Selective catalytic low pressure hydrogenation of acetophenone on Pd/ZnO/ZnAl2O4

Lenarda, Maurizio; Casagrande, Manuela; Moretti, Elisa; Storaro, Loretta; Frattini, Romana; Polizzi, Stefano

doi:10.1007/s10562-007-9046-4

Cited by 37 publications

(20 citation statements)

References 35 publications

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“…4b; Table 1). Analogously in the hydrogenation of acetophenone over Pd/C catalysts in the liquid phase using hexane as a solvent the main product was ethylbenzene when the reaction temperature exceeded 85°C whereas only 40% ethylbenzene was achieved at 60°C [19].…”

Section: Catalyst Characterization Resultsmentioning

confidence: 99%

Mechanism of the chemo–bio catalyzed cascade synthesis of R-1-phenylethyl acetate over Pd/Al2O3, lipase, and Ru-catalysts

et al. 2010

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One-pot synthesis of R-1-phenylethyl acetate was investigated starting from acetophenone hydrogenation performed over Pd/Al 2 O 3 and PdZn/Al 2 O 3 catalysts followed by acylation of the intermediate secondary alcohol, R-1-phenylethanol, over an immobilized lipase. Furthermore, the performance of a third type of catalyst, Ru supported on hydroxyapatite (HAP) was evaluated for racemization of S-1-phenylethanol in one pot together with the two other catalysts. The main objectives of this work were to separate the effects of different catalysts and to reveal the reaction mechanism. For this purpose not only acetophenone, but also (R,S)-1-phenylethanol, S-1-phenylethanol, R-1-phenylethyl acetate, and styrene were used as reactants in combination with Pd/Al 2 O 3 , lipase and Ru/HAP as catalysts. The results revealed that the main side product, ethylbenzene, was formed in two different ways, via dehydration of (R,S)-1-phenylethanol to styrene, followed by its rapid hydrogenation to ethylbenzene, and via debenzylation of the desired product, R-1-phenylethyl acetate to ethylbenzene. The true one-pot synthesis, however, was demonstrated over Shvo's catalyst, but Ru/HAP was not sufficiently active in the racemization step. Ru/Al 2 O 3 was a promising catalyst for racemization of S-1-phenylethanol and for dynamic kinetic resolution of (R,S)-1-phenylethanol, when using only small amounts of the acyl donor ethyl acetate. The challenge in

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Section: Catalyst Characterization Resultsmentioning

confidence: 99%

Mechanism of the chemo–bio catalyzed cascade synthesis of R-1-phenylethyl acetate over Pd/Al2O3, lipase, and Ru-catalysts

et al. 2010

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“…Several authors have cited the consecutive reaction characteristics of acetophenone hydrogenation. Lenarda et al [47] reported that the selectivity of phenylethanol decreases from 98 to 56% when the conversion increases from 44 to 99% over Pd on Zn-Al hydrotalcite. The same authors also accounted that the selectivity of phenylethanol decreases from 60 to 0% and the selectivity of ethylbenzene increases from 40 to 91%, when the temperature increases from 333 to 423 K. Chen et al [48] reported that the conversion of phenylethanol to ethylbenzene increases rapidly with the increase in conversion over reduced Pd/SiO 2 catalyst.…”

Section: Resultsmentioning

confidence: 99%

Controlled Hydrogenation of Acetophenone Over Pt/CeO2–MO x (M = Si, Ti, Al, and Zr) Catalysts

2009

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Vapour phase selective hydrogenation of acetophenone has been performed over a series of Pt/CeO 2 -MO x (MO x = SiO 2 , Al 2 O 3 , TiO 2 , and ZrO 2 ) catalysts. The controlled hydrogenation was carried out in the 453-533 K temperature range at normal atmospheric pressure. The ceria-based mixed oxides were prepared through a co-precipitation or deposition-precipitation route. Platinum was deposited by a wet impregnation method. The obtained catalysts were calcined at 773 K and characterized by means of X-ray diffraction, Raman spectroscopy, BET surface area, temperature programmed reduction, temperature programmed desorption, thermogravimetry, and scanning electron microscopy. XRD analyses suggest that CeO 2 -SiO 2 and CeO 2 -Al 2 O 3 primarily consist of CeO 2 nanoparticles dispersed over the amorphous silica or alumina surface. In the case of CeO 2 -TiO 2 , presence of segregated nanocrystalline CeO 2 and TiO 2 -anatase phase were noted. Formation of cubic Ce 0.75 Zr 0.25 O 2 solid solution was observed in the case of CeO 2 -ZrO 2 . No peaks pertaining to platinum could be detected from XRD profiles. Formation of zirconia rich tetragonal phase (Ce 0.4 Zr 0.6 O 2 ) was observed in the case of Pt/CeO 2 -ZrO 2 sample. Raman measurements revealed the fluorite structure of ceria and presence of oxygen vacancies in all samples. TPR results suggest that the presence of Pt facilitates the reduction of ceria. The catalytic performance of Pt-based catalysts was found to depend strongly on the nature of the support oxide employed. Among various catalysts investigated, the Pt/CeO 2 -SiO 2 catalyst exhibited better product yields.

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“…In recent years, ZnAl 2 O 4 spinel has been largely used as catalyst in several reactions such as degradation of gaseous toluene 8 , ethanol steam reforming 9 , hydroformylation and hydrogenation 3,10 , combustion of soot under NO x /O 2 atmosphere 11 , transesterification of vegetable oil 12 and iso-butane combustion 13 . The photocatalytic degradation of organic pollutants in the water such as dye [14][15][16] , phenol 17 and pesticide 18 using different semiconductor materials has attracted much attention recently.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of zinc aluminate (ZnAl2O4) spinel and its application as photocatalyst

et al. 2014

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ZnAl 2 O 4 spinel was synthesized by co-precipitation using ammonia as precipitating agent, followed by thermal treatment at 750 °C. The structural properties of particles were investigated by X-ray diffraction (XRD), atomic force microscopy (AFM), differential thermal analysis (DTA), and N 2 adsorption/desorption isotherms (BET) techniques. The photocatalytic activity was evaluated in the degradation of organic pollutant in aqueous solution under sunlight. The results showed that the ZnAl 2 O 4 particles exhibited a mesoporous structure, and a promising photocatalytic activity for the degradation of pollutant molecules.

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Selective catalytic low pressure hydrogenation of acetophenone on Pd/ZnO/ZnAl2O4

Cited by 37 publications

References 35 publications

Mechanism of the chemo–bio catalyzed cascade synthesis of R-1-phenylethyl acetate over Pd/Al2O3, lipase, and Ru-catalysts

Mechanism of the chemo–bio catalyzed cascade synthesis of R-1-phenylethyl acetate over Pd/Al2O3, lipase, and Ru-catalysts

Controlled Hydrogenation of Acetophenone Over Pt/CeO2–MO x (M = Si, Ti, Al, and Zr) Catalysts

Synthesis of zinc aluminate (ZnAl2O4) spinel and its application as photocatalyst

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