Nano-Fe3O4 as a New Reusable Catalyst for the Selective Acetylation of Alcohols and Phenols under Solvent Free Conditions

摘要

Our aim in this work was to find an efficient and selective method for protection of alcohols and phenols through acetylation. We carried out all our reactions in the presents of CaCl2 co-catalyst and acetic anhydride, and under solvent free conditions at room temperature. Under such conditions, we compared and contrasted two brands of our heterogonous catalysts including arc discharge fabricated magnetic Fe3O4 nanoparticles (AD-MNPs), and those prepared by the co-precipitation (CP-MNPs) with average particle sizes of about 53 and 28 nm, respectively. The latter was prepared using aqueous NaOH solution as the precipitating agent for FeCl3·6H2O and FeSO4.7H2O. High selectivity was observed for acetylation of phenols carrying electron withdrawing groups. Also 100% yield was observed using benzyl alcohol. The ADMNPs was reused three times without any significant loss of its catalytic activity. The efficiency of ADMNPs was twice that of CP-MNPs.