EFFECT OF INTERNAL DIFFUSION ON HETEROGENEOUS CATALYTIC ESTERIFICATION OF ACETIC-ACID

Theoretical analysis has been performed to determine the effect of int ernal diffusion on a second-order reversible esterification of acetic acid with methanol catalyzed by a solid acid catalyst, Amberlyst 15. T he results of the analysis show that the catalyst effectiveness factor s are above 0.94 for the beads smaller than 0.6 mm diameter at the rea ction temperature lower than 80 degrees C. However, the effectiveness factors were lower than 0.77 for the beads larger than 1.0 mm diameter at reaction temperatures higher than 94 degrees C. For the commercial Amberlyst 15 with an average particle size of 0.7 mm diameter, an ove rall effectiveness factor of 0.87 was predicted for a reaction tempera ture of 94 degrees C. The predicted effectiveness factors agree with t hose obtained from the kinetic measurements. (C) 1997 Elsevier Science Ltd.