Abstract
Oxidation of benzaldehyde to benzoic acid can be performed efficiently with 30% H2O2 as the oxidant and sulfonic acid resin Amberlyst 15 as the catalyst. The reactivities of benzaldehyde derivatives are determined by both hindrance effect and electron effect of substituents, and benzaldehyde derivatives with electron-withdrawing group at the meta- or para-position are highly active and almost quantitatively converted into their corresponding acids. In addition, this method also works well for the oxidation of aliphatic aldehydes. The key characteristic of the procedure is that the catalyst is recyclable.
Notes
a 20 mmol benzaldehyde was used.
b 5 mL solvent was used.
c Determined by GC analysis.
d The regenerated catalyst reused once.
e The regenerated catalyst reused twice.
f The isolated yield.
a Reaction conditions: substrate (10 mmol), Amberlyst 15 (5 wt.%), and 30% H2O2 (15 mmol) in acetic acid (5 mL) at 90 °C for 7 h.
b Isolated yield.