Pd/C-catalyzed transfer-hydrogenation of benzaldehydes to benzyl alcohols using potassium formate as the selective hydrogen donor

Aromatic and aliphatic aldehydes are selectively reduced to primary alcohols under mild conditions with potassium formate in the presence of Pd/C catalyst. The high selectivity obtained is attributed due to the presence of the basic potassium bicarbonate generated in situ from the formate salt via the hydrogen transfer process. Molecular hydrogen shows similar activity in the presence of potassium carbonate salts. Ketones did not react under these conditions; therefore, this method is used to separate aldehydes selectively from a mixture of aldehydes and ketones.