“…3,17,18 They can be produced at low cost, require simple isolation and separation techniques, possess valuable regeneration capacity, are a pure biodiesel product, and exhibit promising ecofriendly properties and no corrosive effect. 16,19,20 Several heterogeneous catalysts were introduced for the transesterification of castor oil as Ni/doped ZnO, 21 Fe doped ZnO, 22 Li−MgO, 23 Sr−MgO, 24 MgO/ MCM-41, 25 and La 2 O 3 -modified Y-zeolite. 26 T h i s c o n t e n t i s The availability, the production cost, the activity, the dispersion properties, and the safety are the essential points that direct the orientation of the researcher for the commercial production of the heterogeneous catalysts.…”