Table 1 Selective aerobic oxidation of benzyl alcohol (1a) to benzaldehyde (2a)a

From: Ultra-stable and highly reactive colloidal gold nanoparticle catalysts protected using multi-dentate metal oxide nanoclusters

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Entry

Catalyst

Yield (%)

Particle size (nm)

Before use

After use

1

Au-TOASiW9

75

2.9

2.8

2

Au-TOASiW9b

92

2.9

2.9

3

Au-TOASiW10

17

3.4

3.3

4

Au-TOASiW11

24

2.9

3.0

5

Au-TOASiW12

4

3.2

4.3

6

Au-TOAB

3

2.5

5.6

7

Au-dodecanethiol

<1

2.6

2.7

8

Au-dodecanethiolb

<1

2.6

Precipitationc

9

TOASiW9

<1

–

–

10

Au-TOASiW9, Ard

<1

2.9

−

  1. aReaction conditions: 1a (0.25 mmol), 3 mL toluene solution of colloidal gold nanoparticles (Au: 4 mol%), K2CO3 (0.5 mmol), room temperature (~25 °C), O2 (1 atm), 24 h.
  2. bCs2CO3 (0.5 mmol) was used instead of K2CO3 (0.5 mmol).
  3. cDisulfide was detected in the reaction solution after the reaction.
  4. dUnder Ar (1 atm). All the reaction yields were determined via GC analysis using biphenyl as an internal standard.
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