Trent (1945)patented a continuous transesterification process. Reactants were fed into a reactor through a steam heated coil in the upper part of the reactor. The transesterification reaction took place when the reactants were heated to the reaction temperature while passing through the heater. The reaction finished before the reactants and products mixture left the heater. The unreacted alcohol vapor was taken out and the products were neutralized before getting into the lower chamber of the reactor where the esters and glycerol were continuously separated (Fig. 5).