Au–Pd/AC as catalysts for alcohol oxidation: Effect of reaction parameters on catalytic activity and selectivity

• Published in: Applied catalysis. A, General General, 2009-07, Vol.364 (1), p.221-228
• Main Authors: Villa, Alberto, Janjic, Nikolina, Spontoni, Paolo, Wang, Di, Su, Dang Sheng, Prati, Laura
• Format: Article
• Language: English
• Subjects: Adsorbents; Alcohol oxidation; Catalysis; Chemistry; Exact sciences and technology; General and physical chemistry; Gold–palladium alloy; Surface physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2009.05.059

The oxidation of different alcohols with molecular oxygen in water has been investigated using a range of activated carbon-supported Au–Pd bimetallic catalysts. The effect of the Au–Pd ratio on the conversion and selectivity was observed and a synergistic effect is present in a large range of the Au–Pd ratio, being maximized for Au 80–Pd 20 composition instead of Au 90–Pd 10 shown in glycerol oxidation [A. Villa, C. Campione, L. Prati, Catal. Lett. 115 (2007) 133]. Moreover the enhancement of conversion observed by adding a base resulted greater for gold-rich catalysts rather than for palladium-rich ones. The effect of the alcohol concentration and the metal/substrate ratio in the presence or the absence of the base was also studied revealing substantial differences in terms of both activity and selectivity. At 1 M concentration under biphasic conditions benzyl alcohol has been selectively oxidized to benzaldehyde (S90 = 98%) even in the presence of NaOH with a TOF of 18,000 h −1 using Au 60–Pd 40/AC as the catalyst. The oxidation of different alcohols with molecular oxygen in water has been investigated using a range of activated carbon-supported Au–Pd bimetallic catalysts. The effect of the Au–Pd ratio was observed on the conversion and selectivity and a synergistic effect is present in a large range of Au–Pd ratio. Moreover the enhancement of conversion observed by adding a base resulted higher for gold-rich than for palladium-rich catalyst. Under controlled conditions, even in the presence of the base, a high selectivity to aldehyde was obtained using Au 60–Pd 40/AC as the catalyst.