Calcium zincate derived heterogeneous catalyst for biodiesel production by ethanolysis

► Calcium zincate treated at 400 °C is active in the ethanolysis of sunflower oil. ► By using a 3 wt.% of catalyst at 78 °C, FAEE yields higher than 95 wt.% are reached after 3 h. ► The catalytic activity is maintained even in the presence of free fatty acids (until 1.1° acidity) in the sunflower oil. ► The addition of Na2CO3 to the catalyst allows removing Ca and Na from biodiesel (<5 ppm).