betti

Badano

Lederhos

et al. 2015

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This is a study on the kinetics of the liquid-phase hydrogenation of styrene to ethylbenzene over a catalyst of palladium supported on an inorganic-organic composite. This support has a better mechanical resistance than other commercial supports, e.g. alumina, and yields catalysts with egg-shell structure and a very thin active Pd layer. Catalytic tests were carried out in a batch reactor by varying temperature, total pressure and styrene initial concentration between 353-393 K, 10-30 bar, and 0.26-0.60 mol L -1 , respectively. Kinetic models were developed on the assumptions of dissociative hydrogen chemisorption and non-negligible adsorption of hydrogen and styrene. Final chemical reaction expressions useful for reactor design were obtained. The models that best fitted the experimental data were those ones that considered the surface reaction as the limiting step. In this sense a two-step Horiuti-Polanyi working mechanism with half hydrogenation intermediates gave the best fit of the experimental data. The heats of adsorption of styrene and ethylbenzene were also estimated.

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Section: Catalyst Characterizationmentioning

confidence: 99%

Kinetic study of the selective hydrogenation of styrene over a Pd egg-shell composite catalyst

Betti

Badano

Lederhos

et al. 2015

Reac Kinet Mech Cat

Self Cite

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“…A careful deconvolution of the spectra was made. The areas under the peaks were estimated by calculating the integral of each peak after subtracting a Shirley background and fitting the experimental peak to a combination of Lorentzian/Gaussian lines of 30-70% proportions [13].…”

Section: X-ray Photoelectron Spectroscopy (Xps)mentioning

confidence: 99%

Resistance to Sulfur and Oxygenated Compounds of Supported Pd, Pt, Rh, Ru Catalysts

et al. 2010

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The poisoning resistance to sulfided and oxygenated compounds of some VIII Group PYGAS selective hydrogenation catalysts based on metals was assessed. Low content alumina supported Rh, Pd, Ru and Pt catalysts (0.35 wt%) were prepared from chlorided precursors. In the case of the palladium catalysts a nitrogenated precursor was also used. The catalysts were mainly assessed in the catalytic test of selective styrene hydrogenation in the presence or absence of known poisons. Model feedstocks spiked with thiophene, thiophane and tetrahydrofuran were used. The catalysts were further characterized by means of chemical analysis, XPS, TPR and chemisorption. The results indicate that chlorided precursors yield more sulfur resistant catalysts. The effect was attributed in part to the formation of oxychlorinated species, refractory to reduction, that leave the metal in an electron deficient state, thus inhibiting the formation of strong poison-metal bonds, the chloride species could also be a steric factor that can contribute to the sulfur resistance of the catalyst. Pd based catalyts had the highest activity and resistance to poisons of all the metals tested. This superior performance was attributed in part to the total occupancy of the 4d electronic levels of the Pd metal that was supposed to promote the rupture of the H 2 bond during the hydrogenation reaction. Keywords Low metal loading catalysts Á Selective hydrogenation Á Sulfided and oxygenated poisons List of Symbols PF Poison free condition TE Thiophene TA Thiophane THF Tetrahydrofuran D Metal dispersion S Metal specific surface (m 2 g met -1 ) d Average metal particle size (Å ) V HAds (CNPT) Volume of hydrogen chemisorbed at normal conditions (cm 3 ) PA Atomic weight of the metal (g mol -1 ) w Metal content per unit gram of catalyst M Mass of sample (g) m Stoichiometry of chemisorption of the gas on the surface metal atoms V m CNPT Volume of the chemisorbed monolayer of the adsorbate at normal conditions (cm 3 g -1 ) N Avogadro's number (6.023 9 10 23 ) V N Molar volume of the adsorbate at normal conditions r Number of metal atoms per square meter (atoms m -2 ) xAdsorption stoichiometry (number of hydrogen atoms adsorbed per unit of metal atom) qDensity of the metal (g m -3 ) M Red /M Tot Reduced metal amount and total metal amount ratio wt M% Nobel metal content (weight percentage) T Red Reduction temperature (K) r°E S Initial styrene hydrogenation rate in poison free condition (mol g cat -1 min -1 ) DESRelative deactivation per concentration of poison (ppm -1 )

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“…16 To increase the selectivity to the alkene, milder conditions of hydrogen pressure and temperature are normally used. 3 In previous papers 17 we have studied the semi-hydrogenation of a long chain alkyne (1-heptyne) using high-loaded Pd and Ru supported catalysts. The influence of different supports (alumina and an activated carbon) as well as reaction and reduction temperatures, were analyzed in those papers.…”

Section: Introductionmentioning

confidence: 99%

Influence of ni addition to a low-loaded palladium catalyst on the selective hydrogenation of 1-heptyne

et al. 2010

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Recebido em 27/4/09; aceito em 30/10/09; publicado na web em 12/3/10 Semi-hydrogenation of alkynes has industrial and academic relevance on a large scale. To increase the activity, selectivity and lifetime of monometallic catalysts, the development of bimetallic catalysts has been investigated. 1-Heptyne hydrogenation over low-loaded Pd and Ni monometallic and PdNi bimetallic catalysts was studied in liquid phase at mild conditions. XPS results suggest that nickel addition to Pd modifies the electronic state of palladium as nickel loading is increased. Low-loaded Pd catalysts showed the highest selectivities (> 95%). The most active prepared catalyst, PdNi (1%) , was more selective than the Lindlar catalyst.

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A study about the effect of the temperature of hydrogen treatment on the properties of Ru/Al2O3 and Ru/C and their catalytic behavior during 1-heptyne semi-hydrogenation

Cited by 15 publications

References 25 publications

Kinetic study of the selective hydrogenation of styrene over a Pd egg-shell composite catalyst

Kinetic study of the selective hydrogenation of styrene over a Pd egg-shell composite catalyst

Resistance to Sulfur and Oxygenated Compounds of Supported Pd, Pt, Rh, Ru Catalysts

Influence of ni addition to a low-loaded palladium catalyst on the selective hydrogenation of 1-heptyne

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