Palladium(II)-catalysed oxidation of alcohols under an oxygen atmosphere in a fluorous biphase system (FBS)

“…Several metals (ruthenium, platinum, palladium and gold) have been used as monometallic catalysts, in some cases with modifier (like Bi, Pb) [2][3][4][5]. The main requirement for a high selectivity and long durability has not been yet achieved.…”

Section: Introductionmentioning

confidence: 99%

Pd on carbon nanotubes for liquid phase alcohol oxidation

et al. 2010

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Pd nanoparticles supported on carbon nanotubes (CNTs) showed a higher selectivity than Pd nanoparticles supported on activated carbon (AC) in the liquid phase oxidation of benzylic alcohol to benzaldehyde. Under solventless conditions a significant improvement in selectivity was observed for Pd/CNTs, whereas using Pd/AC a considerable over-oxidation of benzaldehyde was observed. Differently from other solvents cyclohexane improved significantly the selectivity to benzaldehyde for both catalysts. Characterisation by means of transmission electron microscopy revealed differences in metal dispersion between Pd/AC and Pd/CNTs that can be ascribed to textural, chemical and physical differences between Active Carbon and Carbon Nanotubes. The higher activity in the case of Pd on AC than on CNTs can be attributed to the improved Pd dispersion in the first case. On recycling Pd/CNTs resulted more stable (activity loss 50% in 7 runs) than Pd/AC (activity loss 70% in 7 runs) even a structural change of catalysts after reaction is observed. The Pd leaching and particle coalescence are the main reasons for the loss of activity. An extraordinary improving of catalyst life has been observed by alloying the Pd nanoparticles with Au, When CNTs are used as support the strong Pd leaching can be greatly limited and the activity/selectivity maintained at least for 8 runs.

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“…The advantage of using such oxidants lies in the formation of water as the sole co-product and the low cost of the oxygen/air. Different catalysts (homogeneous and heterogeneous) have been investigated in the alcohol oxidation using molecular oxygen or hydrogen peroxide in the liquid phase [4][5][6][7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

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

Villa

Janjic

Spontoni

et al. 2009

Applied Catalysis A: General

152

119

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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 Au80-Pd20 composition instead of Au90-Pd10 shown in glycerol oxidation [1]. 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 18000h -1 using Au60-Pd40/AC as the catalyst.

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Palladium(II)-catalysed oxidation of alcohols under an oxygen atmosphere in a fluorous biphase system (FBS)

Cited by 99 publications

References 26 publications

Modern Oxidation of Alcohols Using Environmentally Benign Oxidants

Modern Oxidation of Alcohols Using Environmentally Benign Oxidants

Pd on carbon nanotubes for liquid phase alcohol oxidation

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

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