Benzylation of Benzyl Alcohol on Layered Double Hydroxides

Abstract

The effectiveness of Li⁺–Al³⁺ and Mg²⁺–Al³⁺ layered double hydroxide (LDH) intercalated with CO₃²⁻ or Cl⁻ as a reaction media for benzylation of benzyl alcohol with benzyl bromide in toluene was examined. Among a series of LDHs, Li⁺–Al³⁺ LDH was found to be effective. For instance, a reaction in the presence of Li⁺–Al³⁺–CO₃²⁻ heat-treated at 200 °C gave the desired benzylated products in 93% yield by refluxing for 6 h. Also, Li⁺–Al³⁺–Cl⁻ heat-treated at 150 °C gave the benzylated product in 78% yield for same conditions. In the case of Mg²⁺–Al³⁺ LDH, it is found that it possessed less activity, showing reduced yields 34% for containing CO₃²⁻ and 2–6% for containing Cl⁻ respectively.