Kinetics of catalytic esterification of propionic acid and n-butanol over Amberlyst 35

The kinetic behavior of the heterogeneous esterification of propionic acid with n-butanol over an acidic cation-exchange resin, Amberlyst 35, was investigated. The experiments were conducted in a fixed-bed reactor at temperatures from 353.15 to 393.15 K and molar ratios of feed OB, (n-butanol to propionic acid) from 0.5 to 2. The equilibrium conversion of propionic acid was found to increase with increasing reaction temperature and feed composition theta(Bo). Gas-bubble formation was observed when the reaction temperatures were higher than 373.15 K at atmospheric pressure. The kinetic data at temperatures from 353.15 to 373.15 K and OB,, from 0.5 to 2 were correlated with the quasi-homogeneous, the Langmuir-Hinshelwood, the Eley-Rideal, and the modified Langmuir-Hinshelwood models, respectively. The Langmuir-Hinshelwood model yielded the best representation for the kinetic behavior of the liquid-solid catalytic esterification over Amberlyst 35.