Easy and effective synthesis of micrometer-sized rectangular MgO sheets with very high catalytic activity

Hydromagnesite micro-sheets were prepared from MgCl2 by hydrothermal process. Calcination of the hydromagnesite sheets at 450 °C in N2 for 5 h produced porous MgO sheets with similar morphology. The MgO sheets were of rectangular shape with 0.5–1 μm in wall length and 4–5 nm thick. The MgO sheets function as a strong heterogeneous base catalyst for the Claisen–Schmidt condensation of benzaldehyde with acetophenone giving 99% conversion in 5 h due to large surface area (234 m2/g) and presence of numerous basic sites of different strength.