Selective Hydrogenation of Acetylene over Au/Al₂O₃ Catalyst

Abstract

The hydrogenation of acetylene and ethylene was studied on Au/Al2O3 catalyst. Acetylene and hydrogen reacted readily to produce ethylene, but not to ethane on the catalyst in the temperature range between 313 and 523 K. The hydrogenation of ethylene on the catalyst occurred only at much higher temperatures over 573 K. The activity of the selective hydrogenation of acetylene over Au/Al2O3 catalyst depends on the size of ultrafine gold particles of Au/Al2O3 catalyst, which showed a maximum at about 3.0 nm in diameter.

Sites for the selective hydrogenation of ethyne to ethene on supported NiO/Au catalysts

“…6). The high selectivity of Au/Al 2 O 3 is in agreement with results of Jia [28] and Gluhoi [29] reported that ethyne was hydrogenated to ethene on Au/Al 2 O 3 with 100 % selectivity at 313-523 K. The initial TOF for 2.5 nm Au was 36 h −1 that is in agreement with gold hydrogenation activity [1,13,15,18] and lower in comparison with the activity of either NiO (Table 1) or Pt and Pd clusters of the same size deposited on alumina [26,30]. The positive-size effect of activity was found for gold catalysts.…”

“…The better hydrogenation activity of 2.5 nm gold particles can be explained if the chemisorption of H 2 is dependent on gold particle size. Our recent research on the TOF of Au particles of different sizes (2-30 nm) in hydrogenation of ethynylbenzene [13] and studies by Bus [30,31], Serna [32], Boronat [33], and Jia [28] have proved the positive influence of small gold clusters on hydrogenation rate. It was concluded that H 2 is dissociatively adsorbed only at the corners and edges of the supported gold particles [34,35].…”

Hydrogenation over gold catalysts: The interaction of gold with hydrogen

“…As the hydrogen uptake was found to be greater at 473 K than at 300 K it was suggested that the adsorption of hydrogen is an activated process and very likely associated with hydrogen dissociation. The chemisorption of hydrogen on Al 2 O 3 supported gold particles with a mean cluster size of about 4 nm was examined by Jia and coworkers (21). They observed that about 14% of the surface atoms adsorbed hydrogen almost irreversible at 273 K. The hydrogen chemisorption properties of Au/Al 2 O 3 and Au/SiO 2 catalysts were investigated by Bus et al (64) in a temperature range of 298 to 523 K. For the 1 to 1.5 nm supported gold clusters, H/M values (number of adsorbed hydrogen atoms per total number of metal atoms) of at least 0.1 and as high as 0.73 were determined.…”

“…Gold catalyzes various hydrogenation reactions such as the hydrogenation of alkenes (3)(4)(5)(6)(7)(8)(9)(10)(11)(12), alkadiens (13)(14)(15)(16)(17)(18) alkynes (13,(19)(20)(21)(22)(23)(24)(25), , -unsaturated carbonyl compounds and nitro compounds (47)(48)(49)(50)(51)(52)(53). In contrast to traditional hydrogenation catalysts such as platinum, palladium or ruthenium, which require modification, it often shows remarkable selectivities when multiple functional groups are present.…”

Binding of propene on small gold clusters and on Au(111): Simple rules for binding sites and relative binding energies

“…A short while ago it was discovered that, unlike bulk gold, small gold clusters are chemically active and are promising catalysts for partial oxidation [1][2][3][4][5][6][7][8][9][10][11][12][13][14] and partial hydrogenation [15][16][17] reactions. We are particularly interested in Haruta's discovery 1 that Au clusters, supported on TiO 2 , epoxidize propene with very high selectivity.…”