Characterization of Solid Super Acid Catalyst Modified by La Oxide and its Catalysis on Synthesis of Ethgl Acetate

Sulfated zirconia-titania oxide solid super acid catalysts modified by lanthanum oxide were prepared and aged at low temperature (0℃), and were used for the synthesis of ethyl acetate. The catalytic activity was measured by the ester yield obtained from the reaction of acetic acid with ethyl alcohol. The acid strength of the catalysts prepared was tested by Hammett indicators, the sulphur content in the catalyst was analyzed by BaSO4 gravimetric method and the catalyst structure was determined by IR. The results show that: (1) the catalyst molecular structure is bridge biden-tate, L and B acid sites are in existence on the catalyst surface; (2) the optimum reaction conditions are as follows: the molar ratio of C2H5OH to CH3COOH is 2 : 1, reaction time is 5.5 h, the catalyst amount used is 3%(wt) and adding time of acetic acid is 3.5 h; (3) the ester yield can keep more than 77% after the catalyst was reused for 5 times; (4) the sulphur lost of the La modified catalyst during the esterification reaction is less than that of the catalyst without modified by La. For the esterification, the reaction-distillation coincident technique was employed in this study.