Preparation and Characterization of CaO/MgO Catalyst and Its Application for Transesterification of n-Butyl Acetate with Methanol

This work reports the synthesis and characterization of CaO/MgO mixed oxide with different CaO/MgO mass ratios prepared by the co-precipitation method in a basic medium and subsequent calcination of the precursors. These mixed-oxide materials were characterized by XRD, FT-IR, SEM, and BET. The alkalinity of samples was determined by CO2 temperature-programmed desorption (CO2-TPD). Results show that the CaO/MgO samples contained mixed crystalline phases of cubic CaO and hexagonal MgO species. Decreasing the CaO/MgO ratio resulted in low average pore diameter and enhanced BET surface area. Transesterification of n-butyl acetate with methanol was studied using a CaO/MgO catalyst at atmospheric pressure and 95 degrees C, a model reaction to evaluate the potential of these catalysts for biodiesel production. The highest activity was found for a CaO/MgO mass ratio of 8: 2 with conversion percentage of 83. The effects of calcination temperature, reaction time, reaction temperature, methanol/n-butyl acetate molar ratio, and catalyst recycling were investigated.