Esterification of adipic acid with methanol over Amberlyst 35

The kinetic behavior of heterogeneous esterification of adipic acid with methanol over acidic cation-exchange resin beads, Amberlyst 35, was investigated through a packed-bed reactor. The experiments were conducted at temperatures from 313.2 K to 343.2 K and the molar ratios of feed (methanol to acid) at 15 and 20. The reaction rate was found to increase with increasing temperature, but the equilibrium conversions of adipic acid were almost identical over the entire temperature range; that is, the heat effect of this reaction system was minor. It was also found that the equilibrium conversion of adipic acid increases slightly as the molar ratio of feed increasing from 15 to 20. The experimental results showed that the mass-transfer resistance could be neglected over the range of experimental conditions. The kinetic data were correlated with two quasi-homogeneous models. The model parameters were determined and their applicability was discussed.