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.%).