Abstract: Ultra fine zirconia was synthesized by hydrothermal synthesis method and used as building blocks for preparing Pt/SO₄^2--ZrO₂ catalyst with high specific surface area.The acidity and thermal stability of Pt/SO₄^2--ZrO₂ was further enhanced by introducing alumina as modifier. The solid superacid isomerization catalyst RISO-C with high activity, high selectivity, high stability and excellent regeneration performance was developed and applied in the first C₅/C₆ isomerizaiton plant of solid superacid in China. The results of industrial application showed that using topped oil of reformer as feed, under the reaction conditions of reactor inlet temperature of 170 ℃, gas-liquid separator pressure of 1.5 MPa, mass space velocity of 1.26 h^-1 and H₂/oil molar ratio of 1.95, RISO-C catalyst had excellent activity and stability. The isomerization rate of C₅ was higher than 70%, and the isomerization rate of C₆ was higher than 85%,the research octane number of stabilized gasoline reached 85, and its application prospect was good.

Key words: solid superacid, catalyst, C₅/C₆, isomerization, zirconia, alumina