The kinetics of simultaneous transesterification and esterification with a carbon-based solid acid catalyst was studied. Two solid acid catalysts were prepared by the sulfonation of carbonized vegetable oil asphalt and petroleum asphalt. These catalysts were characterized on the basis of elemental analysis, acidity site concentration, the Brunauer-Emmett-Teller (BET) surface area and pore size. The kinetic parameters with the two catalysts were determined, and the reaction system can be described as a pseudo homogeneous catalyzed reaction. All the forward and reverse reactions follow second order kinetics. The calculated concentration values from the kinetic equations are in good agreement with experimental values.