Low metal loading catalysts used for the selective hydrogenation of styrene

Badano, Juan; Lederhos, Cecilia; Quiroga, Mónica; L’Argentière, Pablo C.; Coloma, Fernando

doi:10.1590/s0100-40422010000100010

Cited by 15 publications

(15 citation statements)

References 15 publications

(23 reference statements)

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“…In all the systems tested, the initial reaction order of styrene was 0 and changed to 1 at high conversion values. Therefore a Langmuir-Hinshelwood-type kinetic model can be suggested [7]. Table 1 contains the initial activity results corresponding to the runs without poison (r°E S ) and the values of relative deactivation of the catalysts due to different poisons (DES).…”

Section: Catalytic Activity Resultsmentioning

confidence: 99%

“…In one of our previous works [7] we evaluated the activity of many alumina supported metal catalysts and found that Pd catalysts were the most active in the selective hydrogenation of styrene to ethylbenzene. In this work our attention is focussed on the resistance of these metal catalysts, namely Ru, Rh, Pd and Pt, to the poisoning by oxygen and sulfur compounds.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Catalytic Activity Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2010

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“…In previous works we have reported that monometallic Pd catalysts prepared from chlorinated precursors are more active, sulfur and oxygen resistant than similar Pd catalysts prepared from nitrogenated salts or other noble metal catalysts (Pt, Ru and Rh) [6,8]. We have also reported that when Pd is supported over composite organic-inorganic supports, the resulting catalysts prove to be highly active for the selective hydrogenation of styrene [9].…”

Section: Introductionmentioning

confidence: 81%

“…Generally speaking the compound most refractory to hydrogenation is styrene. For this reason it is usually adopted as a model compound in lab scale tests of selective hydrogenation [6,7].…”

Section: Introductionmentioning

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

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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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“…20 The sol-gel method is well applicable for the synthesis of nanoparticles of oxides of different metals like Sn, Ti, V, Zr, Ta, Nb, Hf, In, Fe, Cr, Ni, Mn, Sm, W, Li, Al in aqueous, 21,22 non-aqueous (organic) 23,24 mediums with or without surfactants. 25,26 Hydrogenation of styrene has been done by a number of catalysts composed of a) transition metals of rhodium, 27 palladium, platinum, 28 iron, 29 and nickel/sepiolite 30 b) complexes of perfluoroalkylated pyridine-palladium, 31 [H 3 Os 4 (CO) 12 ] -32 and c) nanomaterials of NaH, 33 TiO 2 . 34 There is no study concerning the catalytic properties of SnO 2 alone in hydrogenation reaction has been reported in the literature.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of High Surface Area Tin Oxide Nanoparticles via the Sol‐Gel Method as a Catalyst for the Hydrogenation of Styrene

Adnan

Razana

Rahman

et al. 2010

J Chinese Chemical Soc

108

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A systematic study on the preparation of SnO 2 nanoparticles using a simple sol-gel technique has been conducted by varying reaction parameters such as concentration of ammonia, ammonia feed rate and reaction temperature. The tin oxide obtained was characterized by using FTIR, BET, XRD and TEM. Particles size was obtained in the range of 4 to 5.6 nm and the surface area was found to be between 76 to 114 m 2 g -1 depending on the reaction parameters. Meanwhile, the catalytic activity of SnO 2 was first time investigated for the hydrogenation reaction of styrene using ethanol as the solvent at 70°C and 1 atmospheric pressure. It is found that SnO 2 acts as a good catalyst in this hydrogenation process. The product conversions in the presence of catalysts prepared at different conditions were between 37 to 72%.

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Low metal loading catalysts used for the selective hydrogenation of styrene

Cited by 15 publications

References 15 publications

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

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

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

Synthesis and Characterization of High Surface Area Tin Oxide Nanoparticles via the Sol‐Gel Method as a Catalyst for the Hydrogenation of Styrene

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