Deactivation Mechanism Of Cation Resin Catalyst For Esterification Of Acetic Acid And Isopropanol

The cation resin catalyst for isopropyl acetate synthesis can gradually lose its activity during the esterification of acetic acid with isopropanol. Aiming at disclosing the deactivation mechanism of cation resin catalyst, the structure and properties of the catalyst were analyzed and characterized carefully using ICP, EDS, EA and SEM techniques. By making comparison of the structure and properties between the fresh and deactivated catalysts, Fe3+ adsorption on the catalyst was assigned to be the main reason of catalyst deactivation.A minisize fixed-bed catalytic reaction apparatus was set up based on the features of the esterification. A kinetic reaction equation was derived from the experimental data of the reaction occurring in a temperature range of 60 to 90℃. It is shown that the reaction rate is one order to isopropanol and zero order to acetic acid, respectively.In the "acceleration deactivation" experiments, the deactivation process was tested after adding Fe3+(FeCl3, reaction solution as the solvent) to reaction solution deliberately at different temperatures (60～90℃) and different Fe3+ concentrations (0.25-0.75wt%). The results show that the adsorption of Fe3+ on the catalyst fits one-order model, and the deactivation of the catalyst occurs through homogeneous metal adsorption.In addition, the structure and properties of the fresh and deactivated catalysts from the "acceleration deactivation" experiments were characterized by SEM, XRF and XPS techniques, respectively. It was found that Fe3+ adsorption on the catalyst was assigned to be the main reason of catalyst deactivation. It caused the decrease of catalyst activity by replacing H+ of sulfo groups.