The sulfated zirconia project was carried out in order to obtain a broad understanding of the preparation, characterization, and application of the solid superacids of sulfated zirconia. The sulfated zirconia catalysts were prepared by the equilibrium adsorption method and the ammonium sulfate kneading method using the reference catalysts JRC-ZRO-2, -3, -4, and -5, supplied by the Reference Catalyst Division of the Catalysis Society of Japan. The catalysts were characterized by elemental analysis, NH3TPD, XRD, TG-DTA, CO2-TPD, Raman spectroscopy, and measurements of the surface area, pore size distribution. coverage (by the BAT method), and heat of Ar adsorption. In order to compare the catalytic activities, we used the prepared catalysts in the isomerizations of butane and n-heptane, hydroisomerization of heptane, aldol condensation, acylation, esterification, and cracking of cumene. The sulfated zirconia prepared using JRC-ZRO-2 by the equilibrium adsorption method showed the highest activity and larger surface area. On the other hand, the kneading method provided catalysts with high reproducibility. (C) 2009 Elsevier B.V. All rights reserved.