Characterization and application of dolomite as catalytic precursor for canola and sunflower oils for biodiesel production

• Calcined dolomited was evaluated as catalyst for biodiesel production.
• This catalyst is a double carbonate which is thermally converted into CaO and MgO.
• The calcined material showed catalytic activity to oil due to basic properties.
• Biodiesel conversion was optimized analyzing the effect of reaction conditions.

The catalytic activity of precursor dolomite as a heterogeneous catalyst in biodiesel production has been investigated. The dolomitic material is a double calcium and magnesium carbonate, which when calcinated decomposes into CaO and MgO that are highly basic. The materials were characterized by XRD, TG–DTG, CO2-TPD, FTIR, XPS, SEM, and N2 adsorption/desorption at −196 °C. The raw material was activated and used as a catalyst for the transesterification of canola and sunflower oils with methanol. The conversion of canola and sunflower oils to methyl esters was optimized, under different catalyst amount and oil/methanol ratio, and the maximum conversions were: canola (98.81 ± 0.02 wt.%) and sunflower (96.52 ± 0.43 wt.%).