One-Step synthesis of acetals from phenol/alcohols mixtures using a Pd/Aluminoborate catalyst

A one-step synthesis of cyclohexanone acetals from phenol/alcohol mixtures has been explored using bifunctional aluminum borates supported Pd catalysts. Three aluminum borates have been prepared via either a high temperature calcination (9Al ₂O ₃·2B ₂O ₃) or a selfpressured thermal synthesis (PKU-1 and ABO-X) using various aluminum precursors and boric acid. Well dispersed Pd nanoparticles loaded on these materials show excellent phenol hydrogenation activity in both water and ethanol. The reactivity follows the trend of Pd/ABOX[ Pd/9Al ₂O ₃·2B ₂O ₃[Pd/PKU-1, which is similar to the sequence of BO ₄/BO ₃ ratio presented in the aluminoborates as shown by NMR spectra. When ethanol is used as a solvent, 13.5 % yield of cyclohexanone diethyl acetal has been obtained under the conditions investigated on Pd/ ABO-X, which is attributed to its high activity in both hydrogenation and acetalization for the one-step synthesis of cyclohexanone acetals.