From residual to useful oil: revalorization of glycerine from the biodiesel synthesis.

The reaction kinetics for the synthesis of glycerol triacetate (triacetin) from glycerol and acetic acid has been studied in the frame of revalorization of residual glycerol in biodiesel production. The reaction has taken place in a stirred reactor at a pressure of 1070 kPa. No external catalyst has been added because the reaction performs better by using as catalyst an excess of acetic acid. Kinetic parameters were obtained at 120 and 160 degrees C and a model of three reactions with monoacetin, diacetin and triacetin formation was proposed with a good agreement with the experimental results. Arrhenius constants were determined for the involved reactions.