catalyst is accomplished by filtration the alcohol glycerin mixture is separated from the biodiesel mixture by gravimetric or centrifugal decanting the biodiesel is washed with water to remove fine residual catalyst and alcohol particles and then it is dried in the examples below transesterification reactions are performed in the reactor in batches of 300 ml under self generated system pressure mechanical mixing at 500 rpm and the oil alcohol ratio is 1 15 mol mol and 130 mol mol respectively the product yield is measured by nuclear magnetic carbon 13 resonance rmn 13 c the reaction time and the amount of catalyst are shown in each example analysis by atomic absorption to detect alkaline and alkaline earth metals phosphorus and aluminum in the reaction products resulted to be below the detection limit confirming in this way the heterogeneous catalyst reactions were performed using conventional catalytic solids under the same conditions as the reaction conditions shown in the examples the yield of which shall be used as a reference for the yield achieved by this invention experiment performed in a reactor in batches with sampling of 2 in 2 hours conditions of the experiment 100 grams of canola oil 50 grams of methanol molar ratio of oil alcohol 1 15 1 g of apatite catalyst reaction conditions 175 u00b0 c 8 hr in a single stage and at self generated pressure conversion of 95 06 of oil 88 10 in methyl esters and 2 90 in mono and diglycerides reference conversion of 45 43 of oil 37 93 in methyl esters and 7 5 in mono and diglycerides experiment performed in a reactor in batches with sampling of 2 in 2 hours conditions of.