Titanyl sulfate decomposes at high temperatures to form a very active catalyst for easy cumene reaction. Interaction between the formed anatase and the retained sulfate ions accounts for the strong acidity. 650 degrees C is the optimum decomposition temperature for obtaining strong acidity but the formation of anatase is still incomplete at this temperature. Titanyl sulfate was dispersed on silica up to its capacity of 1.3 g/g (0.27 g/100 m(2)). In this supported state, the decomposition of titanyl sulfate and the formation of anatase are enhanced. Upon calcination at 650 degrees C the dispersed titanyl sulfate decomposes completely to anatase. The catalytic activity for cumene cracking is higher for the supported material because a larger amount of both anatase and retained sulfate ions lead to a larger number of strongly acidic sites. The optimum titanyl sulfate loading is consistent with its dispersion threshold.