Characterization and Catalytic Activity of Titanium－containing Aluminum Phosphate Prepared by Sol－gel and Nonuniform Precipitation for O－Alkylation of Catechol with Ethanol

Three titanium-containing aluminum phosphate catalysts with a general formula A10.77Ti0.23PO4 were prepared by the sol-gel method at room temperature(APTS), and a nonuniform precipitation procedure at roomtemperature (APTR) and under reflux(APTF), respectively. The structural features and the surface properties of the three catalysts were determined by means of the physical adsorption of nitrogen at liquid N2 temperature, XRD, UV-Vis, NH3-TPD and IR of adsorbed pyridine. The vapor phase O-alkylation of catechol with ethanol over the prepared catalysts was studied. It was found that the activity and the selectivity of these catalysts are greatly dependent on the preparation method, and catalyst APTF shows the highest activity and selectivity. The characterization evidence indicates that the weak Bronsted acid sites were more effectivo tive for the reaction.