Abstract
The catalytic activity and selectivity of Pd supported on various metal oxides in carbon-carbon coupling reactions of aryl bromides with styrene (Heck reaction) was studied. All reactions were performed without any additional ligands. Most of the supported Pd catalysts showed high activity and selectivity in the Heck reaction of the non-activated bromobenzene with styrene for very low Pd concentrations of 0.1 mole %. trans-Stilbene was observed as the main product in all cases. The selectivity was very similar for all catalysts (trans-stilbene/cis-stilbene/1,1-diphenylethylene = 92:1:7) and comparable to typical homogeneous systems. The activity of the catalysts can be correlated with the nature of the oxide support and the Pd dispersion. The Pd surface area/particle size (determined by H2 chemisorption, transmission electron microscopy, XRD) was dependent on the reduction temperature. Pd on TiO2 was the most active system and showed a reverse correlation between activity and Pd surface area (below reduction temperatures of 600°C).
Original language | English |
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Pages (from-to) | 319-326 |
Number of pages | 8 |
Journal | Topics in Catalysis |
Volume | 13 |
Issue number | 3 |
DOIs | |
State | Published - Aug 2000 |
Keywords
- Formation of carbon-carbon bonds
- Heck reaction
- Oxide-supported palladium
- Pd dispersion