WO3/ZrO2 catalysts were prepared by coprecipitation with 5, 10, 15, 19, and 25 wt.% WO3. These catalysts were characterized by XRD, BET, FTIR photoacoustic spectroscopy (pyridine adsorption), and NH3-TPD, and tested for the acetylation of anisole with acetic anhydride. The catalytic yields of 2- and 4-methoxyacetophenone are found to be proportional to the ratio of Bronsted to Lewis acid site band intensities with WO3 loading up to 19 wt.%. (C) 2004 Elsevier B.V. All rights reserved.