Vitamin B1 supported on silica-encapsulated γ-Fe2O3 nanoparticles: design, characterization and application as a greener biocatalyst for highly efficient acylation

Abstract

A new magnetic catalyst was synthesized by the immobilization of vitamin B₁ (thiamine hydrochloride) on the surface of silica-encapsulated γ-Fe₂O₃ nanoparticles. Its capability was evaluated in the acylation of alcohols and phenols with acetic anhydride under solvent-free conditions and afforded the desired products in high yield. This novel magnetic organocatalyst could be separated from the reaction vessel by use of an external magnet and recovered 5 times without a significant loss of its activity. The amount of loaded vitamin B₁ on the silica-encapsulated γ-Fe₂O₃ was assigned by TGA and confirmed by back titration. Availability, cheapness and low toxicity are reasons associated with the utilization of vitamin B₁ as a catalyst. The catalyst has been characterized by FT-IR, XRD, SEM, VSM and TG/DTA.